NUTRIENT MANAGEMENT FOR ENHANCED YIELD AND QUALITY OF SOYBEAN (

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1 Legume Res., 35 (3) : , 2012 Vol. 35, No. 3, AGRICULTURAL RESEARCH COMMUNICATION CENTRE ccjournals.com / indianjournals.com nals.com NUTRIENT MANAGEMENT FOR ENHANCED YIELD AND QUALITY OF SOYBEAN ( (GL GLYCINE MAX.) ) AND RESIDUAL SOIL FERTILITY Sumit Chaturvedi,* A.S. Chandel and A.P.. Singh Department of Agronomy, College of Agriculture, G.B. Pant University of Agriculture & Technology, Pantnagar , India Received : Accepted : ABSTRACT A field experiment was conducted during rainy seasons of and Four ourteen treatments consisting of two fertility levels (50% and 100% recommonded NPK) and their combination with FYM and supplementary nutrients viz. boron and iron besides control were tested in randomized block design with three replications. The results revealed that soybean yield attributed to cumulative effect of yield attributes viz.,, pods/ plant, seeds/pod and hundred seed weight were increased significantly by the addition of micronutrients and FYM at both the fertility levels (50% and 100% NPK). Integrated use of FYM (10.0 t/ha) and micronutrients viz.,, boron (2.0 kg/ha) and iron (5.0 kg/ ha) with inorganic NPK can replace upto 10 kg N, 30 kg P 2 O 5 and 20 kg K O/ha. Mean relative 2 growth rate (RGR) and net assimilation rate (NAR) and leaf area index (LAI) were significantly affected by supplementation of inorganics (50% and 100% NPK) with FYM and/or micronutrients viz.,, boron and iron. Application of FYM, boron and iron along with inorganic fertilizer (50% and 100% recommended NPK) also significantly increased the root dry biomass, number of nodules, dry weight/plant and leghaemoglobin content at 60 days stage. Net returns and benefit: cost ratio was highest where boron (2.0 kg/ha) was applied with 100 % NPK and lowest in control (Inoculated). Highest protein and oil content and yield were e recorded with RDF + FYM. Application of FYM, Fe and B with both 50 and 100% recommended fertilizers (RDF) markedly improved the content of unsaturated fatty acids (linolenic, linoleic and oleic) and reduced the content of saturated fatty acids (palmatic and stearic). Use of organic sources and micronutrients helped in maintaining soil fertility in terms of available nutrients and fertility balance. It was concluded that application of FYM and micronutrients viz.,, Fe e and B along with 100 % NPK was essential for higher productivity and profitability of soybean as well as maintaining soil fertility tility. Key words:glycine max, Grain yield, Quality, Integrated nutrient management, Leghaemoglobin, Nutrient balance, Residual soil fertility. INTRODUCTION Soybean (Glycine max) with its 40-42% protein and 20-22% oil has already emerged as one of the major rainy season cash crop and its cultivation is fast spreading in India. Still the productivity of the crop is very low (FAI, 2006). Nutrition imbalance is one of the important constraints of soybean productivity in the North Indian plains (Chandel, 1989 and Tiwari, 2001). Due to continuous cultivation of legumes, regular application of phosphate and nitrogenous fertilizers, the native micronutrient content in soils often becomes inadequate (Singh et al., 2008) for crop *Corresponding author bobby_kvk@rediffmail.com nutrition. Plants receiving higher levels of micronutrients have larger nodules and enhanced symbiotic nitrogen fixation (Green wood and Hallsworth, 1960) in subterranean clover and also increased leghaemoglobin content, grain yield and nitrogen content in soybean (Abdel Wahab et al., 1996). Integration of inorganic fertilizers, organic manures and biological sources and their efficient management has shown promise in not only sustaining the productivity and soil health but also in meeting part of crops nutrients requirement. Under present scenario it has become essential to think of soil-plant-atmosphere as a whole rather than

2 176 LEGUME RESEARCH thinking only about crops. This necessitated evaluating the response of soybean and fertility status of soil to different nutrient management modules in mollisols of North India. MATERIALS AND METHODS The experiment was conducted during the rainy season (kharif) of and at the Crop Research Centre of G.B. Pant University of Agriculture & Technology, Pantnagar situated at 29 0 N latitude, E longitude and at an altitude of msl. The soil of the experimental field was silty clay loam mollisol having ph 7.3 with organic carbon 0.79%, available N kg/ha, available P 20.1 kg/ha and available K kg/ha. The M DTPA-extractable Fe (Lindsay and Norvell, 1978) was 4.97 ppm and available boron was 0.43 ppm. The experiment was laid out in a randomized block design with three replications. Fourteen treatments were compared comprising of different combinations of two fertility levels 50 % recommended NPK ( kg/ha) and 100% recommended NPK ( kg/ha) with 10 t/ha and micro nutrients viz. 2 kg/ ha, 0.5 % borax spray and 5 kg/ha, 0.5 % ferrous sulphate spray besides control. All the treatments including control were treated with Bradyrhzobium japonicum culture. The required amount of FYM containing 0.32% N, 0.20% P, 0.40% K, 2.1 ppm B and 2000 ppm Fe as per the treatment was incorporated into the soil 15 days before sowing of soybean crop. Soybean cv. PK 1042 was grown during July to November at a row spacing of 60 cm. Boron and iron were applied as borax (Na 2 B 4 O 7.10H 2 O) and ferrous sulphate (FeSO 4.7H 2 O) commercial grade at sowing and thoroughly mixed in 0-15 cm soil, whereas spray of borax and ferrous sulphate was done at 45 days after sowing in respective treatments. Soybean was inoculated at the rate of 500g Bradyrhizobium japonicum culture/75 kg seed. Optimum plant population of 0.4 million plants/ha was maintained by thinning. The observations on physiological parameters such as leaf area index (LAI), mean crop growth rate (CGR) mean relative growth rate (RGR), mean net assimilation rate (NAR) during days period were calculated by the formula as described by Radford (1967). Roots dry weight and nodulation parameters were also determined. Leghaemoglobin content of fresh nodules was estimated by colorimetric procedure (Proctor, 1963). The protein and oil contents were analyzed following standard procedures given by Association of Official Analytical Chemists (AOAC). Fatty acids were determined in Hewlett Packard (model 5980 series II) gas chromatograph (GC) equipment. Soil samples up to the depth of 30 cm were collected at harvest and analyzed for available N, P, K, Fe and B contents for change in nutrient status from the initial levels. The grain yield at 14% moisture was reported as tonnes/ha. Since data followed the homogeneity test, pooling was done over the seasons and mean data are given. RESULTS TS AND DISCUSSION Growth parameters : Dry matter yield per plant differed significantly due to different treatments (Table 1). Highest dry matter production per plant was recorded when recommended NPK was applied with 10 t /ha. Better response was also observed in treatments receiving boron and iron spray along with 100 % recommended NPK compared to other treatments. Response of soybean to optimum nutrition revealed that dry matter per plant increased with 100 % recommended NPK over biological nutrition (control) and 50% recommended NPK whether applied with FYM, Fe and B or alone. This might be due to high accumulation of net photosynthates due to optimum dose of NPK and availability of energy sources for prolonged time from integrated sources of nutrients. On the other hand, lowest dry matter per plant was recorded in control plots. The results indicate marked differences for all the physiological growth parameters due to different treatments at 60 days stage (Table 1). The LAI increased with the application of nutrients either inorganic, organic or their combination (INM) at recommended rate over and above biological nutrition alone (symbiotic nitrogen fixation) and sub-optimal fertilization (50% recommended NPK). 100 % recommended NPK + 10 t/ha recorded maximum LAI which was at par with 100 % recommended NPK alone and supplied with any of the supplementary nutrients viz., 2.0 kg ha -1, 5.0 kg/ha, 0.5% ferrous sulphate spray and 0.5% borax spray. 50% recommended NPK + 10 t/ha was also statistically at par with treatment

3 Vol. 35, No. 3, TABLE 1. Effect of integrated nutrient management on dry matter, physiological growth parameters, nodulation, leghaemoglobin content at 60 days stage in soybean and residual soil fertility after harvest (Pooled data for 2 yrs). Treatment Dry Physiological Growth Nodulation Leghaemoglobin Available nutrient status matter Parameters Parameters content (g / (mg /g N P K B Fe plant) LAI RGR NAR No. of Nodules fresh nodule (kg/ha) (kg/ha) (kg/ha) (mg/kg) (mg/kg) (g/g/day) (g/cm 2 / nodules/ dry weight 10 3 ) day x plant weight 10 4 ) (g/plant) *199.0 *20.1 *165.8 *0.431 *4.97 Control inoculated Control kg/ ha Control kg/ ha Control + 10 t/ ha % recommended NPK % recommended NPK kg/ ha 50 % recommended NPK kg /ha 50 % recommended NPK t /ha 100 % recommended NPK % recommended NPK kg /ha 100 % recommended NPK kg /ha 100 % recommended NPK t /ha 100 % recommended NPK % Ferrous Sulphate spray 100 % recommended NPK % Borax spray C.D. (p = 0.05) NS * Soil initial values

4 178 LEGUME RESEARCH having highest LAI. Lowest value for leaf area index was in control (inoculated). Bisht and Chandel (1991) reported that application of the fertilizer, singly or in combination increased LAI and photosynthetic efficiency of soybean. Highest mean RGR and NAR was recorded in the treatment where 100 % recommended NPK + 0.5% ferrous sulphate spray was applied which was at par with all the treatments where 100 % recommended NPK was either applied with 0.5% borax spray, 10 t/ha or 5.0 kg/ha. 50% recommended NPK+ 10 t /ha was also statistically comparable to highest recorded treatment viz., 100 % recommended NPK + 0.5% ferrous sulphate spray. High leaf-area and dry matter production in plants receiving 100 % recommended NPK along with FYM, Iron and Boron also resulted in increased growth parameters like RGR and NAR. The results confirm the findings of Kumar and Rao, (1991). Nodulation and Leghaemoglobin content : The effect of application of organics and micronutrients in combination with inorganics was significant on number of nodules, and their dry weight (Table 1) at 60 days. Numbers of nodules per plant and dry weight which are also the indication of extent of root establishment were improved significantly by the application of recommended dose of fertilizer (Table 1). Number of nodules per plant was found maximum in the treatment applied with 100 % recommended NPK+ 10 t/ha which was statistically at par with treatments having iron or FYM at both the fertility levels viz., 100 % recommended and 50% recommended NPK. Nodules dry weight per plant also increased to maximum in the treatment having 100 % recommended NPK+ 10 t/ha which was statistically superior to control inoculated, 50% recommended NPK, 2.0 kg/ha, 5.0 kg/ha and 10 t/ha treatments. Lowest values for nodulation were reported in control. Increase in number of nodules and dry weight per plant due to increased nutrition is expected because balanced availability of nutrients which was very much necessary for growth and development of nodules. Besides, Rhizobium inoculation was also helpful in increasing number of nodules per plant. Similar finding was reported by Tomar et al. (1991). The pooled data indicated that there was a significant increase in leghaemoglobin content in nodules due to integrated application of NPK with organics and micronutrients (Table 1). Highest leghaemoglobin content of the treatment having 100 % recommended NPK + 10 t/ha was significantly higher than control inoculated, 50% recommended NPK, 2.0 kg/ha, 5.0 kg/ha, 10 t/ha and half of recommended NPK kg/ha. Lowest value was recorded in control inoculated. Per cent increase in leghaemoglobin content in 100 % recommended NPK + 10 t/ ha over control was The maximum leghaemoglobin in recommended dose of fertilizer might possibly be due to starter-n which enhanced nodulation and ultimately leghaemoglobin content in root nodule by creating favorable conditions for bacterial growth. These findings are in agreement with Majumdar and Behera (1991). Yield contributing characters and yield : Yield contributing characters of soybean were influenced significantly by the application of organics in combination with inorganic sources of nutrients (Table 2). Hundred per cent (100%) recommended fertilizer dose of NPK resulted in significantly higher values with respect of number of pods/plant, number of grains/pod, and 100 grain weight and harvest index as compared to control. The values of pods/ plant, grains/plant, 100 grain weight and harvest index also increased significantly by integrating FYM and supplementary nutrients like, iron and boron with NPK. However, maximum values of yield contributing characters were recorded in combined application of 100 % recommended NPK + 10 t/ha, indicating that supplementing inorganic fertilizers with organic sources like FYM improved the general soil environment, physico-chemical and biological conditions which helped to improve the soybean growth and yield contributing characters. Similar findings were also reported by Singh, et al. (2007). Grain and straw yield of soybean were affected significantly (Table 2). Recommended rate of fertilizer (NPK) gave better grain yield of soybean than the control. Increased application of chemical fertilizers from 50 to 100 % NPK also increased the yield significantly. Combined application of FYM and supplementary nutrients (Fe and B) with chemical fertilizer also increased the grain and straw yield of

5 Vol. 35, No. 3, TABLE 2: Effect of integrated nutrient management on yield attributes, yield and economics of soybean (Pooled data for 2 yrs). Treatment Number Number 100-seed Harvest Grain Straw Economics of pods/ of grains/ weight index yield yield Cost of Net B : C plant plant (g) (q /ha) (q/ ha) cultivation return ratio (Rs/ ha) (Rs /ha) (Rupees per rupee invested) Control inoculated Control kg/ ha Control kg/ ha Control + 10 t/ ha % recommended NPK % recommended NPK kg/ ha 50 % recommended NPK kg /ha 50 % recommended NPK t /ha 100 % recommended NPK % recommended NPK kg /ha 100 % recommended NPK kg /ha 100 % recommended NPK t /ha 100 % recommended NPK % Ferrous Sulphate spray 100 % recommended NPK % Borax spray C.D. (p = 0.05)

6 180 LEGUME RESEARCH soybean. 100 % recommended NPK + FYM 10 t/ha gave the maximum yield which was 25.3, 59.8, 103.9, 85.1 and 50.0 % higher over 100 % recommended NPK, 50 % recommended NPK, 2.0 kg/ha, 5.0 kg/ha and 10 t/ha applied alone, respectively. Application of 10 t/ha with 50 % NPK gave yield higher then 100 % recommended NPK dose when applied singly. The results on grain yield thus confirmed the trend observed earlier in the yield contributing characters and upheld the need of supplementing the 100 % chemical fertilizer level with 10 t/ha of FYM, emphasized the utter need for organic manuring along with chemical fertilizers. Economics : The mean values of two years revealed that cost of cultivation increased with the addition of FYM and micronutrients at both the fertility levels viz., 100 and 50 % recommended NPK (Table 2). Appreciably maximum cost Rs / ha in soybean production was involved with 100 % recommended NPK kg/ha followed by Rs /ha with 100 % recommended NPK + 0.5% ferrous sulphate spray. Whereas, lowest cost of cultivation of Rs. 7781/ha was observed with control inoculated. Net returns and benefit: cost ratio increased with supplementation of NPK with organics viz., FYM and micronutrients viz., B and Fe at both the fertility levels. Highest net returns and benefit: cost ratio was obtained with 100 % recommended NPK + 10 t/ha. That was because additional cost of organic manures was compensated by the additional yield of soybean. FYM integrated with 50 % recommended NPK also resulted in higher net returns and B:C ratio than recommended NPK. This was due to higher returns obtained and relatively low cost of FYM and 50 % substitution of NPK. Oil and protein content and yield : Quality of soybean grain is decided by proportion of various nutrients accumulated and or developed into an essential molecule. Nutrient management had significant influence on protein and oil content and yield (Table 3). Significantly higher protein and oil content were observed in the treatment applied with 100 % recommended NPK + FYM which were at par with 100 % recommended NPK when applied with 2.0 kg B/ha, 0.5% borax spray, 5.0 kg Fe/ha and 0.5% ferrous sulphate spray. As nitrogen is a basic constituent of protein and with increase in rates of nitrogen application from 50 to 100 % has led to increased protein content of the seeds. Increase of protein content with boron at respective fertility levels has also been reported by Liu and Yang (2003). Increase in oil content might be attributed to balanced nutrition and increased availability of B, Fe, Zn and other nutrients. The supply of these nutrients seems to be involved in an increased conversion of primary fatty acid metabolites to end products of fatty acid by increased activity of acetyl Co-A resulting in higher oil content in seeds, (Hemantaranjan et al., 2000). Lowest protein and oil content and yield were recorded in control. Since, the protein and oil yield are mainly the function of seed yield and their respective content in the seed. Protein and oil yield increased with the increase in the fertility levels and successive addition of supplementary ingredients viz., FYM, B and Fe. Fatty acid composition : The per cent distribution of fatty acid composition except linoleic acid in soybean was significantly affected by integrated plant nutrient management (Table 3). A desirable and significantly negative effect of IPNM was recorded on saturated fatty acid (palmitic and stearic), which decreased with increase in fertilization either inorganic or organic or both compared to control whereas, significantly positive effect was observed for unsaturated fatty acid (oleic, linoleic and linolenic), which increased progressively with increase in nutrient application. All the fertilizer treatments were significantly superior to control in increasing the unsaturated fatty acids (linoleic, linolenic and oleic) content and reducing the undesirable saturated fatty acids (palmatic and stearic) content. Application of 10 t/ha, 2.0 kg/ha and 5.0 kg/ha at both 50 and 100 % recommended NPK proved to be useful in improving the quality of soybean oil, increasing the content of unsaturated fatty acids (linoleic, linolenic and oleic) significantly and reducing that of undesirable saturated fatty acids (palmatic and stearic) significantly. Higher percentage of unsaturated fatty acid with IPNM may be attributed to the balanced nutrition of the crop. Increase in the level of unsaturated fatty acids (UFA) and reduction in saturated fatty acids (SFA) with application of organics and micronutrients at respective fertility levels has also been reported by Rani et al. (2006).

7 Vol. 35, No. 3, TABLE 3: Protein and oil content and yield and fatty acid composition of soybean as influenced by integrated nutrient management (Pooled data of 2 years). Treatment Protein Oil Unsaturated Fatty Acid (%) Saturated Fatty Acid (%) Content Yield Content Yield Linolenic Linoleic Oleic Palmatic Stearic (%) (Kg/ha) (%) (Kg/ha) Control inoculated Control kg/ ha Control kg/ ha Control + 10 t/ ha % recommended NPK % recommended NPK kg/ ha % recommended NPK kg /ha % recommended NPK + 10 t /ha % recommended NPK % recommended NPK kg /ha % recommended NPK kg /ha % recommended NPK + 10 t /ha % recommended NPK % Ferrous Sulphate spray 100 % recommended NPK % Borax spray CD (P = 0.05) NS NS

8 182 LEGUME RESEARCH TABLE 4: Balanced sheet of N, P and K as influenced by different integrated nutrient management practices (Pooled data for 2 yrs). Treatment Total Available nutrients Nutrient harvest Net loss or gain in nutrient (Initial+added through (kg/ ha) content in soil(kg/ ha) fertilizers) (kg/ ha) N P K N P K N P K Control inoculated Control kg/ ha Control kg/ ha Control + 10 t/ ha % recommended NPK % recommended NPK kg/ ha % recommended NPK kg /ha % recommended NPK + 10 t /ha % recommended NPK % recommended NPK kg /ha % recommended NPK kg /ha % recommended NPK + 10 t /ha % recommended NPK % Ferrous Sulphate spray 100 % recommended NPK % Borax spray C.D. (p = 0.05)

9 Vol. 35, No. 3, 2012 Nutrient balance in soil : Soil nitrogen, content in soil. However, K did not increase phosphorus and potassium was highest with 100 % significantly in soil compared to initial values, recommended NPK + FYM followed by 50% whereas, in control plots all the nutrients declined recommended NPK + FYM (Table 4). Increasing the significantly. When FYM and micronutrients (Fe and fertility level up to 100 % recommended NPK and B) were applied with 100 % recommended NPK integration with FYM and micronutrients (Fe and there was improvement in available N, P, K, Fe and B) also resulted in higher harvest of N, P and K in B status (Table 1). The maximum availability of N, general. Highest N, P and K harvest was observed P and K was recorded in treatment of 100 % with 100 % recommended NPK + FYM followed by recommended NPK + FYM giving 10.3, 24.0 and 100 % recommended NPK kg Fe/ha. 50% 4.3% increase over control, respectively, indicating recommended NPK + FYM resulted in higher the benefits occurring from the integrated use of fertilizers and manures which is also evident from harvest than 100 % recommended NPK alone. This the yield data. These findings are in the line of might be due to increased supply of nutrients to the Bharadwaj and Omanvar (1992). Whereas, highest crop, as well as due to the indirect effect resulting available Fe and B content in soil were recorded from reduced loss of nutrients from organic sources. when respective micronutrient was applied with 100 Based on the initial N, P and K values of the soil % recommended NPK. Higher amount of residual and addition and depletion of these nutrients, the N, P and K analyzed might be attributed to the N, P and K balance was positive in all the treatments increased activity of microorganisms and nodulation except P balance which was negative under 100 % leading to greater mineralization of applied and recommended NPK + FYM. In general, the balance inherent nutrients. The reason for higher Fe content was more favorable with the integration of organics in soil with FYM was that FYM improved availability and micronutrients with 100 % recommended NPK. of both native and added Fe through transformation The highest net gain of N (+238.9), P (+21.6) and of solid phase to soluble metal complex (Pathak et K (+62.8) was noticed with 100 % recommended al., 2005) and B availability was increased as FYM NPK + FYM, control kg Fe/ha and 100 % is good source of B in soil. recommended NPK kg Fe/ha respectively. This Use of organic sources and micronutrients could be ascribed to the application of FYM and N helped in maintaining soil fertility in terms of and variation in addition and uptake of nutrients available nutrients and fertility balance. It was by soybean crop. concluded that application of 10 t FYM/ha and Residual soil fertility : Integrated nutrient micronutrients viz., 5.0 kg Fe/ha and 2.0 kg B/ha management had significantly increased the with RDF were essential for higher productivity and available nitrogen, phosphorus, iron and boron profitability of soybean and maintaining soil fertility. REFERENCES Abdel Wahab, A.M., Abd-Alla, M.H. and El-Enany, A.E. (1996). Stimulation of nodulation, nitrogen fixation and plant growth of fababean by 0120 and Environment. Kluwer Academic Publishers. Netherlands, Bharadwaj, V. and Omanwar, P.K. (1992). Impact of long term fertility treatment on bulk density, water content and microbial population of soil. J. Indian Soc. Soil Sci. 49: Bisht, J.K. and Chandel, A.S. (1991). Effect of integrated nutrient management on leaf area index, photosynthetic rate and agronomic and physiological efficiencies of soybean (G. max). Indian J. Agron. 36: Chandel, A.S. (1989). Soybean productivity constraints in north Indian plain An agronomist view. In: Fourth World Soybean Research Conference held at Buenos Aires, Argentina, March 5-9, 1989, Vol. 1, pp FAI. (2006). Fertilizer Statistics, The Fertilizer Association of India, New Delhi. Greenwood, E.A.N. and Hallsworth, E.G. (1960). Studies on the nutrition of forage legumes. II Some interactions of calcium, phosphorus, copper and molybdenum on the growth and chemical composition of Trofolium subterraneum L. Plant and Soil 20: Hemantaranjan, A., Trivedi, A.K. and Miniram. (2000). Effect of foliar application of boron and soil applied iron and sulfur on growth and yield of soybean [Glycine max (L.) Merr.] Indian J. Plant Physiol. 5:

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