Approaches for sustainability of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system in Indo-Gangetic plains of India - a review

摘要

This paper describes the results of some innovative approaches for sustaining productivity of rice-wheat cropping system in the Indo-Gangetic plains. Integrated nutrient management with green manuring as a substitute saved 50% of the chemical fertilizers, with an average productivity of rice (4.8 t/ha) and wheat (3.3 t/ha). Site-specific nutrient management using judicious application of primary, secondary and micronutrients as per soil test and specific yield target was also found an economically-viable option with benefit: cost ratio of 4.9 under multi-location trials, with 15-17 t/ha of productivity of rice and wheat. Resource conservation technologies (RCT) like zero tillage, bed planting and laser land leveling saved substantial quantity of irrigation water. Zero tillage saved 20% irrigation water, along with saving of 300 million litres of diesel per annum. Likewise, bed planting saved 37.5 cm irrigation water. Laser land leveling led to 18.4% saving of water and higher water productivity (1.19 kg grain/m3 water) in wheat under on-farm trials. The average water productivity in wheat under on-farm trials in Punjab was 0.33 and 0.52 kg grain/m3 water under no levelling and laser leveling, respectively. Happy seeder gave 7-8% higher productivity and retained 5-7 t/ha rice crop residue for soil fertility improvement. Besides water-saving and direct productivity gain, RCT was a valuable option for reducing the cost of cultivation in terms of land preparation, timely sowing, decreased seed rate, improved water and nutrient-use efficiency, and left indirect effect on mitigating the adverse effect of climate change. Remote-sensing technology also proved valuable for decision-support system in N saving, based on management-zone approach.