Continental J. Agronomy 4: 1 - 9, 2010 ISSN: 2141 - 4114 © Wilolud Journals, 2010 http://www.wiloludjournal.com

MAIZE (Zea mays L.) - OKRA (Abelmoschus esculentus (L.) Moench ) INTERCROP AS AFFECTED BY

CROPPING PATTERN IN KOGI STATE, NIGERIA

Oyewole, C.I Department of Crop Production, Faculty of Agriculture, Kogi State University, P.M.B. 1008 Anyigba, Kogi State

ABSTRACT Trials were conducted at the Kogi State University Research Farm (Longitude 70 061N, 60 431E) Anyigba, Nigeria, in the Southern Guinea Savanna ecological zone during 2005 and 2006 cropping seasons. The experiment, a Randomized Complete Block Design with three replications had a variety of maize intercropped with a variety of okra at one stand of maize alternated with one stand of okra; one stand of maize alternated with two stands of okra; one row of maize alternated one row of okra; one row of maize alternated with two rows of okra in addition to sole crops. Results of statistical analysis reveal significant (P< 0.05) influence of cropping pattern on final heights of maize and okra, total number of okra pods harvested/ha, total pod weight/ha and maize yield. The treatment did not however, influence leaf number in maize and okra, pod length and diameter in okra. In all the systems investigated Land Equivalent Ratios (LERs) were less than unity except for 1:2 alternate rows, thus cropping maize and okra at 1:2 alternate rows is recommended for farmers engaged in this practice. KEYWORDS: Intercrop, maize, okra, cropping pattern, yield components and yield.

INTRODUCTION The need for scientific approach towards farming in Nigeria is becoming increasingly important as the country struggle with population explosion with the usual attending increase in food demand, stiffer competition for land and its resources, dwindling soil fertility, among other limiting factors cumulating in food insecurity. Feeding the rapidly growing population is becoming a major development concern. Efforts made by governments as well as by development projects of industrialized nations to increase food production by introduction of new technologies relying on commercial inputs have not produced expected results (Steiner, 1982) as these efforts often ignored farmer’s peculiar environment (Oyewole, 2009). Crop production in many parts of Nigeria is dominated by subsistence farming bias towards multiple cropping with over 75 per cent of the cultivated land area based on crop mixtures (Giller and Wilson, 1991) of varying complexities. The planting patterns followed by subsistence farmers involved in these multiple cropping systems are complex and divers. These, vary from simple replacement mixtures to complex superimposed mixtures. These mixtures may be planted either in alternate rows, or intra-row. Multiple cropping has long been recognized as a valuable practice among subsistence farmers in West Africa and Nigeria in particular (Kumar, 1993; Odion, et al., 2000). Its advantages include: flexibility of labor use; reduced risk of total harvest failure; better utilization of land, water, labour and capital and greater stability of annual returns (Kumar, 1993; Okereke and Eaglesham, 1992; Pierce and Lal, 1994; Odunze et al., 1997; Smith, 1993). Until the 1980s researchers generally assumed that single crop field is the ideal towards which African farmers should be moving (Edwards, 1993), but doubts had been raised whether it would be possible to introduce even rotational system of agriculture based on pure stands so long as the hoe is the main agricultural implement (Evans, 1960). Resources of most subsistence farmers simply do not allow the use of equipment, fertilizers and pesticides need to practice the kind of farming found on research stations (Edwards, 1993). Yet, multiple cropping systems seem to be sustainable even in the absence of such inputs. Thus, almost all crop production on small farms in the tropics involved more than crop specie (Giller, 1992). Two most common practices of multiple cropping systems are crop rotation and intercropping (Giller, 1992). However, the various classifications of intercropping systems found in literature are somewhat arbitrary. Their main objective usually being to provide some sense of order for the purpose of research, but in reality, there is a broad continuum of type ranging from the simple intercropping of different crops in different rows through to mixed random planting incorporating various tree crops (Edwards, 1993). Multiple cropping involving vegetables and cereals are not uncommon. However, except in the Sudan savanna part of the country, where horticultural crops like

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. onions, garlic and peppers are grown in commercial quantities in the dry season, in most other parts of Nigeria, vegetables are regarded as secondary crops, thus they form the minor crop in a mixture of two or more crop combinations when ever they exist in the cropping system. Based on their secondary status, little literature exists on the impact of the association between commonly grown farmers’ crops (cereals and legumes) with vegetables. Research was bypassing small - holders who are engaged in such practice. Yet, it is clear that much of the potential for increasing okra production lies with such farmers, considering that these farmers make up the bulk of the farming families (at least 75 per cent of the total crop production systems). Okra (Abelmoschus esculentus (L) Moench) is an important vegetable crop which is grown and consumed throughout Nigeria (Chriso and Onuh, 2005; Katung and Kashina, 2005). Considering the importance of vegetables in the diet of man, this research can not be more justified, particularly when one observes that okra is rich in both minerals and protein (Karakoistsides and Constantimde, 1975), which are both vital to man’s growth and development, and most often lacking in most dietary in-takes in Africa. The research evaluated the effects of cropping pattern of maize and okra on growth, development, and yields of the mixture with a view to recommending the most suitable system to farmers engaged in such practices. MATERIALS AND METHODS Trials were conducted at the Kogi State University Research Farm (Longitude 70 061N, 60 431E) Anyigba, Nigeria, in the Southern Guinea Savanna ecological zone, during 2005 and 2006 cropping seasons. The location of the site lies within the warm humid climate of the North central zone of Nigeria with a clear distinctive dry and wet season dichotomy, an average annual temperature of 27 0C with high level of uniformity through out the year. Annual temperature does not usually exceed 38 0C, while annual rainfall of approximately 1260 mm is common with peaks in the month of July and September. A short dry spell in August marks the start of the second half of the rainy season. Details of the soil characteristics of the experimental site are shown on Table 1. The experimental site was ploughed and harrowed, without ridging, as seeds were sown on the flat, spaced 25 x 75 cm for both maize and okra. 2 seeds of both maize and okra were sown per stand, which were latter thinned to one plant per stand two weeks after sowing (2 WAS). Weed control was by the use of hoes and cutlasses at 2, 5 and 7 WAS. N.P.K (20:10:10) fertilizer was applied to maize stands 2 WAS at the rate of 70kg Nha-1, 35kg Pha-1 and 35kg Kha-1 using the ring method of fertilizer application. Second application of urea 70kg Nha-1 was given just before maize heading. Fertilizer was not applied directly to Okra crop, but in stand replacement treatment, incorporated okra stands may have benefited from fertilizer applied to maize stands. The experiment, a Randomized Complete Block Design (RCBD) with three replications had a variety of maize (Obatanpa yellow) intercropped with a variety of okra (V.35) at one stand of maize alternated with one stand of okra (1 M:1 O alternate stands); one stand of maize alternated with two stands of okra (1 M:2 O alternate stands); one row of maize alternated one row of okra (1 M:1 O alternate rows); one row of maize alternated with two row of okra (1 M: 2 O alternate rows) in addition to sole maize and okra. Data collected on okra include height of plant, number of leaves, number and weight of harvested okra pods ha-1, pod length and diameter, while data collected on maize crop include plant height, number of leaves and fresh cob yield. Collected data were subjected to analysis of variance (ANOVA) using Microcomputer Statistical Programme (MSTAT) MSU (Michigan State University) (1985). Treatment means found to be statistically significant were compared using the Least Significant Difference described by Gomez and Gomez (1984).

RESULTS AND DISCUSSION Effect of Cropping Pattern on Final Height of Maize and Okra Possible means for reduction in competition for growth resources which occur in multiple-cropping systems is through manipulating the arrangement of the component crops in the mixture (Olufajo, 1995). Results of statistical analysis reveal significant (P< 0.05) influence of cropping pattern on final maize and okra heights (Table 2 and 3). Though maize plants were consistently tallest at 1:1 alternate stand; 219.0 and 225.0 cm in 2005 and 2006 cropping seasons, respectively observed plant heights were not significantly different from those of 1:2 alternate stands or sole maize stands. 1:2 alternate row gave the shortest plants, which were also not significantly (P >0.05) different from 1:1 alternate rows. Maize plants intercropped with okra at alternate stands were consistently significantly taller

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. than those in alternate rows. 1:1 alternate stands gave consistently the tallest okra plants (103.0 and 115.9 cm in 2005 and 2006, respectively) probably as a result of greater plant shading from the maize component while the least plant height was in sole okra (32.3 and 30.3 cm in 2005 and 2006, respectively). Since crops are not generally grown in isolation but in closely spaced population, it is expected that at some point, as seedlings grow, they will begin to interfere and compete for growth factors (Hay and Walker, 1989). As the leaf canopy develops the leaves of individual neighboring plants will start to overlap and compete for light. The primary effect of this competition is an increase in the level of gibberellins (Hay and Walker, 1989) thus promoting leaf sheath and blade extension and accelerating developmental processes, including increase in plant height. The impact of competition for solar radiation should be expected to increase as maize components in the treatment increase, which must have been responsible for the observed outcome in the various systems. It has been emphasized that photosynthesis is probably the single most important process, which needs to be controlled during crop production (Adams et al., 1998) and any factor that will affect crop photosynthetic ability will certainly influence its growth and development. Elemo and Chobe (1995) reported that improved productivity of a mixture has been shown to be associated with varietal differences in height and maturity date of the component crops. Most of the advantages obtained from growing crops in intercrops come mainly from the ways in which the crop mixtures complement each other in their exploitation of the environment (Giller and Wilson, 1991). Often the overall benefit of growing two crops in a mixture will be a net benefit in which the increase in growth of one crop exceeds a small competitive reduction in the growth of the other and this is often seen where a low growing legume is intercrop with a tall cereal. However, the correct plant spacing is required to obtain the desired result of the impact of intercropping on plant vegetative characters. In a related trial Olasantan and Lucas (1996) reported the effect of intercropping maize with crops of different canopy heights and similar or different maturities using different spatial arrangements (1:1, 2:1, 2:2). The growth of maize in these systems was similar to that of sole cropped maize. Intercropped maize had greater effect on melon with similar maturity than on those crops with greater maturity period. When maize was intercropped with cocoyam, the height of maize in the cropping patterns (1: 1, 1: 2, and 2: 2) did not differ significantly from that of sole crops. While sole cropped cocoyam, plants had shorter canopy heights compared to the intercrops. Intercropping maize with cassava, irrespective of the pattern, showed no significant difference in maize height. Effect of Cropping Pattern on Mean Number of Leaves Crop biomass accumulation depends on light interception by leaves and on the efficiency, with which the intercepted light is used to produce dry matter (Plenet et al., 2000). Analysis of data indicated that cropping pattern did not significantly (P>0.05) impact on leaf number in maize and okra (Table 4 and 5). The implication of this outcome is that cropping pattern investigated may not interfere with the potential of the components in the mixture to intercept solar energy; as most of the solar radiation incident on the crop canopy is intercepted by its leaves, except if the treatment could have influenced leaf size, or leaf architecture, among other factors that determine leaf ability to intercept solar radiation. That the rate of leaf unfolding from the terminal bud is controlled primarily by air temperature (Hay and Walker, 1989) may have accounted for the observed non-significant influence of the treatment on leaf number. Effect of Cropping Pattern on Yield and Yield Related Parameters in Okra and Maize Yield is determined primarily by crop biomass, which in turn is determined by the quantity of radiation intercepted by the crop canopy (Hay and Walker, 1989). Any influence on the plant canopy either as a result of plant shading, which may result from intercropping, or other means will affect yield. Data of 6 harvests revealed that the total number of okra pods harvested ha-1 (Table 6), total pod weight ha-1 (Table 7), but not pod length (Table 8) nor, pod diameter (Table 9) were significantly (P<0.05) influenced by the cropping pattern investigated. The highest number of okra pods harvested ha-1 (approximately 129,333 and 92,857 in 2005 and 2006, respectively) and the total pod yield ha-1 (4356.83 and 4198.35 kg, respectively in 2005 and 2006 cropping seasons) were obtained in sole plot, which was significantly reduced when intercropped with maize. The lowest total okra yield ha-1 was observed in 1:1 alternate stands.

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. Analysis of data revealed that fresh cob yield in maize and grain yield (Table 10) were significantly (P<0.05) influenced by the cropping pattern investigated, while shelling percentage did not respond significantly to cropping pattern investigated (P>0.05). The highest fresh cob yield (122266.59 kg ha-1) and grain yield (5660.86 kg ha-1) were observed in sole plot, which was significantly reduced when intercropped with okra. Reduction in fresh maize yield and grain yield as a result of intercropping was basically due to reduction in maize population in the intercrops rather than any other factor. LER values were less than unity (LER<1) in all the treatments, except in 1:2 alternate rows (Table 11). There was a drastic reduction in okra yields as a result of intercropping with maize compared to the sole crop. This reduction could not be compensated for by the combined intercrop yields in most of the treatments investigated. Therefore, for all the treatments, except 1:2 alternate rows, the combinations were not advantageous, thus not recommended. LER value was greater than unity (LER>1) at 1:2 alternate rows, thus the system was advantageous (Table 11). The greater than unity (LER>1) LER value obtained in this treatment is an indication of higher biological efficiency of the mixture, due to better utilization of environmental factors (Willey, 1979) compared to other treatments. CONCLUSION Trials were conducted at the Kogi State University Research Farm (Longitude 70 061N, 60 431E) Anyigba, Nigeria, in the Southern Guinea Savanna ecological zone during 2005 and 2006 cropping seasons. The experiment, a Randomized Complete Block Design with three replications had a variety of maize intercropped with a variety of okra at one stand of maize alternated with one stand of okra; one stand of maize alternated with two stands of okra; one row of maize alternated one row of okra; one row of maize alternated with two rows of okra in addition to sole crops. Results of statistical analysis reveal significant (P< 0.05) influence of cropping pattern on final heights of maize and okra, total number of okra pods harvested ha-1, total pod weight ha-1 and maize yield. It was observed that intercropping involving maize: okra should avoid treatments that impose greater shading on the okra component as observed in alternate stand arrangements. Where maize – okra system is practiced, the option should be on alternate rows rather than alternate stands, preferably 1:2 alternate rows, which gave marginal advantage (1 per cent) this study. REFERENCES Adams, C. R.; K. M. Bam ford and M. P. Early (1998). The Principle of Horticulture (2nd edn.), Butter worth Heinemann Publisher, Great Britain, 213 pp Christo, E.I. and M.O. Onuh (2005). Influence of plant spacing on the growth and yield of okra (Abelmoschus esculentus (L) Moench). Proceeding of the 39th Conference of the Agricultural Society of Nigeria, Benin 2005 pp51 -53 Edwards, R. (1993). Traditional systems and farming systems research In: Dry Land Farming in Africa (Rowland, J. ed). Macmillan Education Ltd., London, and Basing stoke, 336 pp Elemo, K. A. and S. M. Chobe (1995). Maize / sorghum mixture as affected by crop proportion, stand arrangement and maize variety. Samaru Journal of Agricultural Research 12:67-76 Evans, A. C. (1960). Studies of inter cropping I. Maize or sorghum with groundnuts. East African Agricultural and Forestry Journal 26:1-10 Giller K. E. (1992). Measuring inputs from nitrogen fixation in multiple cropping systems. In: Biological Nitrogen Fixation and Sustainability of Tropical Agriculture (Mulongoy K. M.; Gueye, M. and spencer, D. S. C. eds). Proceedings of the Fourth International Conference of the African Association for Biological Nitrogen Fixation (AABNF), held at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, 24-28 Sept. 1990. John Wiley and Son, United Kingdom, p 297-308 Giller, K. E. and K. J. Wilson (1991). Nitrogen fixation in tropical cropping systems. CAB International. Oxon, U.K, 313pp

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. Gomez, K. A and A. Gomez (1984). A Statistical Procedures for Agricultural Research. John Wiley and Sons, New York, 680pp Hay, R. K. M. and J. A. Walker (1989). An Introduction to the Physiology of Crop Yield. Long man Group UK. Ltd., 292 pp. Karakoistsides, P.A and K. Constantimide (1975). In: Katung, M.D. and B. D. Kashina (2005). Time of partial defoliation and GA3 effects on growth indices and yield of okra (Abelmoschus esculentus (L) Moench) Proceeding of the 39th Conference of the Agricultural Society of Nigeria, Benin 2005 pp210-213 Katung, M.D. and B. D. Kashina (2005). Time of partial defoliation and GA3 effects on growth indices and yield of okra (Abelmoschus esculentus (L) Moench) Proceeding of the 39th Conference of the Agricultural Society of Nigeria, Benin 2005 pp210-213 Kumar, V. (1993). Crop production in West African dry lands. In: Dry Land Farming in Africa (Rowland, J. R. J. ed). Macmillan Education Ltd, London and Basing stoke, 336pp Odion, E. C.; Y. Yusuf and D. A. Labe (2000). Performance of millet and cowpea in mixed stands in the Sudan savanna of Nigeria. Samaru Journal of Agriculture Research 16:53-62 Odunze, A. C.; I. Okal and J. A. Y. Shebayan (1997). On farm testing for soil moisture conservation in cereal- legume intercrop. In: Management of Marginal Lands in Nigeria (Singh, B. R. ed); Proceeding of the 23rd Annual Conference of Soil Science Society of Nigeria, UDUS, 2 - 5TH March, 1997, pp 227-230. Okereke, G. U. and A. R. J. Eaglesham (1992). Selection of soyabean cultivar for mixed cropping system in Nigeria using 15 N dilution technique. In: Biological Nitrogen Fixation and Sustainability of Tropical Agriculture (Mulongoy K. M.; Gueye, M. and spencer, D. S. C. eds). Proceedings of the Fourth International Conference of the African Association for Biological Nitrogen Fixation (AABNF), held at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, 24-28 Sept. 1990. John Wiley and Son, United Kingdom pp 15-27 Olasantan, F. O. and E. O. Lucas (1996). Inter cropping maize with crops of different canopy heights and similar or different maturities using different spatial arrangements. Journal of Agricultural Science and Technology 2 (1): 13 22 Olufajo, O. O. (1995). Sorghum / Soya bean intercropping as affected by cultivars and plant arrangement in sub humid tropical environment. Samaru Journal of Agricultural Research 12: 3-11 Oyewole, C.I. (2009) Understanding indigenous cropping technology in Kogi State, Nigerian Journal of Indigenous Knowledge and Development. Vol. 1:118-191 Plenet, D.; A. Mollier and S. Pellerin (2000). Growth analysis of maize field crop under phosphorus deficiency. II. Radiation use efficiency, biomass accumulation and yield components. Plant Soil 224: 259-272 Michigan State University (1985). Microcomputer statistical programme Pierce, F. J. and R. Lal (1994). Monitoring impact of soil erosion on crop productivity. Soil Erosion Research Methods (Lal, R. ed). Soil Water and Conservation Society. USA, p235 -263 Smith, P. (1993). Soil and water conservation. In: Dry Land Farming in Africa (Rowland, J. R. J. ed). Macmillan Education Ltd, London and Basing stoke pp 142-171 Steiner, K. G. (1982) Intercropping in the Tropical Small -holder Agriculture with Special Reference to West Africa. German Agency for Technical Cooperation (GTZ) Postfash 5180, D-Eschborn / TS. 1. 303 pp

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. Willey, R. W. (1979). Intercropping - its importance and research needs part 1. Competition and yield advantages. Field Crop Abstract 32 (1): 1-10

Table 1: Pre-planting soil (0 – 30 cm) test value for the experimental site in 2005 and 2006 cropping seasons Soil Characteristics 2005 2006 PH (H20) 5.30 5.40 PH (CaCl) 5.00 5.10 % Organic carbon 2.50 2.52 % Total N 0.15 0.17 Available P (ug g-1) 14.9 15.4 Ca meg 100g 1.50 1.50 Mg (meg / 100g) 0.99 1.00` K (meg / 100g) 0.54 0.56 Exch. Al3+(meg / 100g) 0.02 0.03 Extr. Zn (ug g-1) 9.40 9.40 % Sand 9.40 9.40 % Silt 69.7 70.0 % Clay 23.3 24.0 Textural class 7.00 6.00

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010.

Table 3: Effect of cropping pattern on okra height in 2005 and 2006 cropping seasons Treatment Final okra height (cm)

2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 103.0a 115.9a 109.5a 1:2 alternate stand 96.0a 98.2a 97.1a 1:1 alternate row 51.0 b 46.0b 48.5b 1:2 alternate row 41.7bc 37.3bc 39.5bc Sole Okra 32.3c 30.3c 31.3c SE± 3.56 6.56 5.37 Treatment means within the same column followed by unlike letter are statistically significant at 5%

Table 4: Effect of cropping pattern on number of leaves in maize in 2005 and 2006 cropping seasons

Treatment Mean leaf number in maize 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 13 13 13 1:2 alternate stand 12 13 13 1:1 alternate row 12 12 12 1:2 alternate row 12 12 12 Sole maize 12 13 13 SE± 0.6 ns 0.5 ns 0.9 ns

ns. not significant at 5% probability Table 5: Effect of cropping pattern on number of leaves in okra in 2005 and 2006 cropping seasons

Treatment Mean leaf number in okra 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 10 12 11 1:2 alternate stand 10 10 10 1:1 alternate row 11 10 11 1:2 alternate row 12 12 12 Sole Okra 11 12 12 SE± 1.2 ns 0.39 ns 0.8 ns

ns. not significant at 5% probability

Table 2: Effect of cropping pattern on maize height in 2005 and 2006 cropping seasons

Treatment Final maize height (cm)

2005 2006 Mean Cropping Pattern (Maize: Okra) 1:1 alternate stand 219.0a 225.0a 222.0a 1:2 alternate stand 216.0a 223.0a 219.5a 1:1 alternate row 179.9b 181.1b 180.5b 1:2 alternate row 167.1b 177.7b 172.4b Sole maize 218.0a 224.0a 221.0a SE± 8.56 3.66 5.98 Treatment means within the same column followed by unlike letter are statistically significant at 5%

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. Table 6: Effect of cropping pattern on number of pods of okra in 2005 and 2006 cropping seasons

Treatment Number of pods harvested ha-1 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 45083.32c 50718.74c 47901.03c 1:2 alternate stand 37999.98d 47749.98d 40374.98d 1:1 alternate row 49195.75b 51889.23b 50542.49b 1:2 alternate row 24201.01e 26301.33e 25251.17e Sole Okra 129333.31a 92857.10a 111095.21a SE± 122.568 126.984 119.886

Treatment means within the same column followed by unlike letter are statistically significant at 5%

Table 7: Effect of cropping pattern on pod yield of okra in 2005 and 2006 cropping seasons

Treatment (kg ha-1) 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 101.49d 133.66d 117.75d 1:2 alternate stand 132.13d 167.69d 149.91d 1:1 alternate row 2472.18b 2562.36b 2517.27b 1:2 alternate row 1286.52c 1333.23c 1309.88c Sole Okra 4356.83a 4198.35a 4277.59a SE± 44.668 68.992 55.664

Treatment means within the same column followed by unlike letter are statistically significant at 5% Table 8: Effect of cropping pattern on pod length in 2005 and 2006 cropping seasons

Treatment Mean pod length (cm) 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 3.84 3.42 3.63 1:2 alternate stand 3.41 3.76 3.59 1:1 alternate row 3.36 4.55 3.96 1:2 alternate row 3.39 4.75 4.07 Sole Okra 3.52 4.16 3.84 SE± 0.881 ns 0.556 ns 0.661 ns

ns. not significant at 5% probability Table 9 Effect of cropping pattern on mean pod diameter in 2005 and 2006 cropping seasons

Treatment Mean pod diameter (cm) 2005 2006 Mean

Cropping pattern (Maize: Okra) 1:1 alternate stand 4.10 3.92 4.01 1:2 alternate stand 4.65 4.04 4.35 1:1 alternate row 5.12 4.53 4.83 1:2 alternate row 4.36 3.90 3.41 Sole Okra 4.00 5.06 4.53 SE± 0.556 ns 0.886 ns 0.772 ns

ns. not significant at 5% probability

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Oyewole, C.I: Continental J. Agronomy 4: 1 - 9, 2010. Table 10: Effect of cropping pattern on mean yield of maize in two cropping seasons

Treatment Fresh cob yield (kg ha-1) Shelling percentage

Grain yield (kg ha-1)

Cropping pattern (Maize: Okra) 1:1 alternate stand 10088.75c 66.33 3608.31c 1:2 alternate stand 9370.03b 64.11 4722.67b 1:1 alternate row 5333.40d 65.11 2400.03d 1:2 alternate row 3674.14e 67.32 1579.87e Sole maize 12266.59a 62.23 5660.86a SE± 23.568 4.691 ns 115.363

Treatment means within the same column followed by unlike letter are statistically significant at 5% Table 11: Effect of Cropping Pattern on mean Yield and Land Equivalent Ratio (LER) in two cropping seasons

Treatment (kg ha-1) LER

Okra Maize Cropping pattern (Maize: Okra) 1:1 alternate stand 117.75d 3608.31c 0.67 1:2 alternate stand 149.91d 4722.67b 0.87 1:1 alternate row 1309.88c 1579.87e 0.59

1:2 alternate row 2517.27b 2400.03d 1.01 Sole crop 4277.59a 5660.86a SE± 55.664 115.363

Treatment means within the same column followed by unlike letter are statistically significant at 5%

Received for Publication: 27/02/10 Accepted for Publication: 02/04/10

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Continental J. Agronomy 4: 10 - 14, 2010 ISSN: 2141 - 4114 © Wilolud Journals, 2010 http://www.wiloludjournal.com RESPONSE OF THREE MILLET VARIETIES TO NITROGEN FERTILIZER IN THE SEMI-ARID REGION OF

NORTH-EAST NIGERIA

A.M Hassan1 and A.T.S. Bibinu2

1 Crop Production Programme, Abubakar Tafawa Balewa University, Bauchi-Nigeria, 2 Lake Chad Research Institute, P.M.B. 1293, Maiduguri-Nigeria

ABSTRACT Low soil fertility, especially N and P, are major constraints to increased food crop production and productivity in the sub-Saharan African (SSA). Field studies was undertaken to evaluate the response of millet cultivars (Pennisetum Spp) to different levels of nitrogen. The treatments consisted of factorial combinations of three cultivars (SOSAT-C88, LC-1C9702 and Ex-Borno) and four rates of nitrogen (0, 30, 60, 90 kg Nha-1). Nitrogen levels as well as their interactions affected millet cultivars growth and yield. The cultivar LC-1C9702 out-performed SOSAT-C88 and Ex-Borno with respect to grain yield and harvested panicle per hectare at higher N level than the others. Ex-Borno could be sustained at the rate of 30 kg N/ha. Interaction between cultivars and fertilizer on stand count, plant height, panicle length, grain yield and harvested panicle were significant (P< 0.05). KEYWORDS: Soil fertility, N fertilizer, millet yield, semi-arid.

INTRODUCTION: Extensive research in West Africa has established that nitrogen (N) and phosphorus (P) are major limiting factors for sorghum and pearl millet production and this has lead to development of guidelines for improved production of these crops. N is the key nutrient for crop production. This element is the most mobile and also the most easily exhausted nutrients in the soil. Smallholder farmers rely on natural fallow periods and use of leguminous crops to restore soil N status (Nye and Greenland, 1960; Kwesiga and Coe, 1994; Hartemink et al.1996). However, due to high population density and land pressure in sub humid tropics, long fallow periods are no longer sustainable. To sustain high crop yields in intensive and continuous crop production system, N fertilizer input is required. In this light, nitrogen supply from the soil needs to be assessed accurately in order to decide on the quantity of N fertilizer required to achieve the economic optimum yield and to avoid environmental contamination through excessive use (Goulding, 2000). Millet is a common crop grown in the savanna ecologies. However, maize and sorghum are more dominant in the subhumid Guinea savanna than millet. Accordingly, Egharevba (1978) estimated that about five million hectares is sown to millet in Nigeria with an average yield of 350 kg ha-1 in the Sahel. Millet crop was reported to perform better on marginal lands than other cereals (Tabo, 1995). The cultivars of millet released by the Lake Chad Research Institute, Maiduguri requires extensive information on its adaptability and agronomic practices among others. We decided to choose the three most promising cultivars of SOSAT-C88, LC-1C9702 and Ex-Borno. Though, Ex-Borno is a popular local check known for its compact head. This study was therefore, initiated to determine the effect of N fertilizer on the growth and yield of different millet cultivars. MATERIALS AND METHODS The study was carried out in 2006 rainy season at the Lake Chad Research Institute Research and Demonstration Farm, Maiduguri in Borno State, Nigeria. Rainfall in the experimental site is mono-modal (500mm per annum) with a peak moisture regime in July and August which terminate in September/October. The soils are previously classified as Typic Ustipsamment (Nwaka and Kwari, 1993) with sandy loam in the top soils. The fields were ploughed and harrowed to a fine tilt and marked out into plots of 4.5 m x 5 m. Composite soil samples (0-20 cm) were taken for analyses of texture, pH, organic carbon, total N, available P, K, Ca, Mg, and Na (Van Reeuwijk, 1992). The experiment was laid in a randomized complete block design replicated three times. Treatments consisted of three varieties, SOSAT-C88, LC-IC9702 and Ex-Borno; four levels of N fertilizer (0, 30, 60 and 90 kg N ha-1).

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A.M Hassan and A.T.S. Bibinu: Continental J. Agronomy 4: 10 - 14, 2010. Factorial arrangement of the three varieties and four levels of N-fertilizer constituted the 12 treatment combinations. Urea was the source of N fertilizer applied. Blanket application of 30 kg each of P2O5 and K2O per hectare was done to ensure balanced plant nutrition. All the amount of P and K and half of N in accordance with the treatments were applied at sowing. The remaining half was applied by side dressing four weeks later. Seedlings were thinned to two plants/hill 7 to 10 days after emergence. Manual weeding was done at two and four weeks after sowing. Stand establishment was determined by counting the total number of plants in a plot two weeks after sowing (WAS). The number of days to 50%flowering was determined by careful observation on daily basis when half the number of plants in a plot had flowered. Plant height was determined by randomly selecting ten plants per plot and measuring the heights from the ground level to the base of the panicle with a meter rule at full physiological maturity. Panicle length was determined by randomly selecting ten plant /plot and measuring the length from the base of the panicle to the tip with a meter rule at full physiological maturity. Panicle weight and grain yields were measured by recording the weight of panicles and threshed grains from each net plot using a Salter scale. These were then extrapolated to yield per hectare using the formula (Goldsworthy, 1964) Grain yield= Grain yield/net plot (kg) X 10,000m2/Net plot area (m2). The data collected were subjected to analysis using GenStat (2003) Release 4.2 and differences between means were separated using the least significant difference (LSD 0.05). RESULTS AND DISCUSSION Data on the physico-chemical properties of soils is presented in Table 1. Sand fraction seems dominant with sandy loam texture. One striking feature of these soils is their low inherent fertility which, was expressed in low organic carbon (8 gkg-1), total N (0.49 gkg-1), available calcium (1.70) and magnesium (0.2) c mol (+) kg-1 respectively. Though, the soil is very rich in phosphorus content, this might be traced to the historical management practices of the experimental site. In the near future, the soil may be faced with salinity/sodicity problem (Na= 0.70 C mol kg-1). Deduced from the study, it is expected that only 1500kg ha-1 of nitrogen would be produced. Of this, 750 kg (50%) represents the ‘dynamic reserve’. Only about 1-4% of this is directly available for crop production (Smith, 2006) amounting to 7.5-30 kg ha-1. Van Duivenbooden et al. (1996) estimated that for a target yield of 1000 kg ha-1, Table 1: Some physico-chemical soil properties of experimental site Parameter Value Unit Sand 74 % Silt 18 % Clay 8 % pH H2O 5.5 Total Nitrogen 8 gkg-1 Organic carbon 0.49 gkg-1 Available phosphorus 34.90 mgkg-1 Exch. Potassium 0.19 C mol(+)kg-1 Exch. Sodium 0.70 C mol(+)kg-1 Exch. Calcium 1.70 C mol(+)kg-1 Exch. Magnesium 0.20 C mol(+)kg-1 Exch. Aluminium 0.10 C mol(+)kg-1 Classification Typic Ustipsamment/ sandy loam millet removes 34.6, 5.0 and 48.8 kg ha-1N, P, and K from the soil compared with 30.7, 3.7 and 26.0 kg ha-1 of N, P, and K removed by sorghum and 23.4, 3.5 and 16.6 kg ha-1 of N, P, and K by maize. This indicates that millet is more likely to deplete soil nutrients at a faster rate than maize and sorghum. Results on stand establishment, flowering and plant height presented in Table 2 indicated that, there was significant difference in stand establishment between the cultivars (p>0.05). This could be attributed to improved varieties and fertilizer applications. Cultivars EX-Borno proved adopted to the environment with highest stand count. Researchers (Kwari and Bibinu, 2002; Kumar, 1993) reported generally low stand establishment in Sudan and Sahel Savanna

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A.M Hassan and A.T.S. Bibinu: Continental J. Agronomy 4: 10 - 14, 2010. Zones of Nigeria. Interaction effect of cultivar X fertilizer on stand establishment was significantly (p<0.01). The combination of 60kgN/ha on EX-Borno depicts highest stand establishment in the experiment followed by LC-1C9702 and 0kgN/ha. Table 2: Effect of nitrogen fertilizer on the growth and yield of millet varieties at Maiduguri Variable N SC HFL(DAS) PHT(cm) PL(cm) GYD/ha(kg) HP/ha(kg) Overall 36 45 64.4 196.5 27.6 1689 2870 Cultivars * Ns *** * *** * 1(SOSAT-C88) 42 65.6 201.3 28.0 1713 2808 2(LC-IC9702) 45 63.4 190.5 27.9 1780 2954 3(EX-Borno) 47 64.3 197.6 26.8 1575 2848 LSD 4.18 1.9 4.5 1.6 102.0 142.6 Fertilizer Ns Ns *** * *** *** 1(0kgN/ha) 41 64.3 185.3 26.9 1511 2411 2(30kgN/ha) 45 64.9 200.6 27.7 1422 2317 3(60kgN/ha) 48 64.3 197.8 27.4 1717 3069 4(90kgN/ha) 45 64.2 202.2 28.3 2107 3683 LSD 4.83 2.1 5.2 1.8 117.7 164.6 Cultivars x Fertilizer

** Ns *** * *** ***

1x1 36 64.7 181.7 27.0 1667 2567 1x2 44 67.0 216.7 28.7 1117 1900 1x3 40 66.0 199.3 29.3 1600 2733 1x4 47 64.7 207.7 27.0 2467 4033 2x1 49 63.3 183.0 26.3 1750 2800 2x2 43 64.0 195.3 29.0 1367 2383 2x3 45 63.0 196.3 28.0 1850 2933 2x4 42 63.3 187.3 28.3 2153 3700 3x1 37 65.0 191.3 27.3 1117 1867 3x2 48 63.7 189.7 25.3 1783 2667 3x3 58 64.0 197.7 25.0 1700 3542 3x4 47 64.7 211.7 29.7 1700 3317 LSD 8.36 3.7 9.0 3.2 203.9 285.1 N= Number of observations, SC= Stand count, HFL= Height of the flower length, PHT= Plant height, PL= Panicle length, GYD= Grain yield, HP= Harvested panicle. LSD= Least Significance Difference, *= Significant at (<0.05%), **= significant at (<0.01%), ***= Significant at (0.001%). Flowering by the cultivars was not significantly influenced by nitrogen fertilization although, LC-1C9702 cultivar started flowering at 63 DAS. The earlier flowering in plots to which higher levels of nitrogen were applied might be partially due to enhanced availability of nutrient. Kowal and Knabe (1972) reported higher solar radiation prevalence in the Sahelian Savanna Zone against Sudan Savanna. Plant height was significantly influenced by cultivars (p<0.001). Cultivar SOSAT-C88 had the highest mean (201.33 cm) (Table 2). Plant height within levels of nitrogen fertilizer were greatest in 90kgN/ha>30kgN/ha>60kgN/ha>0kgN/ha, respectively. Interaction effects of cultivar X fertilizer on plant height was significant (P<0.001). The combined effect of SOSAT-C88 and 30kgN/ha gave the highest plant height. Though, did not translate to grain yield. Panicle length was significantly affected by the cultivars (p<0.05) with cultivar SOSAT-C88 highest mean (28.00cm). The trend of individual levels of N was not statistically different. The combined effect of EX-Borno and 90kgN/ha gave the highest panicle length Table 2. Similar studies by Kwari and Bibinu (2002) confirms the assertion. This depicts that EX-Borno is more adapted to the Sahel and Sudan Savanna Zones than the Northern Guinea Savanna Zone.

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A.M Hassan and A.T.S. Bibinu: Continental J. Agronomy 4: 10 - 14, 2010. The grain yield was significantly affected by cultivars (P<0.001) Table 2. Cultivar (LC-1C9702) produced highest grain yield (1780 kgha-1) compared with the other two cultivars. The individual N levels were also significantly (P<0.001) with 90kgN/ha been highly responsive. There was lower response of 30 kg N/ha as against the control (o kgha-1). The interaction between cultivars and fertilizer was also highly significant for grain yield of millet. Cultivar SOSAT-C88 was found to be responsive to nitrogen application and produced the highest grain yield (2467 kgha-1)at higher N level than the others. The responses of cultivars: SOSAT-C88 an LC-IC9702 to N rates followed the same pattern. At 30 kgN/ha the two cultivars shown no response when compared with 0 kgN/ha, 1117 and 1367 k/ha, respectively. The high yielding cultivars can be promising in yield component when adequate nutrient is provided. In other words, high yielding cultivars are nutrient demanding. In balance nutrition is one among the factors of decline crop production and productivity in the tropics (Sanchez, 1976). Cultivar Ex-Borno is a popular local check and attained highest yield when 30 kgN/ha was applied. Application of 60 and 90 kgN/ha have statistically the same effect. The harvested panicle kg/ha has its highest value in the cultivar LC-IC9702 (2954 kg/ha) as compared to SOSAT-C88 which was significantly (P<0.05). The variation in grain yield between the cultivar could be attributed to many factors including the availability of nutrient in the soil and the gene responsible for the nutrient uptake. The interaction effect of cultivar and fertilizer on harvested panicle followed the same pattern as grain yield and were significantly (P<0.001). The result suggests that production of millet in Maiduguri could be enhanced if SOSAT-C88 is combined with 90kgN/ha. Similarly, cultivar (LC-1C9702) produced highest grain yield and harvested panicle 2153 and 3700 kg/ha with 90kgN/ha. It is statistically different with other treatments (N rates). However, with lower rate of 30 kgN/ha, Ex-Borno produced highest grain yield (1783 kg/ha). Though, there was linear trend pattern in harvested panicle up till 60 kg/ha and diminished. This might be due to nutrient toxicity among others. Also cultivar (Ex-Borno) with 60 kgN/ha is promising. The saving of 30 kgN/ha could be substantial (see Table 2) as the yield difference between 2x4 and 3x3 is 158 kg/ha only. ACKNOWNLEDGEMENT We acknowledge with thanks the financial support provided by Lake Chad Research Institute, Maiduguri. We also appreciate the assistance of Dr. K.O. Oluwasemire of Ahmadu Bello University, Zaria for using GenStat to analysis the data. REFERENCES Egharevba, P.N. (1978). A review of millet work at the Institute for Agricultural Research Samaru. Samaru Miscellaneous Paper 77 17pp. GenStat. (2003). GenStat for windows. Release 4.23DE Discovery Edition. VSN International Ltd., Hemel Hempstead, UK.

Goulding, K. (2000). Nitrate leaching from arable and horticultural land. Soil Use and Management. 16:145-151.

Hartemink, A.E., Buresh, R.J., Jama, B.A. and Janssen, B.H. (1996). Soil nitrate and water dynamics in sesbania fallows, weed fallows and maize. Soil Science. Society of American Journal 60:568-574.

Kowal, J. and Knabe, D.T. (1972). An agroclimatological atlas of the Northern States of Nigeria with explanatory notes. Ahmadu Bello University Press, Zaria, Nigeria.

Kumar, A.K. (1993). Pearl millet in West Africa. Pages 1-15. In: Sorghum and Millet Commodity and Research Environments (Byth, D.F. ed) Patancheru, A.P. 502324. India, ICRISAT. Kwari, J.D. and Bibinu, A.T.S. (2002). Response of millet cultivars to sub-optimal rates of NPK fertilizer and sheep manure in different agroecological zones of North-East Nigeria. Nigerian Journal of Soil Research. 3:33-38.

Kwesiga, F. and Coe, R. (1994). The effect of short rotation Sesbania sesban planted fallows on maize yield. For. Ecol. Manage. 64:199-208.

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A.M Hassan and A.T.S. Bibinu: Continental J. Agronomy 4: 10 - 14, 2010.

Nwaka, G.I.C., Kwari, J.D and Shukla, U.C. (1993). Integrated soil fertility/plant nutrition studies in North East Arid Zone Development Programme (NEAZDP) Area. First Technical Report for 1992 Rainfed Trials. 190pp.

Nye, P.H. and Greenland, D.J. (1960). The soil under shifting cultivation. Technical Committee no.51. Commonwealth Bureau of soils. Harpenden.

Sanchez, P.A. (1976). Properties and Managemnt of Soils in the Tropics. Wiley-Inter-science New York 64-152pp.

Smith, B. (2006). The Farming Handbook. Interpak Books, Pietermaritzburg. 431pp. Tabo, R. (1995). Performances of sorghum and millet varieties under varying combinations of animal manures and chemical fertilizer. Pp 53-54. In: ICRISAT and Collaborative Programmes. West and Central Africa Annual Report 1995. International Crops Research Institute for Semi-Arid Tropics.

Van Duivenbooden, N., de Wit, C.T. and Van Keulen, H. (1996). Nitrogen, phosphorus and potassium relations in five major cereals reviewed in respect to fertilizer recommendations using simulation modeling. Fertilizer Research 44:37-49.

Van Reeuwijk, L.P. (ed) (1992). Procedures for soil analysis. Technical Paper No.9. Third Edition. International Soil Refernce and Information Centre. Wageningen. The Netherlands. Received for Publication: 27/02/10 Accepted for Publication: 02/04/10 Corresponding author A.M Hassan

Crop Production Programme, Abubakar Tafawa Balewa University, Bauchi-Nigeria Email: hassanam2002@yahoo.com

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Continental J. Agronomy 4: 15 - 22, 2010 ISSN: 2141 - 4114 © Wilolud Journals, 2010 http://www.wiloludjournal.com

SORPTION - DESORPTION OF ZN BY A RHODIC KHANDIUSTULT IN THE NORTHERN GUINEA

SAVANNA OF NIGERIA.

Anyika, C.C1., Ninyo, A,2 and Kparmwang,T.3 1Department of Soil Science, Federal University of Technology, Minna, Nigeria, 2 and 3 Department of Soil

Science, Ahmadu Bello University, Zaria, Nigeria. ABSTRACT Zinc adsorption at concentrations between 0 to 50 mg Zn l -1 was evaluated in surface and subsurface samples of a basaltic soil in the Northern Guinea Savanna, a Rhodic khandiustult. After adsorption, 3 consecutive extractions (desorption) in sequence were performed to the samples by using 25ml of 0.1NHCl. The results showed that the Ap and Bt horizons have large capacities to adsorb zinc. While the desorption showed that the sorbed zinc was not rigidly bound. The amount of zinc released in the Ap horizon was slightly more than that released in the Bt horizon, i.e. Zn was more difficult to release in the Bt horizon than in the Ap horizon. The adsorption data did not fit the linear form of either the Langmuir or the Freundlich isotherms .The amount of Zn needed to be added to give a critical level of 1.0 mg kg-1 was estimated to be 20 mg kg-1 of Zn and above in the Ap horizon. Whereas it was estimated to be 40 mg kg -1 and above for the Bt2 horizon.The examined soil could offer an effective way to increase or decrease zinc ions concentration. KEYWORDS: Sorption, Desorption, Langmuir isotherm, Freundlich isotherm, Zinc, Rhodic Khandiustult.

INTRODUCTION The Nigerian Savanna covers an area of about 780,000 km2 and has a wide range of climatic conditions. Basaltic soils are found around the Jos plateau, Jema’a plateau of Kaduna, Biu and Mambilla plateau. Basalts approach gabbro in chemical composition (Vilenskii, 1960). Their structure is variable and for most parts, they are minutely granular. The basaltic soil colours range from dark through brown to red and thick depending on its vegetation, slope and drainage (Jamice, 1968). Basaltic soils contain high proportion of micronutrients including Zn, B, Cu, Fe, Mn, Mo, Co and Cl (Nyle, 1974). To that end, widespread Zn deficiency for different crops has been observed in different parts of the world, including from Nigeria. Correction of such Zn deficiency is often accomplished by applying Zn to the soil as fertilizer. Its availability to crops as wells as its concentration in soil solution is controlled by sorption – desorption reactions at the surfaces of soil colloidal materials (Swift and McLaren, 1991, cited in Mandel et al., 2000). Although desorption rather than adsorption likely controls the amount and rate of release of Zn into soil solution for plant uptake, only a few studies have examined the process in detail (Brummer et al., 1983; Dang et al., 1994). Desorption of Zn into soil solution is controlled by the energy with which it is adsorbed onto the soil colloidal surfaces. This in turn depends on the soil characteristics, particularly pH, cation-exchange capacity (CEC), the nature and content of the clay and different oxides of Fe, Al and Mn and CaCO3 (Harter, 1991; Hazra and Mandal, 1996). Zinc adsorption on the other hand is the process by which Zinc is made present in the soils as a mineral and also held by exchange sites and solid surface, this adsorption affects zinc availability to plants. The activity of zinc ions in the ambient soil solution bathing plant roots is controlled by simultaneous equilibra of several competing reactions such as specific bonding, surface exchange, lattice penetration, precipitation reaction and the processes leading to desorption of surface and lattice bound ions. Characterization of the solid phase supply of Zinc in relation to surface chemical reaction provides the net effect of all simultaneous equilibra controlling the activity of zinc ions in the ambient soil solution. This enables calculations of such parameters as quality, intensity and buffering capacity of the soil, which when combined into a united expression called supply parameter, can be related to the uptake of zinc by crops (Khasawreh and Copeland, 1973). The process that control the mobility of zinc in soils include: the desorption of zinc from exchange complex solution, release of zinc from organic matter crystalline minerals, as well as other precipitates of the solution phase. However, the sequential desorption of zinc by water in different electrolytes, complexing agents, and mineral acids provide a measure of different chemical pools of zinc in soils.

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010 Such pools have been referred to as water - soluble, exchange, specifically adsorbed, chelated and complexed - zinc, and zinc in secondary and primary minerals (Keefer and Estepp, 1970, Smith and Shoukry, 1968, Tiller et al., 1972, Sinha et al., 1975). Contribution of these forms to the available pool of zinc may vary depending on the physical and chemical properties of soils. Several factors have been found to influence the available zinc status of the soil (Macias, 1973). The sandy leached Inceptisols and Ultisols or Oxisols of the southern savanna and derived savanna were described as low in available zinc (Lombin, 1983), stated that the organic matter serves as the main reservoir of plant available zinc in these Nigerian savanna soils in view of the small amount of clay content. Responses to zinc application in soils and its corresponding effects on plants have been obtained in several locations within Nigerian savanna zone (latitude 7° 30′to 14° 0′ N). It was observed that plant responses has also been quantified in terms of Phytoremediation which has emerged as an alternative technique for removing toxic metals from soil and offers the benefits of being in situ, cost-effective and environmentally sustainable (McGrath and Zhao, 2003, Banuelos, 2006). A laboratory study was undertaken to determine the zinc retention and release capacity of a Rhodic kandiustult as well as to determine if zinc adsorption by basaltic soils conforms to Langmuir and Freundlich Isotherms and based on the results make recommendations on how zinc could be best economically maintained or increased in the soils. MATERIALS AND METHODS Environment of Study/Location Soil samples used in the study of adsorption and desorption of zinc came from a basaltic soil profile from Manchok on the Jema’a Platform, Kaduna State. Manchok is in the Northern Guinea Savanna zone. Two samples, one (1) from the A horizon (surface horizon; Ap; 0 - 16 cm), the other from the Bt2 horizon (65 - 106 cm). The samples had already been prepared by air drying, grinding and sieving through a 100 - mesh sieve and stored in clean cellophane bags, for laboratory analysis. Table. 1 shows the physical and environmental set - up of the study area and soil classification while Table. 2 shows the analytical properties of the soil. The low content of gravel and sand may be due to popular contention that quartz does not usually form in basalts as a result of low silica content of basaltic lava. Clay content of the basaltic savanna soil is high in both the Ap horizon (61%) and Bt2 horizon (73%). The soil is strongly acidic (pH 5.2 and 5.4), low in exchangeable bases, base saturation and the CEC of the clay fraction, but the CEC of the soil is relatively high. The organic carbon, total N contents are moderately high in the Ap, but available P is low, while available S is high in the Ap horizons but low in the Bt2 horizon. Adsorption studies were carried out by weighing 5g each of the Ap and Bt2 horizon soil samples into 40 different centrifuge tubes, 20 tubes for each of the Ap and Bt2 horizon. Dried Zinc sulphate solution (ZnSO4) i.e. 2.51g in 1000mg (Zn L-1) and water were then added to make a stock solution. The stock solution was further diluted to get the working solution (50ml Zn L-1) by pipetting 50ml of the stock solution into a 1000ml flask and making to mark with distilled water. The centrifuge tubes were labeled A1 - A20 for the A horizon and B1 - B20 for the Bt2 horizon. This preparation was duplicated for A11 - A20 respectively. The above preparation was also duplicated for B11 - B20 respectively. All the preparations were made in duplicate (Arias et al., 2005). Similarly, the standard solutions A1 - A7 were also prepared. After the addition of the solutions as indicated above, the tops of the centrifuge tubes were closed with cellophane before working them to avoid spillage when shaking the tubes in a mechanical shaker. They were now packed into the mechanical shaker and shaken vigorously for 5 hours, within a cumulative period of 24 (Wu et al., 1999). The 47 centrifuge tubes containing the samples were now taken and centrifuged for 30 minutes at a high speed of 40rpm (revolutions per minute) after which the soil samples settled at the bottom and the clear supernatant liquid obtained. Within 24 hours, complete equilibration was attained (Arias et al., 2005) and the solution (clear liquid) now filtered into glass containers and numbered properly A1 - A20 and B1 - B20 and the blank samples C1 - C7. The clear extracts were now taken to the laboratory for reading on the Atomic Absorption Spectrophotometer (AAS) to read the concentration of the element zinc in the sample. The amount of zinc adsorbed was calculated by subtracting the amount of zinc in the supernatant solution after equilibration from the amount of zinc added (Arias et al. 2005). Statistical analysis was made using the (SAS statistical program (SAS Institute, 1988). RESULTS AND DISCUSSION Zinc Adsorption The results showed that adsorption of Zn increases as the amount of Zn added increases both in the Ap and the Bt2 horizon (Fig. 1). Shuman (1976) reported similar findings. The Bt2 horizon adsorption was found to be higher than in the Ap horizon. This may be due to higher clay content of the Bt2 horizon (Table 2) which confers higher adsorptive capacity. This is however, contrary to the results obtained for the A and the Bt2 horizons of a Decateur

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010 soil (Rhodic Paleudult) by Shuman (1976), where the Bt2 horizon had lower adsorption capacity compared to the A horizon, even though it had higher clay content than the A horizon. The A however had higher Fe content than the Bt horizon. Hence, the author concluded that high clay content sometimes had to do with adsorptive capacities per unit clay. The soil studied however, had similar contents of Fe, in the Ap and Bt2 horizons, therefore, clay is likely to be the likely factor affecting the capacities of the Ap and Bt2 horizons to adsorb Zn. This observation was further highlighted by (Al-Qunaibit et al., 2004, Edrem et al., 2004). They suggested that the adsorbent colloidal materials can be clay minerals, organic matter, iron and aluminium oxides, organomineral associations or natural zeolites and therefore, behaviuor of heavy metals in soils therefore depends on the type of soil. The statistical analysis was done using paired t - test procedure to compare the Ap and the Bt2 horizons adsorption. The adsorption data showed that there was no significant difference at 0.05% between the Ap and Bt2 horizons. This means that, there is no much difference in amount of Zn adsorbed in concentration Zn L-1 at both the Ap and Bt2 horizon profiles (Fig.1). The trend in Figure. 2 showed that as the amount of Zn adsorbed increases, the equilibrium Zn concentration also increases. (Fig.2). For example, from 2 - 10 mg kg -1 Zn added, the amount of Zn adsorbed was almost equal in both the Ap and Bt2 horizons. This may be due to the low pH of the Bt2 horizon. Hawari et al. (2009) obtained similar adsorption equilibrium at low pH and therefore, concluded that maximum adsorption capacity of zinc was at pH value of 5. Further, Xue et al. (2009) found out that at pH 6, maximum adsorption of most metals occurred with zinc leading the sequence using a basic oxygen furnace slag. Similar pH was obtained in this study. However, a little variation was when 20 - 50 mg kg -1 Zn was added, the Bt2 horizon adsorbed more Zn than the Ap horizon. This may be attributable to the higher clay content which imparts a higher capacity for it to adsorb Zn as against the higher organic carbon content of the Ap horizon, it was further observed that Zn adsorbed as organic colloids is more readily released than that adsorbed on inorganic colloids. In general, it was observed that the equilibrium Zn mean concentration for the Ap horizon was higher than in the Bt2 horizon. This is an advantage, since the Ap horizon supplies most of the nutrients including Zn required by the plants. Adsorption Isotherms. The Freundlich equation (Giles et al., 1974, cited by Arias et al., 2005) is X = KFC

1/n,

where X is the adsorbed metal concentration (in mg/kg-1), C is the concentration of the metal in solution at equilibrium (in ml L-1) and KF and 1/n are constants, and the Langmuir equation(Giles et al., 1974, cited by Arias et al., 2005) is

X = KLXmC/1+KLC,

where Xm is the maximum adsorbed metal concentration and KL is a constant related to the energy of adsorption. These two equations were applied to the data and the results showed that the data obtained failed to conform to both the Langmuir and Freundlich isotherm as 2 attempts to fit the data to the 2 isotherms failed and hence were not presented. This was probably because; the parameters of the equation had no physico - chemical meanings in the soil (Sposito, 1979, Barrow, 1985). The curves were erratic because the q and c values are low; a situation also encountered by Seyer et al. (1973), with very low P adsorption values. Further, this observation was partially supported by the findings of (Arias et al., 2005) in their own investigations; they found out that the data did not fit the Langmuir equation except the variation in the Freundlich equation which fitted the zinc data. Further, they concluded that the Freundlich equation is often useful for modeling adsorption onto solids with heterogeneous surfaces (Stumn, 1981) and has frequently proved to be superior to the Langmuir equation. Zinc desorption studies The results showed that desorption increases with increase in amount of Zn added. Similar findings were obtained by Sidhu et al. (1976) using 0.1M HCl for four different soils. There was lower desorption of Zn in the Bt2 horizon (15.13 mg Kg -1) than in the Ap horizon (16.69mg Kg -1) ( Fig. 3). This may be due to the higher clay content of the Bt2 horizon than the Ap horizon, and also, the higher organic carbon content of the Ap horizon as earlier explained. In contrast (Yu- huan et al., 2007) observed that desorption was not possible and they attributed this to the ultrafine nature of the particles used for the studies.

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010 When the amount of Zn desorbed (equilibrium concentration) was related to the amount adsorbed as shown in Fig. 4, the Bt2 was found to be higher than the Ap horizon. This property is probably due to the higher retentive capacity of the Bt2 horizon. The statistical analysis carried out using paired t - test between the Ap and the Bt2 horizon for T1, T2 and T3; the desorption was found to be non - significant statistically. However, the summation of the Ap horizon for the 3 stages of desorption was higher than that of the Bt2 horizon, confirming the fact that Zn desorption in the Ap horizon was easier than in the Bt2 horizon. It is important to note that, in the 2nd stage of desorption, the Bt horizon mean was higher than the Ap horizon, indicating higher desorption in the Bt2 2nd stage, but as stated, this was not statistically significant. Similarly, using the analysis of variance procedure (ANOVA) to compare the amount of Zn desorbed at the 3 stages within the Ap and Bt2 horizons, it was observed that at the Ap horizon, the 1st desorption (9.028) was statistically higher than the 2nd desorption (4.681) and 3rd desorption (2.980). The latter two were the same statistically. Thus, desorption was in the descending order of means as follows: replicate 1 > replicate 2 > replicate 3 but in the statistical order of replicate 1 > replicate 2 = replicate 3. For the Bt horizon, replicate 1 (7.163) is statistically similar to replicate 2 but different from replicate 3. However, replicate 2 (5.279) and replicate 3 (2.667) were found to be statistically similar.

CONCLUSION Zinc adsorption and desorption studies were conducted in the Ap (0 - 16cm) horizon and Bt2 (65 - 105 cm) horizon of a Rhodic Khandiustult. The amount of zinc adsorbed increases as the amount of zinc added increases, implying that zinc adsorption is concentration dependent. The statistical analysis showed that there was no significant difference between the amount of Zn adsorbed in the Ap and that of the Bt2 horizons, but the mean amount of Zn adsorbed in the Bt2 horizon was higher than that of the Ap horizon. For desorption, there was also no significant difference between the Ap and Bt2 horizon but the mean amount of Zn desorbed was higher in the Ap than in the Bt2 horizon. The summation of the three sequential desorption were as follows: for Ap: replicate 1 (90.28) > replicate 2 (46.81) > replicate 3 (29.28) while the Bt2 were: replicate 1 (71.63) > replicate 2 (52.97) > replicate 3 (26.67). However, for the replicate 2, Bt2 was higher than the Ap summation implying higher adsorption in the Ap horizon.

In comparing desorption within the Ap and within the Bt2 horizons, replicate 1 was statistically different from replicate 2 and replicate 3 which are the same for the Ap horizon. While in the Bt2 horizon, replicate 1 was not significantly different from replicate 2 but different from replicate 3 which was similar to replicate 2 statistically. The adsorption data did not fit either the linear form of the Langmuir or the Freundlich equation. Hence, the graphs were not presented. The soil was low in available Zn (Kparmwang et al., 1998). But this study showed that the soils had a higher capacity to adsorb Zn. The study also showed that for the soil solution to have enough zinc above the critical available level of 1.0mg Zn kg -1 soil, then 20 - 50 kg -1 Zn would need to be added for both the Ap and Bt2 horizon.

REFERENCES Al – Qunaibit, M., H., Mekhemer, W.K., Zaghloul, A.,A. (2004). Journal of colloidal interface Science (2004), in press. Arias, M., Pérez, - Novo, F., Osorio, F., López, E., Soto, B. (2005). Adsorption and desorption of copper and zinc in the surface layer of acid soils. Journal of Colloid and Interface Science, 288, 21 – 29. Banuelos, G.S.( 2006). Phyto-products may be essential for sustainability and implementation of phytoremediation. EnvironmentalPollution,144(1),19-23. Doi:10.1016/jenvpol.01.015.[PubMed] Barrow, N.J. (1985). Relationship between a soils ability to adsorb phosphate and Residual effectiveness of super phosphate. Australian Journal of Soil Research, 11, 57 - 63. Brummer, G., Tiller,K.G., Herms U., and Clayton, P.M. (1983) Adsorption – desorption and/or precipitation-dissolution processes of zinc in soils. Geoderma ,31, 337 – 354.

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010 Dang, Y.P., Dalal, R.C.,Edwards, D.G., Tiller, K.G. (1994). Kinetics of zinc desorption from vertisols. Soil Science Society of America Journal, 58, 1392-1399. Erdem, E., Karapinar, N., Donat, R. (2004). Journal of Colloidal Interface Science, 280. Giles, C.H., Smith, D., Huitson, A. (1974). Journal of Colloidal Interface Science, 47, 755. Harter, R.D. (1991). Micronutrient adsorption-desorption reactions in soils. In: Mortvedt J.J., et al.,ed. Micronutrients in agriculture, 2nd ed Madison, WI: SSSA,:59-87. Hawari, A., Rawajfih, Z., Nsour, N. (2009). Equilibrium and thermodynamic analysis of zinc ions adsorption by olive oil mill on solid residues. Journal of Hazardous Materials, 168, 1284 – 1289. Hazra, G.C., Mandal B. (1996): Desorption of adsorbed zinc in soils in relation to soil properties. Journal of Indian Society of Soil Science, 65, 659-664. Jamice, R.C. (1968). The genesis of some basaltic soils in New South Wales. Journal of Soil Science, 19, 174 - 184. Keefer, R.F. and Estepp, R. (1970). The fate of zinc. 65 applied to two soils as zinc sulphate and zinc EDTA. Soil Science, 112, 325 - 329. Khasawneh, R.F. and J.P. Copeland. (1973). Cotton root growth and uptake of nutrients. Relation of phosphorus uptake quality, intensity and buffering capacity. Soil Science Society of America Proceeding, 37, 250 -254. Kparmwang, T., Esu, I.E., and Chude, V.O. ( 1998). Available and total forms of copper and zinc in basaltic soils of the Nigerian savanna. Communication. Soil Science and Plant Analysis. 29 (15 and15), 2235 - 2245. Kparmwang, T.T. (1993). Characterization and classification of basaltic soils in the Northern Guinea savanna Zone of Nigeria. Unpublished Ph.D Thesis, Ahmadu Bello University, Zaria. Nigeria. Lombin, G. (1983a). Evaluating the micronutrient fertility of Nigerian Semi - Arid Savanna Soils: Zinc Soils. Soil Science.136, 42 – 47. Macias, F.D. (1973). Copper and zinc status in pasture soils of Salaman. Spain. Soil science, 115, 276 - 283. Mandel, B., Hazra, G.C., Mandal, L.N. (2001). Soil management influences on zinc desorption for rice and maize nutrition, Soil Science Society of American Journal, 64, 1699 – 1705. McGrath, S.P, Zhao, F.J. (2003). Phytoextraction of metals and metalloids from contaminated soils. Curr.OpinBiotechnology.14(3):277-282.doi:10.1016/S0958-1669(03)00060-0. [PubMed] Nyle, C.B. (1974): The nature and properties of soil 8th edition, pp.484 - 502. Prasad, M.N.V, Freitas, H. (2000). Removal of toxic metals from solution by leaf, stem and root phytomass of Quercus ilex L. (holly oak). Environmental Pollution, 110(2), 277283.doi;10.1016/s0269-7491 (99)00306-1.[PubMed] SAS Institute (1988). SAS User’s Guide: Release 6.03.Cary. Shuman, L.M. (1976): Zinc adsorption isotherms for soil clays with and without iron oxides removed. Soil Science Society of American Journal, 40, 349 - 352. Sidhu, A.S., Randhawa, N.S. and Sinha, M.K. (1976). Adsorption and desorption of Zinc in different soils. Soil Science, 124, 211 - 217.

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010 Sinha, M.K., Dhillon, S.K., Pundeer, G.S., Randhawa, N.S. (1975). Chemical equilibria and Q/I relationship of zinc in soils of India. Geoderma, 13, 347 - 362. Smith, R.L. and Shoukry, K.S.M. (1968). Changes in Zinc distribution within three soils and zinc uptake by field beans caused by decomposing organic matter. In Isotopes and radiation in soil organic matter studies. International Atomic Energy Agency, Vienna, Austria. Sposito, G. (1979): Derivation of Langmuir equation for ion exchange reactions in soils. Soil Science Society of American Journal, 43, 197 - 198. Seyers, J.K., Browman, M.G., Smillie, G.W., Corey, R.B. (1973). Phosphate sorption by soils evaluated by Langmuir Adsorption equation. Soil Science Society of America Proceeding, 37, 358 - 363. Stumn, W., Morgan, J., J. (1981). Aquatic Chemistry, Wiley, New York, 1981. Swift R.S., McLaren R.G. (1991). Micronutrient sorption by soils and soil colloids. In: Bolt G.H.,et al., ed.Interactions at the soil colloid-soil solution interface. Dordrecht, the Netherlands: Kluwer Academic Publication: 257-292. Tiller, K.G., Honeysett, J.L. and Devenen, M.P.C. (1972). Soil zinc and its uptake by plant. II. Soil chemistry in relation to availability. Vilenskiii, D.G.(1960). Pochu,Okskoi poimy (Soils of Oka Flood plain), Moscow. Wu, J.; Laird, D.A. and Thompson, M.L. (1999). Sorption and desorption of copper on clay components. Journal of Environmental Quality, 28, 334 – 338. Xue, Y., Hou, H., Zhu, S. (2009). Competitive adsorption of copper (II), cadmium (II), lead (II) and zinc (II) onto basic oxygen furnace slag. Journal of Hazardous Materials,162, 391 – 401. Yu – huan, Y., Hao, C., Gang, P. (2007). Particle concentration effect in adsorption/desorption of Zn(II) on anatase type nano TiO2. Journal of Environmental Sciences, 19, 1442 – 1445. Table 1. Soil sampling site, environmental set up and soil classification.

Location : Gizagnoi village at Manchok (Latitude 09° 40′ N and Longitude 08° 30′ E).

Taxonomic classification : Rhodic Khandiustult (USDA). : Haplic Acrisol ((FAO/UNESCO). Soil parent material : Saprolite from Newer basalts. Geology : Basement complex.

Geomorphology : Nearly level plain with isolated basaltic cones in inselberg landscape.

Topography : Crest, 0 - 1% slope Ecological zone : Northern Guinea Savanna. Main grass species : Hyprrenia spp. Land use : Sorghum (Sorghum bicolor L.), millet (Pennisetuspp.),

cassava (Manihot spp), sweet potatoes (Ipoemia batatas) Soil Erosion hazard : None at profile site. Drainage : Well drained.

Source: Kparmwang (1993).

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010

Table 2. Summary of soil analytical properties of a Rhodic Kandiustult on the Jema’s platform, Nigeria

Ap horizon Bt2 horizon % Gravel 0 1 % Sand 16 12 % Silt 23 15 % Clay 61 73 Textural Class Clay Clay pH ( H2O) 5.20 5.40 pH (CaCl2) 3.70 5.00 Ca (cmol(+) kg -1 1.85 1.85 Mg (cmol(+) kg -1 0.79 0.72 Na (cmol(+) kg -1 0.05 0.03 K (cmol(+) kg -1 0.17 0.07 Exchangeable acidity (cmol(+) kg -1 0.50 0.10 CEC(soil)(cmol(+) kg -1 13.00 9.00 CEC(clay)(cmol(+) kg -1 12.70 11.70 %Base Saturation 22.00 27.00 %Organic Carbon 15.00 3.90 %Total N 1.30 0.60 Available P(mg kg-1) 9.50 0.50 Available S(mg kg-1 ) 11.80 2.30 Fep 0.01 0.02 Feox 0.73 0.70 Fed 6.80 6.90 Alox 0.10 2.00 Ald 0.15 2.00

Source: Kparmwang (1993) .

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Anyika, C.C et al.,: Continental J. Agronomy 4: 15 - 22, 2010

Received for Publication: 27/02/10 Accepted for Publication: 02/04/10 Corresponding author Anyika, C.C Department of Soil Science, Federal University of Technology, Minna, Nigeria, Email: Anyika3c@yahoo.com

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Continental J. Agronomy 4: 23 - 27, 2010 ISSN: 2141 - 4114 © Wilolud Journals, 2010 http://www.wiloludjournal.com

GROWTH AND YIELD OF CUCUMBER VARIETIES AS INFLUENCED BY PRUNING AT ABAKALIKI AGRICULTURAL AREA, SOUTHEASTERN NIGERIA.

Utobo, E.B., L.G. Ekwu, E.O. Ogah and G.N. Nwokwu

Department of Crop Production and Landscape Management, Ebonyi State University, Abakaliki, Nigeria.

ABSTRACT The effect of pruning on the growth and yield of four cucumber varieties was evaluated using a 4 x 2 factorial laid out in a Randomized Complete Block Design (RCBD). Market more 76, Marketer and Point-sett varieties produced significantly (p<0.05) higher total and marketable yield than Market more 70. Similar trend was observed for total and marketable fruit weight, and marketable fruit number per plant. Significant differences in some vegetative growth parameters were found between the cucumber varieties. Market more 76 and Marketer varieties had similar but significantly (p<0.01) shorter days to 50% anthesis than Market more 70 followed by Point-sett. Marketer had significantly (p<0.05) longer stem length than the other cucumber varieties. Market more 76 and Marketer varieties produced similar, but significantly (p<0.05) higher number of branches per plant than Market more 70 and Point Sett. Significant differences (p<0.05) in terms of yield and yield components were found between the two pruning treatments. The no pruning treatment produced the highest total yield and total fruit number per plant. The pruning treatment produced the highest marketable fruit yield, total and marketable fruit weight, and marketable fruit number per plant. Pruning significantly (p<0.05) affected the days to 50% anthesis and stem length. Unpruned cucumber varieties took shorter days of 26 for the 50% of the plants to flower while pruned cucumber varieties produced longer stem lengths of 18.46 than the non pruned treatment. KEYWORDS: Cucumber, pruning, vegetative growth and yield.

INTRODUCTION Cucumber (Cucumis sativus Linn.) is one of the most popular members of the cucurbitaccae (Vine crop) family. Written evidence indicates that cucumber originated in India, which spread westward and became popular throughout the Egyptian and the Greek-Roman eras (Nonnecke, 1992). The crop is cultivated in most parts of Northern Nigeria and some parts of Eastern Nigeria by peasant farmers who lack information on some important cultural practices. This has resulted in very low yield and the production of fruits with yellow belles, which are highly unmarketable (Ekwu, et al., 2007). The significance of yield may be qualified by factors such as fruit quality, fruit size, or price development of the market determined by season. Fruit exceeding a certain size are of no value, and nowadays, consumers demand good fruit shape and quality (Than, 1996). The growth of plants and other factors can be modified by pruning to suit human needs and desires (Than, 1996). Pruning is the act of cutting off plant branches or twigs so as to encourage fruiting or flowering. Shoots, foliage, flower and fruit are pruned to maintain a proper balance between the vegetative growth and fruit load so as to maximize production (Wayne, 1990). There are many purposes for cucumber vine pruning treatments. These are for mechanical harvesting, hybrid seed production, to easily control insect and disease, to use the higher plant population without significant yield reduction, and to obtain uniform fruits (Humphries and Vermillion, 1994). Gobeil and Gosselin (1990) asserted that plant density and pruning are two factors which most likely affect productivity of cucumber. However, the effects of these factors are also dependent on soil regime, vigour of the variety or strain and the cultural management being used. Palada and Chang (2003) reported that the removal of the lateral shoot had a positive effect on the total yield of cucumbers. The first four to six lateral runners that appear should be removed while the other runners above should be allowed to run (Douglas and Larry, 2001). The objective of this study was therefore to determine the effects of pruning on the vegetative growth, yield and yield components of four cucumber varieties.

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Utobo, E.B et al.,: Continental J. Agronomy 4: 23 - 27, 2010 MATERIALS AND METHODS The study was carried out at the Teaching and Research Farm of Crop Production and Landscape Management, Ebonyi State University, Abakaliki (Lat. 06004'N; Long. 18065'E) from June 2008 to September 2008, which was repeated from June 2009 to September 2009 in the second year cropping season. The mean monthly rainfall during 2008 is 153.41 and that of 2009 is 162.10. The mean minimum / maximum temperature and relative humidity in 2008 are 21.14 / 29.49 0C and 76.14% and in 2009, 21.43 / 29.71 0C and 80.14%. The soil is shallow with unconsolidated parent material (shale residuum) within 1m of the soil surface and classified as Dystric leptosol (Anikwe et al., 1999). The soil was formerly cultivated with yam, cassava and maize intercrop but had been under grass-legume fallow for 2 years before the start of the experiment. Data sets analyzed for this study were collected from an experiment originally designed as 4 x 2 factorial laid out in a Randomized Complete Block Design (RCBD). The eight treatments combination consisted of two pruning methods [no pruning (P0) and 4 - lateral stem pruning i.e. pruning out the lateral branches on main stem from node 4 down (P1)] and four cucumber varieties (Market more 70, Market more 76, Marketer and Point-sett). The experimental field measured 26 m x 20 m (520 m2) and it was divided into four equal replicates, 1 m apart. Each replicate consisted of 8 plots, giving a total of 32 test plots. Each plot measured 2 m x 2 m with 0.5 m between adjacent plots. The seeds were sown into well prepared raised beds on June 16, 2008 and June 5, 2009 for the two year trials with recommended spacing of 50 x 50 cm2 per hill. Seedlings were thinned twice, and kept one plant per hill before 3 true leaf stages. 187 kg ha-1 each of N, P and K was added to the soil using N-P-K (15-15-15) as basal fertilizer application. A further 65 kg N ha-1 was split applied at 3 and 6 weeks after sowing (WAS) as top dressing using urea (46 % N) as the nitrogen source. Staking with bamboo sticks was done 3 WAS when the tendrils began to appear while the stems were tied onto the sticks with loosen threads. Weeding was carried out at 3 and 6 WAS to control weeds and mixture of Benomyl (Benlate) and Dithane M45 was sprayed to the crop weekly starting from 3 WAS as a routine preventive measure against fungal foliar diseases. Insecticide, Instakill 35 Emulsifiable concentrate was sprayed at 1st, 3rd and 5th WAS. Pruning was done 4 WAS before flower initiation. Harvesting commenced 8 WAS, thereafter at 2 days interval. Six randomly selected plants were used for the determination of vegetative growth (days to 50% anthesis, stem length (cm), number of branches per plant and days to harvest); yield components {number of fruits per plant and fruit weight per plant (kg)} and yield was computed from fruits harvested from the net plot and converted into tons per hectare. All data collected was subjected to statistical analysis of variance (combined for the two years) to test for the significance of treatment effects using GenStat 5.0 (2003). RESULTS AND DISCUSSION Effect of Variety The cucumber varieties differed significantly in some vegetative growth parameters like days to 50% anthesis, stem length and number of branches (Table 1). Market more 76 and Marketer varieties had similar but significantly (p<0.01) shorter days to 50% anthesis (21.67 and 23.00) than Market more 70 followed by Point-sett in that order. Marketer had significantly (p<0.05) longer stem length of 222.5 cm than the other cucumber varieties. Market more 76 and Marketer varieties produced similar, but significantly (p<0.05) higher number of branches per plant (8.17 and 7.50) than Market more 70 and Point Sett. These differentials of growth rates indices according to Ibrahim et al. (2001) are normally attributed to their genetic make up. Cucumber varieties also differ significantly in yield and yield components (Table 2). Market more 76, Marketer and Point-sett varieties produced similar, but significantly (p<0.05) higher total (22.50 t ha-1 , 21.75 t ha-1 and 20.25 t ha-1) and marketable yield (16.50 t ha-1 , 16.25 t ha-1 , and 14.75 t ha-1) than Market more 70. Similar results were obtained for total and marketable fruit weight, and marketable fruit number per plant. Total and marketable yield (t/ha) and marketable number of fruits per plant which were observed to be highest in varieties Market more 76 > Marketer > Point-sett and Market more 70 least could be attributed to the fact that the first three varieties are semi-determinate (Market more 76, Marketer and Point-sett) and as such directed most of their nutrient flow to their reproductive growth (in this case fruits) unlike Market more 70 which is an indeterminate variety whose nature is such that vegetative growth does not terminate at the on set of

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Utobo, E.B et al.,: Continental J. Agronomy 4: 23 - 27, 2010 reproductive growth and has to share its nutrient flow both ways (Bodunde et al., 1993; Ibrahim, 1994). The higher average total and marketable fruit weight per plant (kg) recorded by Market more 76, Marketer and Point-sett than Market more 70 could be attributed to the fact that the former have bigger fruits (in terms of size) than the latter. Effect of Pruning Pruning significantly (p<0.05) affected the days to 50% anthesis and stem length (Table 1). Unpruned cucumber varieties took shorter days (26 days) to 50% anthesis. This is in agreement with the work of Than (1996) who reported that pruning prolonged number of days to flowering. Pruned cucumber varieties produced longer stem lengths of 18.46 than the unpruned ones. This is because pruning maintains a proper balance between the vegetative growth and fruit load so as to maximize production (Humphries and Vermillion, 1994). Significant differences (p<0.05) in terms of yield and yield components were found between the two pruning treatments (Table 2). The non pruning treatment produced the highest total yield (21.50 t ha-1) and total fruit number per plant (11.00). The pruning treatment produced the highest marketable fruit yield (15.75 t ha-1), total and marketable fruit weight (1.73 kg and 1.45 kg) and marketable fruit number per plant of 8.50. These could be attributed to the more availability of nutrients, water and light to plants under pruning for marketable fruits yield, weight, fruit number and total fruit weight, and lack of pruning for non marketable fruits yield, weight and fruit number per plant (Humphries and Vermillion, 1994; Dao, 1996 and Duong, 1999). Interaction It was observed that pruning had no specific effect on the varieties tested or there was no pruning -variety interaction. CONCLUSION Pruning had significant effect on some vegetative parameters, yield and yield components tested. Thus there is need for pruning in other to increase marketable yield. REFERENCES Anikwe, M.A.N., Okonkwo, C.I. and Aniekwe, N.L. (1999). Effect of Changing Land use on Selected Soil Properties in Abakaliki Agroecological Zone S.E. Nigeria. Environmental Education and Information, 18, 79–89. Bodunde, J.G., Erinle, I.D., Eruator, P.G. and Amans, E.B. (1993). Four heat tolerant varieties. Approved Recommendation. Institute for Agricultural Institute, Samaru Zaria, pp. 8-7. Dao, X. T. (1996). Pruning effect on yield of cucumber variety “Poung”. AVRDC Vietnam, pp. 47. Douglas, C. and Larry, S. (2001). Home garden trellised cucumber. College of Agriculture and Life Sciences, North Carolina State University. Horticultural information leaflet 8014 –B. Duong, H. X. (1999). Effect of pruning on yield and quality of cucumber. AVRDC training report, Kasetsart University Bangkok, Thailand, pp. 51. Ekwu, L.G., Utobo, E.B. and Oyesola, C.A. (2007). Vegetative and Yield Response of Cucumber (Cucumis sativus L.) to Staking and Nitrogen Fertilizer Application. Journal of Applied Sciences, 19 (4):7509 – 7519. GenStat (2003). GenStat 5.0 Release 4.23 DE, Lawes Agricultural Trust, Rothamsted Experimental Station. Gobeil, G. and Gosselin, A. (1990). Influence of Pruning and Season on Productivity of Cucumber Plants Grown in a Sequence Cropping System. Scientia Horticulturae, 41 (3): 189 – 200. Humphries, E.G. and Vermillion, D.L. (1994). Pickling cucumber vine pruning treatments and their implications for mechanical harvesting. V-37 (1) Trans-ASIA, pp. 71-75.

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Utobo, E.B et al.,: Continental J. Agronomy 4: 23 - 27, 2010 Ibrahim, R. (1994). Response of three tomato (Lycopersicon esculentum Mill) cultivars to N and P fertilizer. Unpublished M.S. Thesis, Department of Agronomy, Ahmadu Bello Univ., Zaria, pp. 34. Ibrahim, R., Amans, E.B., Ahmed A. and Abubakar, I.U. (2001). Growth and Yield of Tomato (Lycopersicum esculentum Mill) Varieties Influenced by Crop Spacing st Samaru, Northen Nigeria. Nig. J. Hort. Sc. 5:52-57. Nonnecke, I.B. (1992). Vegetable Production. New York: Van Nostrand Reinhold, pp: 657. Palada, M.C. and Chang, L.C. (2003). Suggested cultural practices for bitter gourd. AVRDC. Pub. No. 03-547, pp: 1-5. Than, T.N. (1996). Pruning effect on yield of different cucumber varieties. ARC Training, pp: 1-5. Wayne, V. (1990). Greenhouse cucumber production. University of Alaska Fairbanks Cooperative Extension Service. HGA – 00434. Table 1. Effects of cultivar and pruning on cucumber days to 50 % anthesis, stem length (cm), number of branches per plant and days to harvest.

Treatments Days to 50% Anthesis

Stem Length (cm)

Number of Branches/Plant

Days to Harvest

Cultivar (C) Market more 70 28.67b 159.4b 5.79b 53.33 Market more 76 23.00c 162.1b 8.17a 55.67 Marketer 21.67c 222.5a 7.50a 60.33 Point Sett 32.33a 164.3b 5.33b 58.00 F-LSD(0.05) 2.354** 42.10* 1.601* Ns Pruning (P) No Pruning 26b 163.5b 6.42 55.67 4-Stem Pruning 29a 184.6a 7.08 58.00 F-LSD(0.05) 1.664* 18.77* Ns Ns Interactions C x P ns ns Ns Ns

Utobo, E.B et al.,: Continental J. Agronomy 4: 23 - 27, 2010 Table 2. Effects of cultivar and pruning on cucumber fruit number per plant, fruit weight per plant (kg) and yield (t/ha)

Received for Publication: 27/02/10 Accepted for Publication: 02/04/10 Corresponding author Utobo, E.B. Department of Crop Production and Landscape Management, Ebonyi State University, Abakaliki, Nigeria. Email: emekabenjamin@yahoo.co.uk

Treatments Fruit Number/Plant Fruit Weight (kg) Yield (t/ha)

Marketable

Non Marketable

Total Marketable Non Marketable

Total Marketable Non Marketable

Total

Cultivar

Market more 70 7.67b 2.50 10.17 0.90b 0.38 1.28b 13.50b 5.75 19.25b

Market more 76 8.57a 2.17 10.74 1.10a 0.40 1.50a 16.50a 6.00 22.50a

Marketer 8.50a 3.00 11.50 1.08a 0.37 1.45a 16.25a 5.50 21.75a

Point Sett 8.33a 2.83 11.16 0.98a 0.37 1.35a 14.75a 5.50 20.25a

F-LSD(0.05) 0.63* ns ns 0.14* ns 0.16* 2.13* Ns 2.42*

Pruning

No Pruning 8.00b 3.00a 11.00a 0.98b 0.38a 1.36b 14.75b 6.75 21.50a

4-Stem Pruning 8.50a 1.39b 9.89b 1.44a 0.29b 1.73a 15.75a 4.63 20.38b

F-LSD(0.05) 0.13* 0.79* 0.92* 0.24* 0.07* 0.31* 1.50* ns 0.91*

Interactions

C x P ns ns ns ns ns ns ns ns ns