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通过9年水稻-小麦轮作田间定位试验,探讨南方稻麦两熟制农田秸秆还田模式对土壤有机碳(SOC)和腐植酸(HE)的影响。试验设置仅麦秆稻季还田(W)、仅稻秆麦季还田(R)、秸秆稻麦季均还田(RW)和秸秆均不还田(CK)共4个处理。结果表明,秸秆还田显著(P<0.05)提高了0~10 cm土层SOC,对土壤总氮(TN)无明显影响;不同秸秆还田模式处理下,0~10 cm土层SOC及TN大小为W>RW>R>CK;10~20 cm SOC及TN大小均为W>CK>RW>R,但各处理之间的差异均不显著。秸秆还田处理中,0~10 cm土层土壤HE、富里酸(FA)和胡敏酸(HA)均低于CK,而在10~20 cm土层则高于CK。不同秸秆还田方式间,0~10 cm土层的HE、FA和HA以W处理为最高,其土壤腐殖化程度最大;而10~20 cm土层则以RW处理为最高,W处理的土壤腐殖化程度最小。相比其他秸秆还田模式,麦秸稻季还田能更好地提高土壤表层有机碳含量和腐殖质品质。
The field experiment of 9-year paddy-wheat rotation was conducted to investigate the effects of straw return to field on soil organic carbon (SOC) and humic acid (HE) in southern China. In the experiment, only four treatments were straw returning (W), straw returning only (R), straw returning (RW) and straw returning without CK (CK). The results showed that the SOC of 0-10 cm soil layer increased significantly with straw returning to field (P <0.05), but had no significant effect on soil total nitrogen (TN). Under different straw returning treatments, soil SOC and TN The size of W> RW> R> CK; the size of 10-20 cm SOC and TN were all W> CK> RW> R, but the differences among treatments were not significant. The contents of HE, fulvic acid (FA) and humic acid (HA) in 0-10 cm soil layer were lower than those in CK, but higher than those in CK layer in 10-20 cm soil layer. Under different straw returning treatments, HE, FA and HA in 0 ~ 10 cm soil layer were the highest in W treatment, and the soil humification degree was the highest in 10 ~ 20 cm soil layer; RW treatment was the highest in 10 ~ 20 cm soil layer, Soil humification is minimal. Compared with other straw returning patterns, straw returning to paddy field can better improve soil organic carbon content and humus quality.