不同覆盖方式对旱作马铃薯生长及土壤水热特征的影响

【目的】探讨不同覆盖方式对西北旱作区农田土壤水热和马铃薯生长的影响。【方法】2015—2016年连续2年设置沟垄地膜全覆盖（DD）、沟垄地膜半覆盖（DB）和沟垄二元覆盖（DJ）3种覆盖方式大田试验,以平作不覆盖为对照（CK）,研究不同覆盖方式下土壤水温变异特征及对马铃薯生长及块茎形成的影响。【结果】覆盖处理全生育期0—200 cm土层土壤含水量均高于CK,DJ处理在播后70—90 d土壤保水效果最佳。覆盖能降低0—200 cm土层土壤水分变异系数,以DJ处理的土壤水分垂直稳定性最强。与CK相比,DD处理在播后30—50 d的0—15 cm土层土壤增温效果显著,而DJ处理在全生育期0—25 cm土层土壤温度表现“降温和增温双重效应”。各覆盖处理能降低0—25 cm土层土壤温度变异系数,以DJ处理最小,其土壤温度垂直稳定性最强。覆盖能提高马铃薯出苗率和影响出苗天数,其中DD处理平均出苗天数较CK提前4.5 d,而DJ处理推迟3.5 d。马铃薯生育期生物量累积动态变化符合Logistic生长模型,以DJ处理生物量理论值和生长速率最大,快速生长持续期最长。通过主成分分析发现,除马铃薯生物量、单株薯数及亩株数等因素外,土壤水分对马铃薯生长的影响高于土壤温度,是限制马铃薯高产的重要因子。【结论】沟垄二元覆盖（DJ）能改善土壤水温状况,维持相对稳定的土壤水热环境,利于马铃薯生长和块茎产量的提高。

Effects of Different Mulching Patterns on Growth of Potato and Characteristics of Soil Water and Temperature in Dry Farmland

【Objective】 The effects of different mulching methods on soil water, temperature and potato growth in dry farmland of northwest China were studied. 【Method】 A field experiment was conducted in 2015 and 2016 for two consecutive years, and three mulching patterns were set up: full mulching of furrows and ridges with plastic film (DD), half film mulching of ridge and furrow (DB) and dual-mulching of ridge and furrow (DJ), the conventional flat field without mulching was used as the control check (CK). 【Result】 The soil water content with mulching treatments at the 0-200 cm soil layer during the whole growth period was higher than that under CK, especially the soil water retention effect under DJ treatment after 70-90 d sowing was the best. Different mulching treatments could reduce the soil water coefficient of variation at 0-200 cm soil layer, and the DJ treatment had the strongest vertical stability of soil water. The DD treatment had significant thermal insulation effect in 0-15 cm soil layer after 30-50 d sowing, while the DJ treatment had double effects of cooling and increasing temperature at 0-25 cm layer during the whole growth period, compared with CK. All the mulching treatments could reduce the variation coefficient of soil temperature at 0-25 cm soil layer, and the variation coefficient of soil temperature under DJ treatment was the smallest, while the vertical stability of soil temperature was the best. Mulching could increase the potato emergence rate, and affect emergence days. The average emergence days under DD treatment was 4.5 d earlier than that under CK, while DJ treatment delayed 3.5 d. The cumulative dynamics of biomass during the growth period of potato were consistent with the logistic growth equation. The theoretical value and growth rate of biomass under DJ treatment were the largest, and the rapid growth duration was the longest. 【Conclusion】 Through the principal component analysis, it was found that besides some factors of potato biomass, number of potatoes per plant, and potato per hectare, the soil water had a higher effect on potato growth than soil temperature, which was an important factor limiting potato high yield. DJ could improve soil moisture status and maintain relatively stable soil. Water temperature environment was beneficial to potato growth and tuber yield.