Balanced Crop Nutrition: Fertilizing for Crop and Food Quality

8/14/2019 Balanced Crop Nutrition: Fertilizing for Crop and Food Quality

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o doubt increase its use. However, the final decisionw much N and K to apply is taken by the farmer,

d on his knowledge. Market conditions, yieldctation, and climate will affect the farmer_s short-decisions, whilst his knowledge and education willhis decisions related to the sustainability and long-

fertility of his soil.come of unbalanced crop nutrition

paper presents 4 different country examples ofive K balances. In India, the slow but continuoustion in the soil_s K supply in the Indo- Gangetic plainsead to stagnating or reduced yields. In China, the

nd for K in regions with highly weathered soils andsufficient K supply, when accompanied by a positivece for N and P, causes a large negative K balance. Int, on the highly productive irrigated land there is ae negative K balance, especially on soils of lowty. In Bulgaria, a recent assessment of farm gateegional nutrient balances shows a decline in soilty.aof mineral fertilizers in India almost tripled fromillion mt in 1980 to currently (2002) 15.1 millionN, P2O5, and K2O of which only ~10% are potashed Crop Nutrition: Fertilizing for Crop and Food Quality

s

1988 1996 2004& tubers

1988 1996 2004ables & fruits

1988 1996 2004

1988 1996 2004

oped countries Developing countries1. Production of major crop groups and meat in developed countries and developing countries, 1980-2004.ource: FAO http://faostat.fao.org/faostat/collections, last accessed December 2005).

oped

984 1988 1992 1996 2000N

nhateiumoping

1984 1988 1992 1996 20002. Nutrient consumption in developed and developing countries, 1980-2004.ource: FAO http://faostat.fao.org/faostat/collections, last accessed December 2005).


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zers. At the same time, production of cerealsased significantly from 140.5 to 233.4 million mteen 1980 and 2004 and that of fruits andables more than doubled from 56.3 to 127.7

on mt in the same period. Do current fertilizationsupport such large increases in production ande the sustainability of the system?vinder-Singh et al. (2004) studied the long-terms of organs on yield and soil fertility in al rice_wheat crop rotation practiced in the Indo-etic plains in India. After the dramatic rise in

productg the 1970s and early 1980s, yields inregion h

remained stagnant or declinedvinder-Singh et al., 2004). Yields of cereals in theb are the largest in India (3953 kg ha -1; FAI, 2005)

hey receive the most nutrients (368 kg ha -1), yetvery little K of only about 10 kg ha-1 (FAI, 2005).detailed balance calculation of input/output for Ked that over a 12-year period the negative K balanced between -932 and -1810 kg K ha -1,depending oneatment and consequent yield and K input throughand farmyard manure (FYM) (Figure 3).

addition

gh organic matter appears tognificant, yet it is not sufficient to supply andnish the K removed. The balance calculation showsor a zero net balance an additional ~90 kg K ha-1as fertilizer would have been sufficient for both(wheat and rice).

h a negative balance may lead to a decrease inangeable potassium (Kex) in soil. Figure 4 shows theterm effects of applying no K in the Control + 150N

ment. There has been a decrease of approximatelyin Kex, as compared to the application of FYM +, which showed only a slight reduction.authors comment that _Current K fertilizer

mmendations for P and K are inadequate in the longand they also rule out the possibility of decline in soilic matter as the reason for negative yield trends.ly the authors conclude that the adverse changes inte along with a decreased soil supply of available K

be the possible reasons associated with yield decline.naspatial and temporal variability of N, P, and Kces for agro-ecosystems in China was described byet al. (2005). Inputs of nutrients in fertilizers andic matter (from crop residues and human and

al excreta) were calculated and compared with theirval in harvested produce. Balances were calculatedvince level, which represent the major agro-stems of China.

ge N and P positive balances were found in almostgions, as also reported by others (Cui et al., 2005;et al., 2005). In sharp contrast, negative K balancesfound in almost all provinces (Figure 5), and theyvery serious in Shanghai, Jiangsu, Zhejiang, Beijing,

AGEN

1. Production and growth rates of major crop groups and averaged nutrient consumption in developed and developing countries (1980-2004).ource: FAO http://faostat.fao.org/faostat/collections, last accessed December 2005).

factor Developed countries Developing countries

1980 2004 Ave. annual 1980 2004 Ave. annualgrowth rate growth rate

Million mt % Million mt %


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s 783.7 990.7 1.4 766.2 1273.3 2.2& Vegetables 271.8 301.2 0.5 355.6 1067.9 4.7and tubers 184.4 182.7 0.2 337.8 532.7 1.9an 51.1 91.6 3.4 29.9 112.7 6.0

89.7 81.6 0.8 47.0 150.6 5.0

nt consumption (%) N= (0.8) N= 3.8P2O5 = (3.0) P2O5 = 4.1K2O = (2.8) K2O = 5.8


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Xinjiang, where the negative K balance exceeded 72ha-1 year-1 (Shen et al., 2005).

w fertilizer input alone appeared to be the mainn for the K deficit in Xinjiang and Beijing. However,Eastern Provinces the negative K balance was due small a K input (even though it was quite large) to

nish the large amount of K removed in the harvestedand losses by leaching. In addition, large areas of

and Southeast China suffer from aive Kce ranging from 48 to 72 kg K ha-1 year-1re 5).

estingly, these provinces are alsoiated withsurplus applications of N, whichvate theive K balance.authors related the nutrient balances to

omicocial factors. They pointed to the correlationeen GOVA (per capita gross output of value ofulture), especially in North China and to NIRH (pera net income of rural households). The lower these-economic factors are, the higher is the negative Kce. These findings demonstrate the important rolecio-economic development on nutrient balances.

ptssium fertilization in Egyptian irrigated

ulture has become very important since theletion of the High Dam in Aswan, which prevented

ontinuous deposition on farmers_ fields of the Nilech in K bearing minerals (Abdel Hadi, 2004). Inon, Nile alluvial soils with high clay content can have

h K fixing capacity. Thus, even with a high Kex levelmight not be sufficient available K for various cropsouly and El-Sayed, 1997). In addition, the newlymed soils (approximately 800,000 ha, 25% of thecultivated land) are sandy and calcareous, and poorganic matter and macro- and micronutrients (Abd El

2004).ng the average yields in 2002-2004 of rice, wheat,and vegetables, the amount of K removed waslated. Approximately 250,000 mt K2O (conservativelation, with all straw of rice and wheat returned toeld) and 489,650 mt K2O (with all straw of rice andt removed from the field) are removed annuallye 2).ing this period, potash consumption (input of K) int was only 57,000 mt K2O, (FAO, 2005). Thiss that the negative balance for potash was between00 and 433,000 mt K2O, or between 3 and 8 timesed Crop Nutrition: Fertilizing for Crop and Food Quality

l N=150 FYM+150 N

K Loss(e)

Wheat CRRice CRSeedRain

IrrigationOrganicInorganic

-932 -1810 -1060


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FYM+150 N

3. Apparent K balance during 1988-2000 in a long-term rice-wheat experiment, Punjab,AU. (Adapted from Yadvinder Singh et al., 2004).

4. Long-term effects of inorganic and organic inputs onailable K content in soil. (Adapted from Yadvinder Singhal., 2004).


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mount of potash used. This calculation is valid forof the cultivated land in Egypt.production of fruit and vegetables is considerable

herefore very significant in K2O consumption. Weate that currently these crops are responsible forximately half of the K2O removed in Egypt (Tablefuture, with increased production of fruit andables on the newly reclaimed land, with its poor K-ying capacity, there should be a need for higher K2O

umption.gariarient consumption in Bulgaria was at its peak

g the mid 1980s, but fell dramatically to about0%, and 0% for N, P2O5, and K2O of its peak useg the mid and late 1990s. During this period, fruit

uction fell by 75%, vegetables by 30%, and cereals%.

olova (2005) calculated K balances at farm gate,nal, and national levels. Only dairy farms showed ave K balance (145 kg K ha-1). Arable and mixed

AGEN

2. Mean (2002-2004) area, production, yield, and calculated removal ofum in various crops in Egypt.urce: FAO http://faostat.fao.org/faostat/collections , last accessed December

) Source:

Nutriental; accessed

mber 2005www.kali-com/duengemittel_en/TechService/utrientsRemoval/graincrops.cfm

K2O removed (mt)(1)Area Production Yield (mt ha-1)

Straw removed Straw left in field

_000 ha _000 mt mt ha-1 mt

626 6143 9.8 168,000 25,0001045 6882 6.6 140,000 41,800

443 7447 16.8 66,450 66,450ables & melons 576 14,854 25.8 115,200 115,200

489,650 248,450

K deficit (ha-1)

>-12.5-12.5 to

-35.6-35.6 to

-47.8-47.8 to

-72.2


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in 7 regions of Bulgaria, representing all types ofand regions, all showed a negative K balance due toery small amounts of K applied. The authorudes that the mean annual K deficiency varieseen 43 and 79 kg ha-1, and the national K balance isximately -200,000 mt K year-1, a similar level since

990s.long-term consequences of a negative K balanceil fertility are obvious. In 13 years (1989-2002), theency of _Low_ K status soils doubled and that ofh_ K status fell from 71% to 27% (Figure 6).anced and timely nutrient application

following examples demonstrate variousquences of correcting unbalanced nutrientgement. These are related to i) long-termzation; ii) organic agriculture; iii) the effect ofced fertilization on yields, quality, and pest andse infestation and iv) the economics of balancedzation.g-term observationsilization is a decision taken by the farmerding to economic parameters. When there is no-term economic response to applied K, the farmerto eliminate this factor from his manuring policy.3-year experiment in cotton grown on vermicultic

an increase in cumulative yield in the order of 13%

% was found for applying 120-240 kg K ha-1;ver, at 480 kg K ha-1, an increase of 42% wasved (Dobermann et al., 2005; Figure 7). These datamislead, because in 1985 there was only a very smallase in yield from the applied K compared to that ofIn addition, application of 480 kg K ha-1 was the

rate in which yields were increasing in all 3 years. Inast to the large K application, where no K wased there was a decrease in organic matter and ofable soil K that caused K fixation and resulting in a 3-downward trend in yields. This example illustrateseed to consider the longer-term effect of repeated Kzation, especially with high K rates in heavy soils

fixation capacity.anic agricultureanic agriculture is often perceived as a clear-cuton for better crop production. A mixture of beliefscientific data hinders the real questions andquences from long-term practice of organic

ulture. Can organic farming match today_s largerements for balanced and timely nutrientcation? Soil fertility status after 21 years of organiculture shows a greater decline in available K in soilwhere fertilizers have been used.1-year long-term experiment at Forschungsinstitutologischen Landbau (FiBL) in Frick, Switzerland,ares 4 farming systems differing mainly in thegement of fertilization and plant protection (Mder2002). Four basic treatments were compared: 2ic systems (biodynamic and bioorganic) that used

yard manure and slurry corresponding to a certainnt of livestock per area unit; 1 conventional systemthe same amount of farmyard manure as theic systems but with the addition of mineralzers to reach the plant-specific Swiss standard

mmendation; and another conventional system usinged Crop Nutrition: Fertilizing for Crop and Food Quality


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1986 1987

l K application (kg ha-1)7. Response of response of annual seed cotton yield to annual

applications on a vertisol (adapted from Dobermann et al.,05).

Medium High

K status1989

6. Change in K status in soils, 1998-2002. (Source: Nikolova,05).


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rtilizer during the first crop rotation, then mineralzers exclusively, as in regular non-livestock farming.esults show that yields of winter wheat, potatoes,rass clover were 20% higher with the 2 non-organic

ments by an amount corresponding to lower inputincluding fuel. However, there was a negative K

ce with the organic treatment (-36 K2O ha-1),ared to a positive balance with mineral NPK. Therenegative N balance with all 4 systems but it was

r with the organic systems (-173 kg N ha -1)ared to that (-108 kg N ha -1) with mineral NPKzers (Figure 8).

ontrast, organic dairy farms have reportedve nutrient balances, mainly due to larger inputs ofents in animal feed (born et al., 2005).ely application of nutrients from organic sources islicated. Nitrogen supply is highly dependent onralization of the organic matter, which can besed in terms of total N supply, but for practicalns is usually insufficient to meet the requirements ofp at the appropriate time (Johnston and Poulton,). Dahlin et al. (2005) discussed the use of N fromic material. They showed that the expected leachingf N from poultry manure is far greater than thatammonium nitrate (Figure 9) and that N uptakeammonium nitrate is much higher than that from

over manure. Clearly, the precise timing and splitcation of ammonium nitrate can supply N in a muchcontrollable way than can be achieved with organicials.

wever, efficiency of phosphate use from singlephosphate (SSP) or poultry litter compost was equalra and Enkiri, 2005). Even greater efficiency of

phate use is achieved with fertigation systems, whendded in very frequent applications of water andzer (Silber, 2005). In fact, both P and K efficiencyincreased by daily and even more frequentcation of water and nutrients.ummary, organic agriculture may cause soil

ent mining due to insufficient nutrient applicationmay lead to large losses, especially of nitrogen andsium, but not necessarily in dairy farms. In contrast,mineral fertilizers that can be applied at flexible

g and rates can increase the uptake of nutrients andeduce loss to the environment.ct on yields, quality, and plant healthrient application is highly unbalanced in Punjab. In05, the state consumed 1.562 Mt of nutrients, of

h 1.2; 0.32 and 0.043 Mt was N, P2O5, and K2O,ctively. The N:P2O5:K2O ratio of 28:5:1 is highlyanced, due to the very high N application (282 kg Ncompared to the very small K application (10 kg K2OIn order to evaluate the effect of potassium in a

al crop rotation performed in districts of Punjab, IPInitiated research and extension activities at the KVKwal, Directorate of Extension of Punjab Agricultureersity. The effect of K was demonstrated in farmers_in 5 districts on a typical pea-sunflower-maize crop

on, grown on sandy loam soil. This project has afic extension character and includes demonstrationfarmers_ field days, and literature in the localage (Punjabi). Both scientific and extension activitiespossible in these experiments.

AGEN


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niumey manure -yovereniumtey manure -yoveretake9. Nitrogen in harvested crops and leaching as affected byrious N sources (adapted from Dahlin et al., 2005).

18

7

ganic

al NPK-100 0

nt balance (kg/ha-1 year-1)8. Nutrient balance after 21 years comparing organic and

ineral fertilization treatments (adapted from Mder et al.,02).

N -Leaching


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enoud (1990) reviewed almost 2450 literatureences on this subject and concluded that the use of Kased the incidence of fungal diseases in 70% of. The corresponding decrease of other pests wasria 69%, insects and mites 63%, and viruses 41%.ltaneously, K increased the yield of plants infestedfungal diseases by 42%, with bacteria by 57%, withts and mites by 36%, and with viruses by 78%.afi et al. (2001) recently reviewed the role of both Khloride on the suppression of diseases and stressesnts. Potassium may exert its greatest effect onse through specific metabolic functions that alter the

atibility relationship of the host-parasiteonment (Huber and Arny, 1985). A number ofble mechanisms may be involved. These include: (i)nced host tolerance due to increased water potentialestricts infection by pathogens and, in consequence,s are better able to withstand disease; (ii)ession/inhibition of pathogens through lower tissue

hich decreases crop susceptibility), nitrificationition and to increased soil NH4NH4

+ uptake,ing in rhizosphere acidification (Magen and Imas,).

er nutrient management, which involved reducedplit N application, along with increased P and Kcation, reduced the intensity of disease by 50% andased yield by 12.5% (Table 4). These results fromte Specific Nutrient Management (SSNM) project in

hilippines demonstrate the positive effect of nutrientgement on plant health (Buresh et al., 2005).economics of balanced fertilization_Reaching Towards Optimal Productivity_ (RTOP)group of the Irrigated Rice Research ConsortiumC) has been instrumental in the development,ation, and promotion of site specific nutrientgement (SSNM) as an approach for increasing the

of Asian rice farmers through more efficient use ofnutrients. It operates through partnerships with thenal agricultural research and extension systemsRES) in Bangladesh, China, India, Indonesia,nmar, Philippines, Thailand, and Vietnam. In 2005,P activities were incorporated into the newductivity and Sustainability_ workgroup of Phase III-2008) of the IRRC (IRRI, 2005). The projectnstrates the importance of N management through

se of the Leaf Color Chart (LCC) in increasing N useency and yields, and consequently larger P and Krements. Potassium fertilization recommendationsalculated through SSNM plots on farmers_ fields,g into account also the amount of straw recycledto the field.

AGEN

4. Effect of real-time N management on sheath blight ()tensity and rice yield in the 2001 wet season at IRRI in thehilippines (Source: Buresh et al., 2005).

agement Disease intensity Grain yield% mt ha-1

time and rate 33 (6) 4.0 (0.8), real time 21 (11) 4.5 (0.2)

within parentheses are SD.


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5 50 75

5 50 75

5 50 75

24

5 50 75cted

ication (kg K2O ha-1, as MOP)eetlely11. Effect of K on infection of soybean from various insects and disease. (Source: IPI, 2005).

% infestation % mortalityGirdle beetle Collar rot


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economics of SSNM have been analyzed fort years. Table 5 shows the increased net profitd from using the SSNM approach. Farmers in

hern India increased their net profit by 47%, whilein Southern Vietnam by only 4.25%. Thislation does not take into account additional benefits,though not directly related to the farmers, ofer N losses to the environment through emissions tomosphere and leaching.RTOP workgroup is supported also by IFA, IPI,PI.cational and extension activities are performed

at the scientific level and by meetings at the fieldRecommended K levels (set by the local extensionce) match the latest findings of SSNM in the Oldin Southern India, reflecting the need to promoteto farmers. However, in the New Delta, the higher

es recommended by SSNM (Table 6) need to bessed at research, extension, and farmers levels to be

ght into practice to benefit farmers.ed Crop Nutrition: Fertilizing for Crop and Food Quality

rencesbdel Hadi, A.H. 2004. Country report on Egyptian Agriculture. In:

ceedings of the IPI workshop on Potassium and Fertigationelopment in West Asia and North Africa Region. (Eds.: M.raoui, R. Bouabid and A. At Houssa). Horgen, Switzerland,

58-73.h, R.J., C. Witt, M.M. Alam, S. Ramanathan, B. Chandrasekaran,Laureles and M.I. Samson. 2005. Site-specific nutrient

management for rice: principles and implementation. In:eedings of the 15th Int. Plant Nut. Coll. (IPNC) on Plantition for Food Security, Human Health and Environmentalection (Eds.: Li, C.J. et al.), Beijing, pp. 1062-1063.5. Annual net benefits for SSNM and farmers_ fertilizer practiceFP) as determined through focus-group discussions (total2 rice crops(Source: IRRI, 2005).

Annual net benefit

SSNM FFP Difference

USD ha-1 year-1

rn India 520 352 168 (+47%)l Luzon, Philippines 1218 1078 140 (+13%)rn Vietnam 834 800 34 (4.25%)

6. SSNM recommendation for K, as compared to the currentcommendation and farmers_ practice, in the dry season ine Cauvery Delta of southern India. (Source: Buresh et al.,05).

Fertilizer Keter

Old Delta New Delta

kg ha-1

nt recommendation 42 42y surveyed farmers 21 37

recommendation 42 65lusionsg-term negative K balances, mainly caused byficient K fertilization and limited use of crop residuesred for increased yields, cause deterioration of soilty that leads to stagnating and decreased

uction. Common reasons for inadequate K use arermers_ lack of knowledge, and frequently of theirors, as well as socio-economical factors. The

ant shift from staple low cost crops to high valuecultural crops is a major driver in correctinganced fertilization.


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g-term experiments with various fertilizationments reveal valuable processes that cannot be seenort-term experiments. Even though long-termiments may lack immediate economic results, theyvalue for the longer term sustainability of food

uction and thus require support and advice.anced and timely nutrient application contributestainable growth of yield and quality; influenceshealth and reduce the environmental risks. Balancedion with mineral fertilizers can assist in integrated

management and reduce damage from infestationssts and diseases and save inputs required to control

anced fertilization generates higher profits for theers, not necessarily through reduced inputs. The roleucation and extension in delivering the up-to-dateledge on nutrient management is crucial,

enging, and continuous.

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Balanced Crop Nutrition: Fertilizing for Crop and Food Quality