Water management in irrigated rice - Rice Knowledge Bank ...

Table 3.5. Water input (I = irrigation, R = rainfall) and yield of aerobic rice variety HD297 under aerobic conditions in 2003and 2004, Beijing, China. Data from Xue Changying et al (2007).2003 2004Water input (mm) Yield (t ha −1 ) Water input (mm) Yield (t ha −1 )I I + R Exp 1 Exp 2 I I + R408 688 4.25 3.11 535 705 5.58408 618 3.70 2.54 535 675 5.35408 648 2.11 1.26 535 645 5.35408 578 − 0.46 535 605 4.99Table 3.6. Performance of aerobic rice grown by farmers around Kaifeng, northern China, in terms of yield and water use,2002-03. Data from Bouman et al (2007).Farmer (code letter) A B C D E F GYield (t ha −1 ) 3.8 4.4 3.8 5.1 5.5 4.7 3.4Irrigation (mm) 225 225 80 231 230 300 225Rainfall (mm) 337 337 337 337 337 337 337Total water input (mm) 562 562 417 568 567 637 562Farmer (code letter) U V W X Y ZYield (t ha −1 ) 1.2 3.8 2.4 3.8 3.6 3.0Irrigation (mm) 156 159 145 169 146 162Rainfall (mm) 674 674 674 674 674 674Total water input (mm) 830 833 819 843 820 836Kaifeng in the North China Plain, Feng Liping etal (2007) obtained relatively low yields of 2.4−3.6t ha −1 with 750−1,000 mm of total water input. Itis estimated that aerobic rice systems are currentlybeing pioneered by farmers on some 80,000 hain northern China using supplementary irrigation(Wang Huaqi et al 2002). Bouman et al (2007)reported yields of aerobic rice obtained by farmersaround Kaifeng of up to 5.5 t ha −1 with sometimesas little as 566 mm of total water input, with onlyone or two supplementary irrigation applications(Table 3.6). Table 3.7 compares the performanceindicators of aerobic rice, lowland rice, and maizeobtained by farmers in the same area. Simulationmodel predictions even suggested that no irrigationwould be needed for high yields with some 400−600mm of rainfall and groundwater tables of 2 m deepand less. In Brazil, a breeding program to improveupland rice has resulted in aerobic varieties with ayield potential of up to 6 t ha –1 (Piñheiro et al 2006).Farmers grow these varieties in rotation with cropssuch as soybean and fodder on large commercialfarms with supplemental sprinkler irrigation on anestimated 250,000 ha of flat lands in the Cerradoregion, realizing yields of 3−4 t ha −1 .The development of tropical aerobic rice is ofrelatively recent origin. De Datta et al (1973) grewlowland variety IR20 in aerobic soil under furrowirrigation at IRRI in the Philippines. Water savingswere 55% compared with flooded conditions, butyield fell from about 8 t ha −1 under flooded conditionsto 3.4 t ha −1 under aerobic conditions. Usingimproved upland rice varieties, George et al (2002)reported aerobic rice yields of 1.5−7.4 t ha −1 inuplands with 2,500 to 4,500 mm of annual rainfallin the Philippines. Yields of 6 t ha −1 and more,however, were realized only incidentally in the firstyears of cultivation, and most yields were in the 2−3t ha −1 range. Atlin et al (2006) reported aerobic riceyields of 3−4 t ha −1 using recently developed aerobic25