陇中半干旱区不同覆盖种植方式对土壤水热效应和玉米产量的影响

【目的】探讨黄土高原半干旱区不同覆盖种植方式对土壤水热效应及春玉米产量和水分利用效率的影响,为优化陇中旱作农业区春玉米农田土壤水热环境,提高作物产量提供依据。【方法】于2015—2016年在甘肃省榆中县石头沟省级旱作农业示范点开展田间定位试验,设平地全膜覆盖（WM）、平地半膜覆盖（HM）、隔沟覆膜垄播（MRM）、全膜双垄沟播（WRF）、秸秆覆盖（SM）和露地平播（CK）6种种植方式,测定分析春玉米各生育时期土层剖面水热状况、物候特征、不同生长阶段耗水特性和水分利用效率,以及收获后春玉米产量与水分利用效率。【结果】与露地平作（CK）相比,地膜覆盖处理较CK具有增温效应,全生育期土壤平均增温2.42℃,而SM处理表现为降温效应,平均降温0.36℃,且该调节效应主要表现在苗期,随后温度调节效应逐渐减弱;MRM、WRF、HM和SM处理在春玉米整个生育期内保墒效果显著,而WM处理不利于降水收集,仅在春玉米生长前期具有保墒效果,而在中后期随作物耗水增加,土壤含水率低于CK;春玉米在生长中期（拔节至吐丝）耗水最多,生长后期（吐丝至成熟）次之,生长前期（出苗至拔节）耗水最少,其中地膜覆盖耗水量大于秸秆覆盖,全膜覆盖耗水量大于半膜覆盖;地膜覆盖能显著提高春玉米中前期水分利用效率,其中生育前期和中期分别以HM和WRF处理提高幅度最大,2年平均较CK分别提高250.68%和61.30%;地膜覆盖种植方式在增温、促进耗水作用下使春玉米各生育期提前并增加单株干重,最终表现为产量和水分利用效率的提高,其中以WRF和MRM处理增产和提高水分利用效率效果最为显著,产量较CK分别平均增加171.40%和155.05%,水分利用效率分别平均增加142.80%和125.44%。【结论】垄沟集雨种植方式可明显改善黄土高原半干旱地区土壤水热环境,增加玉米物质积累量,其中全膜双垄沟播种植方式的玉米产量和水分利用效率最佳。

Effects of Different Covering Planting Patterns on Soil Moisture,Temperature Characteristics and Maize Yield in Semi-Arid Region of the Loess Plateau

【Objective】 This experiment explored the dynamic changes of soil water and thermal environment and spring maize yield and water use efficiency in semi-arid areas of the Loess Plateau, which provided a theoretical basis for optimizing the soil water and heat environment and improving the crop yield of spring maize field in the dry farming area in central Gansu. 【Method】 The field positioning experiments were carried out in Yuzhong Agricultural Technology Promotion Center of Gansu from 2017 to 2018, which were set up 6 planting methods, including non-contoured seedbed with film mulching (WM), non-contoured seedbed with half film mulching (HM), ridge-furrow with polyethylene film and straw mulching (MRM), ridge-furrow with full film mulching (WRF), ridge-furrow with straw mulching (SM) and non-contoured seedbed without mulching (CK). Based on the experiments, the water and heat conditions of soil layers profiles in different fertility period of spring maize, phenological characteristics, yield and water use efficiency during harvest period were measured and analyzed. 【Result】 In this study, the film mulching treatment had a warming effect compared with CK, the average soil temperature during the whole growth period was 2.42 °C, while the SM showed a cooling effect with an average temperature drop of 0.36 °C, and the adjustment of soil temperature by the planting method was mainly manifested in the seedling stage, the effect of temperature regulation gradually weakened with the progress of growth period. MRM, WRF, HM and SM had significant effect on the preservation of spring maize during the whole growth period, while WM was not conducive to precipitation collection. It only had the effect of preserving in the early stage of spring maize growth, while the water consumption in the middle and later stages increased with the crop growth, and the soil moisture content was lower than that under CK. The most water consumed of spring maize was in the middle growth stage (jointing to silking), followed by the later growth stage (silking to maturity), and the least was in the early growth stage (budding to jointing), in which the water consumption of plastic film mulching was greater than straw mulching, and full film mulching was greater than half film mulching. Plastic film mulching planting method could improve biomass water use efficiency of spring maize least and middle growth stage significantly. The improvement was highest (up to 250.68%) at early growth stage of HM and at the middle stage of WRF (up to 61.30%), compared with CK. Plastic film mulching planting method resulted in increased soil temperatures and improved soil water consumption, therefore, these treatments extended the growing period for spring maize and increased the dry matter weight per plant, the final performance was the improvement of yield and water use efficiency. The most significant effect on increasing yield and water use efficiency was WRF and MRM, increased yield by 171.40% and 155.05%, respectively, and increased water use efficiency by 142.80% and 125.44%, respectively, compared with CK. 【Conclusion】 The plastic film mulched ridge and sowing furrow planting changed the soil water and thermal environment and increased dry matter accumulation in semi-arid areas of the Loess Plateau. The yield and water use efficiency of the ridge-furrow with full film mulching planting method was the best under these treatments.