The rice is called aerobic because it is grown in soil where oxygen is present compared with anaerobic soil where no oxygen is present because of flooding by irrigation. It was displayed - along with the management technologies needed to grow it - at a special farmers’ field day near Paniqui in Tarlac province on 12 March attended by the Secretary for Agriculture, the Hon. Luis P. Lorenzo Jr.

The aerobic rice project is a joint effort involving farmers, the Philippine Rice Research Institute (PhilRice), the National Irrigation Authority (NIA) and the International Rice Research Institute (IRRI). On the same day as the introduction of aerobic rice, NIA also inaugurated its Deep Well Irrigation Project in the same district.

Already being commercially grown in China and Brazil, aerobic rice is seen as a potentially vital tool for the Asian rice industry, which already faces serious water shortages in many important rice-growing areas. While such varieties are important, just as essential are the crop management technologies needed to get them to produce high yields.

To grow rice under conventional irrigation usually takes twice as much water as other important crops such as wheat or maize. Traditional estimates are that it takes from 3,000 to 5,000 liters of water to produce just one kilogram of rice. Mostly because of this, irrigated agriculture in Asia accounts for 90 percent of the total diverted freshwater, with more than 50 percent of this used to irrigate rice.

Until recently, this amount of water has been taken for granted in most tropical rice-growing nations and provided free to many of their farmers who use irrigation. However, a looming global water crisis clearly threatens the sustainability of irrigated rice production right across Asia, including in the Philippines. Already rice farmers near Manila have had their irrigated water supplies reduced because of competing demands from the city.

“Aerobic rice is just one technology we hope will help rice farmers deal with this new challenge,” IRRI Director General Ronald P. Cantrell said. “And we are especially pleased that some of the first farmers to benefit are right here in our host country, the Philippines.”

Dr. Cantrell explained that the Philippines is in an especially favorable position to exploit the latest water saving technologies because some improved upland varieties developed by IRRI, the University of the Philippines Los Banos (UPLB) and PhilRice are already well adapted to aerobic production. These include Apo and UPLR1-5.

At IRRI, initial field experiments with aerobic rice varieties for the tropics produced yields of 4-6 t/ha and water savings of around 50 percent compared with lowland rice. Last year, the same aerobic varieties were tested in six farmers’ fields in the wet season in Tarlac and Nueva Ecija, and also yielded 4-6 t/ha.

This year, the same farmer participatory trials were expanded to involve 29 farmers in Tarlac and Nueva Ecija. “We are very keen to harvest so we can see how these trials went compared to last year,” said Bas Bouman, IRRI water scientist and Tarlac aerobic rice project leader.

Dr. Bouman explained that, as part of the Tarlac project, scientists and researchers from different organizations are working together with farmers to further develop aerobic rice and the related technologies it needs. “We want to develop an integrated aerobic rice package for farmers that will solve all the main problems that will confront them when they start growing aerobic rice.

“This includes the best management practices for crop establishment, integrated weed control, water and fertilizer use, labor, sustainability and environmental impact,” Dr. Bouman added. “As part of these strategies, we are also including indigenous and local technologies - such as the lithao (a wooden implement for sowing seeds) and the sagad (a wooden spike-toothed harrow) for crop establishment and improved weed control - as well as more advanced, high-tech options such as direct machine seeding and laser land leveling.”

In turn PhilRice and NIA have also been working on a similar package of water-saving, rice farming technologies under the name controlled irrigation. These achieve many of the same goals as the aerobic rice technologies.

In northern China, newly developed aerobic rice varieties have been studied alongside lowland irrigated rice, with their highest recorded yields reaching 7t/ha compared to 10t/ha for the lowland rice. These Chinese aerobic rice varieties were considered especially promising because of their relatively high yields under both aerobic and flooded conditions and because of their good eating quality, which suggested they would fetch a high market price.

At two other small field sites tested last year in China, the farmers involved were also reportedly very satisfied with the results. They realized net returns of US$400-600 in fields where water scarcity prohibited normal irrigation. In addition, the returns to water use - both physical and financial - were 50-100 percent higher than in lowland fields without water constraints. Moreover, mechanization cut their labor needs by one-half up to three-quarters.

Dr. Bouman said one reason for these additional financial benefits is that farmers can spend less on fuel for their water pumps because aerobic rice does not need to be fully irrigated. “This also leaves more water in the aquifer for use with other short-duration dryland crops such as mungbean, green corn and forage corn."

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