摘要
依据盆栽试验数据 ,采用 Jenson模式 ,研究了黄土区夏玉米的水分模型。结果表明 ,玉米在拔节 -抽穗期和抽穗 -灌浆期对缺水最敏感 ,拔节前和灌浆 -成熟期敏感性小 ;较高肥力水平使需水关键期水分敏感性指数增加相对较多 ,而在非水分关键期增加较少。较高的 N、P水平增大了玉米叶片的光合速率 ,中度干旱条件下 ,N、P肥对 Pn的增加幅度大于充分供水时的增加幅度 ;施用 N、P增加了玉米叶片的蒸腾速率 ,但土壤水分条件影响了 N、P对蒸腾速率的作用 ;施用 N、P肥可以提高玉米的单叶 WUE,随水分条件的改善而增加。高 N处理的玉米根重均低于相应的低 N处理 ,施 P对玉米根系生长有明显的促进作用 ,中度干旱条件下的增幅大于充分供水时的增幅 ;不同施 P处理玉米地上生物量的增幅明显大于不同施 N处理的增幅 ;随水分条件的改善 ,玉米的根冠比增加 ,不同水分条件下施 N均降低了根冠比 ,而施 P增加了根冠比。
As water is a major factor limiting agricultural productivity in dryla nd farming, it is very important, and possible, to regulate crop water use throu gh fertilizer application under limited water resources. There are extensive re searches reported on water sensitivity of different crops during different growt h stages, however, there are few reports on the effect of inorganic nutrients on crop water sensitivity. In terms of methods and crops used in studies, the rep orts about the impact of inorganic nutrition on crop growth and development unde r water deficit conditions are inconsistent. The results presented in this pap er address three issues: (1) the effect of nitrogen (N) and phosphorus (P) on su mmer maize's water sensitivity; (2) the function of inorganic nutrition in adjus ting summer maize's CO-2 and H-2O exchange parameters and growth of roots and shoot s; and (3) better solutions to fertilizer application for better water-saving i rrigation schemes. Potted summer maize was used in the experiments. Six fertilizer treatments and two water treatments were used. Based on the experimental data, the water suppl y model of summer maize in the Loess Plateau was proposed with reference to Jens en's model. The results show that water sensitivity index of summer maize reach es the highest value from the booting to heading stages, and from heading to fil ling stages, and becomes comparatively low before booting and after filling. At a high fertilizer application rate, a higher water sensitivity index is achieve d at key water-demand stages than that at unimportant water-supply stages. Hig her N & P application rates also increase the photosynthesis rate, transpiration rate and water-use efficiency. The root dry matter under a high N level is low er than that under a low N level; the use of P boosts root growth obviously, and the enhancement under 50% Relative Soil Water Content (RSWC) is greater than th at under 80% RSWC. The increase of above-ground biomass under different P trea tmen ts was greater than that under different N treatments distinctly. The root/shoo t ratio is increased with the improvement of water condition. Under different wa ter supply conditions, the use of N reduces the root/shoot ratio while the use o f P raises it.ater
出处
《生态学报》
CAS
CSCD
北大核心
2003年第4期751-757,共7页
Acta Ecologica Sinica
基金
中国科学院知识创新资助项目 ( KZCX1 -0 6-0 2 -0 1 )
黄土高原土壤侵蚀与旱地农业国家重点实验室基金资助项目 ( 0 2 -B0 0 3)~~
关键词
夏玉米
水分敏感性
磷营养
生态参数
生理参数
氮营养
summer maize； water sensitivity； nitrogen and phosphorus； physiological parameter
