【作者】 张继；

【导师】 翟丙年；

【作者基本信息】 西北农林科技大学 ， 农业环境保护与食品安全， 2011， 硕士

【摘要】 水分不足和养分亏缺是限制我国旱地农业发展的关键因素,因此,如何提高旱地作物水肥利用效率便成为该地区农业生产中亟待研究解决的问题。目前,秸秆覆盖的蓄水保墒措施与有限灌溉技术结合的农田水分调控模式成为了干旱、半干旱地区农业发展的方向,但现存的研究多为单因素或双因素,而综合考虑施氮量、秸秆覆盖、灌水量和灌水时期对产量及水氮利用效率影响的研究报道甚少。本文以冬小麦为研究对象,深入系统地研究了陕西关中半旱地不同施氮量和水分调控模式对冬小麦的产量及其构成因素、水分利用效率及其生育期土壤水分动态变化、收获后土壤硝态氮在土壤剖面累积和分布规律及不同生育期地上部氮素累积、转移及其利用效率的影响,并且分析了产量及水氮利用效率差异的生理机制,旨在为该地区冬小麦高产及资源高效利用提供理论依据和技术支撑。取得的主要结论如下:1合理的施氮量(N150)可以显著提高冬小麦籽粒产量,增加有效穗数和穗粒数,增施氮肥,对小麦产量影响不大。各水分调控模式中,覆盖+拔节期补灌处理的产量最高,其次为拔节期补灌和越冬期漫灌处理,均显著高于不灌水处理;秸秆覆盖和灌水措施显著提升了有效穗数和穗粒数。相关分析表明,产量构成三因素中,有效穗数对产量的贡献性最大。2施用氮肥可以显著提高冬小麦的群体总茎(穗)数、功能叶叶面积和叶绿素含量;对小麦生育后期光合速率、蒸腾速率作用明显。秸秆覆盖结合灌水减少了冬小麦的小蘖死亡,增加了成熟期的有效穗数,其中结合拔节期补灌的保蘖效果显著高于越冬期补灌。灌水对冬小麦各生育期的群体总茎(穗)影响不大,却显著增加了有效穗数;越冬期灌水推迟到拔节期可以显著提高叶片的气孔导度和蒸腾速率;秸秆覆盖和灌水延缓了小麦生育后期叶绿素的降解,延长了叶功能期。3在小麦拔节期,施氮水平下的0～40 cm土层含水量要低于不施氮水平;灌浆期施氮水平下40～120 cm土层含水量显著低于不施氮水平,且随着小麦生长发育,深层土壤水分降低明显,而施氮处理间差异不大;适宜的施氮量(N150)可以显著提高冬小麦生育期耗水量和水分利用效率,增施氮肥(N225),土壤水分利用效率变化不大。在各水分调控模式中,灌水可以提高0～60 cm土层的含水量,增加了小麦总耗水量;在不覆盖秸秆条件下,将越冬期灌水推迟到拔节期,小麦耗水量和水分利用效率没有显著差异,而在秸秆覆盖条件下,则显著降低了小麦总耗水量,增加了水分利用效率,其中覆盖+拔节期补灌处理显著降低了冬小麦生育期总耗水量,水分利用效率达到最大。4施用氮肥(N150、N225)显著地增加了冬小麦地上部和籽粒的氮素累积量,但过量施用(N225),会导致0～200 cm土壤剖面硝态氮的大量残留,且氮肥利用效率显著降低。不同水分调控模式中,覆盖+拔节期补灌处理下冬小麦地上部的氮素累积量最高,0～200 cm土体的硝态氮残留量也较高,其次为拔节期补灌处理;覆盖+拔节期补灌处理的氮肥利用效率显著高于其它水分调控模式,而氮肥农学效率较其它处理没有显著差异;不灌水处理的氮素转移量和贡献率均显著低于其它处理。更多还原

【Abstract】 Water shortage and nutrient deficiency are key factors that restricted crop production in arid and semiarid areas. Therefore to improve the utilization efficiency of water and nitrogen have become researching and pursuiting of the goal. At present, combination of straw mulching and supplemental irrigation patterns is an option for the utilization of limited water resource in arid and semi-dryland farming, But more research about single factor or double factors, study considering the N rate, straw mulching, irrigation amount and irrigation time on the yield, water and nitrogen use efficiency was rare.A field experiment was conducted in Guanzhong region of Shaanxi Province to study the effect of different nitrogen application rates and water control patterns on winter wheat grain yield and yield component, water use efficiency and soil water content dynamic change in different growing stages, the accumulated amount and distribution of nitrate N in soil profiles after harvesting and nitrogen accumulation and transportation in different growing stages, and analyze the physiological mechanisms that causes different yield, water and nitrogen use efficiency. The experiment was aimed to provide a scientific theory basis for increasing grains yield and resource using effiency in winter wheat of arid and semiarid areas. The main conclusions included:1. Application of nitrogen fertilizer (N150) can significantly improve the grain yield, effective panicles and grains per spike of winter wheat, and there was not have significant difference between N150 and N225. The yield in MJS(Straw mulch+ jointing stage irrigation (40 mm)) treatment was significant higher than No irrigation (CK) treatment in N0 and N150, there was not have significant difference in N225 of grain yield. Effective panicles and grains per spike in MJS were significant higher than CK. In short, Straw mulch+ jointing stage irrigation (40 mm) were the best treatment under N0, N150 and N225. Correlation analysis showed that the effective panicles made the greatest contribution to the grain yield in yield component.2. Application of nitrogen fertilizer can significantly improve the total population of winter wheat stems (spikes) number, leaf area and chlorophyll content. Application nitrogen fertilizer did not have significant effect on photosynthetic rate, transpiration rate on winter wheat earlier stage, and had significant effect on filling stage. The water control patterns that combination of straw mulching and irrigation can reduce the number of tillers in regreening stage and the total number of stems in jointing stage, however, it reduce the small tillers deaths, straw mulching combined with supplementary irrigation at jointing stage had significantly effect than supplementary irrigation at overwintering stage. Irrigation had little effect on winter wheat total stems (spikes), but it can significantly increase the effective panicles. Irrigation at jointing stage can significantly improve the stomatal conductance and transpiration rate more than irrigation at over-wintering stage. Straw mulch and irrigation delayed the degradation of chlorophyll, extended the period of leaf function.3. At jointing stage, water content in 0 ~ 40 cm soil layer in N150 and N225 was lower than the N0, At filling stage, water content in 40 ~ 120 cm soil layer in N150 and N225 treatments was significantly lower than N0, and with the winter wheat growth, water content in deeper soil layer decreased obviously. There was not haveing significant difference between the N150 and N225 treatments. N150 can significantly improve water consumption and WUE (water use efficiency) than N0. Irrigation can increase the water content in 0 ~ 60 cm soil layer and the total water consumption. The consumption and water use efficiency is not having significant difference between jointing stage irrigation and overwintering stage under No straw mulching condition. In straw mulching condition, jointing stage irrigation can significantly reduced the total water consumption, increased water use efficiency. In short, straw mulching+jointing stage supplementary irrigation (MJS) treatment can significantly reduced total water consumption and increase the WUE than other treatments.4. Application of nitrogen fertilizer (N150, N225) can significantly promote the nitrogen accumulation in shoot and grain. But when nitrogen fertilizer excessively applicated (N225), the residual nitrate N in the 0~200 cm soil profiles significantly increased, and NUE(nitrogen use efficiency) was significantly decreased. Straw mulch+ jointing stage irrigation (MJS) treatment had the highest accumulation of N in shoot, the residual nitrate N in the 0~200 cm soil profiles was also higher. The NUE of MJS treatment was significantly higher than other water control patterns, and N agronomic efficiency did not have significant differences. The amount of nitrogen transfer and contribution rate in No irrigation (CK) treatment were significantly lower than other treatments.更多还原