黄土高原旱地马铃薯田土壤水分动态变化及供需研究

摘要

为掌握甘肃黄土旱塬地区马铃薯田土壤水分变化动态、需水特征及需水关键期，通过测定不同栽培方式下马铃薯田主要生育期不同土层含水量，从而分析不同处理土壤水分动态变化及耗水量。结果表明，半干旱地区黄土高原旱地马铃薯田季节水平变化与垂直层次变化是土壤水分变化的主要运行规律。随时间变化，传统露地对照呈“降—升”、覆膜种植呈“升—降—升”变化趋势；随深度垂直变化，总体上露地对照呈“降—升”、覆膜种植呈“升—降—升”变化趋势。0~20 cm土层变化剧烈，是马铃薯田的速变层；40~80 cm土层变化活跃，是马铃薯田的活跃层；20~40 cm与80~100 cm土层变化较缓，是马铃薯田的渐变层与缓变层。马铃薯田耗水量与年型密切相关，随着降雨的增多而增大。传统露地种植一生耗水258.6 mm、地膜覆盖种植一生耗水264.1 mm，以块茎形成期耗水强度最大，日均耗水分别为2.2 mm与2.8 mm，是半干旱地区马铃薯的需水关键期，此时期间降雨69.8 mm，土壤可用水基本耗尽，缺水7.0~29.6 mm，集雨补灌将是应对关键期旱灾，获得稳产的必要应变措施。%The effects of moisture dynamics and water consumption were analyzed by measuring the soil water content for different treatments at different growth stages in order to understand the moisture dynamics, water demand characteristics and water demand critical stage in potato fields in the southern loess Plateau. The results indicated that seasonal level and vertical level changes of potato fields were the major function at soil moisture changes in arid areas of the southern loess Plateau. Changing with time, the trend of traditional field culture was"drop-up", and mulching planting was"up-drop-up". Changing with depth, the trend of traditional field culture was"drop-up", and mulching planting was"up-drop-up"in general. Soil moisture content in the 0-20 cm layer changed intensively, being the most variable layer of potato field. Soil moisture in the 40-80 cm layer changed actively, being the vigorous layer of potato field. Soil moisture in 20-40 cm and 80-100 cm layer changed slowly, being the gradient layer and sluggish layer of potato field. Water consumption was related closely to the model year in potato field, increasing with the increase of rainfal . The water consumption was 258.6 mm for traditional field culture, and 264.1 mm for mulching in the whole potato lifetime. The maximum water consumption was at the tuber formation stage, with a consumption of 2.2 mm and 2.8 mm each day, respectively, for the two culture modes, being the key water requirement stage of potato in the semi-arid areas. The rainfal was 69.8 mm during this time, and soil available water was depleted substantial y. Shortage water reached 7.0-29.6 mm. Therefore, col ecting water for supplemental irrigation would be a contingency measure to deal with the dry conditions in critical stage and obtain stable yield.