河西走廊绿洲杨树防护林内玉米营养生长的变化及其成因

Variation and Reasons of Maize Vegetation Growth in Poplar-maize System in Heixi Corridor Desert Oasis of China

对河西走廊绿洲杨树防护林(南北走向)内13个位置的玉米在营养生长阶段叶面积和株高变化进行了研究,结果发现,不同方位和不同距离上玉米营养生长受影响程度不同。杨树抑制了东、西两面与其毗邻玉米的营养生长;杨树东面玉米的营养生长比中部和西面迅速,其中东面5 m处玉米营养生长期末单株叶面积达到0.43 m2,营养生长显著加强。从玉米生理生态参数变化方面对以上变化成因进行分析,表明防护林内气温空间变化是导致玉米叶面积和株高增长产生变化的根本原因。上午杨树西面温度低、东面温度高,导致前者玉米叶面积较小、后者则显著增大;而中午气温的空间变化则直接造成了杨树西面玉米植株较矮、东面较高的生长规律。

Variations of maize leaf area and height during vegetation stage were studied on thirteen locations within poplar-maize system of North-south-trending in Hexi Corridor desert oasis of China.The results showed that,the impact degrees of poplar trees on vegetation growth of maize were different from their direction and distance.Vegetation growth of maize neighboring to trees was restrained significantly.All the maize plants at the eastern side of trees,whose vegetation growth were promoted and with a maximum leaf area of 0.43 m2 at 5 meters eastern side（E5） especially,showed rapid growth rate than the middle and western locations.The reasons were analyzed with eco-physiological parameters and found that air temperature change within the system was the basic reason of variation in maize leaf area and height.In the morning,the temperature of western side of tree was lower;while the eastern side was higher（e.g.the temperature of E1 was even 7.1 ℃ higher than W1）,which resulted in lower leaf area at western side and higher at eastern side respectively.As for plant height,the basic reason of lower at western side and higher at eastern side was the spatial variation of air temperature during midday.