Rice-maize systems of South Asia: current status, future prospects and research priorities for nutrient management

Abstract

Rice (Oryza sativa L.) and maize (Zey mays) are grown in 3.5 million hectares (Mha) in Asia that includes 1.5 Mha in South Asia. These crops are grown in sequence on the same land in the same year either in double-or triple-crop systems to meet the rice demand of a rapidly expanding human population and maize demand of livestock and poultry. The objective of this review is to provide a comprehensive overview of the current state of technical knowledge on agroecosystems and adaptation, area and distribution, yield potential and yield gaps, and nutrient management for rice-maize (R-M) systems in South Asia. Rice-maize systems are emerging all around South Asia but in particular are developing quite rapidly in Bangladesh and South and North India. Yield potential of rice and maize, as estimated by ORYZA2000 and Hybrid Maize models, reaches up to 15 and 22 t ha -1 , respectively. However, data from several environments in India reveal gaps between potential and attainable yields of maize of upto 100% and between attainable and actual yields of upto 25-50%. Nutrient demand of R-M system is high due to high nutrient removal by high-yielding maize. Nutrient balance studies for these highly-productive and nutrient-extractive systems are scarce in South Asia. The review outlines principles of nutrient management for R-M systems, and identifies development, refinement, and dissemination of the integrated plant nutrition system technologies based on site-specific nutrient management principles as priorities for future research to increase yield, profitability, and sustainability of R-M systems.

Climate change skepticism and index versus standard crop insurance demand in coastal Bangladesh

“…These events can cause defoliation and Blodging,^where the crop is knocked down by the wind, breaking stems, injuring roots, and lowering yield. Waterlogging can also result, spurring root degeneration and disease (Timsina et al 2010). Compared to other loweryielding cereals or pulses, maize also requires increased seed and nutrient investments, heightening farmers' risk exposure relative to less capital-intensive crops.…”

Effect of Integrated K Management on Productivity and Nutrient Use Efficiency of Maize-Wheat Cropping System

“…A large amount of K is absorbed from rhizospheric soil through roots and it plays crucial role in antagonistic and synergistic interaction with other essential nutrients of required for crops (Zhang et al, 2010). Timsina et al, (2010) observed that even with the recommended levels of nutrient application, there is continuous gap between nutrients removal to nutrient applied in soil under different cropping systems. Continuous intensive cropping, low K application and heavy mining of K results into declining in available K in soils under long-term fertilizer experiments (Sharma et al, 2014).…”

The effect of crop rotation between wetland rice and upland maize on the microbial communities associated with roots

“…Crop rotation between flooded rice and a nonflooded maize is becoming increasingly popular, as it saves irrigation water and provides a cash crop (maize) in addition to the food crop (rice) (Timisina et al 2010). Previous studies on rice-planted flooded soil showed that the microbial community in rhizospheric soil was different from that of unplanted bulk soil (Breidenbach et al 2016b), while the difference between the microbial communities in rhizospheric soil from flooded rice and non-flooded maize was relatively small (Breidenbach and Conrad 2015).…”