为探索一种能够加快秸秆分解速率和促进冬小麦生长的秸秆还田新措施，2011－2014年采用小区试验方法，对比研究了秸秆覆盖（CK1）、秸秆翻压还田（CK2）、长秸秆氨化翻压还田（AS）和粉碎秸秆氨化翻压还田（PAS）4种秸秆还田方式对秸秆分解速率、土壤水分蓄积、冬小麦叶面积指数和地上部干物质积累、产量及水分利用效率的影响。结果表明，秸秆还田210 d后，AS处理秸秆残留量为48.46%，分别较CK1和CK2降低24.31%和13.68%；PAS处理秸秆残留量为41.84%，分别较CK1和CK2降低34.64%和25.46%；且氨化处理加快秸秆分解速率的效果主要体现在冬小麦生长前期。土壤呼吸与秸秆分解速率呈显著正相关关系，相关系数为0.67（P＜0.05）；AS和PAS处理土壤呼吸速率在冬小麦生长前期分别较CK1增加109.66%和170.13%，分别较CK2增加34.55%和73.36%。连续3 a冬小麦生长季，氨化秸秆还田能显著（P＜0.05）提高冬小麦生长后期0～100 cm土壤蓄水量。粉碎并氨化秸秆（PAS）较未氨化秸秆还田（CK1、CK2）能显著（P＜0.05）提高冬小麦拔节期后叶面积指数，促进地上部干物质质量的积累。AS和PAS处理冬小麦3 a平均产量分别较CK1提高6.13%和9.53%，分别较CK2提高3.99%和7.32%；水分利用效率分别较CK1提高5.03%和8.73%，分别较CK2提高5.13%和8.83%。其中，PAS处理3 a平均水分利用效率较AS高。因此，氨化并粉碎秸秆还田（PAS）能有效加快秸秆分解，促进冬小麦生长，提高产量和水分利用效率，对于干旱、半干旱地区改良秸秆还田措施具有重要的实际意义和理论价值。%Straw is often incorporated into field by covering on soil surface or being plowed into soil in China, which may cause problems such as competition of nutrients between soil microbes and crop because of slow decomposition of straw, and frequent occurrence of pests and diseases when crop straw is applied into soil, thereby negatively affecting the crop yield. An appropriate method may solve the problems above. The objectives of this study were to select an efficient straw incorporation method that could accelerate the decomposition rate of crop straw and promote the growth of winter wheat in semi-arid region of Shaanxi, China. To achieve these goals, a 3-year field experiment was carried out in the year of 2011-2014at the Key Laboratory of Agricultural Soil and Water Engineering in Area sponsored by Ministry of Education (34°18′N, 108°04′E), at Northwest A & F University. Using summer maize straw harvested last season, two control treatments were designed including long straw returning by covering soil (CK1), and long straw plowed into soil (CK2). In comparison, another two straw treatments were long-ammoniated straw plowed into soil (AS) and powdered-ammoniated straw plowed into soil (PAS). The straw decomposition rate, soil respiration, leaf area index (LAI) and aboveground biomass of winter wheat were measured during different growth stage in the growing seasons of 2013-2014. Soil water of 0-100 cm depth during different growth stages and winter wheat yield under different treatments in the growing season of 2011-2014 were measured. Results showed that compared with the CK1 and CK2, the straw left in soils with the treatment AS was significantly (P<0.05) decreased by 24.31% and 13.68%, respectively, and the remaining with the treatment PAS was significantly (P<0.05) decreased by 34.64% and 25.46%, respectively. And the treatment of ammoniated straw accelerated the decomposition rate mainly in the early growth stage of winter wheat. The correlation coefficient between soil respiration and straw decomposition rate was 0.67 (P<0.01); Soil respiration rate of the treatment AS and PAS was significantly (P<0.05) higher than that of CK1 and CK2 in the early winter wheat growth stage, which was increased by 109.66% and 170.13%, respectively, compared with CK1, and by 34.55% and 73.36%, respectively, compared with CK2. The variation tendency of soil water of 0-100 cm depth in three-consecutive growing seasons during different growth stages was almost consistent. The treatment of ammoniated straw had higher soil water storage at the late growth stage of winter wheat. The treatment PAS could significantly (P<0.05) improve the winter wheat LAI, and promoted the accumulation of aboveground biomass. And at the mature stage of winter wheat, the aboveground biomass for the treatment PAS was significantly (P<0.05) increased 7.02% and 9.78%, respectively, compared with CK1, and by 5.52% and 8.25%, respectively, compared with CK2. The three-year mean winter wheat yields with AS and PAS was higher than that of conventional straw incorporation, which was significantly (P<0.05) increased 6.13% and 9.53%, respectively, compared with CK1 and by 3.99% and 7.32%, respectively, compared with CK2. However, the difference of grain yield between PAS and AS was not significantly (P>0.05). The three-year mean water use efficiency (WUE) with AS and PAS was significantly(P<0.05) increased by 5.03% and 8.73%, respectively, compared with CK1, and by 5.13% and 8.83%, respectively, compared with CK2. And the three-year mean WUE of the treatment PAS was higher than that of the treatment AS. Comparably, the treatment of PAS was the best among the four treatments in accelerating the straw decomposition, promoting the growth of winter wheat, and increasing winter wheat yield and water use efficiency, which could be an effective straw incorporation measure for winter wheat cultivation in the arid and semi arid area.
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