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 Irrigated Rice Research Consortium
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Work groups push forward in China
Although China is the world’s largest rice
producer, accounting for 32–35% of total world production, it is also the most
populous country in the world, with about 13 million people added to the
population each year. Two of the country’s main concerns in rice production
nationally are how to increase rice productivity to ensure the nation’s food
security and how to find varieties that can cope with the looming water
shortage. The Irrigated Rice Research Consortium (IRRC) has two work groups in
place in China to help national partners find solutions to these problems.
Research on the development and evaluation of site-specific nutrient management (SSNM) for rice began in 1997 in collaboration with Professor Guanghuo Wang at Zhejiang University. Based on the promising results, research on SSNM started in 2001 in Jiangsu, Hunan, and Guangdong provinces, and later started in Hubei and Heilongjiang provinces. After 2 years of experiments in Jiangsu, Hunan, and Guangdong, SSNM was shown to be superior to farmers’ traditional fertilizer practices, producing 5–10% more grain yield with 20–30% less N fertilizer. Disease and insect incidence was lower, especially for leaf roller, sheath blight, and brown planthopper, and pesticide use could be reduced. Lodging, or rice plants falling over, also decreased. In 2003 and 2004, Professor Ruifa Hu of the Center for Chinese Agricultural Policy (CCAP), Chinese Academy of Sciences, collaborated with partners in Guangdong, Hunan, Hubei, and Jiangsu in farmer participatory research for on-farm testing of improved N fertilization in 14 villages. Among 514 farmers, 95% were willing to adopt either a standard or locally modified SSNM, while 76% were willing to conduct experiments using either of the technologies. As compared with traditional fertilizer practices, SSNM and modified SSNM raised yields slightly by 0.2 ton/hectare using significantly less N fertilizer and no increase in labor input. The extension of SSNM continues across six provinces through partnerships within the provinces. In addition, the principles of SSNM for rice were incorporated into a national initiative on improved fertilization led by Professor Zhang Fusuo at China Agricultural University (CAU), and which included partners working on SSNM from the six provinces. The Productivity and Sustainability Work Group (PSWG) continues to collaborate with CCAP and CAU in building harmonization on improved nutrient management practices for wide-scale dissemination to rice farmers across China. The PSWG has also been active in developing the scientific principles for integrated crop and nutrient management leading to a healthy crop canopy, which results in higher yields with less susceptibility to rice diseases and pests. Collaborative research in China shows that establishment of a healthy canopy through N management optimally tailored to crop establishment practice produces higher yield with low sheath blight occurrence. The decrease in this important disease was associated with reduced maximum tiller number, lower N content of leaves, and greater openness of the crop canopy.
As a result of this research, the “three-controls”
technology developed in collaboration with the Guangdong Academy of Agricultural
Sciences (GAAS) was endorsed for adoption in Guangdong in January 2007. The
three controls are:
The locally adapted SSNM guidelines developed
through collaboration in China are available on the SSNM Web site (www.irri.org/irrc/ssnm),
and more information on the benefits and impacts of SSNM is available at a new
Web site (www.irri.org/irrc/ssnmrice).
Aerobic rice is a production system in which specially developed, input-responsive rice varieties with “aerobic adaptation” are grown in well-drained, nonpuddled, and nonsaturated soils without ponded water, with a management system aiming at yields of 4–6 tons/hectare. Water use is 30–70% less than in flooded rice, depending on irrigation water management and anticipated yields. In 2002, the area of aerobic rice in the North China Plain was estimated to be around 80,000 hectares. Aerobic rice yields range from 2 to 5.5 tons/hectare, using only 2–3 supplemental irrigations, compared with 10–13 irrigations for flooded rice and 0–2 irrigations in upland crops. In 2005 in Kaifeng and Fengtai counties, 49 adopters realized average yields of 4.2 tons/hectare, compared with 5.8 tons/hectare with flooded rice. Net returns were US$326/hectare, compared with $442 for flooded rice, $301 for maize, $133 for soybean, $715 for peanut, and $652 for cotton. When water is too scarce to grow flooded rice, aerobic rice was an attractive option and yield targets of 6 tons/hectare were most common. The driving forces behind the adoption of aerobic rice are farmers’ wishes to grow their own rice and labor shortage (aerobic rice requires less labor than flooded rice). In the temperate climate of northern China, IRRC research focuses on improved management practices, characterizing and mapping extrapolation domains, and impact assessment. More studies are needed on impact and adoption to identify suitable target domains. AWD is a common water management practice in China. Field experiments were conducted in 1999-2000 at sites in irrigated lowland areas in China (Hubei) and the Philippines (Nueva Ecija) to compare continuously flooded fields with AWD fields. By keeping the rice field alternately flooded and drained, 53–87 millimeters (13–16%) of irrigation water was saved without affecting grain yield significantly (7.2 to 8.7 tons/ hectare). Water productivity was significantly higher in AWD conditions than in the flooded field in two out of three experiments, indicating higher resource-use efficiency of water. (For more on aerobic rice and AWD in China, read RIPPLE Vol. 2, No.3.) With SSNM, aerobic rice, and AWD, rice production in China has better chances of increasing yields to meet the growing consumption demand.
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