南方丘陵典型季节性干旱区水稻节水灌溉的密肥互作效应研究

Study on combined effects of nitrogen and planting density in rice water-saving irrigation in Southern China seasonal drought hilly region

采用裂区试验设计,研究了南方丘陵季节性干旱地区间歇灌溉水稻密度与氮肥互作效应及其对水稻光合特性、稻谷产量及产量结构的影响。结果表明,随着密度的增加,孕穗期前,间歇灌溉水稻群体净光合速率增加,但孕穗期后,高密度大群体净光合速率衰退较快。与此同时,高密度大群体剑叶光合速率、穗粒数、结实率及千粒重均较低;随着施氮量的增加,水稻群体净光合速率、剑叶光合速率、叶绿素含量、单位面积穗数及穗粒数增加,而结实率与千粒重降低。在本研究条件下,间歇灌溉水稻密度为281 250穴/hm2、施氮量225 kg/hm2时,其产量最高,达10 297.90 kg/hm2。

The effect of amount of nitrogen and planting density on canopy apparent photosynthetic （CAP）rate, photosynthetic rate and chlorophyll content in flag leaves, yield components and grain yields were studied with indica hybrid rice Liangyoupeijiu in intermission irrigation in southern China seasonal drought hilly region. The results are as follows： as the increment of density, canopy apparent photosynthetic（CAP）rate increased before anthesis and decreased quickly during grain filling. Meanwhile photosyn- thetic rate in flag leaves, grain number per panicle, seed setting rate and 1000-grain weight decreased. As the increment of amount of nitrogen, canopy apparent photosynthetic（CAP）rate, photosynthetic rate and chlorophyll content in flag leaves, panicle number and grain number per panicle increased. But seed setting rate and 1000-grain weight increased. The result showed that the tiptop output is 10 298 kg/hm^2 when the transplanting density is 281 250 hills/hm^2 and the applying amount N-fertilizer is 225 kg/hm^2 in intermission irrigation.