Agric.Re~,22(3/4): 141-162,2001

INTEGR..J\TED NITROGEN MANAGEMENT THROUGH GRAINLEGUMES AND GREEN MANURES IN IRRIGATED TROPICAL,

RICE BASED CROPPING SYSTEMS '- A REVI.EW,iK. Ramamoorthy, T.M. Thiyagarajan and S.V. Subbaiah*

Department of Agronomy,Tamil Nadu Agricultural University, Coimbatore· 641003, India

ABSTRACTThis review article consolidates more information with special reference to effect of legumes

and green manures integration on rice based cropping systems of the Tropics both in normal soilas well as problem soils. The factors influencing the nitrogen dynamics in soil by addition of foodlegumes and green manures besides their influ~mce on the rice production and productivity inlowland irrigated conditions are also briefly reviewed because nitrogen is the most limiting nutrientin rice production world wide and inclusion of legum..'s and green manures with their wideradaptability to different rice cultures and their abi'lity to fix nitrogen offer high scope to increaseand sustain productivity and income in rice based cropping systems.

Low sdil fertility, particularly nitrogendeficiency is an important constraint in ricegrowing countries in South and South EastAsia, with the increase in canal water facilitiesfor irrigation, rice based cropping systemsemerged as an important cropping system(Mahapatraand Sharma 1996). Deteriorationof soil physical properties and decline in thefertility status of rice soil are often associatedwith this system. Inclusion of legumes andgreen manures in the cropping system knownto improve the soil conditions for enhancedand sustained rice production (IRRI, 1988;Hiremath and Patel, 1998).

Rice (Oryza sativa L.) is the staple foodof millions of people throughout the world,more particularly in Asia. The InternationalRice Research Institute (IRRI, 1989) estimatedthat the global annual rice production·mustincrease from 460 m tonnes in 1989 to 560m tonnes by 2000 and to 760 m tonnes by2025. This increase in rice production canonly be possible if soil and water resources andnon-monetary inputs are used more efficientlyin the future.

Nitrogen is the most limiting nutrientin rice production worldwide. According to

Barker et al. (1985), an estimated 24% of theincrease in Asian rice production from 1965to 1980 was attributed to use of fertilizer,mainly N. However, higher application of in­dustrial N to rice prone to high losses of Ngases (De Datta and Buresh, 1989).

Legumes and green manures with theiradaptability to different rice based croppingpatterns and their ability to fix nitrogen mayoffer scope to increase and sustain productiv­ity and income in rice based cropping sys'tems. Food legumes provide protein for hu­man and animal nutrition. Green manure le­gumes, forage legumes and residues of foodlegumes can supply N to rice, improve soilphysical and chemical properties and decreasepests and diseases of rice (Buresh and De Datta,1991).

Worldwide, irrigated lowland rice ac­counts for about 50% of the total rice area and70% of the total rice production. Rainfed low­land rice accounts for about 30% of the totalrice area and 5% of the total production. Up­land rice is of less importance, accounting forabout 13% of the land area and 5% of theproduction~ Whereas deep water and tidal wet­land rice comprise the remaining 7% of thearea (IRRI, 1989).

• Division of Agronomy, Directorate of Rice Research, Hyderabad - 500 030, Andhra Pradesh, India.

142 AGRICULTURAL REVIEWS

In most of the low land rice fields, ni- Factors affecting nitrogen fixation bytragen accretion and contributions from le- legymes include soil mineral nitrogen inocula­gumes and green manures have attracted in- tion, water regime and soil and crop manage­creased research interest. However, less at- ment practices. Root nodulation and nitrogentention has been paid to the role of food le- fixation dramatically decrease as plant avail­gumes and leguminous green manures in N able soil N increases (Brockwell et aI., 1989;cycling, gains and losses in rice based crop- Bergersen et ai., 1989). Increased rates ofping systems, even though food (grain) legumes inoculation can minimise but not eliminate theare more commonly grown than green manures adverse ¢kct of plant available soil N on N2in tropical rice fields. fixatiofi (Herridge and Brockwell, 1988).

This articlerevtews some new research Water scarcity is in general to decreasepriorities in grain legumes and leguminous N

2fixation by legumes (Kirda et aJ., 1989).

green manures of wetland rice ecosystem, and Irrigation tWice in a week as compared totheir impact on sustainable rice production. weekly irrigation did not reduce yield or N

2fixa-

FACTORS INFLUENCING tion in Soybean but delaying irrigation mark-ACCUMULATION OF NITROGEN IN edly reduced yield and N2 fixation (Kucey

GRAIN LEGUMES AND LEGUMINOUS etaJ., 1988).GREEN MANURES Tillage systems generally enhrlOces soil

(A). Grain. legumes : Several factors nitrate N which, in turn can suppress N2

fixa­viz., water regimes, photoperiod, soil fertility tion. Compare to no tillage fallow a cultivatedstatus, legume growth duration and inocula- fallow observed greater nitrate N in the toption etc. influenced the N accumulation by le- soil layer (Herridge, 1986). Kucey et aJ. (1988)gumes and green manures in tropical rice based reported that N2 fixation by food legumes in

\ cropping systems (Alam, 1989; Becker et aJ., the tropics and sub tropics is highly variable1990b

; Herrera et ai., 1989; BhiJiyan et ai., and inconsistent. Among food legumes, soy­1989; Ndoye and Dreyfas, 1988). beans gives the most consistent response to

With adequate water and nutrient sup- inoculation. Acc~rdi~g to H.enzell (1988),ply, fast growing flood tolerant legumes can gre~test success w1th mo~ulabon ~ave beenaccumulate more than 100 kg erial Nih in ach1eved when a legume 1S newly mtroduced50 to 60 days duration. Nitro;en accum~la- to a site and when rhizobia numbers in soiltion by legumes sensitive to soil water logging, decrease greatly between legume crops.such as cowpea and green gram grown before An aerobic conditions during growthwet season rice, is retarded by soil saturation of wetland rice between legume crops may re­(Morris et aJ., 1989). suit in depletion of soil rhizobia (Wood and

Nutrient deficiencies and soil acidity Myers, 1987~. ~ccording to Craswell(.1990),which are serious crop production constraints l~ck of effecbve m?cula~ts. to.developmg n~­in South East Asia which retard the growth bon far~~rs, remams a hm1tabon under trop1­and production of legumes (Craswell et aJ., cal cond1tions.1987). A starter dose of 20 - 25 kg N/ha is (B). Leguminous green manures:recommended for tropical food legumes which Biomass production and N accumulation by le­can increase the Nitrogen accumulation of guminous green manure crops differ widelygreen manure legumes and yield of grain (food) under diverse cultural climatic and edaphic con­legumes particularly on infertile heavy soils ditions and for different durations. The most(Becker et aJ., 1990"; Carangal et aJ., 1987). productive green manure crops yielded about

The biomass production and N accu­mulation in Sesbania is mainly controlled byage factor rather than soil factors. Cowpea isvery sensitive to waterlogged conditions andproduced significantly less biomass thanSesbania and Sunhemp (Morris et al., 1986a

).

Rainfall and temperature influence thebiomass production and N accumulation ofgreen and greenleaf manures. Palaniappanet al. (1990) reported that at 45 days, Sesbaniaaculeata and S. rosrata in South India accumu­lated 185 and 219 kg N/ha. respectively.Chapman and Myers (1987) reported that Soy­bean green manure at early flowering stagefixed 124-167 kg N/ha in different years.Evans et al. (1989) indicated that dry matteryield and ~ .pccumulation of narrow leaf lupin(Lupinus augusti!olius) varied from 2 to 14 t/

Vol. 22, No. 3/4, 2001 143

4-5 t/ha of dry biomass in 50-60 days. ha and 45 to 267 kg N/ha respectively. MahlerClusterbean has generally been less productive and Auld (1989) studied the green manuringthan Sesbania, Sun hemp and Cowpea in de- potentital of Australian winter peas (Pisumscending order (Singh et aJ., 1981; Beri et aJ., sativum sp. arvense) and reported mean biom­1989a). ass and N yield of 8.3 t/ha and 167 kg N/ha,

respectively.

The contribution of roots in legumi­nous green manure crops to total N yield isgenerally less than shoot contribution. Meeluet al. (1990) reported that S.aculeata, root drymatter averaged about 1.0 t/ha, adding aboutonly 10 kg N / ha. at 50-60 days of growth.Chapman and Myers (1987) estimated that60-72% of the total plant N was from biologi­cal Nz fixation when the legumes were grownafter 12 months of fallow and 93-95% whengrown immediately following dry season crop.

Different workers have measured bio­mass production and N accumulation of vari­ous legumes and leguminous green manuresfor different durations and edaphic conditionsare presented in Table given below:

Table 1. Biomass production and "N" accumulation of legumes and leguminous green manures

Crops and Countries Age Dry Matter 'N accumulated Source(days) (t/ha) (kg/ha)

1 234 5

LEGUMESINDIACrotalaria junceaCyamopsis tetragonalobaS~bania aculeata

Sesbania ae~ticaSesbania canna'binaSesbania grandifloraSesbania glabraCowpea

PHILIPPINESAeschynomene afrasperaCrotalariai junceaLab-lab purpureusIndigofera tinctoriaSesbania aculeataSesbania cannabina

50-55 3,4-4.8 97-149 Alazard and Becker (1987)60 3.8 87 Alazard and Duhoux (1987)45 2.0 70 Beaur;:~1. (1989)

50-55 3.7 98 Alazard and Becker (1987)60 5.6 132 Beauchamp et a1. (1989)57 39 Bantilan et al. (1989)55 5.3 147 Becker et aI, (1989)57 24 Bantilan et al. (1989)57 '27 Bantilan et al. (1989)60 2.8 73 Becker et a1. (1988)

42 3.9' 78 Abrol and Palaniappan (198£)60 7.6 144 Alberto' (1989)60 3.0 76 Alberto (1989)

178 13.3 267 App. et al. (1989)60 8.0 173 Alberto (1989)60 7.2 171 Becker et al. (1990a)

(Contd,

144 AGRICULTURAL REVIEWS

1 2 3 4 5

Sesbania rostrata 60 7.7 219 Becker et al. (1990a)Sesbania sesban 60 4.9 -' 156 Becker et aI. (1990a)Cowpea 60 3.6 80 Alberto (1989)Mungbean 60 4.7 136 Alberto (1989)Soybean 60 7.9 141 Bacon et/rI986)

JAPANAsragalus sinicus FuU bloom 4.3 138 .A'fam (198.

BANGLADESHSesbania aculeata 60 6.3 170 .' Barker et al. (1985)

THAILANDSesbania rostrata 61 4.0 100 Beri et al. (1989a)

SRI LANKASesbania sesban 84 4.4 83 Beri et al. (1986a)

USATrifolium subterraneum 84 4.8 106 Bhardwaj (1982)

GREEN MANURE CROPSINDIASesbania aculeata 60 23.2 133 Sanyasi Raju (1952)Sunhemp 60 30.6 134 Sanyasi Raju(1952)Cowpea 49 4.4 99 Singh etal. (1981)5. aculeata 56 3~7 98 Sharma and Mittra (1988)S. rostrata 60 6.1 145 Salam et al. (1989)

CHINAMilk vetch Rowering 75 338 Bin (1983)Aeschynomene indica 30 15 Liu (1988)

JAPANMilk vetch Flowering 37.5 131 Watanabe (1984)

TAIWANS. sesban 92 Staker (1958)

THAILANDS. rostrata 61 ;).1 116 Herrera et al. (1989)

PHILIPPINESMungbean' 40 86 Morris et al. (1986b)S. aculeata 60 8.9 199 Meelu and Morris (1988)

USAPurple vetch 1.3 49 Williams et aI. (1957)

SRI LANKAS. sesban 84 4.3 83 Palm et al. (1988)

EFFECT OF LEGUMES AND GREEN an iJcrease in soil nitrate during growth of aMANURES ON SOIL NITROGEN mungbean crop between wheat and rice on a

In general, the proportion of legume sandy loam soil in Punjab, India.N derived from soil rather than from N

2fixa- Wetselaar et al. (1973) found that soil

tion increases with increased availability of soil N03 ' after 3 consecutive years of legume crop-N. Legum::s utilise both soil N and atmospheric ping in Australia, was greater under cowpeaNz in mepting their N requirements (George and groundnut than under stylo (Stylosantheset aI., 1988). Sharma et al. (1985) reported humilis Kunth) and c1usterbean [Cyamopsis

The values of nitrogen fertilizer effi­ciency of different leguminous green manurecrops in wetland rice are given in Table 2.

Vol. 22, No. 3/4, 2001 145

released from roots and nodules during legumegrowth (Poth etal., 1986).

Application of 30 kg ammonium sul­phate N/ha as a starter dose to mungbean ona lowland rice field slightly increased the ni­trate N in the top 60 cm soil layer (IRRI, 1992).The contribution of N from green manures isthe most commonly derived benefit in wetlandrice soils. Roger and Watanabe (1986) re­ported that incorporating one legume crop isequivalent to applying 30-80 kg fertilizer N/ha in rice.

tetragonaloba (L) Taub].

Legumes grown in rotation with low­land rice can scavenge soil mineral N whichmight otherwise be lost by denitrification orleaching after the soil is flooded for rice pro­duction (Singh, 1984). Considerc:.ble nitratemay remain in soil after a N2 fixing legumecrop. Post-harvest soil N03 are often higherafter grain legumes than after non-fixing crops(Herridge, 1986).

Nitrate sparing rather than a net in­crease in the soil N pool following growth of afood legume may account for the N benefit offood legumes to a following upland crop(Herridge and Bergersen, 1988). Anotherpossible benefit of legumes to soil N may be N

Table 2. Contribution of leguminous green manures to nitrogen fertilizer efficiency (NFE) andN accumulation in rice soils

Green manure crops Age N contribution NFE(Days) (kg/ha) (kglha)

Purple vetch 49 34Crotalaria quinqui!olia 105 100Sesbania aculeata 50 57 50Sun hemp 50 78 75Sesbania rostrata 55 131 80Mungbean 45 86 80Cowpea 60 113 120Milk vetch 23.4 t/ha (GMt 94S. sesban 84 83 96S. cannabina 65 147 120

• GM = Green Matter

Source

Williams eta!. (1957)Ten Have (1959)Bhardwaj et a!' (1981)Bhardwaj et al. (1981)Crozat and Sangchyosawat (1985)Morris et a!' (1986)Beri etal. (1989" JIshikawa (1988)Palm et al. (1988)Bhardwaj and Dev (1985)

Appartmt N recovery from green ma- land rice (Table-3).nures have been re\X)rted to 25 to 58% in low-

Table 3. Green Manure N recovery in lowland rice

Green Manure Crop N recovery (%) Source

Mungbean 33-49Sesbania aculeata 44S. rostrata 41Sun hemp 34Milk vetch 25Milk vetch 38Sun hemp 45

Morris et a!' (1986l)

Ghai et a!' (1988)Rabindra et al. (1989)Rabindra et a!' (1989)Gu and Wen (1981)Liu (1981)Huang eta!. (1981)

Williams and Finfrock (1962) working vetch green manure crop than other greenon different soils and rice cultivars and found manures in flooded rice.that N recovery rates as high as 103% in milk

146 AGRICULTURAL REVIEWS

Buresh et aJ. {1993} showed that mungbean during drysea\lon. The maximumSesbania rostrata grown for 45-60 days and level of mineral N in the top 60 cm soil layerincorporated into the soil before planting low- of a rice lowland during a dry season as mea­land rice reduced the loss of soil N. Singh sured by Ladha et aI. {1996} was 113 kg N/(1984) speculated that legumes grown in rota- ha, and forage legume Crotalariajuncea growntion with. lowland rice can scavenge soil min- through the seasoporecovered 80 kg soil N/haeral N. from the site . .

In another study, Georgeet aI. (1995) .Beorge eta1. (l994) grew mungbean andconserved 57-75 kg soil N/ha by growing grain S. 1'Q8frafa during the dry to wet transition periodlegumes such as soybean, cowpea and and conserved 66-125 kg N/ha (Table 4).

Table 4. Soil N uptake (kg/ha) by legumes and weeds in a rice lowlandduring dry to wet season of 1991 (George et aI., 1994)

Fallow management Maximum mineral N measured Soil 'N' uptake by abovein soil before flooding (kg/ha) ground parts of crops (kg/ha)

Sesbania rostrata 164 . 125Mungbean 125 80Weeds 11, 46Weed free 11~

C.D. (P = 0.05) 28 18

Continuous addition of organic mat- ing systems can greatly help in sustaining Nter either through green manuring or FYM is fertility in lowland rice soils.more essential to sustain soil N fertility. It also The 45 to 65 days fallow period be-improves soil physical properties and increases tw tw . b d t f tth t f CO '1 bl tit d een 0 nce crops can e use 0 grow ase amoun 0 z aval a e 0 p an s an . .

. . {K d d Ladh 1999} growmg legummous green manure crops suchmlcroorgamsms un u an a . 5 ban' d ""'_I' h d' .es Ja an L-rotaiana or s ort urahon gram

When biological nitrogen fixing sys- legumes such as cowpea and mungbean. They~e~s i.e. symbiotic Nz fixi~g systems are used usually accumulate 80-120 kg N/ha and atleastIf! nce lowlands, the ~ontnbuhonof N can be 50% of this 9ffiount comes from symbiotic Nzmuch larger. Legummous green manures and f' t· {L~Ah t 1 1992}. I I d . rt:::-·t I' . txa Ion QU a ea., .gram egumes p aye an lmpo OJ I ro em mam-taining soil N fertility i1nder traditional rice pro- Symbiotic Nz fixing systems throughduction systems of the tropics. According to grain forage and green manure legumes in riceLadha and Kundu {1997}, promoting Nz fix- lowlands a~ presented in Table-5.

Table 5. N2 fixed by different species of grain, forage and ~een manure legumes in rice.

, Legume species GroWth duration (days) -Alllountof N2

,- Sourcefixed (kg N/ha)

CrotalariaClitoriaDesmanthusSiratroPigeonpeaS. rostrataS. .cannabinaSoybeanCowpea

190-195190-195190-195190-195190-195

45-6545·5570-8470-84

199-223200-240196-226

91-132111-167

70-458149

7878

Source:

Ladha et al. (1996)

Ladha et al. (1992)George et al. (1995)George etal. (1995)George et al. (1995)

Kundu and Ladha (1999)

Vol. 22, No. 3/4, 2001 147

In an inigated double cropped lowland, legumes accumulated 60-90 kg N/ha (Table­two green manure legumes or N

2fixing aquatic 6) of which 50% corne from biological nitro­

fern Azolla each of 45-60 days duration could gen fixation.be grown and incorporated. Each of these

Table 6. Dry matter (DM) yield and N accumulation of two green manure (GM) legumes in rice lowlands,

Year First GM legume· Second GM legume

Duration DM yield N accumulation Duration DM yield N accumulation(days) (t/ha) (kg/ha) (days) (t/ha) (kg/ha)

1985-861986-871987-881988-891989-90

46 3.2 74 60 2.7 6453 4.0 79 61 3.2 5553 4.0 90 57 3.6 6567 6.0 82 62 3.4 8550 2.7 61

• Rood tolerant stem nodulating Sesbania rostrata.

The green manure legumes or residuesof the grain legumes may then be incorporatedinto the field to supply the fixed N2 to soil.The Azolla can be grown before transplanting~ as a cover crops with rice which cansubsequently be incorporated into the soil. TheAzolla produced 10-15 tlha of fresh dry mat­ter and accumulating about 20-30 kg N.Atleast 70% of this N is derived from the at­mosphere through symbiotic N2 fixation. Kunduand Pillai (1992) suggested that in many double

Source: (Ventura and Watanabe, 1993)

rice cropped areas of India, a short durationgrain legume could be accommodated duringthe fallow period to increase the annual foodgrain productivity by 1.0 t/ha and make a netsaving of 30 kg Nlha.

In rainfed lowlands where only onecrop of rice is grown in wet season leaving along dry season fallow due to lack of watergrowing legumes (grain and forage) helps inimproving the soilN balance (Table 7).

Table 7. Contributions of one grain and four forage legumes to soil 'N' balance in rice lowlands.

Legumes Above ground N in the legumes N returned Apparent N Apparent N(kg/ha) to the soil balance contribution

------'---- (kg/ha) in soil of legume rootsNdfs" Ndfab Total

Pigeonpea 43 111 154 113 +70 26Crotalaria 54 223 277 118 +64 19Clitoria 56 200 256 114 +58 33Desmanthus 55 196 251 137 +82 20Siratro 41 91 132 81 +40 17

I

, Adopted from Ladha et al. (1996)a ; Ndfs - N derived from soilb ; Ndfa - N derived from Nz fixation.

It is therefore, green manure crops canbe grown solely for its beneficial effects on soilfertility. But where other benefits like suppres­sion of weeds, reduction of incidence of pestand diseases or control of soil erosion are also

found, fanners may be encouraged to use themextensivelyIto sustain higher rice productivity.

A ~ajor problem for adoption is thatthe green manure legumes often occupy landat a time when some more remunerative crops

148 AGRICULTURAL REVIEWS

could be grown. A possible compro'Uise isthe use of grain or forage legumes which canprovide young pods/gratns as food/vegetablesor periodic cuttings of foliage as fodder whilestill leaving sufficient green leafy materials tobe used as green manure for improving soil Nstatus (Kundu and Ladha, 1999).

NITROGEN USE EFFICIENCY IN RICESOILS THROUGH OTHER SOURCES

In lowland rice, losses of applied Ntake place through ammonia volatilization,denitrification, leaching and run off. Therecovery of fertilizer N applied to rice seldomexceeds 30-40 % fertiiizer N use efficiency in

lowland rice soils may be minimised through abetter timing of application to coincide withthe stages of peak requirement of the crop,and placement of N fertilizer in the soil. Otherpossibilities though much more costly, are theuse of modified N fertilizers (or) controlled re­lease N fertilizer or of urease and nitrificationinhibitors and finally the exploitaion of vari­etal differences in efficiency of N utilization(IFA, 1992).

In IFA, the general guidelines for effi­cient N management in rice soils (Table 7a)were given for N management.

Situation

Table 7a. Guidelines for efficient N management in rice

Strategy

Upland (dryland)

Rainfed deep waterLowland (Submerged)Soil very poor in NAssured water supplyPermeable soilsShort duration varietiesLong duration varietiesColder growing seasonOveraged seedlings used

.Broadcast and mix basal dressing in top 5 cm of surface soilIncorporate top dressed fertilizer by hoeing in between plant

rows and then apply light irrigation, if availableApply full amount as baSal dressingUse non-nitrate sources for basal dressing.Give relatively more N at plantingTop dress every 3 weeks up to panicle initiationEmphasis on increasing number of split applicationsMore basal N and early top dressing.Increased number of top dressingLess basal N and more as top dressingMore N at planting

Nitrogen efficiency and N recoverywere apparently higher with green manure thaninorganic N sources because of the otherfavourable changes like N build up in the soilsystem, maintenance of soil fertility, improve­rrie,nt of organic C and soil physical propertiesetc., that occur in the soil with green manureincorporation (IRRI, 1992).

According to Subbaiah (1995) greenmanure incorporation enhancing the availabil­ity of other macro and micro nutrients in ricesoils besides improving soil fertility. Similarfindings were also reported by Ranjan andKothandaram (1986) and Takkar and Nayyar(1986). In general the lower the C/N ratio ofthe green manure the higher the crop response

Source (IFA, 1992)

as dbserved by Bin (1983). Arunin etal. (1987)reported that incorporation of Sesbaniaspeciosa as green manure (CN ratio 24: 2)gave the highest rice yield in lowland soils.

Subbaiah and Mahender Kumar(1997) found that N use efficiency of appliedorganic fertilizer can be enhanced under rice­safflower sequential cropping system than thatof a rice - pigeonpea and rice-sorghum se­quence. Pillai and Subbaiah (1993) found thatplacement of N as Urea Super Granules (USG)as superior in terms of agronomically efficient,economically viable and environmentally safetechnology for transplanted rice growing ar­eas especially in heavy clay soils with low in­ternal drainage reduced permeability and mini-

More than the total quantity of N ap­plied, the source, time and method of applica­tion are really more important in rice low lands.According to Pillai (1978), sulphur coated ureais one of the most widely tested controlled re­lease N fertilizer for rice which helps the crop

Vol. 22, No. 3/4, 2001 149

to produce more panicle and hence yield. Pillaiand Katyal (1976) reported that use of shellaccoated urea and neem coated urea has alsofound beneficial for rice in lowland soils.

Shinde (1980) stated that dual advan­tages of deep placement and slow release pat­tern can be achieved through the use ofmudballcoated urea (Hulk + urea; straw + urea) as com­pared to sulphur coated urea and large gran­ules of urea in transplanted rice.

Deep incorporation of straw followedby split application of urea soil balls reducedthe leaching loss over 50% as compared tourea granules or urea soil balls without straw(Shinde and Chakravorty, 1975).

The best qop recovery of N and grainyield with the minimum possible dentrification/volatilization loss was obtained when urea soilballs were applied basally at a depth of 8 cm(Rajendra Prasad et al., 1971).

According to Ram Singh et al, (1986),urea super granules or urea briquettes if deepplaced by hand into rice soils increase the effi­ciency of urea for wetland rice. This was con­firmed by several scientists (De Datta andGomez, 1981; Servant etal., 1982).

According to Mahapatra (1989), fer­tilizer use efficiency in rice so far as N is con­cerned can be increased by resorting toa) Split application of urea in uplands and

medium lands with controlled water supply.b) Use of urea super granules by depositing

the same a few em below the soil surface.c) Sulphur coated 'Vea, neem coated urea,

gypsum coated utea and rock phosphatecoated urea in lowlands have increased theN use of efficiency besides enhanced therice yield.

Over and above, Subbaiah (1995)enumerated the various advantages of greenmanure incorporation in rice for increased Nuse efficiency.i) Green manure species are potential N

mum leaching losses of N.

Subbaiah and Sharma (1987 & 1988)observed that coated drilled urea (PO) LargeGranule Urea (LGU) and Urea Super Granules(USG) hand placed 7 days after transplantingrice either with or without new coating mate­rial (5% neem cake power coating) incree.sedthe N use efficiency and grain yield significantlyover drilled area as standard splits (2/3 basal +1/3 at panicle initiation).

Subbaiah et ai. (1983) reported thatcomplementary use of organic (rice straw in­corporation) and inorganic sources of N in ju­dicious combinations had a significant posi­tive influence on grain and straw yield of bothwet and dry season rice with increased N useefficiency on a heavy clay soil.

Application of organic manure(Sesbania rostrata) at 10 t/ha gave significantlyhigher grain yield when it was combined withinorganic fertilizers in lowland rice. The aver­age mean grain yield increase was 2.21 t/haover absolute control by incorporation of greenmanure crops with increase nitrogen use effi­ciency (Subbaiah 1998). Yield response toUrea Super Granules and Sulphur coated ureawas significantly more than prilled urea inIndia in irrigated wetland rice (Subbaiah et al ,1994). They also found that nitrogen use effi­ciency and recovery of fertilizer N applied .totransplanted rice is seldom more than 30-40%.

Subbaiah (1990) reported that largegranular forms of Nand P fertilizers are betterthan powdered or prilled forms like prilled ureaand single super phosphate for increasing thenutrient use efficiency and grain y.eld in low­land rice.

150 AGRICULTURAL REVIEWS

sources with relatively high efficiency.ii) Improve soil physical properties and con­

serve and recycle nutrients.iii) Increases biological activity of microbes in

the soil.iv) Reduce soil erosion and build up organic

C content.v) Cropping in fallow lands helps to control

pest and diseases.vi) Many green manures species had effec­

tively controlled weeds besides providefood, feed and fuel.

EFFECT OF LEGUMES AND GREENMANURES ON RICE YIELD

The beneficial effect of legumes andgreen manures on yield of a following rice cropis dependent upon incorporation of legumesand green manures in both non puddled soilswith water seeded rice and puddled soils withtransplanted rice (Williams and Finfrock, 1962;

IRRI, 1986).

Rajendra Prasad (1985) reported thatincorporation of residue remaining after soy­bean harvest increased grain yield of the sub­sequent rice crop. On the other hand, in a 7year rice - rice soybean trial, rice yield was notincreased when soybean haulm was returnedrather than removed (Morris and Meelu, 1985).

According to Rekhi and Meelu (1983),removal of the cowpea residue dramatically re­duced yield of the subsequent rice crop.

Many studies have shown that legu­minous green manures and food legume resi­dues remaining after harvest grain, increasethe yield of a subsequent lowland rice crop andreduce the requirements for industrial N fertil­izer. The saving in industrial N fertilizer byusing legume N is frequently referred to as theN fertilizer equivalence (Table-8).

Crop species(Country)

Table 8. Legume incorporation on a' following lowland rice crop.

Biomass Rice N fertilizerincorporated yield (t/ha) equivalance

Dry wt. N -Biomass +Biomass(t/ha) (kg/ha)

Source

101

Cowpea (Philippines)Lentil (India)

Mungbean (India)

4.0 532.74.6

3.34.23.2

4.24.36.5

5056

100

Abrol and Palaniappan (1988)Alazard and Becker (1987)

Alazard and Duhoux (1987)

Atleast a part of the increase' in riceyield from the legume green manures and resi­dues can be attributed to increased soil avail­able N following incorporation and the trendsin rice grain yield are directly related to theaccumulation of soil N following rice planting(Nagarajah, 1988).

Yield response of high yielding culti­vars ranged from 0.65 to 3.10 t/ha and weregenerally higher than those reported for low

yielding rice cultivars. Work done on greenmanuring in wetland rice in China, India, Phil­ippines, Japan, Thailand, USA and Sri Lankahas been reviewed by Gu and Wen (1981);Chela and Gill (1973l; Hernandez et ai. (1957);Yamazaki (1959); Chen (1988); Williams et ai.(1957) and Rabindra et ai. (1989). In longterm studies carried out in South and SouthEast Asia, green manuring increased grainyield of rice up to 127% (Table 9).

Table 9. Response of rice grain yields to green manuring.

Green manure crop Age (days) Yield (t/ha)

-GM +GM Increase (%)

Source

1Milk vetch

213 years (mean)

3 42.9 4.2

544.8

6Ishikawa (1998)

(Contd.

Vol. 22, No. 3/4, 2001 151

1 2 3 4 5 6

Soybean 1.3 1.9 46.2 Chapman and Myers (1987)Sesbania sp. 4.1 5.5 34.2 Roy et al. (1988)S. speciosa 1.3 2.3 84.0 Sawasdee etal. (1976)S. rostrata 1.5- 1.6 2.2 37.5 Herrera et al. (1989)S. aCl,Jleata 60 3.2 4.0 25.0 Bharadwaj etal. (1981)Sun hemp 60 3.2 3.9 21.9 Tiwari et al. (1980)Cowpea 60 2.7 5.5 105 Beri etal. (1989.)S. sesban 84 2.0 4.0 100 Palm et al. (1988)S. rostrata 20- 2.6 5.9 127 Kalidurai and Kannaiyan (1990)Mungbean 40-45 2.1 4.1 95.2 Morris et al. (1986')S. cannabina 60 1.8 4.1 128 Meelu and Rekhi (1981)Soybean 60 3.3 4.3 30.3 Rinaudo et al. (1983)Aeschynomene 49 4.8 8.9 85.4 Alazard and Becker (1987)

afsasperaAcacia nilotica

- Biomass (tlha)

Westcott and Mikkelsen (1987) foundthat application of 120 kg N/ha through vetchgreen manure increased the rice yield by 2-4t/ha (43.3%) over the control.

The response to green leaf manurein wetland rice depends on the amounts ofgreen matter added, th~r succulence and nu­trient content. Bhatti et al. (1985) found thatmaximum rice yield with fertilizer N alone was3 t/ha, but fertilizer along with green manureincreased yield potential to ~ 4 t/ha. Reddiet al. (1972) observed that in the presence of7.5 t/ha green manure, an additional rice yieldof 0.7 t/ha (12.5%) was obtained at recom­mended fertilizer N application. The yield po­tential further increased to 1.08 t/ha when 15t/ha of green manure was applied.

Short duration pulses such as~Q.ean and cow pea can be grown in thefallow period before transplanting rice pro­vide much needed protein for human consump­tion and their residues can still be turned underto serve as a green manure. Rekhi and Meelu(1983) reported that in addition to about 0.9 tgrains /ha, mungbean residues supplied about100 kg N/ha, and when incorporated into thesoil along with 10 kg N/ha through urea, gaveas much rice yield as obtained with the appli­cation of 120 kg N/ha through urea alone.

Xiao (1980) reported that incorporating awinter crop of beans after pod harvest gave a19% increase in the yield of a subsequent ricecrop.

In tropical regions, where two ricecrops are grown in a rotation, incorporatingcrop residues of short duration grain legumes(Mungbean, Blackgram, Cowpea) substitutedfor 50% N in wet season rice (Kulkarni andPandey, 1988). Grain legumes of cowpea andmungbean are IJnsuitable for poorly drainedsoils where short term flooding occurs duringthe cropping season.

High amounts of green manure canbe unfavourable, even harmful, to plant growthbecause the nutrients are released faster andare more concentrated. The result is ineffec­tive tillering and lodging (Ishikawa, 1988).

TIME OF INCORPORATION OFLEGUMES AND GREEN MANURES

ON RICEThe optimum time interval from le­

gume incorporation to rice transplanting infldoded soils varies with soil type and climaticconditions. On coarse textures, non-acid soHsin tropical lowland rice environments, trans­planting immediately after green manure in­corporation gives higher rice yields than does

152 AGRICULTURAL REVIEWS

delaying transplanting to allow for decomposi- season rice (Diekmann, 1990).tion of green manure (Beri et al., 1989 b; Generally, green manures were grownBhardwaj, 1982). Immediate transplanting in fallow fields on rain water and incorporatedalso resuit~ in more efficient use of irrigation 2 to 4 weeks before sowing of the followingwater (Ben et al., 1989 b). crops. While studying the possibility of green

Singh et al. (1990) reported that 50 manuring in the present da~' rice based cro~to 60 days old green manure incorporated one ping systems, Bhardwaj (1982), Ghai et al.day before transplahting contained 41 to 150 (1988) and Beri et al. (1989 b) showed on thekg above ground N/ha and substituted for an basis of yield responses, that a 2 week delayequal or slightly greater amount of urea N (72 between incorporation of green manure andto 148 kg N/ha). On coarse textured acid soils, transplanting of rice was not only unnecessarya delay between organic matter incorporation but also disadvantageous. The reason for lowand transplanting may be beneficial. Herrera efficiency of green manure when incorporatedet aI, (1989) observed slightly greater yield of for a longer period before transplanting rice orrice when a delay of 14-21 days rather than 2 flooding could be the loss of green manure Ndays was allowed between incorporation of 2- released dUring aerobic decomposition through3 t/ha of 5. rostrata green manure (76 kg N/ ammonia volatilization, nitrification, de-nitrifi­hal and transplanting on a poorly buffered cation and leaching after flooding of rice fieldsacidic soils. (Ishikawa, 1988; Chapman and Myers, 1987).

On many tropical soils, a 1 to 2 week A few investigations have shown that it is notperiod for anaerobic decomposition of incor- always necessary to incorporate green manureporated legumes before transplanth.g can in- a day or two before transplanting riee (Iso,crease the rice yield. A one week decomposi- 1954; Staker, 1958; Roy et aI., 1988; Tiwarition of incorporated Sesbania green manure et al., 1980; Rana et aI., 1988). Decomposi­significantly increased rice yield on a sodic soil tion of Sesbania for 1 week under flooded con­(Swarup, 1988). A 15 day tiecomposition ditions in sodic soils significantly improved riceperiod follOWing incorporation of 5. aculeata yields over simultaneous incorporation andmade no significant difference on rice yield on transplanting of rice possibly through improve­a reclaimed saline sodic clay loam in India ment of physico-chemical properties of sadie(Tiwari et aI., 1980). On flooded clay soils, soils (Swarup, 1987).initial growth of rice is occassionally reduced W (1984) d H t 1 (1989)

h 1 ·· d· t I f II . en an errera ea.w en transp antmg Imme la e y 0 ows mcor- rt d th t ·t· b tt t t d.. . repo e a I IS e er a urn un er greenporatIon of readIly decomposable orgamc ma- b t 15 d b fIt·

(D· k 1990) manure crop a au ays e are pan 109nures Ie mann. ..'< nce seedlmgs so that plants do not wffer dam-

In temperate regions, maximum con- age from the decomposition products of thetribution of legume N to rice likely o<;:curs when green manure. To avoid losses of green ma­the period between incorporation and flood- nure N it was recommended to keep the fieldsing is insufficient for conversion of legume N flooded during the decomposition period be­ta Nitrate (Williams and Finfrock, 1962). fore transplanting rice. Vande Goor (1954)

Leguminous green manures in the reported increases in rice yield when greentropics, parti~ularly stem nodulating legumes, manure was incorporated into the soil ratherwith an adequate supply of soil nutrients can than applied on its surface. Although it is notaccumulate more than 120 kg N/ha when practicable, it should be well turned into thegrown for about 50 or more days before wet soil for more effectiveness of applied legumes

In corporation of Sesbania green ma­nure before transplanting on sandy loam soil,found greater rice yield when 60 kg urea N/hawas applied in equal splits at 21 OAT (7.8 t/hal (Singh etal., 1987).

Application of urea as large granules(urea super granules) at about 10 cm soil depthbetween hills of transplanted rice is frequentlymore effective than conventional broadcastingof prilled urea on puddled rice soils (Savant andStangel 1990). Dhane et ai. (1991) showedthat the superiority ()f USG over conventionalbroadcast urea can be enhanced with green

Vol. 22, No. 3/4. 2001 153

other study, when urea was applied after in­corporation of green manure, losses of urea Nwere not reduced. Goswami etai. (1988) foundthat the S.aculeata green manure incorporated1 week before transplanting had no effect on ..loss of urea applied in equal doses at 10 and30 days after transplanting.

Response of rice to N fertilizer de­pends on source and timing of N application(Bouldin, 1988). Higher lowland rice y'ld (0.8and 0.3 t/ha) for basal application of 40 kg5.aculeata N/ha with 40 kg urea N/ha thanfor a split application of 80 kg urea N/ha(Mahapatra and Sharma, 1989).

On the other hand, Chakraborty etai.(1988) found no greater rice yield for basal ap­plication of 90.kg urea N/ha. In addition toreducing the industrial N fertilizer requirementsfor rice, application of legume N to rice mightconceivably after the optimum timing and man­agement of N fertilizer for rice.

In temperate climates, a basal appli­cation of 20 kg N/ha as industrial N fertilizertogether with green manure can increase riceyield by increasing early tillering (Watanabe,1984). According to Meelu'Cind Morris (1988)delaying industrial N fertilizer application untilabout panicle Initiation when green manure isincorporated before transplanting in the tropi­cal climate.

and green manures to lowland rice.

USE OF LEGUMES AND GREENMANURES IN INTEGRATEDNITROGEN MANAGEMENT

Generally legumes and green manureswere not substituted entirely for industrial Nfertilizer because legume N remaining afterremoval of grain or all above ground pla;rt bio­mass will normally, only partially meet the Nrequirements for a following high yielding ricecrop. Similarly, leguminous green manure N,except when large quantities are applied be­fore rice with limited potential for respondingto N (Becker et ai., 1990 a; Garrity and Flinn,1988). Therefore, use of legumes and greenmanures as an N source for low land rice willtypic~lly require iLegrated use of industrial Nfertilizer for sustained high rice yields. The ef­fectiveness of integrated organic and inorganicN fertilizer use depends on the magnitude of N

:doses, timing of N fertilizer and the sources of"N" applied.

• Jana and Ghosh (1996) reported thatthe rice produttivity can be improved with 50%NPK through industrial N fertilizer and 50%through green manure (Sesbania cannabina)incorporation in a rice-rice sequential croppingsystem.

Application of vetech straw with ureareduced urea N losses from 19 to 12% (Huangand Broadbent, 1989). Basal application of30 kg S. rostrata N/ha with 60 kg urea N/hareduced loss of urea N from 54 to 46% andwith 30 kg urea N/ha reduced loss of urea Nfyom 37 to 24% as reported by Diekmann

-et al. (1991).

However, the reduced loss of urea Nreported by Biswas and De Datta (1988) mightalso be due to decreased percentage loss' ofurea N with decreasing urea application rate,as observed by Diekmann et ai. (1991). Ap-plication of green manure with urea reducedfloodwater pH and consequently the partialpressure of ammonia (Biswas, 1988). In an-

Grain legumes are a rather minor crop

Combinations of green manuring andgypsum or sulphur or lignite fly ash or pressmudor pyrite amendments helped in registering .large increases in rice yields on the saline sodicsoils (Somani and Saxena, 1981; Jauhari andVerma, 1981). These results indicated thatgypsum alone is sometimes not as effective asgreen manuring in reclaiming problem soils.

Ghai et aJ. (1988) reported that incor­poration of 40 to 50 day old Sesbania resultedin rice yield equivalent to that obtained with80 to 120 kg N/ha in sodic soils. Growingand incorporation of Sesbania speciosa greenmanure in saline and alkali soils helped to ob­tain rice yields of 1.25 t/ha compared to 0.4tlha in no green manure treatment (Aruninet aI., 1987).

LEGUMES AND GREEN MANURES INRICE BASED CROPPING SYSTEMS

(A) GRAIN LEGUMES: Food le­gumes generally yielded less because they areoften grown with low management and inputsunder marginal production conditions in whichcereals perform poorly or cannot grow. Atleast18 grain legume species are considered im­portant at various locations in Asia (Byth et al.1987). The major grain legumes grown onrice soils include soybean, mungbean, ground­nut and cowpea. Soybean is an important cropon rice lands in China, India, Thailand,Vietnam and Indonesia (Carangal et al., 1987).Mungbean is an important crop in India, Thai­land, Burma and Indonesia (Singh, 1988).Cowpea is an important food legume in SriLanka (Singh, 1988). It performs better thanother food legumes on highly acid soils (Pandeyand Ngarm, 1985).

154 AGRICULTURAL REVIEWS

leaf manuring. Basal application of 2t/ha of crop recommended for the reclammation ofGliricidia sepium toppings increased rice yield sodic soils (Beri et aJ., 1989 b). Beneficialby 0.2 to 0.7 t/ha for split applied urea and by effects of submergence on rice growth become0.4 to 1.0 e/ha for USG (Urea Super Gran- more pronounced by incorporation of greenules). manure.

EFFECT OF LEGUMES AND GREENMANURES ON PROBLEM SOILS

In corporation of legumes and greenmanures has been recognized as a useful prac­tice for reclaiming saline and alkali soils. Italso brings out some favourable changes in thephysico chemical properties of these problemsoils, which ultimately leads to an increasedyield of rice on these soils.

Sesbania used as green manures areremarkably suited to saline and alkali soils ascompared to other green manures (Rao, 1985;Evans and Rotar, 1986). Sesbania invariablygave double the biomass yield over that ofclusterbean and sunhemp in alkali soils. In­creasing soil salinity and alkalinity upto pH 10.6had no adverse effect on the growth and num­ber of nodules of Sesbania (Bharadwaj, 1974;Singhbutra et aJ., 1987).

Increasing exchangeable sodium per­centage (ESP) in sodic soils from 16 to 32 hadno significant effect on biomass and N yield ofS. acuIeata (Rao, 1985). On the otherhand,germination, growth and nodulation of greenmanure crops are adversely affected only byhigh levels of salinity and alkalinity (Sinha,1982; Hangen and Munns, 1985).

Application of gypsum alongwithgreen manure crops affected favourably the soilstructure and hydraulic conductivity of saline'sadie soils resulting in leaching of displaced so­dium ions into the deeper soil layer (Yadav andAgarwal, 1959; Jen etaJ., 1965). Root growthof Sesbania also caused a marked decrease inESP and an increase in soil porosity (JenetaI., 1965; Swarup, 1987).

Wetland rice, due to its high toleranceto exchangeable sodium is the most suitable

Matiwade and Sheelavantar (1994)observed increased grain yields of rice whenSesbania rastrata applied together with 1oQl.!-ll

recommended N/ha in transplanted rice. Ac­cording to Budhar and Palaniappan (1997),200 kg N/ha through industrial N fertilizer andgreen manure of S. rastrata registered higheryield of 6.98 t/ha as compared to 200 kg N/ha through urea N alone (6.88 t/ha).

Balasubramanian and Veerabadran

Vol. 22. No. 3/4, 2001 155

in Asia as compared with cereals. Yet they are ha with rice-wheat system (Lal, 1988; Tiwarian important component both in terms of hu- et al., 1980).man and animal nutrition and as a source of (8) LEGUMINOUS GREEN MA­biological N. Legumes in irrigated environ- NURES: Green manures can be grown in ricements of tropical and sub-tropical regions, can fields before rice and then incorporated dur­be grown in rotation with one or more rice ing land preparation for rice. Alternatively,crops per year. In general, legumes are grown the green manure crop can be grown else­in rice based cropping systems for protein, oil, where, such as border areas, nearby uplandfodder, green manure and fuel production fields and then transported as cut green matter(Buresh and De Datta, 1991). to rice for incorporation (Jiao, 1983). In sub

When legumes grown after wet sea- tropical and temperate regions. where theson rice, encounter excess water during the growing period for rice is restricted by low tem­vegetative phase and water deficit during the perature, leguminous green manures can bereproductive phase. Post rise legumes depend grown as the winter crop in rotation with rice.primarily on residual soil water, and their roots In China, winter green manures of white milkmay follow a receding water table (Timsina, vetch (Astragalus sinicus L.) is the most im­1989). In Northern India, the production of portant crop to occupy large areas (Wen,irrigated mungbean as a third crop between 1989). Alternatively, green manure can bewheat and rice is increasing (Singh, 1988). basally applied to rice after composting underMungbean is more sensitive to reproductive water logged conditions (Wen 1989: Liu,phase and full season water deficit than are 1988). They found that waterlogged com­cowpea and soybean (Pandey et al.. 1984: post can eliminate possible adverse effedsofSenthong and Pandey, 1989). Water deficit toxins initially formed during aerobic decom­reportedly reduces Nz fixation more than it re- position and provide a steady long lasting re­duces plant growth and N uptake (Kirda et aJ., lease of N.

1989). Rao et aJ. (1996) found that incorpo-Soil saturation and temporary water ration of Sesbania aculeata and S. rastrata

Jogging adversely affect growth, N accumula- alongwith prilled urea N 50 t/ha in two splitstion and Nz fixation of food legumes (Wien recorded maximum grain yield of 5.79 andet aJ., 1979). Soybean is more tolerant to ex- 5.78 t/ha in lowland rice. Hegde (1998) re­cess water than is cow pea (Wien et aJ., 1979; ported that 50l

Y(l NPK + 50% N through pricklyHulugalle and La!, 1986) and cow pea is more sesban green manure gave higher grain yieldtolerant to temporary soil water logging than of rice and wheat in a rice-wheat cropping sys­is mungbean (Minchin and Summerfield, 1978; tern.IRRI, 1985):

Growing mungbean either for grain orgreen manure purpose during pre-rainy sea­son in rice-rice cropping system was found to

'be not only feasible but also economical inIndia. Yield of rice when grown after cow peafodder was 0.4 t/ha more as compared tofallow-rice. Higher net return of $ 451 and $477/ha was recorded with rice-chickpea andrice-wheat +chickpea as compared to $ 269/

In Philippines, Indigo (Indigo/eratinctoria L.) is grown as a green manure of wetseason rice in rainfed conditions and after asecond rice crop in partially irrigated condi­tions. The indigo is incorporated during landpreparation for wet season rice and rice is trans­planted immediately after biomass incorpora­tion found promise in rice based cropping sys­tems (Bantilan et al., 1989; Garrity et al.,1989).

Food legumes in contrast to greenmanures, offer the attractive dual benefits ofseed production for income or food and pro­duction of residue, which can be used for ani­mal feed or a N source on the foIlowing ricecrop (Kulkarni and Pandey, 1988). Nitrogenaccumulation was consistently less formungbean and cowpea residue than for S.rostrata green manure. Rice yields were slightlyincreased by legume residues and S. rostratagreen manure. According to Chandra (1988),irrigated mungbean grown with recommendedmanagement practices for grain production andincorporation of residue reportedly reduces theindustrial N fertilizer requirements on the fol­lowing rice crop by 20 to 30 kg N/ha. Insome regions, legume residue may serve asanimal feed. Recognizing that farmers are of­ten reluctant to grow crops solely for animalfeed, Carangal et ai. (1988) proposed post riceinter cropping of food legumes or cereals withforage legumes to provide food, fodder andresidue for ~he next wet season rice crop.

156 AGRICULTURAL REVIEWS

(1997) reported that 75% N (inorganic) + 25% logging appear to have the greatest scope for'N' through prickly sesban or daincha increased future green manure cultivation (Garrity andthe yield by 1.65 tlha as compared to 100% Ainn, 1988). The recent identification of floodN through inorganic fertilizer. Gill et ai. (19,94) -tolerant, stem-nodulating legumes has in­observed that an yield increase of 0.2 t/ha (6.0 creased research interest in green manures fort/ha) in rice was obtained under green manure environments prone to waterlogging (Rinaudo(daincha) incorporation together with 60 kg N/ et al., 1988). Sesbania rostrata (Rinaudoha as compared with 120 kg Nlha (5.8 t/ha). et ai., 1983) and Aeschynomene abrasperaSesbania rostrata and Crotalaria juncea at 60 (Alazard and Beker, 1987) have been exam­and 45 days of age incorporated into the soil ined in great detail for their potential as greenenhanced grain yield of rice as compared to S. manures.aculeata (45 days old seedlings) incorporation(Chandra and Pareek, 1998).

In worldwide, use of green manure inrice based cropping systems has declined. Milkvetch in Japan, vetches and clovers in USAwere now of minor importance, in rotation withrice (Ishikawa, 1988; Westcott and Mikkelsen,1988). Berseeem clover is used as a wintergreen manure in Egypt (Hamissa and Mahrous,1989). In the tropics, Sesbania sps. especiallydaincha (S.cannabinaSyn: S. acuJeata) are usedas green manures in rice cropping systems.Sesbania sps. Are well adapted for use as agreen manure before rice because of their abil­ity to withstand soil waterlogging and flood­ing, to grow on fine textured soils, and to tol­erate soil salinity (Evans and Rotar, 1987).

Sesbania cannabina and Croto/ariajuncea L. (Sunhemp) are common green ma­nures in rice in India (Abrol and Palaniappan,1988; Garrity and Flinn, 1988). According toBrewbaker and Glover(1988), Woody legumespecies, particularly Gliricidia sepium; Leucaena/eucocephala (Lam) and Sesbania bispinosa(Jacq) W.F. Wight (Syn : S. aculeata, S.cannabina) are used as green leaf manure in­corporated before transplanting can signifi­cantly increase rice yield (Jayaraman andPurushothaman, 1988; Zoysa eta/., 1990).

Worldwide, the use of leguminousgreen manures in rice crbpping systems is cur­rently found primarily in irrigated environments.Rainfed rice enwonments prone to soil water

The residual effect of green manureapplication to wetland rice has generally beenmeasured in terms of grain yield of the suc­ceeding crop. Reviewing green manuring re­search; Beri and Meelu (1981), Hesse (1984)and App et ai. (1980) reported that there islittle or no cumulative benefit of green manur­ing of rice to the succeeding crops. Signifi­cant residual effects of green manures appliedto rice on the following crops have been re­ported by several researchers (Tiwari et ai.,1980; Furoc and Morris, 1989; Maskinaet al., 1990). Residual effects of green ma­nuring on the succeeding crops are locationspecific. Residual effects of green manure un­der tropical climates are in fact likely to besmall~r than under temperate climates.

In corporation of Sesbania cannabina

Vol. 22, No. 3/4, 2001 157

RESIDUAL EFFECTS OF LEGUMINOUS along with 75% NPK/ha in rice increased theGREEN MANURES APPLIED TO RICE grain yield and had positive residual effect on

Mixed cultivation of leguminous and succeeding wheat crop as compared to 50%non-leguminous green manure crops, often NPK in a rice-wheat sequential cropping sys­gives a bigher humification co-efficient thus tern (Rajput, 1995).being advantageous to the accumulation of SUMMARY AND RESEARCH NEEDSorganic matter in soil (Woodward and Burge, Nitrogen contribution from legumes in the­1982; Chen, 1986). This may be a promis- tropics has focussed on short duration le­ing way of growing green manure crops under gumes grown and subsequently incorpo­the conditions where enough quantity of crop

rated soley as green manures immediatelyresidues is not returned to the soil. Higher ac-

before the monsoon rice crop. Little iscumlliation of organic matter and N in threedifferent soils was observed from the applica- known about the transportation losses,tion to rice of 65-day-old Sesbania green ma- gains and recycling of N from post ricenure as compared with 45 to 55 day old crops legumes.(Bhardwaj and Dev, 1985). Singh and Verma Little is lmown about N transportation and(1969) also found that organic carbon content contribution to rice in forage-food inter-of soils was high when green manuring was crops because post rice legumes in asso-practiced every year, suggesting that the effect ciation with food legumes or cereals mayof green manures on soil organic matter levels offer greater scope for providing fixed Nzare short-lived unless continuous additions are to the subsequent rice crop in addition tomade. Warman (1980) observed that green food and fodder production:manuring will either increase soil organic mat- Research is needed to de't~rmine whetherter or increase the immediate N supply and legumes influence losses and availability ofother plant nutrients but cannot effectively do native soil N by cycling soil N03 -N throughboth at the same time. residue incorporation before rice.

Addition of legumes in rice based croppingsystem could conceivably result in en­hanced formation of methane duringani,ierobic decomposition and enhancedformation of nitrous oxide. Hence, fur­ther research is needed to quantify meth­ane and nitrous oxide emissions in low landrice based cropping systems with and with­out legumes.

Integrated use of industrial N fertilizers withlegumes will be essential for sustained highproduction in most rice-legume systems.Study of integrated Nmanagement in in­tensive rice based cropping systp.m has tobe focussed in future.

Rc~eGrch on perennial tree legumes should beintensified since they ore slow growing andcan be used for green leaf manuring ex­tensively.

158 AGRICULTURAL REVIEWS

The multi-purpose legumes and green manurescan be grown with advantage where thefallow period interval before rice transplant­ing is more than 60 days and the soils arewell drained.

Green manuring can improve both thephysical and biological properties of soil.The practical advantages from greenmanuring are great enough to justify fur­ther research.

Green manuring hastens the reclam~tion ofsaline and sodic soils, and has thus provedan important management practice fortheir reclamation. Further research shouldbe tuned for better advantages of greenleaf manuring in problem soils.

Improved management practices like in situincorporation of legumes and green ma­nure crops over the periods with less in­put requirements and energy saving etc.,needs extensive and immediate study ft'rsustainable crop production in future.

ACKNOWLEDGEMENTThe authors are grateful to Dr. K.

Krishnaiah, Project Director, Directorate of RiceResearch for constant encouragement and pro­viding facilities in writing this review article.The authors also wish to thank Mr. A.PremKumar, Stenographer of this Directorate forthe neat typing and execution of the Reviewarticle.

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Philippines. pp. 71-82.Alam. M.M. (1989). M5. Thesis, University of the Philippines. Los Banos. Laguna.Alazard. D. and Hecker. M. (1987). PI. Soil, 101: 141-143.Alazard. D. and Dlihoux, E. (1987). BioI. Fertil. Soils, 4: 61-66.Alberto. M.C.R. (1989). M.S. Thesis. University of the Philippines, Los Banos. Laguna.App. A. et al. (1980). In. Priorities for Alleviating Soil Related Constraints to Food Production In the Tropics. lRR!.

Philippines. pp 319-337.Arllnin, S. et al. (1987). Res. Report., Dept. Land Deve., Bangkok.Bacon. P.E. et al. (1986). Soil Bioi. Biochem., 18: 173-178.l3alasubrcllmmian, R. and Veerabadran, V. (1997). Indian J. Agron., 42: 285-287.Bantilan. RT. et al. (1989). Indigofera tinctoria L. as a green manure in rain fed rice based cropping systems

SClturday Seminar Paper, IRRL Philippines.Barker. R. el al (1985). The Rice Economy in Asia - Resources for the future, Washington DC.Heauchamp. E.G. et al. (1989). Adv. Soil Sci.. 10: 113-142.Becker M. et al. (1990 a). PI. Soil. 104: 120-125.Becker. M. et al. (1988). Biol. Fertil. Soils, 6: 279-281.Becker. M. et al. (1990 b). Soil BioI. Biochem.. 22: 150-156.Becker. M. etal. (1989). Int. Rice Res. Newsl., 14: 27, 30-31.Bergersen. F.J. et al. (1989). Aust J. Agric. Res., 40: 763-780.Beri. V. etal (1989a). Trap. Agric., 66: 11-16.Bed. V. and Meelu a.p. (1981). Indian Farming, 31: 3-4.Beri, V. et al (1989b). Trop. Agric., 66: 209-212.Bhardwaj S.P. etal. (1981). IndianJ. Agric. Sci., 51: 86-90.Hhardwaj, K.K.R. (1974). Indian J. Agric. Sci.• 44: 683-684.Bhardwaj, KKK (1982). Indian J. Agron., 27: 284-285.B:latdwaj. KKK and Dev., S.P. (1985). Trop. Agric., 62: 233-236.Bhatti. H.M. et al. (1985). In: Nitrogen and the Environment (N. Malik, ed), NIAB, Faizalabad. Pakistan.

pp.275-284Bhuiyan, N.!. et al (1989). In: Proc. Workshop on Experiences with Modern Rice Cultivation in Bangladesh.

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