【作者】 薛澄；

【导师】 王朝辉；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2011， 硕士

【摘要】 冬小麦是渭北旱塬区最重要的粮食作物之一,而该区水分供应不足和土壤肥力低下严重影响了冬小麦生产。因而,寻求有效措施提高降水利用和养分利用是该区小麦稳产高产的关键,也是该区农业生产中亟待解决的重要问题。本研究针对以上问题,于2008年9月至2010年6月在陕西省长武县十里铺村布置田间试验,采用7种不同施肥与覆盖栽培模式,即对照、农户模式、顶凌追肥、减氮追肥1、减氮追肥2、垄覆沟播和高密垄覆沟播,探讨不同施肥与覆盖栽培措施集成对冬小麦产量、养分吸收,土壤温度和水分、养分利用的影响。结果表明:1、旱地早春追肥使冬小麦两季平均增产10%,水分利用效率提高8.5%。减氮追肥结合垄覆沟播模式平均增产28%,水分利用效率提高20%。2、顶凌追肥和垄覆沟播模式两季冬小麦吸氮量平均分别提高10.3%和17.9%,吸磷量分别提高14.3%和25.9%,吸钾量分别提高4.7%和30.1%,而单纯减氮追肥效果不明显。3、追肥提高冬小麦花前氮素累积和氮素转移量,且追肥量高时效果明显,但追肥不利于冬小麦花后氮素累积。减氮追肥结合垄覆沟播栽培促进冬小麦花后氮素累积,最终提高作物总氮素累积量。4、不同追肥与覆盖栽培模式冬小麦氮肥效率存在显著差异。追肥可促进冬小麦氮肥利用。减氮追肥与垄覆沟播相结合可进一步提高冬小麦氮肥利用。各模式间氮肥回收利用率、偏生产力、生理效率和农学效率趋势一致,均表现为垄覆沟播模式>追肥处理>农户模式。5、两年的结果表明,在渭北旱塬区夏闲期垄上覆膜、沟内覆盖秸秆的栽培模式在不同降水年份均可最大限度地提高夏季休闲效率。垄覆沟播模式两季冬小麦夏闲期休闲效率均最高,平均为56.8%。6、不同施肥与栽培模式土壤氮和磷含量变化明显。硝态氮的变化可达到300 cm深度,而磷的变化主要集中在0-50 cm土层。垄覆沟播模式可以促进冬小麦对深层土壤养分的吸收和利用,收获期50-300 cm土壤硝态氮和速效磷含量均较低。垄覆沟播模式经过夏季休闲期土壤硝态氮下渗的深度可达200-220 cm,需注意氮肥调控,防止过多的氮素残留在土壤中随降水向深层土壤的淋失。冬小麦生育期土壤速效钾含量变化的深度可达300 cm,且各层次间变化均匀,不同施肥与栽培模式对土壤不同深度速效钾含量无显著影响。7、垄覆沟播模式在冬小麦全生育期提高了耕层地温,尤其是孕穗期至收获期的增温效果显著。顶凌追肥不利于提高冬小麦生育期耕层地温。更多还原

【Abstract】 Winter wheat is one of the most important crops in Weibei dryland, while the shortage of water and low soil fertility seriously restrict winter wheat production. In this area, therefore, searching for effective measures to improve the use of limited precipitation and nutrient is the key to obtain high and stable yields of winter wheat as well as the important issues of agricultural production urgently need to be resolved. In this study, we delt with the above problems in the way of setting field experiments in Changwu County, Shaanxi Province during September 2008 to June 2010. By integration of different fertilization and mulching cultivation practices, seven different kinds of fertilization and mulching cultivation modes were designed and used to explore their impacts on winter wheat yield, absorption of nutrients, soil temperature and the use of water and nutrient, which included control, farmers’mode, early spring topdressing, N reduced topdressing 1, N reduced topdressing 2, ridge-mulching and furrow seeding and ridge-mulching and furrow seeding with higher seeding rate. The results were as below:1. Topdressing in early spring in drylands increased winter wheat yield by 10% and water use efficiency by 8.5%. Besides, N reduced topdressing with ridge-mulching and furrow seeding mode averagely increased the yield by 28%, while the water use efficiency by 20%.2. Early spring topdressing mode and ridge-mulching and furrow seeding mode averagely increased N uptake of winter wheat by 10.3% and 17.9%, P uptake by 14.3% and 25.9% and K uptake by 14.3% and 25.9% separately, with the effect being not obvious with N reduced topdressing treatment.3. Topdressing promoted nitrogen accumulation by winter wheat before anthesis and enhanced nitrogen transportation. The impact was more obvious when the amount of topdressing fertilizer was increased. Topdressing decreased nitrogen accumulation of winter wheat after anthesis. N reduced topdressing with ridge-mulching and furrow seeding mode enhanced the nitrogen accumulation of winter wheat after anthesis and finaly increased total nitrogen accumulation. 4. Nitrogen efficiency was significantly different with different topdressing and cultivation mode. Topdressing promoted nitrogen use of winter wheat. N reduced topdressing combined with ridge-mulching and furrow seeding mode further increased nitrogen use of winter wheat. The sequent trends of recovery effienciey of applied N, partial factor productivity from applied N, physiological efficiency of applied N and agronomic efficiency of applied N among different treatments were the same with the performance of ridge-mulching and furrow seeding mode > topdressing mode > farmers’mode.5. According to two-year results, ridge-mulching and furrow covering with straw maximized fallow efficiency during summer fallow. Fallow efficiency of ridge-mulching and furrow covering with straw averagely reached 56.8%, the highest among 7 treatments.6. Soil nitrogen and phosphorus content changed obviously during different stages of winter wheat among different topdressing and cultivation mode. Changes of nitrate nitrogen reached the depth of 300cm soil layer while phosphorus mainly to 50cm soil layer. Ridge-mulching and furrow seeding mode promoted unptaking and usage of deep soil nutrients by winter wheat, therefore its soil nitrate nitrogen and available phosphorus contents were lowered between 50 to 300cm soil depth. Rdge-mulching and furrow seeding mode soil nitrate nitrogen leached to 200-220cm soil depth after summer fallow, therefore much attention should be paid to regulation of its nitrogen input to prevent too much fertilizer nitrogen residual in the soil leaching to deep soil layers by rainfall. Soil available potassium content changed uniformly through 0-300cm soil layers during whole growing stages of winter wheat and different fertilization and cultivation modes had no significant effect on soil available potassium content.7. Ridge-mulching and furrow seeding mode increased topsoil temperature during whole stage of winter wheat, especially from booting stage to harvest. Early spring topdressing mode decreased topsoil temperature during whole stage of winte wheat.更多还原