Sustainable Maize Based Cropping Sequences for Northern Transition Zone of Karnataka, India

Maize in SW monsoon and sorghum, wheat and chickpea during winter are the important crops in Northern Transition Zone (NTZ) of Karnataka, India. But, due to rising temperature and erratic rainfall patterns the productivity and profitability of maize based cropping sequences are being threatened under rainfed condition. As a result, a modelling research was conducted utilising the DSSAT model's seasonal analysis tool to test and determine sustainable and profitable cropping sequences for current climates of NTZ in Karnataka state. Field experiments were conducted from 2015 to 2018 to calibrate and validate the DSSAT model for four crop cultivars (maize, chickpea, wheat, and sorghum) grown under rainfed conditions on deep black soils, and then the DSSAT model's sequential analysis tool was run for 32 years (1985-2016) for three cropping sequences (maize-sorghum, maize-wheat, and maize-chickpea). The yield, number of years the crop failed throughout different seasons, and the B:C ratio of each sequence were used in the simulated output study. Out of 32 years maize crop, grown during kharif, failed three times whereas, during rabi season wheat, sorghum and chickpea failed nine, eight and five years, respectively. Out of 32 years maize-sorghum sequence recorded the highest B:C ratio (2.86) followed by maize-chickpea (2.82) and maize-wheat (2.66). Considering chances of crop failure, B:C ratio and owing to cereal followed by short duration legume, maize-chickpea sequence under rainfed condition was proven to be the most reliable and profitable system for NTZ of Karnataka under of current climate.