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研究地表覆盖对土壤有机碳氮和生物活性的影响,对改进旱地作物栽培,提升土壤肥力和提高作物产量具有重要意义。采取5 a田间定位试验的土壤进行室内培养试验,研究不同地表覆盖土壤轻质有机碳、轻质有机氮及微生物活性的变化。结果发现,经过61d培养之后,覆草、覆膜和常规土壤矿质态氮含量分别减少4.0,2.5,3.9 mg/kg,有机碳矿化累积量分别为125,100,101mg/kg。覆草土壤微生物量碳含量及土壤代谢熵在培养过程中均高于覆膜。培养前后,覆草土壤的轻质有机碳氮均明显高于覆膜,覆膜和常规没有差异。培养结束后,覆草土壤轻质有机碳氮含量分别减少36%和47%,覆膜土壤分别减少26%和45%,常规土壤分别减少31%和44%。覆草土壤轻质有机碳氮含量的减少值明显高于覆膜和常规。覆草能增加土壤有机碳氮的易矿化组分,提高土壤有机质的生物有效性,覆膜则会降低土壤有机质的生物有效性。
Studying the effects of surface mulching on soil organic carbon and biological activity is of great significance to improve the cultivation of dryland crops, increase soil fertility and increase crop yield. The 5 years field experiment was conducted in soil to study the changes of soil organic carbon, light organic nitrogen and microbial activities under different land cover types. The results showed that the content of mineral nitrogen in mulched, mulched and conventional soils decreased by 4.0, 2.5 and 3.9 mg / kg respectively after 61 days of culture, and the accumulative amounts of organic carbon mineralization were 125, 100 and 101 mg / kg, respectively. Microbial biomass carbon content and soil metabolic entropy in mulched soils were higher than those in mulching. Before and after culturing, the soil organic carbon and nitrogen of grass mulching was obviously higher than that of mulching film, there was no difference between mulching and conventional method. At the end of cultivation, soil organic C and N contents decreased by 36% and 47% respectively, while soil cover decreased by 26% and 45% respectively, while conventional soil decreased by 31% and 44% respectively. The reduction of light organic carbon and nitrogen in grass cover soil was significantly higher than that of the cover and conventional. Mulch can increase soil organic carbon and nitrogen easy to mineralization components, improve the bioavailability of soil organic matter, the film will reduce the bioavailability of soil organic matter.