半干旱雨养区不同覆膜方式对冬小麦土壤水分利用及产量的影响

Influences of different plastic film mulches on soil water use and yield of winter wheat in semiarid rain-fed region

在黄土高原半干旱雨养条件下,于2008—2009、2009—2010两个年度,以露地种植为对照(CK),研究了不同覆膜方式(全膜覆土穴播,全膜穴播,垄膜沟播)对旱地冬小麦产量和水分利用的影响。结果表明:两年度覆膜平均较CK产量分别显著提高49.4%和53.2%,水分利用效率提高11.8%和14.3%。覆膜的高产建立在高生长量、高耗水基础上,产量与生育期耗水量显著正相关(r=0.952*—0.958*),两年度覆膜分别平均较CK多耗水33.5%和34.1%。覆膜处理中以全膜穴播较CK的增产幅度和WUE提高幅度最大,耗水量也最大。由于覆膜耗水量大,覆膜各处理收获期0—200 cm土壤贮水量均显著低于CK,但通过全年连续覆膜和夏闲期降水补充,在下茬秋播时,覆膜各处理0—200 cm土壤贮水量均超过CK,夏闲期覆膜的水分休闲效率两年度分别平均高出CK 41.8和86.4个百分点,覆膜有利于土壤水分恢复和下茬作物的可持续生产。覆膜方式中,以全膜覆土穴播种植效益最高,两个年度纯收益平均达5531.6元/hm2,较CK增收2542.2元/hm2。综合考虑,全膜覆土穴播是一种高产高效兼顾、操作简单、适宜于半干旱雨养区推广应用的冬小麦覆膜种植方式。

Plastic film mulching has been shown to increase crop yields in many crop species, but little has been reported how this technology can be applied to winter wheat in rainfed areas. This study determined the effects of different plastic mulching modes on water use and grain yield of winter wheat in a semiarid rain-fed region of Loess Plateau, Northwest China during 2008--2009 and 2009--2010 growing seasons. The experiment was carried out in a randomized complete block design with three replicates, including four treatments ： （i） whole field plastic mulching with soil covering on the top of the plastic mulch and bunch-seeding, （ii） whole field plastic mulching without soil cover on the top of the plastic mulch and bunch-seeding, （iii） ridges mulched with plastic film and row-seeding in the furrow, and （iv） un-mulched with row- seeding as control （CK）. Results showed that compared to the CK, the mean plastic film mulching increased the grain yield of winter wheat by 49.4% in the 2008--2009 season and 53.2% in the 2009--2010 season, and water use efficiency （WUE） was increased by 11.8% and 14.3% in the two seasons, respectively. The increased grain yield with plastic film mulching was largely attributable to improved plant growth and high water consumption. The grain yield of winter wheat was significantly and positively correlated （ r = 0.952 ＊ --0. 958 ＊ ） with water consumption during the growth period. Winterwheat with plastic film mulching used 33.5% and 34.1% more water than the CK in the two years, respectively. Of the mulching methods evaluated in the study, the whole field plastic mulching without soil cover and bunch-seeding achieved the highest grain yield and WUE, and also highest water consumption. Due to the large amount of water consumption with plastic film mulching, the water storage in the 0--200 cm soil layer at harvest was significantly lower in the fields with plastic film mulching compared to the CK. However, due to the year-round continuous plastic mulching coupled with the recharge of soil water during the summer fallow period after winter wheat harvest, the water storage in the 0--200 cm depth in the fields with plastic film mulching exceeded that in the CK field by 41.8 to 86.4 percentage points by the autumn sowing date the following year. Plastic film mulching and soil moisture conservation during summer fallow period is beneficial to the rehabilitation of soil moisture and sustainable production of the crops the following year. Among the plastic film mulching methods, the whole field plastic mulching with soil covering on the top of the mulch and bunch-seeding gained the highest economic benefit, and reached up to 5531 Chinese Yuan/hm-2, which was 2542 Yuan more than the CK. Additionally, the whole field plastic mulching with soil cover on the top of the mulch and bunch-seeding allows the plastic film to be reused for the crops grown in the following year, helping save film cost, and improving economic benefits. Therefore, we recommend that whole field plastic mulching with soil cover on the top of the mulch and bunch-seeding is suitable to be popularized in the semiarid rain-fed areas.