Effects Of Different Irrigations On Yield Formation And Quality Of Aerobic Rice

A two-year field trial was carried out in Chang Ping experiment station in 2001 and 2002 to study the effects of different water treatments on yield and qualities of Han dao502 and Han dao297. Five treatments were designated; there were fully irrigation (W1), limited irrigation after jointing (W2), limited irrigation befor jointing (W3), limited irrigation in all grow stage (W4) and rainfed irrigation. This research mainly focused on the difference of carbon and nitrogen accumulation, photosynthetic character, yield and yield components, rice qualities and water use efficiency among different water treatments. The main results were given below:1, The yield of upland rice decreased with decreased irrigation amount, resulting from higher spikelets per panicle and 1000-grain weight. There was no obvious difference between Wl and W3, and W3 has the highest water use efficiency, and rice appearance and nutritional qualities were not affected by limited irrigation before jointing stage, so limited irrigation before jointing stage (W3) was a better irrigation method.2, Limited irrigation before jointing accelerated the transportation of pre-anthesis stored assimilation to grain, enhanced the transportation of stem carbon to grain, increased the movement of pre-anthesis nitrogen of leaf to rice grain.3 , Comparison of chlorophyll fluorescence of flag leaf, sheath and stem node among different treatment showed Fv/Fm of Han dao502 and Jin dao305 declined with water decrease. But w3 has higher Fv/Fm, The photosynthesis rate and root dry matter of Wl was higher than w4, but the distribution of root in deep soil layer was lower than W4.4, Yield of upland rice was higher in paddy field than in dry land, resulting from higher spikelets per panicle and 1000-grain weight. Upland rice accumulated more dry matter in paddy field, and root matter mainly distributed in 0~20cm soil layer. There was higher water-soluble carbohydrate and nitrogen content of leaf and stem in dry land than paddy field, because of the restriction of soluble matter movement.5,Comparison of yield of Han dao502 and Han dao297 under different irrigation treatment showed Han dao502 was better than Han dao297, and Han dao502 can achieve hiegher yield than Han dao297.For Han dao502, limited irrigation before jointing is a reasonable irrigation method.