Nishant K. Sinha

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.

CROPPING SYSTEM EFFECTS ON SOIL QUALITY FOR THREE AGRO-ECOSYSTEMS IN INDIA

Soil quality integrates the effects of soil physical, chemical and biological attributes. Some of them are dynamic in nature and behave differentially in various agro-ecosystems (AESs) and are quantified in terms of a soil quality index (SQI). An attempt has been made in this paper to develop an SQI based on a minimum data set (MDS), which could be used to evaluate the sustainability of the crop production in three varying AESs in India, namely sub-humid, semi-arid and arid. Thirteen indicators were utilized to develop the SQI from the properties measured from the surface soil layer (0–15 cm). Each indicator of the MDS was transformed into a dimensionless score based on scoring functions (linear and non-linear) and integrated into four SQIs. The weighted non-linear index (WNLI) was identified as the most sensitive for all the AESs and was recommended as an index for future assessments. Based on this index, the quantification of soil quality under several cropping systems was carried out for sub-humid, semi-arid and arid AESs and the most suitable cropping system was identified. WLNI was positively and significantly correlated ( R 2 = 0.79, p