R. S. Chaudhary

Pothole Formation and Occurrence in Black Vertisols of Central and Western India

Soil cracks are a unique feature of black vertisols. Evaporation loss is inevitable from lateral exposure of surface and sub-surface cracks. On the other hand, these cracks provide increased opportunity for soils to recharge during the rainy season. In this process, water that drains into larger size cracks moves down the soil profile and eventually results in pothole formation due to the existence of a network of sub-surface cracks. An investigation was done to evaluate pothole characteristics under different land use systems in black vertisols of central and western regions of India. In both the regions, the potholes had smaller volume in arable land than in non-arable uncultivated land. The size and volume of potholes in central India were greater compared to that in western India, where the highest volume of potholes was registered under perennial vegetation followed by agriculture–horticulture system, uncultivated fallow fields and arable lands. However, cultivated fields had less a incidence/occurrence of potholes than uncultivated fields. Similarly, the marginal land in western India registered the highest volume of potholes than other land use systems. The study gives insight to some of the researchable issues and strategies to minimize soil slumping in black vertisols, characterization of soil properties within and adjacent to potholes as well as soil and nutrient loss through potholes.

Climate Change Impacts on Rainfed Soybean Yield of Central India: Management Strategies Through Simulation Modelling

Soybean [Glycine max (L.) Merrill] has emerged as one of the major rainy season oilseed cash crops in central India. Despite its phenomenal growth in this agro-climatic zone, the average productivity of soybean has remained more or less at 1 t ha−1 due to several abiotic, biotic and socio-economic factors. The climate change (increase in temperature, CO2 concentration and rainfall) will affect this rainfed crop in the future. So, proper management practices which include crop management (use of nutrients, planting time and plant population) will play a major role in future productivity in these regions. Simulation models with demonstrated accuracy and reliability provide an alternative method of investigating both short- and long-term agricultural practices with less time requirements and low cost. They have been evaluated and used as a research tool to study risks associated with various management strategies and to assist in decision-making. Hence, the present study aims at using the APSIM model in the decision-making process to evaluate the impact of climate change on soybean yield.

Characterization of Humic and Fulvic Acid under Long-Term Integrated Nutrient Management of Soybean-Wheat Cropping System in Vertisol

The nature, content, composition and behavior of organic matter in soil are fundamentally important for growth of crops under diverse climatic conditions. Humic substances, present in soil, act as highly reactive natural polymers. The quality of soil organic matter according to functional groups governs the rate of sequestration of organic carbon. In the present investigation, effect of five years application of different integrated nutrient management (INM) interventions was assessed to note the changes in the fulvic acid and humic acid composition using fourier transform infrared (FTIR) technique. Humic acid and fulvic acid from selected treatments viz., control, inorganic NPK fertilizer (25, 30, 20 in soybean and 70, 30, 30 in wheat) and organic manure (8 t FYM ha−1 in soybean and 16 t FYM ha−1 in wheat) were fractionated from soil, separated and prepared for FTIR spectroscopy by following standard procedure. The obtained fractions were analyzed using FTIR spectroscopy. In control plot N-H stretching of amines, amides, aliphatic C-H stretching, C=O stretching of carboxylic acids, amides, ketones salt of carboxylic acid, C2H4-in plane deformation (−CCH), aromatic C-H out of plane bend were found in humic acids, whereas aliphatic C-H stretching asymmetric COO-stretching, C-O stretching of polysaccharides, -C-C-stretching were observed in fulvic acid. Due to long-term humification in treated plots humic acid contained more number of functional groups than fulvic acid. Results indicated that application of 8 t FYM ha−1 in soybean and 16 t FYM ha−1 in wheat in soil helped in the formation of long chain humic acid which can sequester more organic carbon and subsequently improve soil quality and health. Experimental results were discussed with respect to the utility of FTIR spectroscopy in the assessment of organic matter quality in long term fertilizer experiment.