全膜覆土一茬和二茬小麦蓄水保墒效应研究

Water-saving Effect of the Full Plastic Film Mulching with Soil Covered on Plastic Film on First-crop and Second-crop Wheat

为了明确旱地全膜覆土一茬和二萑小麦的蓄水保墒效应，2008-2012年研究了全膜覆土一茬和二茬小麦在生育期和夏闲期水分动态变化。结果表明，全膜覆土一茬和全膜覆土二茬小麦水分动态变化趋势基本相同，土壤含水量在苗期达最大值，抽穗期降到最低点，收获期略有升高。全膜覆土穴播一茬小麦和二茬小麦表层土壤含水量较露地小麦分别提高了1．1个百分点和1．6个百分点；20～100cm土层土壤含水量分别提高了0．3个百分点和1．8个百分点；100～200cm土层全膜覆土一茬小麦较露地小麦降低了0．2个百分点，而全膜覆土二茬小麦较露地小麦提高了1．3个百分点。夏闲期全膜覆土一茬小麦、全膜覆土二茬小麦和露地小麦0～200cm土层土壤储水量分别增加了97．6、148和65．9mm，蓄水率分别为42％、65％和29％，由此可见全膜覆土二茬小麦蓄水保墒效应显著。全膜覆土穴播一萑和二茬小麦产量均较露地小麦明显提高，差异达显著或极显著水平，而全膜覆土一茬与二茬小麦产量间的差异不显著。在旱地推广全膜覆土二茬小麦，有利于把自然降水蓄于土壤，减少水分无效蒸发，提高自然降水的利用效率，增产增收效果显著。

In order to investigate the water-saving effect of the full plastic film mulching with soil covered on plastic film （FPFM） on first-crop wheat （FFPFM） and second-crop wheat （SFPFM） in dryland, an successive 5 -year field experiment was carried out during the wheat growth period from 2008 to 2012 and during the summer fallow in 2012 by means of measuring dynamics of soil moisture content （SMC）. The results showed that the SMC dynamics was similar between FFPFM and FFPFM during the experimental period, reaching the maximum at seedling stage, reducing to the minimum at heading stage and increasing slightly at ripening stage. Compared with no-mulching wheat, SMC under the treatments of FPFMFW and FPFMSW increased respectively by 1.1% and 1.6% in soil surface, and O. 3% and 1.8% in 20 - 100cm soil layer, respectively. SMC under the FFPFM treatment reduced by 0.2 percent while that of SFPFM increased by 1.3 percent in 100 -200cm soil layer. In the summer fallow period, Soil water storage under three treatments including FFPFM, SFPFM and no-mulching increased 97.6mm, 148mm and 65.9mm, respectively. Soil water storage rate were 42% , 65% and 29% , respectively. Water-saving effect of FFPFM was significant. The significant yield improvement of FFPFM and SFPFM was also found in this experiment compared with no-mulching wheat. FFPFM, as a new agronomic technology in dryland, is beneficial to accumulate more natural precipitation in soil, lessen the ineffective evaporation and enhance the natural precipitation efficiency.