黄土高原半干旱区不同覆膜方式对土壤水热环境及糜子耗水特性的影响

Effects of Different Film Mulching-Patterns on Soil Thermal-Moisture and Broomcorn Millet Water Consumption Characteristics in Semiarid Region on Northwest Loess Plateau

【目的】探明黄土高原旱作区不同覆膜方式中的土壤水温效应及糜子增产机制。【方法】2015—2016年,以陇糜10号为试验材料,设置全膜双垄沟留膜免耕穴播(A1)、全膜双垄沟穴播(A2)、全膜平铺膜上覆土穴播(A3)、全膜平铺穴播(A4)、露地等行距条播(CK)5个处理,研究土壤水热效应及其对糜子耗水特性、水分利用效率及产量的影响。【结果】与露地条播(CK)相比,两年间在糜子生育期内,A1、A2、A3、A4处理5—25 cm土层平均温度变化及土壤平均温度日变化均表现出不同程度的增温效果。糜子生育期内,丰水年份(2015年)A1、A2、A3、A4处理较CK贮水量分别提高94.7、67.9、58.0、21.0 mm,而耗水量表现为CK>A1>A4>A2>A3,且各处理在不同土层、不同生育阶段耗水均衡;严重干旱年份(2016年)A1、A2处理较CK贮水量提高83.9、57.4 mm,而A3、A4较CK降低27.1、25.3 mm,耗水量表现为A3>A4>A1>A2>CK,其中,A3、A4、A1、A2较CK依次加强了对80—100 cm土层水分的利用,且播种至苗期4种覆膜方式较CK耗水量降低,均衡调控了拔节至成熟期的耗水强度;基于4种覆膜方式间土壤水热环境的不同和对糜子生育期内耗水特性的差异,A1、A2、A3、A4处理较CK水分利用效率分别提高1.3—3.9、5.2—5.5、3.4—3.5、4.1—4.2 kg·hm-2·mm-1,增产9.0%—43.3%、34.8%—58.2%、20.8%—49.4%、29.0%—52.9%,且干旱年份的增产幅度更高。【结论】4种覆膜栽培均改善了糜子生育期内的土壤水热环境,调节了其不同生育阶段的耗水强度,显著提高作物水分利用效率、产量及其相关性状,增产潜力依次为A2>A4>A3>A1。

【Objective】The objective of this paper was to explore effect of soil thermal-moisture and the yield-increasing mechanism of broomcorn millet under different plastic mulching-patterns in the dry farming regions of Loess Plateau.【Method】 In this study, ＂Longmi 10＂ was used as trial material with different plastic mulching modes, including ridge-furrow planting with whole film mulching under no tillage（A1）, ridge-furrow planting with whole film mulching（A2）, flat planting with whole film mulching beyond covering soil（A3）, flat planting with whole film mulching（A4）, uncovered and row-planting（CK） to explore the effect of them on soil thermal-moisture, water consumption characteristics, water use efficiency, and yield of broomcorn millet in rainfed agriculture area during 2015-2016.【Result】 Compared with CK, soil average temperature, and average temperature daily variation of 5 to 25 cm soil layer under A1, A2, A3, and A4 treatments showed different degrees of warming effect. During the growth period of broomcorn millet, in the rainy year（2015）, the water storage amount of A1, A2, A3, and A4 treatments were 94.7, 67.9, 58.0, and 21.0 mm higher than that of CK, respectively. The water consumption was CK〉A1〉A4〉A2〉A3, and its contents in each treatment was more balanced in different stages of fertility and different soil layers. In the severe drought year（2016）, treatments of A1 and A2 were 83.9 mm and 57.4 mm higher than that of CK, respectively. However, A3 and A4 treatments reduced 27.1 mm and 25.3 mm, respectively. The water consumption, the use efficiency of 80-100 cm deep soil moisture were A3A4A1A2CK, and the water consumption of the 4 kinds of film mulching was lower than that of the CK from sowing to the seedling stage. The water consumption intensity of the jointing to mature period was controlled by a more balanced approach. Based on the different soil thermal-moisture environment in 4 kinds of mulching methods and the water consumption characteristics of broomcorn millet under treatments of A1, A2, A3 and A4 were increased by 1.3-3.9, 5.2-5.5, 3.4-3.5, and 4.1-4.2 kg·hm^-2·mm^-1, the yield of broomcorn millet were increased production by 9%-43.3%, 34.8%-58.2%, 20.8%-49.4%, and 29%-52.9%, respectively. Furthermore, the increase in yield was higher in arid years.【Conclusion】 Four kinds of mulching could improve the soil thermal environment of soil water in the broomcorn millet growing period, adjust the water consumption rate of the different growth stage, and significantly improve the water utilization efficiency, yield and related traits. The yield-increasing potential was A2〉A4〉A3〉A1.