New Paradigms of Growing Rice to Address Shortages of Water and Labor, and Global Warming Potential.

Asia is the home of about 4.3 billion people and 920 millions living in less than $1.25 per day. Intensive cereal system which is the lifeline of vast majority of Asians facing dual challenges – shortages and untimely availability of water and labor. Among the cereals, rice is the most important food crop and heavily depends on large amounts of water and labor because the way it is grown. Globally rice is grown by transplanting on puddled (wet tilled) soil in more than 100 million ha annually. Rice consumes about 50% of total irrigation water in Asia and accounts for about 24-30% of the withdrawal of world total freshwater. To grow a kg of rough rice, on average 2500 l of water are applied. The higher water application in rice is also due to water requirements for puddling and losses associated with continuous flooding such as seepage and deep percolation losses to groundwater. Rice transplanting largely done manually is highly labor intensive requiring 25-50 person-days ha^-1. Rapid economic growth in Asia has increased the demand for labor in non-agricultural sectors, resulting in reduced labor availability for agriculture. For example, labor forces in agriculture are declining at 0.1% to 0.4%, with an average of 0.2% per year in Asia leading to sharp increases in the labor wages. Rice cultivation is also a major source of CH₄, currently accounting for 10-15% of all global GHG emissions from agriculture and 10-12% of the world’s total anthropogenic CH₄ emissions

 Although this practice of growing rice is highly capital and energy-intensive, survived for centuries since it provides certain advantages notably weed control. It is argued that this has been a most sustainable crop production system on earth but whether under the emerging scenarios of acute shortages of water and labor, it would maintain sustainability in future is highly uncertain. 

Our research has shown that the traditional practice of puddling (wet tillage) and transplanting of rice can be avoided by growing rice without soil tillage followed by direct seeding – referred as dry direct seeding or aerobic culture. Much progress has been made in perfecting this technology and in developing a package of practices. Not only, aerobic rice culture saves water and labor, it allows crop residue recycling (which is otherwise burnt), reduces much of methane emissions, lowers energy use and increases farmers profit. Avoiding puddling also improves soil structure which is an essential soil health requirement for the succeeding aerobic crops such as wheat, maize and vegetables.