华北旱地覆膜春玉米田水温效应及增产限制因子

为探求覆膜栽培春玉米旱作田土壤水温变化特征及其对玉米产量和水分利用效率(WUE)的影响，设计垄作覆膜、垄作裸地、平作覆膜、平作裸地(对照)4个处理的田间试验，对春玉米田各生育时段的土壤温度、土层水分、耗水结构及玉米产量进行了监测.结果表明：自播种到抽雄的生育前期春玉米田覆膜较裸地增温1～3 ℃，土壤积温增加155.2～280.9 ℃；延长生育期约5.9～10.7 d.自播种到成苗期覆膜保水效应显著，WUE较裸地提高81.6%～136.4%.春玉米成苗到拔节期正值该区域稳定干旱期，覆膜处理土壤供水层深达80～100 cm，干旱胁迫使WUE较对照降低17.0%～21.6%，产生奢侈耗水.春玉米小喇叭口期后进入雨季，各处理土体复水，并产生过饱渗漏，最终使收获期土体水分与播期持平，贮水丰富.垄作覆膜较裸地增产9.5%；平作覆膜不利于降水入渗而导致渍水，减产5.0%；垄作裸地与平作裸地差异不显著.以雨季前气象干旱期的土壤枯水与雨季后的土壤库水为特征的春玉米田水分供求时序失衡，限制了春玉米的高产.

Effects of plastic mulch on soil moisture and temperature and limiting factors to yield increase for dryland spring maize in the North China.

Four treatments, including ridge tillage with plastic mulch (RP), ridge tillage without mulch (RB), flat tillage with plastic mulch (FP) and flat tillage without mulch (FB), were carried out to examine the tillage type and mulch on the effects of soil moisture and temperature, yield and water use efficiency (WUE) of dry land spring maize in the North China. Results showed that the average soil temperature was increased by 1-3 ℃ and the accumulated soil temperature was increased by 155.2-280.9 ℃ from sowing to tasseling by plastic mulch, and the growing duration was extended by 5.9-10.7 d. The water conservation effect of plastic mulch was significant from sowing to the seedling establishment, with WUE being increased by 81.6%-136.4% under mulch as compared with that without mulch. From the seedling to jointing stage, which coincided with the dry period in the region, soil water utilization by the maize under mulch could reach the depth of 80-100 cm, and its WUE was about 17.0%-21.6% lower than the maize without mulch, since the latter was affected by dry stress. With the coming of rainy season around the trumpeting stage, soil water in each treatment was replenished and maintained at relative high level up to harvest. Yield of maize was increased by 9.5% under RP as compared with RB. However, yield was reduced by 5.0% under FP, due to the plastic film under flat tillage prevented the infiltration of rainfall and waterlogging occurred. No significant difference in yield was found between RB and FB. Higher yield of spring maize was limited because of the mismatching in water supply and demand characterized by soil water shortage before the rainy season and abundant soil water storage after the rainy season.