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ABSTRACT
Limited water availability is a major constraint for cultivation of rice (Oryza sativa L.) in the traditional flooded systems, particularly in the semiarid regions of the world. Aerobic rice cultivation provides feasible alternative to traditional rice production in these regions, allowing significant water savings. Field experiments were conducted at the ANGR University Agricultural Research Station, India during 2009-2010 and 2010-2011 to compare crop growth, yield, and water savings under aerobic rice-maize (R-M) and flooded R-M rotation systems. The effect of aerobic rice on the succeeding maize crop was also studied. The total amount of water applied (including rainfall) in the aerobic plots was 967 and 645 mm compared to 1546 and 1181 mm in flooded rice system, during 2009 and 2010, respectively. This resulted in 37 to 45% water savings with the aerobic method. The soil moisture in aerobic treatment was maintained in the -30 to -40 kPa range throughout the crop growth. The aerobic rice system produced significantly lower grain yields in 2009 and 2010, where differences between flooded and aerobic rice were 39 and 15.4%, respectively. The yield differences were attributed to the differences in spikelet number per panicle and grain weight. Significant increase in yields was recorded in both systems with increased N rates up to 120 kg ha-1. Significantly higher yields were obtained in no-till maize grown subsequent to the aerobic rice than flooded rice, possibly due to residual soil N and improved soil physical conditions.
Abbreviations: BCR, benefit/cost ratio; DAP, days after planting; DAT, days after transplanting; LAI, leaf area index; R-M, rice-maize; VWC, volumetric water content.
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Rice is an important staple food crop around the world. In Asia, the flooded rice production is a key element for economic and social stability as more than two billion people depend on rice for their dietary requirements. Rice production involves submerged conditions, with approximately 5- to 10-cm deep standing water throughout the crop growth period. Worldwide, rice production uses about 30% and within Asia more than 45% of total fresh water (Barker et al., 1999). Increasing scarcity due to increasing demand for water from various sectors threatens the sustainability of irrigated rice production and calls for development of novel technologies that can reduce water requirement...