栽培模式、施氮和品种对冬小麦冠层结构和产量的影响

在黄土高原南部半湿润易早区土垫旱耕人为土上进行大田试验，研究氮肥、品种和栽培模式对冬小麦叶面积指数（IAI）和透光率（DIFN）及产量的影响。结果表明，小麦生长过程中IAI先增大后减小．在开花期最大。成熟期最小。施氮能够显著增加IAI；DIFN的变化规律与LAI相反。不同品种间IAI和DIFN差异显著。全程覆膜和覆膜150d的LAI极显著大于常规栽培、集雨面栽培和三密一稀栽培模式，DIFN与此相反；施氮后籽粒产量极显著增加。在不同栽培模式下，以全程覆膜、覆膜150d和集雨面栽培模式的产量较高，但从维持土壤质量角度考虑，则覆膜150d和集雨面2种栽培模式优于其它几种栽培模式；从冠层结构特征分析，这2种栽培模式更有利于增加群体光合能力。

Effects of cultivation mode, nitrogen fertilization, and cultivar on winter wheat canopy parameters and grain yields in sub-humid area

A field experiment was conducted on the Earth-Cumulic-Orthic Anthrosols in south Loess Plateau to investigate the effects of nitrogen fertilization,cultivar,and cultivation mode on the leaf area index(LAI),diffuse non-interceptance(DIFN),and grain yield of winter wheat.The results showed that during the growth period,LAI increased first and decreased then,which was the highest in flowering but the lowest in maturing stage.Nitrogen fertilization improved the LAI significantly.DIFN had a change pattern reverse to LAI.There were significant differences in LAI and DIFN among cultivars.The LAI under plastic-film mulching for whole growth period(PFMW) and plastic-film mulching for 150 d(PFMD) was significantly higher than that under other three cultivation modes,while DIFN was in reverse.Nitrogen fertilization increased grain yield significantly.The grain yield under PFMW,PFMD,and rainfall harvest cultivation was higher than that under other two cultivation modes,but from the viewpoints of grain yield,canopy parameters,and soil quality,PFMW and PFMD were better than the other three cultivation modes.