在我国北方地区的旱作农田，从1992年秋季开始至2011年，进行了连续19年的不同秸秆还田方式的春玉米长期定位试验，研究秸秆不还田（CK）、 长期秸秆覆盖还田（SM）、 秸秆粉碎直接还田（SC）、 秸秆养畜粪肥还田（CM）对玉米籽粒产量、 经济效益和水分利用的影响。结果表明，   1）秸秆还田具有显著的增产增收效果，19年累计增产13.43~24.28 t/hm2，增产幅度11.57%~20.92%，纯效益增加了1283118171 Yuan/hm2； 2）秸秆还田可以减少玉米生育期耗水量、 增加土壤贮水总量、 明显提高水分利用效率，其中秸秆养畜粪肥还田的增产增收效果以及秸秆覆盖还田的保水效果最为明显。不同的降水年型，对玉米产量和水分利用也存在较大影响，正常降水年型玉米产量最高， 偏旱年型玉米水分利用效率最高。丰水年份和偏丰年份应当注意减少降水的无效耗散，秸秆覆盖还田在偏旱年份的增产效果尤为突

出。

Based on the results from a 19-year location experiment in rainfed experimental areas of northern China, the effects of various kinds of straw return to field on maize yield, economic benefit and water use efficiency were studied. There were 4 treatments, no straw returning (CK), straw mulching(SM), straw crushing(SC), and cattle manure(CM). The results show that compared to the CK, the experiment of returning stalks to field could increase the yield, net benefit and water use efficiency of spring maize significantly, decrease the accumulated water consumption and increase the soil water storage amount. The accumulated yields of

the nineteen years are increased by 13.427-24.284 t/ha with increases of 11.57%-20.92%, and the net economic benefits are improved by 12831-18171 Yuan/ha. The total corn yield and net economic benefits of the cattle manure treatment are the highest. In different rainfall years, the corn yields and water use efficiencies are very different. In normal years, the corn yields are the highest, while in dry years, the water use efficiencies of spring maize are highest. The yield increasing effect from the straw mulching is significant. In rainy and wet years, water conservation should be paid more attentions.