不同氮素水平下生物质炭、秸秆添加对陇中黄土高原旱作农田土壤活性有机碳的影响

Effects of Biochar and Straw Addition on Soil Active Organic Carbon Under Different Nitrogen Levels in Dry Farmland on the Middle Gansu Region of Loess Plateau

针对黄土高原旱地小麦产量和土壤肥力水平低的问题,为更好地提升土壤肥力,达到稳产增产的效果,通过布设在定西李家堡镇的长期定位试验,研究了3种氮素(N)水平下(不施氮,施氮50 kg/hm^2,施氮100 kg/hm^2)生物质炭(B)、秸秆(S)添加(共9个处理)对陇中黄土高原旱作农田土壤有机碳及活性有机碳的影响。结果表明:相比于不施氮肥(CNO),其余施肥方式均可显著提升土壤有机碳含量,且以BN100的效果最为显著,0-5,5-10,10-30 cm土层分别提升了84.7%,69.3%,47.8%,BN0、BN50、BN100对土壤有机碳含量的提升效果明显好于SN0、SN50、SN100、CN0、CN50、CN100;相比于土壤有机碳,各处理对土壤各活性有机碳(MBC、EOC、DOC、HWOC)的影响以SN100最为显著,且均显著高于CN0、CN50、CN100;各处理对土壤有机碳及其组分含量的影响均表现出随土层加深而降低的趋势;相比于只施氮肥,生物质炭、秸秆添加下土壤有机碳及其各组分之间的相关性更加显著。相比于只施氮肥,生物质炭、秸秆的添加对于农田土壤有机碳及其活性有机碳组分含量的提升效果更加显著,生物质炭的添加对土壤有机碳含量的提升效果较好,而秸秆添加对活性有机碳含量的提升效果较为显著。研究结果对于土壤微生物环境的改善、土壤肥力的提升、减少土壤养分淋失、作物产量的提高都具有重要意义。

In view of low wheat yield and low soil fertility in the dry farmland of Loess Plateau, a study was carried out in a long-term localized experimental field in Lijiabao Town, near Dingxi, to study the effect of biochar(B) and straw(S) addition under three nitrogen levels(no nitrogen application, nitrogen application 50 kg/hm^2, nitrogen application 100 kg/hm^2)(9 treatments in total) on soil organic carbon(SOC) and activated organic carbon in the middle Gansu region of Loess Plateau with the purpose of improving soil fertility and maintaining stable and increased yield. The results showed that compared with no nitrogen fertilizer(CNO), the other fertilization levels could all significantly increase the SOC content, and the effect of BN100 was the most significant as BN100 increased 84.7%, 69.3% and 47.8% of the SOC content in 0-5, 5-10 and 10-30 cm soil layers. The increase of the SOC content by BN0, BN50, and BN100 was significantly better than that of SN0, SN50, SN100, CN0, CN50, and CN100. Compared with SOC, the effect of SN100 on various active organic carbons(MBC, EOC, DOC, and HWOC) was the most significant, and significantly higher than that of CN0, CN50, and CN100. The effects of each treatment on the SOC content and its components showed identical trend as decreased with increment of soil depth. Compared with application of only nitrogen fertilizer, the correlations between SOC and its components were more significant in the treatments received biochar and straw. Addition of biochar showed more significant improvement of the SOC content, and straw addition showed more significant improvement of the soil active organic carbon content. Therefore, the results are of great significance to the improvement of soil microbial environment, the enhancement of soil fertility, the reduction of soil nutrient leaching, and the promotion of crop yield.