Growing rice with less water
IT is common knowledge that among the staple crops cultivated globally, it is rice that consumes the largest volume of water. Also, rice cultivation releases a big amount of methane that contributes to global warming.
The Asian Development Bank (ADB) said that flooded rice paddy fields account for 12 percent of global anthropogenic methane emissions, which is equivalent to 1.5 percent of the total warming effect of all greenhouse gases.
“Under common rice production practices, farmers keep rice fields flooded to suppress weed emergence. Underwater, methane is produced as organic matters decay with little access to oxygen,” the ADB said in a briefer for a recent webinar on how to incentivize the reduction of methane emissions in rice farming in Asia.
The ADB recommended the alternate wetting and drying (AWD) method in cultivating the staple, which allows rice farms to grow under dry conditions periodically. The institution added that AWD can reduce methane emissions by 30 to 50 percent, and water utilization by 10 to 20 percent. AWD also does not reduce the yield of rice.
Direct-seeded rice system
From the private sector, Bayer Global is introducing what it calls the direct-seeded rice (DSR) method for cultivating the staple, which the company claims has the potential to reduce by up to 40 percent both greenhouse gas emissions and water use.
During the 6th International Rice Congress held in Manila on October 16, Bayer Global said that under its DirectAcres program, it plans to scale up the DSR system to 1 million hectares and to support 2 million early adopter-smallholder farmers and their families in India by 2030.
For the Philippines, Bayer Global is seeking to upscale the DSR system starting next year.
In India, which has less water resources compared to the Philippines, the DSR system through the DirectAcres program is already applied in 11 percent of its rice lands. Bayer Global said that it expects 75 percent of rice farms in India to switch to the DSR system by 2040.
“Already underway, DirectAcres has seen considerable success with 99 percent of Indian farmers achieving successful plant establishment and 75 percent a higher return on investment compared to rice grown using the conventional transplanted method. Bayer plans therefore to introduce DirectAcres in other rice-growing countries in Asia-Pacific, starting with the Philippines in 2024,” Bayer Global said in a statement.
Frank Terhorst, head of Strategy and Sustainability at Bayer’s Crop Science Division, added that the company is building systems based on the principles of regenerative agriculture to also help address global food security.
Bayer Global said another benefit of the DSR system compared to the traditional method of transplanting rice seedlings is less labor, or up to a 50-percent reduction.
Drip irrigation for rice farming
Another private firm, Netafim in Israel, has developed a drip irrigation system for rice farming that it claims can reduce water usage by up to 70 percent while increasing yields by 50 percent.
“Producing a ton of rice in a paddy system will consume 5,000 cubic meters of water. Alternatively, that same ton grown with drip irrigation will need only 1,500 cubic meters. Drip eliminates evaporation, run-off and percolation,” Netafim said in its website.
The Israeli firm also said that reducing water usage in rice farming through drip irrigation can do wonders for the environment.
“Paddy rice cultivation generates 20 percent of methane gas emissions worldwide. If only 10 percent of paddy rice farmers switch to drip, the drop in emissions will be equivalent to taking 40 million cars off the road,” the company said.
Netafim also said the submerged rice roots make the plants absorb heavy metals, resulting in the grains having arsenic. By utilizing drip irrigation, arsenic absorption of rice is reduced by as much as 90 percent.
PhilRice advocates AWD
In the Philippines among local institutions, it is the Philippine Rice Research Institute (PhilRice) that is advocating AWD to reduce water usage in rice farms.
PhilRice released in September 2022 a policy paper titled “Policy Imperatives to Increase Uptake of the Alternative Wetting and Drying Technology” explaining the benefits of AWD. The paper said that AWD has already been adopted in many rice-producing countries but in the Philippines, the adoption is low as there is no incentive for farmers to save on water.
The institution added that AWD has been practiced for decades but farmers still find it hard to break the old practice of submerging rice fields in water.
To upscale AWD, PhilRice is recommending the following, and let me quote them: use participatory approaches in agricultural extension; review of some provisions of the Free Irrigation Service Act; and improve irrigation water governance to modernize tools to practice AWD.
I strongly believe that saving water in cultivating crops should be piloted and upscaled nationwide while our country still has enough water resources. This should also be made alongside efforts to reduce chemical input use in farming, and making farms part of an overall ecosystem that includes water sources, forests, which are all part of the paradigm shift to regenerative agriculture.
And since rice is among the top five most cultivated crops in the world, scaling up measures to reduce water and chemical input use, and preserving soil resources in cultivating the staple can be one big step in mainstreaming regenerative agriculture.
