不同有机物料还田对东北黑土活性有机碳的影响

Impacts of Returning Organic Materials on Soil Labile Organic Carbon Fractions Redistribution of Mollisol in Northeast China

【目的】阐明不同有机物料培肥对黑土总有机碳和活性有机碳组分的影响,探讨合理调控农田土壤肥力的施肥模式。【方法】以黑龙江省海伦市国家野外科学观测研究站试验区上进行了6年田间定位试验的小区土壤为研究对象,通过对土壤活性有机碳的提取以及室内作物栽培试验,对比和分析不同有机物料配施化肥处理下土壤活性有机碳与土壤生产力的变化。【结果】与试验初期相比,经过6年单施化肥处理后,土壤总有机碳(TOC)、微生物量碳(MBC)、水溶性有机碳(WSOC)以及轻组有机碳(LFOC)的含量显著下降;而有机无机配施则显著提高了土壤有机碳及各活性有机碳组分的含量。不同有机物料还田对土壤总有机碳和各活性有机碳组分的作用存在显著差异,作物秸秆与化肥配施更有助于TOC和LFOC的积累,其中以玉米秸秆配施化肥的效果最为突出,与单施化肥相比,增幅分别为26%和136%;粪肥配施化肥对MBC和WSOC的积累效果优于作物秸秆,其中以猪粪配施化肥的效果最为突出,与单施化肥相比,增幅分别为52%和85%。室内作物栽培试验表明,单施化肥处理将引起土壤生产力的下降,有机无机配施则能明显改善土壤生产力水平。不同有机物料配施化肥对土壤生产力的提升效果表现为:猪粪>牛粪>小麦秸秆≈玉米秸秆。【结论】在东北黑土区,不同有机物料处理之间土壤总有机碳、活性有机碳以及土壤生产力存在明显差异,玉米秸秆配施化肥能够显著提高土壤总有机碳和轻组有机碳的含量,而猪粪配施化肥则更有助于土壤微生物量碳和水溶性有机碳的积累,有利于土壤生产力的提升。

[Objective] The objective of this study was to clarify the effect of returning different organic materials on characteristics of soil labile organic carbon fractions, and discuss fertilization system for controls of soil fertility. [Method] A six-year field experiment was carried out in Hailun county to study the effects of returning different organic materials on changes of soil total organic carbon （TOC） and redistribution of labile organic carbon fractions, as well as a greenhouse experiment with different soils was established to analyze soil productivity. [ Result] Compared with the initial soil sample, 6-years application of chemical fertilizers （NPK） alone resulted in significant decreases in TOC, microbial biomass carbon （MBC）,water-soluble organic carbon （WSOC） and light fraction organic carbon （LFOC）. However, in plots amended with chemical fertilizers and organic materials （NPK＋OM）, the SOC and labile organic carbon fractions increased markedly. Compared with other organic materials, application of maize straw could be more suitable for the accumulation of SOC and LFOC, which was 26% and 136% greater than that of NPK application, and application of pig manure favored buildup of MBC and WSOC, which was 52% and 85% greater than NPK application. Soil productivity reduced in NPK plot, however, increased in NPK＋OM plots. The decrease order of soil productivity in different NPK＋OM plots was NPK＋ pig manure〉NPK＋ cattle manure〉NPK＋ wheat straw ≈NPK＋ maize straw. [Conclusion] There were significant differences in TOC, labile organic carbon fractions and soil productivity among treatments amended with various organic materials in black soil. Application of chemical fertilizer amended with maize straws could be prone to increase TOC and LFOC pool, as well as amended with pig manure was the most effective measure to 13romote MBC, WSOC and soil productivity.