膜下滴灌水氮耦合对玉米光合特性的影响

通过大田试验设置水氮2因素3水平计9种组合处理,研究膜下滴灌水氮一体化施用条件下二因素不同用量对玉米灌浆前期穗位叶光合速率和蒸腾速率的影响效应及其他光合因子与光合速率的关系,寻求适宜松辽平原到内蒙古高原过渡地带的水氮施用量。结果表明:气孔导度、蒸腾速率与光合速率线性正相关,胞间CO_2浓度与光合速率线性负相关。灌水与施氮均能提高光合、蒸腾速率,灌水作用大于施氮。氮亏缺抑制光合速率的程度大于抑制蒸腾速率,灌水量的增加促进光合速率的程度小于促进蒸腾速率。生育期1 351~1 465 m~3/hm~2的低灌溉量阻碍氮对光合速率和蒸腾速率的作用,水分亏缺引起过量施氮的负效应。1 802~2 315 m~3/hm~2的中高灌溉量下氮效应显著,而施氮量由240 kg/hm~2增至288 kg/hm~2效应微弱。生育期施氮240 kg/hm~2与灌水1 802~2 315 m~3/hm~2可作为适宜的水氮耦合用量。

The Effects of Water and Nitrogen Coupling on Photosynthetic Characteristics under Mulched Drip Irrigation

Through a field experiment, in which the two elements of water and nitrogen, 3 levels and total 9 combination treatments are set, this paper study the effects of different amount of water and nitrogen on ear leaf's photosynthetic rate, transpiration rate, and the relation be-tween other photosynthetic elements and photosynthetic rate, at grain filling pre-stage under the condition of mulched film drip irrigation with integration of water and nitrogen, to look for the fittest water and nitrogen amount for the transitional area from Song-Liao plain to Inner Mon-golia high land.The result shows that stomatal conductivity and transpiration rate is positively linear correlated with photosynthetic rate;inter-cellular carbon dioxide concentration is negatively linear correlated with photosynthetic rate;both irrigation and nitrogen can improve photo-synthetic and transpiration rate, and irrigation has more effect than nitrogen;nitrogen deficit (192 kg/hm2) causes a bigger inhibitory effect on photosynthetic rate than transpiration rate; the effect of increasing irrigation quantity on improving photosynthetic rate is larger than on transpiration rate;low irritation quantity (1351~1465 m3/hm2) in the growth period obstructs the effect of nitrogen on photosynthetic and transpiration rate;water deficit can cause negative influence of over nitrogen treatment; nitrogen effect is significant under the condition of middle-high irritation amount of 1802~2315 m3/hm2 , while the effect of nitrogen is weak when the application amount increases from 240 kg/hm2 to 288 kg/hm2 .The nitrogen amount of 192 kg/hm2 and irrigation amount of 1802~2315 m3/hm2 during the growth period can be taken as appropriate coupling application amount of water and nitrogen.