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Abstract: The effect of sole application of inorganic fertilizers (NPK) (N:P:K:: 30:26:25kgha−1) and combined application of farmyard manure (FYM) @ 4Mgha−1 and inorganic fertilizers (NPK+FYM) vis-a-vis non-application of fertilizers and manures (control) on changes in soil physical properties and plant growth characteristics of soybean (cv. JS 335) was studied in a deep Vertisol at the Indian Institute of Soil Science, Bhopal during the year 2001–2004. The results indicated that conjunctive use of recommended dose of fertilizer and farmyard manure (NPK+FYM) resulted in significant (P <0.05) decrease of bulk density (9.3%), soil penetration resistance (42.6%) and increase in hydraulic conductivity (95.8%) and mean weight diameter of the water stable aggregates (13.8%) and soil organic carbon content (45.2%) compared to control. Among the aggregates, in macro-aggregate fraction (250–500μm and 500–1000μm size fraction) and in large macro-aggregate fraction (>2000μm) maximum soil organic carbon concentration was recorded under NPK+FYM. The root mass of soybean was mostly (98%) confined to 15cm soil depth. Combined application of NPK and FYM recorded significantly higher (P <0.05) root length density and root mass density of soybean in the 0–15cm soil layer at flowering stage over NPK (28 and 65%) and control (63 and 175%). The root length density of soybean was significantly negatively correlated with the penetration resistance (r =0.98, P <0.05). Application of FYM @ 4Mgha−1 with NPK significantly (P <0.05) improved the biomass partitioning towards pod over NPK and control. The grain yield, water use efficiency and nitrogen use efficiency of soybean under NPK+FYM were significantly (P <0.05) higher than NPK and control. The total above ground biomass and the leaf area index at R8 stage could account for respectively, 89 and 63% variation in grain yield of soybean. Therefore in every crop season, integrated use of farmyard manure at 4Mgha−1 and recommended dose of chemical fertilizers may be practised in Vertisols for improving soil physical environment and achieving higher soybean productivity through efficient utilization of water and nutrients. [Copyright &y& Elsevier]

Abstract: Distillery effluent, a foul smelling, dark coloured by-product of distillery industries, is usually applied as irrigation water or as an amendment to arable land in some areas which are in the vicinity of the distillery industries. A field experiment on soybean–wheat system was conducted for 3 consecutive years in a Vertisol of central India to evaluate the effect of distillery effluent (DE) as an amendment on soil properties and crop productivity. The treatments were control (no fertilizer or manure or DE, T1), 100% NPK+FYM @ 4Mgha−1 to soybean (T2) and four graded levels of DE, viz.: 2.5cm DE to soybean and wheat on residual nutrition (T3), 2.5cm DE to soybean and 1.25cm to wheat (T4), 5cm DE to soybean and wheat on residual nutrition (T5), 5cm DE to soybean and 2.5cm to wheat (T6). The organic carbon, microbial biomass carbon and electrical conductivity (EC) of the surface (0–10cm) soil increased significantly with application of DE compared to T1 and T2, but the soil pH was not affected. The EC increased from 0.47dSm−1 and 0.58dSm−1, respectively, in T1 and T2 to 1.52dSm−1 in T6, where highest dose of DE was applied. This indicated a slight build-up of salinity with DE application. The application of DE showed a significant improvement in the physical properties of the soil. The mean weight diameter (MWD), saturated hydraulic conductivity, water retention at field capacity and available water content were significantly (P <0.05) higher, while bulk density (BD) and penetration resistance of the surface soil were significantly lower (P <0.05) in all DE treated plots except in T3 than those in T1 and T2. The fractions of WSA of more than 1mm diameter in T6, T5 and T4 were, respectively, 141%, 107% and 116% more than the control. The MWD showed a positive linear relationship with the organic carbon (r =0.84**) and microbial biomass carbon (r =0.90**) of the soil. A significant (P <0.01) negative linear relationship (r =0.70**) was found between soil organic carbon and BD. Except T3, all the DE treated plots recorded significantly higher total and microporosity of the soil than control. Water retention at permanent wilting point and macroporosity of the soil were not affected by treatment. The seed yield of soybean in all the DE treatments was similar with T2 (1.86Mgha−1) but significantly more than control (1.28Mgha−1). The DE application levels have not affected the seed yield of soybean. In wheat highest grain yield was recorded in T2 (3.47Mgha−1), which was similar with T4 (3.16Mgha−1), T5 (3.22Mgha−1) and T6 (3.46Mgha−1). DE application up to T4 level was found suitable from productivity, salinity and sustainability point of view. The study showed that judicious application of DE as an amendment to the agricultural field could be considered as a viable option for safe disposal of this industrial waste. [Copyright &y& Elsevier]

Abstract: In Vertisols of the semi-arid tropics lack of optimum soil water and low soil temperature (<18°C) during germination, and high soil temperature (>37°C) during pod development stage has been a major barrier to realizing yield potential of summer groundnut. Seven field experiments (comparing straw with polythene, 50μm gauge mulch, duration of retention of polythene mulch, testing the combined effect of straw and polythene mulch, N management in straw mulch and field demonstration) were carried out from 1992 to 1999 in a sequence to identify a suitable mulch material, which was socially and economically acceptable and could overcome soil water and soil temperature related problems for summer groundnut. In general, straw mulch (wheat or paddy) produced more pod (17–24%) and haulm yields (16%) of groundnut than polythene mulch (black or transparent) and no mulch because of favourable soil water and soil temperature, earlier seedling emergences, more flower and mature pods numbers, lower bulk density and less weeds. We observed that groundnut plants showed N deficiency under wheat straw mulch at the early stage (up to 60 days after sowing). However, towards maturity N deficiency occurred at the early stage had no significant negative impact on pod yield of groundnut because the plants recovered N deficiency and had greater chlorophyll content and pod yield. This is presumed to be associated with bio-availability of macro and micronutrient during decomposition of organic mulch. The pod yield of groundnut under black polythene was higher than under transparent polythene. The polythene mulch increased soil temperature by 4–5°C through out the crop growth (germination to maturity), which increased seeding emergence but was detrimental to pod setting and pod development (soil temperature exceeded 40°C). Thus, the benefit of polythene was only observed when it was retained up to podding stage, but not up to harvest. The combined application of wheat straw and black polythene out-yielded sole application of wheat straw mulch but the former was 45% less profitable than the later one because of the cost of polythene. Wheat straw mulch was finally demonstrated to the farmer''s field. It was found that sacrificing 5t wheat straw as cattle feed, farmers on return get additional 0.47tha−1 legume fodder due to mulching which is nutritionally superior quality fodder in terms of crude protein, phosphorus content, crude fiber, ash and silica content compared to wheat straw as cattle feed. Thus, 16% additional production of highly nutritive groundnut haulm due to mulching has a significant implication on (i) nutritional fodder security, especially during the dry season when green fodder is costly and its availability is limited, and (ii) additional income of Rs. 3935ha−1 from mulch. These two considerations, apart from solving temperature related problems convinced 32 farmers of Vadhvi and Zanjarda village of Junagadh district, Gujarat for adoption of wheat straw technology for summer groundnut in about 50ha areas. [Copyright &y& Elsevier]

A field experiment was conducted on a deep Vertisol of Bhopal, India to compare root and shoot biomass, chlorophyll content, enzyme activity and nodulation in three cropping systems at three combinations of organic manure and inorganic-fertilizer: 75%NPK + 5 t farmyard manure (FYM), 75%NPK + 1.5 t poultry manure (PM), and 75%NPK + 5 t phosphocompost (PC) vis-a-vis 0%, 75% and 100% of fertilizer-NPK. In general, nodule number and its mass were lower in intercrop soybean than sole soybean. Also there was decrease in the nodule number with higher NPK dose. The FYM treated plots recorded 22.0% and 7.6% higher nodule mass than poultry manure and phosphocompost plots, respectively. Also, the total chlorophyll content was higher in organically treated plots than that in 100% NPK particularly at 30 days after sowing (DAS, pre-flowering). In sorghum the peak nitrate reductase (NR) activity was recorded at 60 DAS while in soybean it was at 30 DAS. The NR activity was higher in intercrop sorghum than that in sole sorghum. Maximum NR activity was observed in 100% NPK. Soybean/sorghum intercropping system recorded significantly higher root and shoot biomass than sole soybean and sorghum. The crop growth rates were relatively rapid during 30–60 DAS and followed the order; intercropping > sole sorghum > sole soybean. With the increase in NPK dose from 0% to 100% there was significant improvement in the dry matter (DM) production in sole sorghum and soybean/sorghum intercropping system. Soybean as preceding crop recorded the highest DM, chlorophyll content, NR activity in wheat while these values were the lowest in sorghum–wheat system. [Copyright &y& Elsevier]

A field experiment was conducted on deep vertisols of Bhopal, India to evaluate the manural potential of three organic manures: farmyard manure (FYM), poultry manure (PM), phosphocompost (PC) vis-a-vis 0%, 75% and 100% recommended dose of fertilizer-NPK and to find out the most productive cropping system at various combinations of organic manures and chemical fertilizers. The seed yield of intercrop soybean (population converted to 100%) was 8.7% less than sole soybean whereas the grain yield of intercrop sorghum was 9.5% more than that of sole sorghum. However, the productivity in terms of soybean equivalent yield (SEY) was relatively high in intercropping system. The increasing NPK dose from 0% to 100% significantly improved SEY in sole sorghum and soybean/sorghum intercropping system and the integrated use of organics and inorganics recorded significantly more SEY than inorganics. The effect of nutrient management followed the order; 75% NPK + 5 t FYM ha-1 > 75% NPK + 1.5 t PM ha-1 > 75% NPK + 5 t PC ha-1 > 100% NPK. Sorghum, both as sole and intercrop, responded more to PM while soybean to FYM. Application of 75% NPK in combination with PM or FYM or PC to preceding rainy season crops (soybean and sorghum) and 75% NPK to wheat produced significantly higher grain yield of wheat than those in inorganics and control indicating noticeable residual effect on the succeeding wheat crop and saving of 25% fertilizer-NPK. The effect of PC on rainy season crops was not as prominent as those of FYM and PM, but its residual effect on grain yield of wheat was comparable to those two organic manures. Among the cropping systems, soybean as preceding crop recorded the highest seed yield of wheat and was on a par with that of soybean/sorghum intercropping system. The yield of wheat following sorghum was the lowest. The total system productivity (TSP) was the highest in sorghum + soybean–wheat system and the lowest in the soybean–wheat system. [Copyright &y& Elsevier]

Abstract: Balanced application of inorganic fertilizer and organic amendments greatly influence the accumulation of organic matter in soil and also influence the soil physical environment. An investigation was carried out to study the long-term impact of fertilizer and manure application in a soybean–wheat–maize (fodder) crop rotation on soil organic carbon status and physical properties of a vertisol (Typic Haplustert or Pellic Vertisols) in sub-humid sub-tropical India. Five treatments namely, control (no fertilizer and manure), 100% of the optimum rate for nitrogen (100% N), 50% of the optimum rate for nitrogen, phosphorus and potassium (50% NPK), 100% of the optimum rate for NPK (100% NPK) and 100% NPK+farmyard manure at 15Mgha−1 (100% NPK+FYM) from a long-term fertilizer experiment continuing at Jabalpur, India, were chosen for this study. Soil samples were collected from the topsoil horizon (0–15cm) of all the four replications of the selected five treatments in April 2000 after 28 crop cycles and analyzed for physical and chemical properties. The results showed that the soil organic carbon (SOC) content in 100% NPK and 100% NPK+FYM treatments increased, respectively, by 22.5 and 56.3% over the initial level (1.14kgm−2). The electrical conductivity, SOC content, aggregation, water retention, microporosity and available water capacity of the soil were increased while the bulk density was reduced significantly with the 100% NPK+FYM treatment over all other treatments. However, the use of imbalanced (100% N) and suboptimal rate of inorganic fertilizer (50% NPK) as compared to the unfertilized control showed no significant effect on the physical properties of the soil. The study indicates that application of balanced rate of fertilizers in combination with organic manure could sequester soil organic carbon in the surface layer, improve the soil physical environment and sustain higher crop productivity under this intensive cropping system. [Copyright &y& Elsevier]

Abstract: A field experiment was conducted on a Vertisol for three consecutive years (1998–2000) to study the effects of combined use of inorganic fertilizer (NPK) and organic manure (farmyard manure) on soil physical properties, water-use efficiency, root growth and yield of soybean [Glycine max (L.) Merr.] in a soybean–mustard cropping system. Application of 10Mg farmyard manure and recommended NPK (NPK+FYM) to soybean for three consecutive years improved the organic carbon content of the surface (0–15cm) soil from an initial value of 4.4gkg−1 to 6.2gkg−1 and also increased seed yield and water-use efficiency by 103% and 76%, respectively, over the control. The surface (0–15cm) soil of the plots receiving both farmyard manure and recommended NPK had larger mean weight diameter (0.50mm) and a higher percentage of water stable aggregates (55%) than both the inorganically fertilized (NPK) (0.44mm and 49%) and unfertilized control plots (0.41mm and 45.4%). The saturated hydraulic conductivity (13.32×10−6 ms−1) of the NPK+FYM treatment of the 0–7.5cm depth was also significantly greater than that of the NPK (10.53×10−6 ms−1) and control (8.61×10−6 ms−1) treatments. The lowest bulk density (1.18Mgm−3) in the 0–7.5cm layer was recorded in NPK+FYM whereas it was highest in the control plots (1.30Mgm−3). However, at sub-surface (22.5–30cm) layer, fertilizer and manure application had little effect on bulk density and saturated hydraulic conductivity. Root length density (RLD) up to the 30cm depth was highest in the NPK+FYM plots and it was 31.9% and 70.5% more than NPK and control plots. The RLD showed a significant and negative correlation (r =−0.88∗∗) with the penetration resistance. [Copyright &y& Elsevier]