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THE UTILIZATION OF SUBTERRANEAN CTOYER (TRIFOLIUMSUtsTERRANEUM L.) IN SPAIN FOR PASTURE IMPROVEMENT

C. GOMEZ PTTENA '

1. THE ENVIRONMENT OF THE SOUTH WESTERN PASTORALAREA

The area in which subterranean clover is used lies between360 and 4lolatitud with elevations varying from sea level in the south to 1000 m inthe north, extending along the border of Portugal.

1. 1. The climate

Most part of the area is on Extremadura region and West Andalusiawith altitudes generally below 500 m, mean annual rainfall rangingfrom 450 to 650 mm in the plateau and from 650 to 1000 mm inhigher elevations. No effective rains for pasture growth are receivedmost years from June to october, while precipitation in winter andspring is often characterised by extended spells without effectiverainfall. The growing season extends from five to seven months asevapotranspiration potentiel suffers a rapid raising by middle of sprlngwith more than 80 mm in May which cannot be compensated by rain(Llano-Ponte et al, 1975).

Temperatures in winter are fairly cool with mean minimum temperatu-re in January ranging f rom 2 "

to 40 C. Snow is infrequent for the mainpart of the area except to the north with elevations over 900 m. Frosts,however, are common in winter and sometimes in early spring.Nevertheles winter temperatures are not low enough to completely

* c/o INIA, Badajoz/ gpain

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stop pasture growth and some prodi.rction is obtained. Summers, bycontrast, are quite hot, day temperatures exceeding 40cC are commonthroughout the region.

1. 2. The soils

The soils derived from Paleozoic shales and granites which containsmost pastures resources are ClaSSified as " Sguthern BrOwn Earths ".

Their pH is acid ranging from 4 to 6 with the soils derived from granitesreaching the more acidic values in some places (Jiménez et al, 1974!'.

These soils are highly deficient in phosphorus and phosphorus fertilizerapplications are necessary for the establishment and persistence ofsubterranean clover bassed pastures. Molibdenum shows a quite widespread picture of clear responses to its application while calcium appli-cation is only of practical interest in the more acid soils, i. e. pH lessthan 5. As subterranean clover is present in spontaneous forms innatural pastures, suitable Rhizobium colonies are l iving in old pasture

lands. Despite of this there are many situations in which inoculation isneeded or recommended at the time of seeding.

1. 3. Agricultural systems in pasture lands

Most pasture lands are in private hands, being farms - " dehesas " -

devoted to mainly animal productions with some agricultural activity inlong leys phases. Not always the owner of the land and the owner ofthe stock are the same person and in this case a contract is made forpartionning benefits.

Part of the pastoral resources surrounding villages are communalpastures which use to be intensively stocked and, at times, cropped'

Some transhumant practices still persist from north to south, i.e. fromhighland snow covered pastures to temperate pastures in the plains.

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Another significant portion of the regional stock is moved everysummer from pastures to cereal stubbles in the wheat areas. These arepurely agricul tural entreprises with no stock that use to sel l the bycropresidues to the owners of stock of the neighbouring pasture lands. Asthe costs of moving the animal are increasing and mechanisat ion andintensif icat ion of cropping is progressing transhumant pract ices withinand between regions are decreasing.

The trend at present in the pastoral farms is to set stock by fencing andintensification of pasture production and cropping for forages whereverpossible.

2. SI.'BTERRANEAN CLOVER SCENE

2. 1. Early commercial sowings

While attempts were made earl ier i t was not unt i l the 60's whensubclover started to be sown commercially in a wider scale in privatefarms. By that t ime, Austral ian cul t ivars and technology, chief ly thoseexist ing in South Austral ia, were used. Thus cult ivars Mount Barker,widely used at the beginning, and Clare there after gaining in popular i tywere extensively used in univar ietal sowings. Other cul t ivars wereintroduced in much less extent Tal larook, Geraldton and Yarloop(Mus lera , 1978, 1984) .

Soon the occurrence of dry years revealed an imbalance with the envi-ronment and those cult ivars coming from milder areas in Austral ia.However new sources of cul t ivars were avai lable in Austral ia and newfashion cul t ivars were imported. Woogenel lup, Seaton Park, Dal iak andHoward were tested with clare, the number one in popular i ty as i ts

adaptabi l i ty was much greater than Mount Barker. l t was var ied thedegree of success of those cult ivars with Dal iak wel l adapted but not

wel l accepted by farmers because i ts unimpressive looking. Woogenel lup,

more impressive looking, was better accepted but not very wel l adapted.

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Seaton Park was a real success as did Clare.

More recently by the 80's, cultivars of recent release in Western Australiahave been brought into the Spanish scene, Trikkala, Larissa, Nungarinand Esperance. These were released in Australia since 1975 to coverthree main objectives (Stern et al, 1981 ):

Replace the highly oestrogenic Yarloop in wetter areas : Trikkala andLarissa.

Replace Seaton Park and Woogenellup in "scorched" ( Kabatiella caulivo-ra) areas : Esperance and Trikkala.

To spread furtherthe subclover pastures into drier areas of the wheatbelt under less than 400 mm rain : Nungarin.

Although none of these three objectives have been identified in Spain,the dynamic of searching for newer varieties in a need for improvedadaptation, made possible this apparently contradiction.

At the same time an effort was made to produce local seed, first toward:with Mount Baker and later with the easier harvesting Clare.

TABLE l :Behaviour of cultivars brotrght in Spain

Decades

60's Mount Barker Fai lure. Part ial ly adapted to higher rainfal l .Clare SuccessTal larook Fai lureYarloop Partially adapted. Highly qqstrojeniçGeraldton Success in lower raintati.dEffiit

70's Woogenellup Partially adapted. Soft seeded

Dal iak

Seaton ParkHoward

80's TrikkalaLarissaEsperanceNungarin

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Well adapted. Small leafed. Relatively smallcommercial successSuccessUnsuccessSoft seeded. No well fittedSoft seeded. No well fittedFitted. Small growthAdapted to low rainfal l and shallow soils

3 . TECHNOLOG ICAL PROBLEMS

3. 1. The rchnology of establishment

Many of the early sowingg never reached a real establishment as subter-ranean clover pasture. Efficiencies of less than 20 o/owêre the rule ratherthan exception. Whereas a variety of reasons are responsible ; we mayidentify the rnost common cause for the initial failure of establishmentin the wron:j method and time of sowing. Seed broadcast withoutcovering in early autumn well behind the start of the season was acommon practire in many cases. Thus seeds lying on top of the roughsoils

gave an uneven germination due to washing down by rain water anddragging by ants, etc. ;

seedlings died due to radicles failed to penetrate crusted soils ;

were more susceptible to pathogenic attacks after several cycles ofwetting and drying conditions when isolated rains came {Hagon, 1974l..

Therefore plant densit ies as lowas 5 - 10 plants p., t2often resulted,and such low densities rendered subterranean clover plants verysusceptible to the aggressive competence of other plants (Rossiter, 1966),

Later when specific machinary and techniques for covering the broad-

casted seeds were used, efficiencies were greatlY enabled, particularly

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when sown in more appropriate time, close to the start of the season orimmediately after that.

For those stands properly established another problem raised right fromthe beginning. An unsuited level of regeneration caused a rapid drop ofpfant densities to below 5 - 1O o/o for the introduced subterraneanclover.

Again various causes may be identified, some of them being related toincorrect utilization :

Failure to topdress with phosphate. A number of pastures, althoughreceiving phosphate in the first year, have not received subsequentapplication in soi ls highly deficient in P. This may contribute by nomeans to clover deterioration.

Grazing mismanagement. Although subterranean clover is a very versati-le specie adapted to a wide range of grazing systems, it is in fact verysusceptible to the aggressive competition of plants which develop in zerograzing situations.

Incorrect varieties. The utilization of varieties which are not fit to theenvironment is, in general opinion, the most common cause of failure inpersistence.

3. 2. Differential behaviour of cultivars

ln the early times cultivars from the wetter areas in Australia enteredinto Spain. Thus cvs. Mount Barker, Tallarook, Yarloop and Clare wereused. While being of use in Austral ia in areas of 500 - 80C mm of rainwith 7 - 9 months growing season as in the South-West of Spain, theenvironment here was not withstanding harsher due to

hot summers

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colder winters.

TABLE 2

Air mean maximum temperatures (o)- in two experimental sites ofExtremadum durant the dry period (May ' September), versus two"typical" sites of Australia in the conesponding period (November -

March)

Extremadura Austral ia

La Orden El Gaitan Merreding W.A. Hamil ton,Vic.

May

June

July

August

BadaiozMonth (1 )October 24November "17December 13January 13February 15March 18Apr i l 21May 25

( I) Maximum temPeratures

(2) Minimum temPeratures

November 28 20

December 32 23

January 34 25

February 33 26

Source : Llano-Ponte et al, l9ZS,

Climatic averages

Austnlia, l9Z5

20

27

33

33

2 1

2934

34

TABLE 3Mean temperatures (o C) of the growing season in Spain and Australia

Merred in ,W.A. Hami l ton ,V ic .12) (1) (2) ruonth m13 24 12 Apr i t ZO I8 2 0 g M a y 65 17 7 June 44 1 6 6 J u t y 45 16 5 August 48 20 6 September b

10 25 10 October 612 28 13 November 19 i

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Comparing (tables 2,31 a " cool " place in Austral ia l ike Hamifton,Vic., versus Extremadura with similar winter temperatures, can berealized that summer temperatures are muoh higher in the later. Onthe other hand a temperate place like Merredin, W.4., with hotsummers has a milder winter that the Spanish places.

Furthermore the erratic nature of the rain between and withinseasons in Spain, soon revealed symptoms of responses "out of shape"in cultivars.

ln 1975, Gomez, Ramos and Francis conducted a simultaneous studyin Spain and Australia to assess differential behaviour in maturitygrade. ïhey found that the early group of cultivars delayed floweringfor some 30 days in average in Spain. The dealy was considerablyreduced in late group with some very late lines with high cold requi-rements flowering earlier in Spain.

TABLE 4

Maturity grade (1) of rlifolium subtenaneum varietes cultivatêd at LaOrden (Spain and Perth (lV. Australia)

La Orden Perth

NorthamNungarinDal iakGeraldtonYarloopTrikkalaHowardClareNangeelaLarissaL . D . 1 1 8 7L . D . 1 1 9 5L .D . 1190L .D . 1184 ,

GreeceSpainSpainSpainSp,ain

1 1 91211241241321331371441471 5 11 6 1165174186

8379

1041031 1 31 1 51 2 71331 5 1146162180187196

Perth, W. AustraliaPerth, W. AustraliaNorthan, W. AustraliaGeraldton, W.AustraliaWaroona, W. AustraliaPerth, W. AustraliaCanberra, Austra lia AGTClare, S. Austral iaNangeela, Vic.Larissa,Avila,C. Rodrigo,C. Rodrigo,Avila,

( l) expressed in days from germination to f irst f lower

Source z G imez e t a l , I979.

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Of special agronomic significance is the case of the early types as theyshorten their range of maturities flowering closer to each other inSpain. This ease the choice of cultivars and it allows that earliest typeswhich would have never been recommended can be tested.

For the late cultivar Mount Barker, although its delay in Spain isn'tlonger than one week, it needs around five months to flowering, i.e.early Apri l . By that t ime season is about f inishing and the risk for apremature f inal is high. Yet the soils are usually hardly crusted in latespring so preventing burrs to buried. Unburied burrs produce less seedsof smaller size and reduced viabil i ty (Coll ins et al, 1976).

Thus it is again realized that relative adaptabil i ty is inversely related tomaturity grade (Rossiter, 1959, 1966).

3. 3. The seed phase

It is known that for correct regeneration enough number of seeds mustbe present in the field ready to germinate and produce plants at theright t ime in the beginning of the season (Hagon, 19741. For these twointeracting principles must occur :

the plant must be able to produce enough quantity of seeds ;

enough quantity of seeds must arrive in good conditions to germinateat the real start of the season.

This late pr incipteenvironment act ingformed in the soi l .

strongly related to the adverse nature of thethe sense of eroding the seeds bank previously

One of the environmental aggression comes from predators, one ofthem is the seed harvesting ant (Messor barbara) very active in Spain.This aggression was evaluated in an experiment carried out in

t si n

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Extreamadura (Gomez et al, 1977). By the end of September morethan half of the seed laying on top of the soils and covered with a layerof sand, have disappeared (G6mez et al, 19771. Although these resultsare restracted and figures for wide areas still remain unassessed, thesepredators, is clear, that are very active and can cause patches of bareground in the stands.

The most important environmental aggression is by no means thewetting and drying cycles of the start stop nature of the seasoncharacteristic of this environment. Erratic rains occur during summerand very often in September before the season starts, promoting germi-nation in those permeable seeds whose impermeability coat has beenbroken by temperature cycles. lt is known that as greater the cycle andas higher the maximum temperatures as rapid the rate of "softening"

(Ouinlivan, 1961). lt is also known that a genetic component isinvolved so that some varieties are more resistant to the temperaturesoftening effect (Ouinlivan, t 970).

In the Spanish environment temperatures of 600 C in the top of thebare soil are very common during the summer together with nighttemperatures of 25o C or less. The effect of these temperatures on theseeds bank of the soil was investigated in two places of Extremadura(Gomez et al, 1975; Ramos et al, 1979). A range of six variet ies wasused including local and commercial lines. Soon after seed set samplesof each variety were collected and placed in two experimental sites withadequate replications. Along the three months time periodicalanalyseswere made to determine the residual hard seeds. Results showed adramatical effect of the temperatures on cv. Mount Barker :92 % of itsseeds being softened. For the cultivars Daliak and Geraldton the figureswere 47 % hard seeds, showing a high genetic resistance as did theSpanish line 67 CAE with 45o/ohard seeds (table 5)

Another annual legume investigated, all of them represented by localtypes, shoived a picture of very sligh response to temperature treatmentwith Medicago polymorpha L. being more susceptible than others.

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TABLE 5

Percent hard seeds that remain impermeable after 90 days duringsummer in the fiels in two localities of Extremadtrra

Variety La Orden El Gaitan Transfor- Retrans-med mean formed

mean

Rep 1 Rep 2 Rep 1 Rep 2

Victor 5.0 10.0 27.4 25.O - 15.6(12.921 (18.441 (31,56) (30.00) (23.231

67- CAE 43.5 42.3 51.3 44.9 45.5(41.27!. (40.57) (45.751 (42.07\ t42.421

Mt.Barker 30.9 16.9 0.9 0.0 7.9(33.771 (24.271 ( 5.441 ( 1.ee) (16.37)

Clare 43.0 34.7 38.4 29.3(40.98) (36.0e) (38.2e) (32.771 (37.03) 36.3

Daliak 37.3 23.2 89.5 34.9 47.3{37.64) (28.791 (71.09) (36.21) (43.43)

Geraldton 30.6 45.5 30.6 80.3 47.1(33.58) (42.421 (33.58) (63.65) (43.31)

Repit i t ions 3 36.70318 1 N.S.

Treatments 5 545.58145 3.21 *

Error 15 169.79070

L . S . D . b e t w e e n t r e a t m e n t m e a n s P 0 ! 0 5 = 1 9 , 6 3 .

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3. 4. Fitting the maturity of cultivars

As we said beforehand, there is a strong correlation between maturityor earliness of flowering and adaptability to succeed in a particularenvironment (Rositer, 1 966).

It was first stated (G6mez, 1975) after observations made on differentcollections and years that for local types the mean flowering time,while similar to that of Mount Barker and Clare, showed a range as wideas 60 days, for whole samples.

Francis et al (1976) established another approach for the subterraneumL. (S) types by making observations on a restricted cotteétlon-lro6-lberian peninsula available in w. Australia. They established the correctmaturity in that of the cultivar Daliak i.e. some three to four weeksearlier than Mount Barker.

Ecological evidences however indicated a greater complexity. Gomezand Ramos (1981) conducted a study looking through a sample ot73glines collected from 1967 to 1969 in Extremadura. Thesample contai-ned 52 % of Stypes,4So/oof brachycalvcinum Katz. et Morl. (B) typesand the rest 3 % of yanninicum Katz. et Morl. (y) types. The first lookat the sample as a ffiape with frowering timeranging from 1 1 5 to 190 days (Table 4). When splitting rhe sample intosubspecies, it was found the B types flowering at the 160 -165 days range in great majority (71 % frequency), the rest of themranging from 150 to 190 days. The S types on the other hand rangedtheir f lowering t ime from 1 15 to 16b days with 86 % of them in a widerange of 125 to 1 55 days in which individual frequencies are lower than2OYo.

f n this context cv. clare, a B type, flowered at 147 days mark slighlybehind the range of the local group and some two weeks earlier thanthe most common type. within the s group cvs. Northan and Nungarinare earlier and Tallarook is later than the range encountered in localgroup, cv. Mount Barker was in theT o/o tail (Tables 3, 4).

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4. SELECTING CULTIVARS. A NEWER APPROACH

Owing to the pressing search for new cultivars in the yet reducedSpanish market for subterranean clover an attempt was med to produceCult ivars special ly tai lored to f i t the environment. The programmeaimed at exploiting the genetic resource of a local germplasm bank ofmore than 2.000 introductions which contains in great majority locallycollected l ines.

It aimed from the beginning at producing cult ivars for those situationsuncovered by the exist inq cult ivars. In the low rainfal l areas under 500mm and in shallow soils cvs. Daliak and Geraldton were available withthe former being not very much appreciated because of its short andpoor winter growth and the latter being potentially oestrogenic. whitenew cultivars have appeared in Australia for low rainfall areas, Nungarinand Northam are some two weeks earl ier than the model.

For the medium-early range cv. Seaton Park is available and is produ-cing good results because of its good forage production, moderatelyhigh hardseededness and good burr burial and seed production.

On the contrary there is no suited cult ivar for the medium-late range asTrikkala is soft seeded, Esperance has an inherently poor forage produ-ction, Dinninup is out of the market for i ts oestrogenicity and Wooge-nellup has low hardseededness. This model needs to combine someability to produce good seed on top of the soil as it has to face situa-t ions of increasingly crusted soils in spring.

Finally the programme aims at producing a f i t ted B type for high forageproduction in the higher rainfal l areas and I or clay deep soils. Thesituation require a late type able to set seed when soils are crusted andcannot be penetrated. This ability has been developped in thebrachvcalvcinum group. cult ivar clare is the only one adequated of theexisting cultivars but its forage production can be improved.

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_ 4 2 _

5. SUMMARY

ln the Extremadura and West Andalusia site conditions are ratherVariable. Altitude ranges from sea level to 1.000 m, rainfall variesbetween 450 and 1000 mm, mean minimum temperature in Januarylrom 2 to 40 C. Soil pH is low (4 to 6). There is a high phosphorusdef iciency. Sometimes calcium application and inoculation forsubclover is needed.

!919.4., frequent failures of subclover pastures were observed due topoor establishment techniques, grazing mis-management and choice ofincorrect varieties. Among the reasons why Australian cultivars only fitinto part of the target area are : 1) Their maturity range is much smallerin Spain than in Austral ia ; 2) Most of them fai l to burry their burrs inusually hardly crusted soils (unburried burrs produce less seed) ; Seedimpermeability is mostly low resulting in a hck of persistence. There-fore only Çlare and Seaton Park are so far well accepted for commer-cial sowings. By an own selection program promising lines wereidentif ied with caracters that are not covered by Australian cultivars.

6 . B IBL IOGRAPHY

Climatic Averages Australia - 1975. Metric edition. Aust. Gov. Pub. Ser.-Camberra.

Coll ins, W.J., C.M. Francis and B.J. Ouinl ivan - 1976. The interrelationof burr burial, seed yield and dormancy in strains of subterraneanclover - Aust. J. Agric. Res.,27.

Francis, C.M., A. Ramos Monreal, and B.J. Quinl ivan lg7O.Predicting maturity requirement of subterranean clover cultivars forfarm grazing in Extremadura, Spain - 11 Plant lut. Rew.

G6mez, Pitera, C. - 1975. Some aspects of subterranean clover ecotypesfrom natural pastures in the South West of Spain. - proc. 6th Gen.Meet. Eur. Grassl. Federation, Madrid.

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G6mez, C., A. Ramos, and B.J. Ouinlivan - 1976. Varietal differencesin subterranean clover with special reference to persistency undersemiarid conditions in South West Spain. - FAO Study Gioup onMediterranean Pastures. Tunis. Manuscr. roneot.

Gomez, C, A. Ramos, and C. Francis - 1979. Diferencias en tiemposde floraciôn y contenido estrogénico en el trébot subterraneo en dosambientes mediterraneos de Espana y Australia. - Anales lNlA, Ser.Prod. Veg., 10.Gomez, C. and A. Ramos,). - 1981. Estudios sobre madures en unacoleccion de treboles subterraneos extremenos. - Rev. Pastos, 10.

Gomez, C., A. Ramos and M. Leon - 1982. Primeras variedadesespaf-oles de trebol subterraneo - XXll Reunion Cientifica de la SEEP.La Goruna,24-28 Mayo.

Hagon, M.W. - 1974. Regeneration of annual winter legumes atTamworth. - Aust. J. Exp. Agric. Anim. Husb., 14 (6).

Jimenez, J., F. Lazaro, and A. Gonzalez. - 1974. Clasificacion a nivelde Asociaciones de Grandes Grupos de los suelos de la RegionExtremefiS y sus principales caracteristicas edaficas. - lNlA /CRIDA 08.

Llano-Ponte, G.. J. Jimenez Mozo, and A.C. Robinson - 1975. Thephysical environment of Southwest Spain. - | Georgifili XXI supl.

Ministerio de Agricultura, Pesca y Alimentacion - 1984. Mejora d.epastos en secanos semiaridos de suelos acidos. - Publ. de ExtensionAgraia ISBN 84 - 341 - 0357-5.

Muslera Pardo, E. and C. Ratera Garcia - 1978. La mejora de pastos yel desarrollo de la ganaderia extensiva en el S.O. espanol. - Agencia deDesarrollo Ganadero. Bol Tec.

Muslera, E. and C. Ratera - 1984. Praderas y Forrajes. - Ed. Mundi-Prensa, Madrid.

Ouinlivan, B.J. 1961 . The effect of constant and f luctuatingtemperature on the permeabilily of

'the hardseéds of some léguine

spec-ies. - Aust. J. Agric. Res., 12.

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Quinlivan, B.J. - 1968. Seed coat impermeability in the commonannual pastures legumes. - Aust. J. Anim. Husb., 8 (351.

Ramos, A. and C. Gomez. - 1977. Aproximacion a un modelo de T,subterraneum para el S.O. espagnol. - Rev. Pastos (1) 7.

Ramos, A., C. Gomez and B. Ouinl ivan, 1979. Inf luencia de las altastemperaturas estivales en el ablandamiento de semillas de trâbol subter-raneo y de otras leguminosas anuales en el S.O. de la Espana peninsular.Anales lNlA, Ser. Prod. Veg., 10.

Rossiter, R.c. - 1966. The success of failure of strains of sub. clover ina Mediterranean environment. - Aust. J. Agric. Res., l7 (4).

Serna, J., E. Osorio, anO l. Bodes, 1982. Determinacion de Formonone-tinas Biocanina y Genisteina por cromatografia en cepa f ina. una modi-f icacion a la tecnica establecida por francis y Mil l ington .- Anales lNlA,Ser. Ganadera, 15.

Stern, W.R., J.S. Gladstones, C.M. Francis, W.J., Collins, D.L., Chatel,D.A., Nicholas, D.J., Gil lespie, D.C., Wolfe, O.R., Southwood, p.E.,Beale and 8.c., curnow, 1981. subterranean clover improvements : -an Australia programme. XIV int. Grassl. congr. Lexington, Kentucky,USA.