固定道结合垄面覆盖种植模式对春小麦冠层结构特性的影响

为了进一步丰富固定道耕作技术理论体系，2005年在河西走廊中部小麦种植区通过结合垄面覆盖试验，探讨了固定道耕作技术对春小麦株高、叶分布、叶面积指数、群体内光分布和光合速率等冠层结构特性的影响。结果表明，固定道结合垄面覆膜(CTP)、固定道结合垄面秸秆覆盖(CTS)、固定道无覆盖(CT)处理的小麦株高分别比平作(对照, LT)低2.09、3.27和5.65 cm。CTS和CTP处理的旗叶与倒3叶间距、旗叶与倒2叶间距以及倒2叶与倒3叶间距的比值接近3:2:1，有利于光能在群体各个层次均匀分布。叶面积指数在6月25日后呈LT>CTP>CTS>CT的变化规律，3个固定道处理的叶面积指数都小于LT处理，而垄面覆盖可以减弱这种影响。LT处理入射光线的97.2%被小麦群体截获，其中77.3%在旗叶层被截获，旗叶光合速率较低，光能利用率不高；CTP和CTS处理的群体内光分布较均匀，漏射损失的光线分别占入射光线的8.0%和11.2%；CT处理生长中期旗叶光合速率较高，但入射光线的透射损失率较高，占入射光线的23.7%，而且整个生育期叶面积指数偏低。总之，CTP和CTS处理构建的“松塔型”结构有利于光能有效利用，增加作物产量；而LT和CT处理则分别由于群体过于密闭遮蔽和稀疏导致光能反射和透射损失严重而降低了作物生产力。

Canopy Architecture Characteristics of Spring Wheat under Controlled Traffic Tillage with Mulching in Ridge

In a field test on the experimental farm of Gansu Agricultural University in Zhangye, Northwest China, the characteristics of colony canopy architecture was investigated in spring wheat under the treatments of controlled traffic tillage with straw mulching in ridge (CTS), controlled traffic tillage without mulching in ridge (CT), controlled traffic tillage with film mulching in ridge (CTP), and conventional cultivation (LT, control). The plant height, leaf distribution, leaf area index, light intercept and capture ratio, and photosynthetic rate were measured at a thesis stage. Compared with LT, the plant height was 2.09, 3.27, and 5.65 cm lower in CTP, CTS, and CT, respectively, and there was a significant difference between CT and LT treatments. Under the treatments of CTP and CTS, an approximate ratio of 3:2:1 was observed in the relationship among the distance between flag leaf and the second leaf from top, and the distance between the second and the third leaf from top. Such ratio was optimal for the uniform distribution of light in the wheat colony. The leaf area index was in the order of LT>CTP>CTS>CT, especially from June 25 to July 15. Controlled traffic tillage reduced leaf area apparently, however, mulching in ridge alleviated such influence. In terms of the distribution of incident light within layers of wheat canopy, although wheat colony intercepted the most lights in treatment LT (97.2%), the light distribution varied sharply in the flag leaf layer (77.34%), the second leaf layer (12.17%), and the third leaf layer (7.17%), indicating an incompact colony canopy configuration and low photosynthetic rate. However, the light distribution in the three leaf layers was relatively well-proportioned in CTP and CTS, with only 8.03% and 11.23% of light penetration, respectively. The photosynthetic rate of flag leaf was higher in treatment CT than in other treatments at anthesis stage, but treatment CT had the highest penetration ratio of light and the smallest leaf area index among the four treatments. The results showed that treatments CTP and CTS were in favor of better colony architecture and solar energy use efficiency, resulting in yield promotion in spring wheat. In contrast, the colony configuration was too compact in treatment LT and too incompact in treatment CT to obtain high yield.