Soil water storage (SWS) is the critical factor influencing wheat yield in dryland area. A field experiment was carried out in Wenxi County, Shanxi Province from July 2009 to June 2012 (three cropping seasons) to study the effect of tillage during fallow period on annual SWS and wheat yield. Compared to no tillage (NT), deep plowing (DP), subsoiling (SS) increased SWS in 0-300 cm soil layer at sowing stage by 63-91 mm in dry year, 41-70 mm in normal rainfall year and 54-74 mm in humid year. The annual SWS efficiency was much improved by tillage during fallow period, especially the late growth stage of wheat in dry and humid years, resulting in increases of grain yield and yield components. In dry year, wheat yield was enhanced as high as 34%(SS) and 45%(DP). In normal rainfall year, spike number, grain number per spike, and grain yield significantly increased in DP and SS compared to NT. In yield components, spike number received the largest effect of tillage, either DP or SS, under normal and rich rainfall conditions. In DP and SS treatments, spike number had close correlation with 120-180 cm soil water reduction from sowing to jointing and 60-120 cm soil water reduction from jointing to anthesis, grain number per spike was correlated with 60-120 cm soil water reduction from sowing to jointing, and grain yield was correlated with 60-120 cm soil water reduction from jointing to anthesis and 120-180 cm soil water reduction from anthesis to maturity. Clear, tillage during fallow period could sig-nificantly increase rainfall productive efficiency and water use efficiency in rainfed field. DP and SS have positive effects on SWS during fallow period and utilization of water in deep soil layers. The improved water utilization is the basis for improved yield components and high yield ultimately. Tillage during fallow period is recommended with DP practice in dry and normal rainfall years and SS practice in humid year.%为明确旱地小麦通过休闲期耕作实现蓄水增产的技术途径,2009-2012年连续3个小麦生长季,在山西省闻喜县进行了休闲期深翻、深松或无耕作的田间试验,以明确不同耕作措施对土壤水分变化、小麦产量形成的影响。结果表明,深翻和深松处理播种期0~300 cm土壤蓄水量增加,枯水年增加63~91 mm,平水年增加41~70 mm,丰水年增加54~74 mm,尤其在枯水年和丰水年生育后期蓄水效果仍显著,休闲期土壤蓄水效率显著提高,枯水年提高147%~205%。深翻和深松处理在枯水年和丰水年可促进小麦生育后期吸收300 cm土层土壤水分,使产量和产量构成因素显著提高,尤其在枯水年产量提高34%~45%。在平水年,穗数、穗粒数和产量显著提高,且在平水年和丰水年深翻和深松处理对产量构成因素中的穗数影响最大。深翻和深松处理后降水生产效率和水分利用效率显著提高。不同降水年型休闲期耕作条件下,穗数与播种至拔节期120~180 cm、拔节至开花期60~120 cm土层土壤贮水减少量关系密切,穗粒数与播种至拔节期60~120 cm土层关系密切,产量与拔节至开花期60~120 cm、开花至成熟期120~180 cm土层关系密切。总之,在本研究条件下,旱地小麦休闲期深翻或深松耕作有利于蓄积休闲期降水,改善底墒,尤其枯水年的效果更为明显；有利于增加土壤水分,促进小麦向深层吸收土壤水分,优化产量构成,实现增产。在枯水年和平水年,以休闲期深翻效果较好,在丰水年以休闲期深松效果较好。
展开▼
