秸秆覆盖中原料切碎/粉碎对土壤水热的影响

果园秸秆覆盖是西北旱区果业提质增效的有效途径,但人工作业的低效性制约了该技术的发展。本研究旨在探明秸秆原料切碎/粉碎加工对覆盖土壤水分和温度的影响,为秸秆机械化覆盖技术开发提供理论依据。本文以切碎加工的小麦(CW)、玉米(CC)、大豆秸秆(CS)和粉碎加工的小麦(SW)、玉米(SC)、大豆秸秆(SS)为覆盖基质,以无覆盖处理(CK)为对照,在室外容器中模拟研究秸秆—薄土分层覆盖在果园土壤保墒、保温、抑制杂草方面的效果。结果表明:试验期内,各覆盖处理的底层土壤含水率均高于CK,切碎、粉碎秸秆覆盖的土壤含水率分别高于CK 3.16%和2.35%。小麦、玉米秸秆切碎覆盖的土壤保墒效果优于粉碎覆盖,而大豆秸秆相反。各覆盖处理均有效地减小底层土壤全天的温度波动,即在早、晚提高土壤温度,而午间则降低土壤温度。小麦、玉米秸秆粉碎覆盖的土壤保温效果略优于切碎覆盖,而大豆秸秆相反。从3种秸秆的土壤保温效果综合评价,切碎、粉碎加工方式对其影响不明显。各覆盖处理均有明显地隔离上、下层土壤水分交换的效果,能起到抑制杂草的作用。CW、CC和CS处理的表土层和底土层土壤含水率差值分别为9.50%、9.05%和9.18%,而对应的SW、SC和SS处理差值分别为8.1 3%、8.2 8%和9.4 7%。综合分析秸秆切碎、粉碎加工对分层覆盖土壤水热的影响,认为果园秸秆分层机械化覆盖中,秸秆加工应优先采用切碎方式。

Effects of Mulch by Cutting/Smashing Straw on Soil Water and Thermal in Orchard

Straw mulch in orchard has sustainable benefit to fruit industry in arid regions in northwest China. However, this technology is constrained by the low efficiency of manual operation. This study aims to estimate the influences of straw cutting/smashing methods on water and thermal effects of the mulched soil. Hope the study provides a theoretical basis for developing mechanized straw mulch technology. In this study, cut wheat straw (CW), cut corn straw (CC), cut soybean straw (CS) and smashed wheat straw (CW), smashed corn straw (CC), and smashed soybean straw (CS) were used as mulch materials, and no mulch was used as a control experiment (CK). Simulation study was conducted in outdoor containers to investigate the effects of straw layered mulching on soil water retention, heat preservation and weeds suppression. The results showed that during the test period, the mean water content of soil at each treatment was higher than CK. The mean water contents of cutting and smashing treatments were 3.16% and 2.35%, respectively, higher than CK. The water retention effects of cutting treatments were better than smashing treatments for wheat and corn straw, but the effect was contrary for soybean straw. All mulching treatments effectively reduced the daytime temperature fluctuation of the mulched soil layer. That is the soil temperature in morning and evening was raised, and it was decreased at noon. The soil temperature holding effects of smashing treatments were a little better than cutting treatments for wheat and corn straw, but the result was contrary for soybean. Generally, cutting and smashing processing methods had not obvious influence on soil temperature. Straw mulch layer significantly isolated water exchange between the upper and lower soil layer at each treatment, implying it is helpful to prevent weeds growing. The temperature difference between the upper and lower soil layers treated by CW, CC, CS were 9.50%, 9.05% and 9.18%, respectively, while the difference at SW, SC, SS treatments were 8.13%, 8.28%, and 9.47%, respectively. Combining all of the analysis results of cut and smashed straw mulch on the soil effects, it is suggested that cutting is better than smashing for mechanized straw layered mulching in orchard.