recycling of organic wastes for the production of vermicompost and its response in rice–legume...

European Journal of Agronomy 15 (2001) 153–170

Recycling of organic wastes for the production ofvermicompost and its response in rice–legume cropping

system and soil fertility

A. Jeyabal a,*, G. Kuppuswamy b

a Nagarjuna Agricultural Research and De�elopment Institute, C 15, Vikrampuri, Secunderabad 500 009, Indiab Department of Agronomy, Annamalai Uni�ersity, Annamalainagar 608 002, Tamil Nadu, India

Received 21 February 2000; received in revised form 28 June 2000; accepted 26 October 2000

Abstract

Investigations were made to recycle agricultural and agro-industrial wastes for the production of vermicompostusing earthworms (Eudrilus eugeniae). Its response was studied in a rice–legume cropping system. Differentcombinations of coirpith/weeds and cowdung/sugarcane pressmud/biodigested slurry were tried for vermicomposting.The study showed that biodigested slurry and weeds was found to be an ideal combination for vermicompostingconsidering the nutrient content and compost maturity period. The C/N ratio of vermicompost reduced to 12–17:1from 21–69:1. A pot culture study evaluated the effect of vermicompost in comparison to biodigested slurry andfarmyard manure (FYM) on an equal N basis with and without biofertilizer in rice. The study showed that theintegrated application of vermicompost, fertilizer N and biofertilizers viz., Azospirillum and phosphobacteriaincreased rice yield by 15.9% over application with fertilizer N alone. A field experiment studied the direct andresidual effect of different sources of organic N with fertilizer N and biofertilizers in rice–legume crop sequence. Theintegrated application of 50% N through vermicompost, 50% via fertilizer N and biofertilizers recorded a grain yieldof 6.25 and 0.51 t ha−1 in the rice and legume, respectively. These yields were 12.2 and 19.9% higher than thoseobtained with 100% fertilizer N alone. On average, integrated application increased the N, P and K uptake by 15.3,10.7 and 9.4%, respectively in rice over fertilizer N alone. Organic carbon content in the residual soil after rice wasnot depleted due to integrated application. After the legume, organic carbon content increased by 4.55 to 6.82% dueto integrated nutrition compared to fertilizer alone. Available N in the residual soil was stable after the rice–legumesystem. Available P and K contents of the residual soil were depleted considerably in the rice–legume sequence.However, the amount of depletion of available N, P and K in the fertilizer alone treatment was greater than to theintegrated nutrition. The microbial population of the residual soil was increased by integrated application. The studiesindicate that integrated nutrition comprising vermicompost, fertilizers N and biofertilizers could be applied torice–legume cropping system to achieve higher yields and sustain soil health. © 2001 Elsevier Science B.V. All rightsreserved.

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* Corresponding author. Present address: EID Parry (India) Limited, R&D Centre, Kurumbur, Pudukkotta, 614622, Tamil Nadu,India. Tel.: +91-4322-6124, fax: +91-44371-36451.

E-mail address: [email protected] (A. Jeyabal).

1161-0301/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.

PII: S1161-0301(00)00100-3

A. Jeyabal, G. Kuppuswamy / Europ. J. Agronomy 15 (2001) 153–170154

Keywords: Organic wastes; Vermicompost; Biodigested slurry; Rice; Blackgram; Soil fertility

1. Introduction

Rice is a major staple food crop grown in Asia.An estimated 24% of the increase in Asian riceproduction from 1965 to 1980 was attributed touse of fertilizer, mainly N (Barker et al., 1985).Despite past gains in rice production throughfertilizer, recent observations of stagnant or de-clining yields under continuous rice growing withhigh levels of N fertilizer have raised concernsabout the long-term sustainability impacts ofmonoculture rice receiving high inputs of N fertil-izer. Cropping sequences are regarded as oneagronomic manipulation to preserve productivity.In crop sequences, legumes, with their adaptabil-ity to different rice-based cropping patterns andtheir ability to fix N2, may offer opportunities tosustain increase productivity. Legumes often en-hance soil microbial populations and activity(Bolton et al., 1985) as well as soil structure.Singh (1984) speculated that legumes grown inrotation with rice can scavenge soil mineral N,which might otherwise be lost by denitrification orleaching after the soil is flooded for rice produc-tion. Hence rice– legume crop sequences are con-sidered to be the best crop sequence in thesouthern part of India.

To increase the productivity and to meet theheavy demand for food of the growing popula-tion, it is necessary to recycle available resourcesand wastes. Wastes of animal and plant origin areone of the major under-utilized resources in manycountries. These wastes could not be fully ex-ploited due to the non-availability of a viabletechnology for their economic recycling. Com-posting, the biological oxidation of organic mat-ter, is an important process. However, traditionalmethods of composting result in losses of about55% of organic matter and from 30 to 50% ofnitrogen (Ketkar, 1993).

Vermicomposting has been recognized as aneco-friendly technology for converting organicwastes into high value organic manure (Kale etal., 1982; Senapathi, 1993). Earthworms accelerate

the mineralization rate and convert the manuresinto casts with higher nutritional value and degreeof humification than traditional method of com-posting (Albanell et al., 1988). The increased min-eralization and conservation of nutrients is due tothe biocatalytic role of earthworms in the decom-position and conservation mechanism (Senapathiand Dash, 1984). Anaerobic composting is ananother method by which animal dung can becomposted in 30 to 45 days without considerableloss of nutrients (Kuppuswamy and Jeyabal,1996). In this process, biomass is convertedthrough the action of bacteria breaking downorganic waste in an oxygen free environment andthe effluent (biodigested slurry) is the product ofthe biogas digester and the slurry is rich source ofnutrients (Jeyabal, 1997).

Although there is some information on themanurial value of vermicompost and biodigestedslurry (Kuppuswamy et al., 1992; Jeyabal et al.,1992), research evidence of the direct and residualeffect of vermicompost and biodigested slurry oncrop sequences is lacking. Hence, a series of inves-tigations were carried out to convert differentorganic substrates into vermicompost using theearthworm, Eudrilus eugeniae ; to study the directand residual effect of vermicompost in compari-son to biodigested slurry, FYM and fertilizer Non an equal N basis in a rice– legume croppingsystem and to study the impact of vermicomposton soil fertility.

2. Material and methods

A series of experiments were conducted in twophases from 1994 to 1996 at the Department ofAgronomy, Annamalai University, Annamalaina-gar (India). The experimental site is situated at11o24’ N latitude and 79o44’ E longitude at analtitude of 5.79 m above mean sea level, in thesouthern part of India. The mean annual rainfallis 1512 mm, distributed over 57 rainy days. Themean maximum and minimum air temperatures

A. Jeyabal, G. Kuppuswamy / Europ. J. Agronomy 15 (2001) 153–170 155

are 31.9 and 23.3°C, respectively. Relative humid-ity ranges from 78 to 96%. Soil samples werecollected using a screw auger from 15 to 20 cmdepth. The organic carbon and available N, P andK were analysed adapting a method outlined byJackson (1973). The experimental soil of both thepot and field studies was clay (Udic chromustert).The soil had a pH of 7.4 (1:2 soil and watersuspension), electrical conductivity 0.34 dS m−1

(1:2 soil and water suspension), an organic carbonlevel of 0.43% and available N, P and K were 175,20.5 and 230 kg ha−1, respectively.

3. Phase I

3.1. Vermiculture studies

Five organic substrates were chosen. Cowdungwas fed, at 8% total solid with 45 days retentiontime, to the biogas digester (capacity: 60 m3) andthe biodigested slurry was collected. The biodi-gested slurry as it comes out of the biogas digestercontained about 93 to 94% moisture at pH 7.0.Agricultural and agro-industrial wastes such assugarcane pressmud (a by-product of the sugarindustry), biodigested slurry (effluent from biogasplant), coirpith (a by-product of the coir indus-try), cowdung and weeds from rice fields wereutilized for the preparation of vermicompost.Analyses of these organic materials are presentedin Table 1. Combinations of organic materials

such as coirpith+biodigested slurry, weeds+biodigested slurry, coirpith+cowdung, weeds+cowdung, coirpith+pressmud, weeds+pressmudwere mixed in a 1:1 proportion (Table 2). Hun-dreds of kilograms of these materials were utilizedfor vermicomposting and 250 adult earthworms(Eudrilus eugeniae), known for their higher feed-ing and growth rate (Kale and Sunitha, 1993)were added. The materials were incubated for 120days during which the temperature was main-tained at 20°C with 80% moisture. The earth-worm population at different periods ofcomposting was counted and earthworm livebiomass, compost recovery and duration of com-posting were recorded in all the samples. After thefeed material was converted to loose granularmounds due to feeding and defecation by theworms, the sprinkling of water was stopped tolower the moisture content of the vermicompost.The entire material was collected and two pyrami-dal heaps were made. After a day, a heap wasslowly brushed aside and the adult worms werecollected. The rest of the compost was dried in theshade for 2 days and later sieved with a 3-mmsieve to collect the compost. Samples (100 g) werecollected for analyses. Organic carbon was esti-mated using the method described by Walkleyand Black (1934). Total, ammoniacal and nitratenitrogen, total phosphorus, total potassium andmicronutrients were estimated by adapting amethod outlined by Jackson (1973).

Table 1Composition of nutrients in different organic materials (on total solid basis)

CowdungConstituents CoirpithBiodigested slurry Sugarcane pressmud Weeds

18.6Total solid (%) 6 29 18 2747.3Organic carbon (%) 27.3 44 33 30

1529C:N ratio 11525271.65 1.78Nitrogen (%) 1.61 1.30 0.26

Phosphorus (%) 0.440.70 0.76 1.20 0.36Potassium (%) 0.81 0.88 0.71 0.68 0.29Lignin (%) 29

72018Copper (mg kg−1) 111020131 122 123 84Manganese (mg kg−1)

54 19Zinc (mg kg−1) 298455127125294193225Iron (mg kg−1)


Table 2Nutrient contents of different types of vermicompost at maturity period

Organic N FeNH4−N MnP ZnKC/NOrganic materials Cu(%) (%) (%) (mg kg−1)ratio (mg kg−1)(%) (mg kg−1)(mg kg−1)

Biodigested 17.6 0.68 0.84 0.74 0.52 8 120 51 182slurry+coirpith

13.7 0.78 1.25 0.75 0.54Biodigested 11 115 55 195slurry+weeds

0.61 0.63 0.76 0.51Cowdung+coirpith 817.3 132 57 2250.87 0.98 0.79 0.55Cowdung+weeds 1212.4 125 50 222

16.2 0.60 0.66 1.20Sugarcane 0.62 13 119 53 198pressmud+coirpith

12.5 0.90 0.96 1.39Sugarcane 0.60 10 123 56 229pressmud+weeds

0.16 0.19 0.21 0.043.5 NSLSD (0.05) NS NS NS

4. Phase II

4.1. Response of �ermicompost in rice– legumesequence

4.1.1. Pot culture studyA pot study was carried out during the wet

season, to study the integrated effect of soil appli-cation of N through vermicompost, fertilizer Nand biofertilizers in comparison to fertilizer N onan equal N basis in rice. In this phase of theexperiment, the effect of vermicompost was com-pared with FYM and biodigested slurry with andwithout biofertilizers. The treatment details wereas follows:

T1-50% N through FYMT2-50% N through FYM+AzospirillumT3-50% N through FYM+Azospirillum+phosphobacteriaT4-50% N through biodigested slurryT5-50% N through biodigested slurry+AzospirillumT6-50% N through biodigested slurry+Azospirillum+phosphobacteriaT7-50% N through vermicompostT8-50% N through vermicompost+AzospirillumT9-50% N through vermicompost+Azospirillum+phosphobacteriaT10-100% N through fertilizerIn T1 to T9, the remaining 50% N was supplied

through inorganic fertilizer. Vermicompost devel-

oped from a combination of biodigested slurryand weeds was used. The organic manure wasincorporated 15 days before transplanting as perthe treatment schedule. Biofertilizers, viz.Azospirillum (Azospirillum lipoferum) and phos-phobacteria (Bacillus megaterium var. phos-phaticum) each at 2 kg ha−1, were applied.Thirty-day-old seedlings were transplanted at aspacing of 15×10 cm. Nine seedlings wereplanted per pot. The experiment was conducted ina completely randomized design with threereplications.

4.2. Field studies

Based on the pot study, selected treatmentswere chosen for a field study. The study focusedon the direct and residual effect of soil applicationof vermicompost, biodigested slurry and FYM, incomparison to fertilizer N on an equal N basiswith biofertilizer(s) on a rice– legume croppingsystem. In this phase of the experiment, seventreatments were used. The treatments were asfollows:

T1-50% N through FYM+AzospirillumT2-50% N through FYM+Azospirillum+phosphobacteriaT3-50% N through biodigested slurry+AzospirillumT4-50% N through biodigested slurry+Azospirillum+phosphobacteria


T5-50% N through vermicompost+AzospirillumT6-50% N through vermicompost+Azospirillum+phosphobacteriaT7-100% N through fertilizerAs in the pot studies, organic manure and

biofertilizers were applied. The fertilizer schedulewas 100:50:50 kg N, P2O5 and K2O ha−1. Fertil-izer N through urea was applied in three splits,viz., 50% at basal, just before planting, 25% at 25days after transplanting (DAT) and the remaining25% at 55 DAT. Entire phosphorus was appliedas basal. Potassium was applied in three splits,viz., 50% at basal, 25% at 25 DAT and theremaining 25% at 55 DAT. Plot size was 19.8 m2

(4.95×4.0 m). The experiment was conducted ina randomized block design with three replications.The residual effects of different treatments testedin the main rice crop (Oryza sati�a L. cv. ADT38) were evaluated in the succeeding legume crop,which was blackgram (Phaseolus mungo cv. ADT5). The legume seed was sown 10 days beforeharvest of the rice crop in the residual soil mois-ture as a rice fallow legume. Sowing was donewithout disturbing the rice soil. No organic andinorganic nutrients were supplied as basal to theresidual crop. At the flowering stage, 1% di-am-monium phosphate was sprayed twice. Plant sam-ples of rice and blackgram crops were collected,dried and ground in a Wiley mill and analysed forN, P and K contents. Pre- and post-experimentalcomposite soil samples were collected andanalysed for organic carbon, available nitrogen,phosphorus and potassium. Post-harvest estimatesof soil microbial populations of bacteria, fungiand actinomycetes were made at 45, 120 and 180days after planting of the rice, via the methodoutlined by Alexander (1977).

4.3. Obser�ations

In rice, plant height, the number of tillers andpanicles per m2 were counted from 10 randomlychosen samples from the field experiments. Leafarea index was measured at the flowering stageusing an automatic leaf area meter. The paniclelength, number of filled grains per panicle and1000 grain weight were recorded from 10 ran-

domly selected plants. In the pot study, observa-tions were recorded in all the plants. Grains weredried to 13% moisture content and the pot/plotyield was weighed. In blackgram, plant height,number of nodules per plant, nodule weight, num-ber of filled pods per plant, number of seeds perplant and 100-seed weight were recorded from 10randomly selected plants. The grains were dried to12% moisture content, and weighed for each plot.

5. Results

5.1. Phase I: De�elopment of �ermicompost

5.1.1. Earthworm populationThe earthworm population during the initial

period of composting (30 days) was higher incoirpith (449–473 per m3) than in weeds (334–358per m3). At 60 and 90 days, the earthworm popu-lation in weeds was greater than in coirpith. At 60and 90 days, the sugarcane pressmud and weedscombination showed the highest population ofearthworm (1435 and 2271 per m3, respectively),which was 5.7 and 9.1 times higher than the initialpopulation (Fig. 1). Multiplication rate of earth-worm in biodigested slurry and weeds combina-tion increased by 5.6- and 8.6-fold in 60 and 90days, respectively compared with the initial popu-lation. The corresponding increase in the cow-dung and weeds combination was 5.3- and8.5-fold.

5.1.2. Nutrient content of �ermicompostThe nutrient content of vermicompost varied

due to the different kind of input materials used.The NPK contents were higher in weed-basedvermicompost than in coirpith-based vermicom-post, which may be due to higher content ofnutrients in weeds than in coirpith. Vermicompostbased on a digested slurry and weeds combinationincreased the N content from 1.51% (input mate-rial) to 2.03%. In coirpith-based vermicompost,the N content ranged from 1.24 to 1.52% ascompared with 0.89% in the input material (Table2). Digested slurry based vermicompost had ahigher N content (1.52–2.03%) than cowdung-based vermicompost (1.24–1.85%) and pressmud-


based vermicompost (1.26–1.86%). This may bedue to higher N in digested slurry than in cow-dung and pressmud. However, P and K contentswere much higher in pressmud-based vermicom-post compared with the others because of higherP (1.2%) and K (0.7%) contents in pressmudcompared with cowdung and biodigested slurry.

The carbon nitrogen (C/N) ratio in general wasreduced by all the treatments. Weed-based vermi-compost had a lower C/N ratio (13:1) than thecoirpith-based vermicompost (17:1). The durationof coirpith composting was 85 days, whereasweeds took only 55 days. The compost recovery(weight reduction during the composting) over 30days was about 38% for vermicompost based onweeds as compared with 26% in vermicompost-based on coirpith. This could be due to betterprimary mineralization in the weeds sample thanthat in coirpith. However, at the end of the com-post maturation period, total weight loss wassimilar in all samples.

5.2. Phase II

5.2.1. Response of rice to �ermicompost (potstudy)

The integrated application of 50% N throughorganic manure and 50% N through fertilizerimproved the growth and yield attributing charac-ters compared with 100% N through fertilizer.Application of 50% N through vermicompost in-tegrated with 50% fertilizer N, Azospirillum andphosphobacteria gave 25.9 and 20.1% more tillersand panicles, respectively than 100% fertilizer N.Larger LAI was recorded with integrated applica-tion of N through organic manure, fertilizer Nand biofertilizers than in fertilizer N treatment.Application of vermicompost in combination withfertilizer N and biofertilizers increased the numberof filled grains by 12.0% over the fertilizer Ntreatment (Table 3). Application of 50% Nthrough vermicompost and 50% N through fertil-izer integrated with Azospirillum and phosphobac-

Fig. 1. Earthworm population at different periods of composting.

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Table 3Effect of vermicompost, fertilizer N and biofertilizers on growth and yield of rice (pot study)

Plant No. tillers Leaf areaTreatment No. of panicle Straw yieldPanicle Filled grains Test Grain yieldlength (cm)index per panicleheight (cm) weight (g)per hill (g pot−1)per hill (g pot−1)

48.07 7.90 5.01 6.83T1 20.13 98 20.07 127 21848.43 7.90 5.13 7.10T2 21.43 100 20.33 134 22048.03 8.03 5.40 7.27T3 18.97 103 20.30 142 22248.47 8.07 5.07 6.80T4 19.37 100 20.17 128 212

T5 48.30 8.07 5.10 7.20 20.40 100 20.30 135 21349.17 8.07 5.47 7.63T6 20.07 102 20.40 144 23247.73 8.13 5.06 6.83T7 19.47 98 20.40 131 20849.07 8.17 5.10 7.13T8 19.73 102 20.20 138 213

T9 48.90 8.40 5.40 7.67 21.07 104 20.27 146 23348.30 6.67 5.11 6.57T10 18.53 88 19.93 126 208

LSD (0.05) NS 0.29 0.28 0.35 NS 7.14 NS 3.7 9.8


teria gave 15.9% higher yield than the fertilizertreatment alone. Application of 50% N throughbiodigested slurry integrated with 50% fertilizerN and biofertilizers gave 14.3% higher yield than100% N through fertilizer. However, neither ap-plication of vermicompost nor biodigested slurrycombined with fertilizer N and biofertilizers infl-uenced the panicle length and 1000 grain weightover fertilizer N treatment.

5.2.2. Effect of �ermicompost on the rice– legumecropping system ( field studies)

5.2.2.1. Effect on rice. Integrated application oforganic N, inorganic N and biofertilizers(Azospirillum and phosphobacteria) increased thegrowth and yield attributes of rice under fieldcondition. The highest plant height (75.6 cm) andtiller number (445 per m2) were obtained withthe application of 50% N through vermicompost,50% N through fertilizer, Azospirillum and phos-phobacteria. Irrespective of Azospirillum andphosphobacteria, the effect of vermicompost wasbetter than that of biodigested slurry or FYM.Application of vermicompost in combinationwith fertilizer N and biofertilizers produced asignificantly larger LAI (5.28) than that of fertil-izer N (5.06). Vermicompost integrated with fer-tilizer N and biofertilizers (Azospirillum andphosphobacteria) produced 7.1 and 13.3%greater dry matter production at flowering andmaturity stages, respectively, than application of100% fertilizer N alone (Table 4). In most of thegrowth and yield attributes, the effect of the ad-dition of N through biodigested slurry rankedsecond to that of vermicompost.

Application of vermicompost in combinationwith fertilizer N and biofertilizers gave thehighest number of panicles (339 per m2), whichwas 13.8% higher than fertilizer N (298 m2).Biodigested slurry integrated with fertilizer Nand biofertilizers produced 11.9% more paniclesthan fertilizer N. Addition of Azospirillum andphosphobacteria to either biodigested slurry orvermicompost had a significant effect on thenumber of filled grains. These treatments in-creased the filled grains by about 9.5% over fer-tilizer N. The integrated use of organic N

through vermicompost, fertilizer N, Azospirillumand phosphobacteria gave a grain yield of 6.25t ha−1, which was 12.2% higher than that ob-tained with fertilizer N (5.57 t ha−1). Regardlessof fertilizer N and biofertilizers, application of Neither through vermicompost or biodigestedslurry had a clear advantage over FYM.

Integrated application of N through vermi-compost, fertilizer N and biofertilizers produced20.6% higher N uptake than the application offertilizer N alone (Fig. 2). Irrespective of fertil-izer N and biofertilizers, the application of ver-micompost produced 10.1% higher N uptakethan FYM. Phosphobacteria addition increasedthe P uptake by 14.1% over treatments withoutphosphobacteria. The combination of biofertiliz-ers with either vermicompost or biodigestedslurry gave 15.1% higher P uptake than fertilizerN. Integrated application of organic, inorganicand biofertilizers improved K uptake by 8.8–14.0%.

5.2.2.2. Residual effect on the legume. The resid-ual effect of organic manures, inorganic nutrientsand biofertilizers applied to the rice was studiedin the succeeding legume. The residual effect ofN supplied through vermicompost, fertilizer Nand Azospirillum produced 26.8 and 11.6%higher nodule number and nodule weight, respec-tively, than fertilizer N (Table 5). Nitrogenthrough vermicompost produced greater noduleweight than N through either biodigested slurryor FYM. Biodigested slurry and FYM were simi-lar with respect to number of nodules and nod-ule weight. The application of vermicompost incombination with fertilizer N and biofertilizersgave 23.3 and 8.1% higher number of filled podsand seeds, respectively, over fertilizer N alone.Application of N through vermicompost inte-grated with fertilizer N and biofertilizers gave thehighest grain yield (0.51 t ha−1), which was19.9% higher than fertilizer N alone. Integratedapplication of biodigested slurry, fertilizer N andbiofertilizers gave 16.8% higher yield than fertil-izer N. Irrespective of fertilizer N and biofertiliz-ers, vermicompost gave 2.4 and 7.6% highergrain yield than digested slurry and FYM, re-spectively.

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Table 4Effect of integrated application of vermicompost, fertilizer N and biofertilizers on growth and yield of rice (field study)

PlantTreatment Number of Total TestLeaf area DMP* FilledPanicle Straw yieldPanicle Grain yieldtillers grains perindex (t ha−1) length (cm) number (t ha−1)height (cm) grains per weight (g) (t ha−1)

per m2per m2 paniclepanicle

73.2 404 5.20 10.3T1 21.3 313 149 130 20.6 5.72 7.7673.9 422 5.21 10.4 22.3T2 329 155 133 20.8 5.95 7.9973.5 428 5.31 10.6 22.2 320T3 149 130 20.6 5.98 7.8973.6 434 5.38 10.7 22.6T4 334 156 134 20.7 6.18 8.17

T5 74.0 422 5.27 10.9 22.3 332 152 130 20.6 6.07 8.0075.6 445 5.28 11.2 22.6 339 157T6 134 20.8 6.25 8.2168.3 388 5.06 10.2 20.1T7 298 145 122 20.6 5.57 7.61

LSD (0.05) 1.17 4.60 0.12 0.15 1.21 4.40 2.99 3.18 NS 0.13 0.35

* DMP, dry matter production.

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Table 5Residual effect of vermicompost, fertilizer N and biofertilizers on growth, nutrient uptake and yield of the legume

Plant Number of podsTreatment DMP* Nutrient uptake (kg ha−1)Nodule number Grain yieldNodule Number ofper plant seeds per podheight (cm) weight (mg)(t ha−1) (t ha−1)per plant

N P K

22.7 0.85 33.4 147T1 15.5 6.5 0.467 24.2 5.3 29.522.4 0.86 32.5 149 15.5T2 6.4 0.472 26.4 5.7 31.4

T3 23.5 0.84 29.7 143 15.6 6.5 0.493 23.1 4.8 32.924.1 0.86 32.4 147 15.5T4 6.5 0.495 25.8 5.5 30.8

T5 22.5 0.99 34.5 154 16.3 7.1 0.504 27.1 6.2 33.223.7 1.00 33.8 151 16.7 6.9T6 0.506 27.3 6.3 32.822.3 0.82 27.2 138 13.6T7 6.4 0.422 21.4 5.0 25.6

LSD (0.05) NS 0.06 3.6 6.4 0.28 NS 0.003 4.3 0.2 2.4

* DMP, dry matter production.


Fig. 2. Effect of integrated nutrient on crop nutrition uptake and soil-available nutrients.

5.2.3. Post-har�est soil nutrient statusOrganic carbon content of the soil after rice did

not vary due to the integrated application oforganic, inorganic nutrients and biofertilizers overthe initial soil level, but application of N throughfertilizer alone depleted organic carbon by 4.7%over the initial soil (Fig. 3). After the legumecrop, integrated application enhanced the organiccarbon status by 4.55 to 6.82% over the fertilizeralone treatment, and even, organic carbon in thefertilizer alone treatment was not depleted in com-parison with the initial soil value due to theeffective root nodules produced by legumes,which will have contributed atmospheric nitrogento the soil. Soil pH was not significantly influ-enced by the different treatments.

Integrated nutrition improved the available Ncontent (179–182 kg ha−1) in the rice– legumecrop sequence over the fertilizer alone treatment(157 kg ha−1). But, after the rice– legume crop-ping sequence, although there was considerable Nremoval by the legumes (23–27 kg ha−1), theavailable soil N did not vary from the initial soillevel (175 kg ha−1) due to integrated nutrition(Fig. 4). Whereas application of the entire Nthrough fertilizer treatment depleted the availableN status (153 kg ha−1) by 12.6% over the initial

soil (Fig. 5). Regardless of fertilizer N and biofer-tilizers, the application of vermicompost gave 5.2and 8.9% higher soil P than biodigested slurry andFYM, respectively (Fig. 6). Regardless of thedifferent organic manure integrated with fertilizerN and biofertilizers, the available K in post-har-vest soil of rice– legume sequence was depletedover the initial soil (Fig. 7). However, in treat-ments involving integrated nutrition, the depletionlevel was less compared with the inorganic Nfertilizer treatment.

6. Discussion

6.1. Phase I: Vermiculture studies

6.1.1. Earthworm populationThe earthworm population during initial period

of composting (30 days) was higher in coirpiththan in weeds. The fibrous nature of coirpith andits high moisture holding capacity might haveinfluenced higher earthworm population in coirp-ith than in weeds. It was observed that weedsrequired 2–3 days partial degradation for stabi-lization of earthworm activity. This might haveresulted in low population of earthworms in


weeds compared with coirpith. However, at 60and 90 days, the sugarcane pressmud and weedscombination showed the highest population ofearthworm, which was 5.7- and 9.1-fold higherthan the initial population, respectively (Fig. 1).At 60 and 90 days, the earthworm population inweeds was greater than in coirpith, which couldbe attributed to higher multiplication rate ofearthworms after the partial degradation ofweeds. Higher lignin content (29%) in coirpith,which is less preferable to earthworms, may be thereason for low multiplication rate in coirpith atlater periods.

Vermicompost was developed using six combi-nations of organic sources. In general, irrespectiveof vermiculture media, the N content in vermi-compost was higher than in the pre-vermicompost(input) materials. Production of vermi-castings,earthworm dead tissue, nitrogen excretion andstimulated activity of N-fixing bacteria during thecomposting process would have been responsible

for higher N content in vermicompost (Danieland Anderson, 1992). The duration of the com-posting and the nutrient content of vermicompostwere varied due to the different kind of inputmaterials used. A longer duration for compostingfor coirpith could be ascribed to its higher lignincontent (29%) and high C/N ratio (115:1). TheC/N ratio, which is one of the most widely usedindices for compost maturation, decreased in thedifferent vermicompost samples from 25–115 to18–12. This could be due partly to an increase inthe total N and partly to a carbon decrease in thevermicompost (Vinceslas-Akpa and Loquet,1994).

6.2. Phase II

6.2.1. Effect of �ermicompost integrated withfertilizer N and biofertilizers on rice

The effect of vermicompost integrated with fer-tilizer N and biofertilizers on rice was studied in

Fig. 3. Effect of integrated nutrition on soil organic status.


Fig. 4. Effect of integrated nutrition on residual soil nutrient status.

both pot culture and the field experiments. Formost of the growth and yield characters, theresponse of soil applying 50% N through vermi-compost integrated with 50% N through fertilizer,and the biofertilizers, namely Azospirillum andphosphobacteria, was better than that via applica-tion of N through either biodigested slurry orFYM, combined with fertilizer N and biofertiliz-ers. The favourable effect of vermicompost ongrowth could be attributed to the readily availableN (NH4–N) from the assimilable products ofexcretion, mucoprotein, vermicast and rapid min-eralization of body tissues of the earthworms(Satchell, 1967), which lead to greater availabilityof nutrients in the initial stages of crop growth.

This could be the reason for taller plants andproduction of higher number of tillers in thevermicompost-applied treatments.

Application of vermicompost in combinationwith fertilizer N and biofertilizers produced largerLAI than that of fertilizer N. The presence ofnitrates and available forms of phosphorus, cal-cium and magnesium in vermicasts (Madan, 1993)might have favourably influenced LAI. With ahigher leaf area index, plants may become photo-synthetically more active, which would contributeto improvement in yield attributes (Sharma andMittra, 1988).

Addition of Azospirillum and phosphobacteriato vermicompost had a significant positive effect


on the number of filled grains. Integrated use oforganic N through vermicompost, fertilizer N,Azospirillum and phosphobacteria increased yieldby 12.2 and 15.9% in pot and field studies, respec-tively, over that obtained with fertilizer N. Theincreased yield in this treatment is mainly due tobetter mineralization, increased nutrient uptakeand the enhanced microbial population.

In most of the growth and yield attributes, theaddition of N through biodigested slurry rankedsecond to that of vermicompost. Early mineraliza-tion of nitrogen due to a high level of NH4–N inthe biodigested slurry might have been responsiblefor greater grain yield in biodigested-slurry-ap-plied treatments. Application of 50% N throughbiodigested slurry integrated with 50% fertilizer Nand biofertilizers gave 14.3% higher yield than100% N through fertilizer. The biodigested slurryhad mineralized N to the extent of 21.3% of totalN compared with 16.2% in traditional compost(Ketkar, 1993). Barnett et al. (1978) observed that

N and P contents in biodigested slurry were in-creased by 40 to 50% as a result of mineralization.The presence of a higher amount of readily avail-able N in biodigested slurry might have influencedplant height, tiller production, LAI and dry mat-ter production. The lower grain yield in N sup-plied through FYM may be attributed to the poornutrient supplying capacity of FYM, which hasmost of its N in the organic form. There couldalso be less fixation of N and less solubilization ofP due to the low microbial population observedwith the FYM treatment.

An increased uptake of nitrogen, phosphorusand potassium was observed in the integratedapplication of nutrients as a consequence of betternutritional environment offered through the cu-mulative effect of organic, inorganic sources ofnutrients and biofertilizers. The greater mineral-ization of N, increased availability of nutrients byvermicompost with presence of Azospirillum,which increases root enzymatic activities and pro-

Fig. 5. Effect of integrated nutrition on nitrogen balance in rice– legume cropping systems.


Fig. 6. Effect of integrated nutrition on P balance in rice– legume cropping systems.

duces greater root vigour and density due tonitrogen fixation (Bashan and Levanony, 1990),might have enhanced the N uptake. This could bealso attributed to the substantial increase in mi-crobial population at post-harvest soil in the ver-micompost applied treatment (Fig. 8). Theincreased uptake of P by phosphobacteria couldbe attributed to its greater P-solubilization poten-tiality in the presence of organic matter (Sharmaand Singh, 1971). Further, numerous bacteria arealso responsible for greater P solubilization (Alex-ander, 1977). Organic fertilizer provides signifi-cant cation exchange capacity to hold cationssuch as K+. The change in cation exchange ca-pacity of organics by acidification might haveenhanced K availability (Magdoff and Bartlett,1985).

6.2.2. Residual effect on legumesApplication of N through vermicompost inte-

grated with fertilizer N and biofertilizers increased

legume seed yield by 19.9% over the fertilizer Ntreatment. The narrow C/N ratio (12:1) andhigher microbial population in vermicompost, inaddition to the role of Azospirillum and phospho-bacteria, could be the reason for the favourableeffect of integrated application of vermicompost,fertilizer N and biofertilizers on residual legumecrop. The integrated application of biodigestedslurry, fertilizer N and biofertilizers gave 16.8%higher yield than fertilizer N. The higher micro-bial population and enhanced nutrient uptake inintegrated application involving organics (vermi-compost/ biodigested slurry), inorganic nutrientsand biofertilizers observed in the present studymight have influenced the yield of the residuallegumes.

6.2.3. Post-har�est soil nutrient statusThe increased population of beneficial microor-

ganisms in the rhizosphere of plants due to theaddition of vermicompost reflected the synergy


Fig. 7. Effect of integrated nutrition on K balance in rice– legume cropping systems.

Fig. 8. Effect of vermicompost integrated with N fertilizers and biofertilizers on soil microbial populations.


between microorganisms and vermicompost in thesoil, which might have favourably influenced theavailable N content. This effect could also beascribed to high N fixation as a result of inclusionof Azospirillum in the integrated nutrition. Ascould be expected, addition of phosphobacteriawas effective in increasing the available P in thepost-harvest soil after the rice crop, by solubiliza-tion and mobilization of the native soil P. Thedistinct effect of vermicompost could be at-tributed to a higher population of several bacteriaand fungi, which are capable of solubilizing soil P(Gaur, 1984). Regardless of different organic ma-nures integrated with fertilizer N and biofertiliz-ers, the available K in post-harvest soil of therice– legume sequence was depleted over the initialsoil. However, in treatments involving integratednutrition, the depletion level was less comparedwith the entire N through fertilizer treatment.

7. Conclusion

This study clearly showed that the judiciousintegration of 50% N through vermicompost, 50%N through fertilizer and biofertilizers, Azospiril-lum and phosphobacteria, each at 2 kg ha−1 willgo a long way in achieving the much desiredincrease in yields of the rice– legume croppingsequence and meet the requirements of an ever-growing world population without affecting theproduction base – the soil.

References

Albanell, E., Plaixats, J., Cabrero, T., 1988. Chemical changesduring vermicomposting (Eisenia fetida) of sheep manuremixed with cotton industrial wastes. Biol. Fert. Soils 6,266–269.

Alexander, M., 1977. Introduction to Soil Microbiology, 2ndedn. Wiley, New York.

Barker, R., Herdt, R.W., Rose, B., 1985. The Rice Economyin Asia. Resources for the Poor. Washington, DC.

Barnett, A., Pyle, I., Subramanian, S.K., 1978. Biogas Tech-nology in the Third World: A Multidisciplinary Review.Int. Dev. Res. Centre, Ottawa, Ontario, Canada.

Bashan, Y., Levanony, H., 1990. Current status of Azospiril-lum inoculation technology: Azospirillum as a challenge foragriculture. Can. J. Microbiol. 30, 591–608.

Bolton, H., Jr Elliot, L.F., Papendick, R.I., Bezdicek, D.F.,1985. Soil microbial biomass and selected soil enzymeactivities: Effects of fertilization and cropping practices.Soil Biol. Biochem. 17, 297–302.

Daniel, O., Anderson, J.M., 1992. Microbial biomass andactivity in contrasting soil materials after passage throughthe gut of the earthworm Lumbricus rubellus Hoffmeister.Soil Biol. Biochem. 24, 465–470.

Gaur, A.C., 1984. Bulky organic manures and crop residues.In: Tandon, H.L.S. (Ed.), Fertilizers, Organic Manures,Recyclable Wastes and Biofertilizers. Fertilizer Develop-ment and Consultation Organization, New Delhi, pp. 36–51.

Jackson, M.L., 1973. Soil Chemical Analysis. Prentice Hall ofIndia Inc., New Delhi.

Jeyabal, A., 1997. Agronomic evaluation of bio-digested slurryfor rice–blackgram cropping system. PhD Thesis, DepAgron, Annamalai Univ, Annamalainagar, Tamil Nadu.

Jeyabal, A., Kuppuswamy, G., Lakshmanan, A.R., 1992. Ef-fect of seed coating in yield attributes and yield of soybean(Glycine max L.). J. Agron. Crop Sci. 169, 145–150.

Kale, R.D., Bano, K., Krishnamoorthy, R.V., 1982. Potentialof Perionyx exca�atus for utilization of organic wastes.Pedobiologia 23, 419–425.

Kale, R.D., Sunitha, N.S., 1993. Utilization of earthworms inrecycling of household refuse – a case study. In: BiogasSlurry Utilization. Consortium on Rural Technology, NewDelhi, pp. 76–79.

Ketkar, C.M., 1993. Use of biogas slurry in agriculture. In:Biogas Slurry Utilization. Consortium on Rural Technol-ogy, New Delhi, pp. 24–26.

Kuppuswamy, G., Jeyabal, A., 1996. Biogas from alternativefeedstocks. Dept Agron., Annamalai Univ, Annamalaina-gar, India.

Kuppuswamy, G., Jeyabal, A., Lakshmanan, A.R., 1992. Ef-fect of enriched biogas slurry and farm yard manure ongrowth and yield of rice. Agri. Digest 12, 101–104.

Madan, M., 1993. Organic waste recycling with earthworms:Potential sources for energy conservation in India. In:Biogas Slurry Utilization. Consortium on Rural Technol-ogy, New Delhi, pp. 83–91.

Magdoff, F.R., Bartlett, R.J., 1985. Soil pH buffering revis-ited. Soil Sci. Soc. Am. 49, 145–148.

Satchell, J.E., 1967. Lumbricidae. In: Burges, A., Raw, F.(Eds.), Soil Biology. Academia, London, pp. 259–322.

Senapathi, B.K., 1993. Vermitechnology in India. In: SubbaRao, N.S., Balagopalan, C., Ramkrishna, S.V. (Eds.), NewTrends in Biotechnology. Oxford and IBH, New Delhi, pp.347–358.

Senapathi, B.K., Dash, M.C., 1984. Functional role of earth-worms in the decomposer sub-system. Trop. Ecol. 25 (2),54–73.

Sharma, A.R., Mittra, B.N., 1988. Effect of combination oforganic materials and nitrogen fertilizer on growth, yieldand nitrogen uptake of rice. Agri. Sci. Camb. 3, 605–608.

Sharma, J.P., Singh, M., 1971. Response of rice to phosphaticand nitrogenous fertilizers with and without phosphobacte-ria in culture. Indian J. Agron. 16, 15–18.


Singh, N.T., 1984. Organic matter and rice. Indian Agri. Res.Inst., New Delhi, pp. 217–228.

Vinceslas-Akpa, M., Loquet, M., 1994. CPMAS NMR spec-troscopy of organic matter transformation in ligno-cellu-losic waste products composted and vermicomposted

(Eisenia fetida andrei ). Eur. J. Soil Biol. 30, 17–28.Walkley, A., Black, I.A., 1934. An estimation of the effect of

degtjareff method for determining soil organic matter anda proposed modification of the chromic acid titrationmethod. Soil Sci. 37, 29–38.

recycling of organic wastes for the production of vermicompost and its response in rice–legume...

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