A study has been conducted in swell-shrink and associated soils to assess the influence of soil-site characteristics on rainfed soybean yield attained with low and improved management practices across four microwatersheds viz., Varkhed and Panubali in Maharashtra; and Jaitpura and Khuj in Madhya Pradesh. There was a wide spatial variability of soil-site characteristics of swell-shrink and associated soils viz., Typic Ustorthents, Typic Haplustepts, Vertic Haplustepts, Typic Haplusterts within and across four microwatersheds. In general, soybean productivity was high in Typic Haplusterts followed by Vertic Haplustepts while it was low with Typic Ustorthents under both management levels. Based on correlation and regression analysis, the most important soil-site characteristics influencing soybean yield were found to be drainage among site characteristics; soil depth and AWC among soil physical, and OC and CEC among soil chemical characteristics. The study indicated that for improving the productivity of rainfed soybean cultivated in swell-shrink and associated soils, soil depth, AWC, OC and CEC with ideal conditions were essential for attaining a yield level of 7–8 q ha−1 with low management, while only two soil characteristics viz., soil depth and AWC were found important for attaining a yield level of 12–14 q ha−1 with improved management.
Based on permanent manurial experiments of soybean conducted with 9 fertilizer treatments during rainy seasons of 1992 to 2006 (June to October) in a semiarid Vertisol at Indore, an attempt has been made in this paper to model the sustainability of yield based on rainfall received during crop growing period, soil and plant-nutrient relationships. The fertilizer treatments comprised control, 20 kg N (urea) + 13 kg P ha· l, 30 kg N (urea) + 20 kg P ha· l, 40 kg N (urea) + 26 kg P ha'l, 60 kg N (urea) + 35 kg P ha'l, 20 kg N (urea) + 13 kg P + FYM @ 6 t ha'l, 20 kg N (urea) + 13 kg P + FYM @ 5 t ha'l, FYM @ 6 t ha'l and crop residue @ 5 t ha and were tested on the same site for 15 years. Based on analysis of variance, the F-test indicated that the fertilizer treatments differed significantly in influencing the yield, soil and plant N, P, K and S in both individual years and also when pooled over 15 years. An assessment of relationship of yield with rainfall received during crop growing period, plant and soil nutrients was made for each treatment based on Pearson correlation coefficients derived for the pooled data over years. Based on regression models of yield through rainfall, plant and soil nutrients, the treatments were assessed for predictability of yield, prediction error and sustainable yield index over years. Ranks were assigned to fertilizer treatments for mean and variation of yield, plant and soil nutrients apart from prediction error and sustainable yield index measured under different regression models of yield. The rank sum indicated that 20 kg N (urea) + 13 kg P + FYM @ 6 t ha'l was the most efficient treatment with a minimum rank sum for different parameters. This treatment attained a maximum sustainable yield index and predictability of yield with minimum prediction error over years, apart from providing a maximum mean yield and uptake of N, P, K and S by plant with minimum variation over 15 years. The study indicated that this treatment significantly improved the soil fertility status of N, P, K and S compared to other treatments tested under semi-arid Vertisols. Additional key words: Plant and soil nutrients, crop growing period, correlation, regression, prediction error, sustainability yield index
The soils in the hot semi-arid tropical (SAT) regions generally have low organic matter and nutrient reserves. Soil-management problems in these soils primarily occur because of poor physical conditions and inadequate drainage through excess runoff, finally resulting in poor crop growth. Hence, the present investigation was conducted to study the long-term impact of conjunctive nutrient use treatments on soil quality indicators and soil quality indices under three cropping systems: (i) sole soybean, (ii) soybean + maize, and (iii) sole maize cropping systems at the Indore Centre of the All-India Coordinated Research Project for Dryland Agriculture (AICRPDA) using Navjot and JS-335 as cultivars of maize and soybean, respectively. In 2005, the soil quality assessment study under this experiment was undertaken after 8 years of experimentation. Soil quality assessment was done by identifying the key indicators using principal component analysis (PCA) and linear scoring technique (LST). Soil quality indices (SQI) and relative soil quality indices (RSQI) were also computed. Results revealed that most of the soil quality parameters were significantly influenced by the conjunctive nutrient management treatments. The common key indicators that emerged in all the treatments were pH, organic carbon (OC), exchangeable magnesium (Mg), available zinc (Zn), copper (Cu), manganese (Mn), and boron (B). The soil quality indices across the management treatments under sole maize system varied from 1.70 to 2.40 and application of 20 kg nitrogen (N) (compost) + 20 kg N through urea as top dressing emerged as a one of the most superior treatments with SQI value of 2.40. The soil quality indices in maize + soybean system varied from 1.12 to 1.47 and application of 20 kg N (compost) + 20 kg N through urea + azotobacter at 2 kg ha−1 proved to be significant with the greatest SQI value of 1.47. In the case of the sole soybean system, the SQI varied from 1.21 to 1.61. After considering all the systems together, the average best performance SQI score (ABP-SQI score) was computed, which varied from 1.14 to 1.56. The greatest value was recorded in the treatment with 20 kg N (compost) + 20 kg N (gliricidia) + 10 kg N (urea). The quantitative relationship developed in this study between mean soybean and maize yields (Y) and RSQI values (X), irrespective of the management treatments, could be quite useful to predict the yield quantitatively with respect to a given change in key indicators for these rainfed Vertisols.
Based on research experience gained during the recent past, appropriate cost effective conservation measures for land and water have been suggested in the present paper. Cost effective land and water management practices have been developed and verified at field scale for conserving and efficiently utilising these resources for enhanced sustainable productivity. However, the resource base and physical features of the site concerned will enable one to select the most appropriate land and water management measures. Paper presents the results of series of long term studies carried out to assess the impact of different measures on the conservation of land, water and plant nutrients and productivity of crops grown in black soil regions of central India.
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