不同有机替代对黄土旱塬土壤碳、氮组分及冬小麦产量的影响

探讨黄土旱塬冬小麦区不同有机肥替代化肥氮对小麦产量及土壤碳氮组分的影响,为该区减施化学氮肥、促进小麦提质增效和农业绿色可持续发展提供理论依据。于2019年在山西黄土旱塬冬小麦种植区设置100%化肥N处理(HF)、10%腐殖酸N+90%化肥N (F1)、30%腐殖酸N+70%化肥N (F3)、50%腐殖酸N+50%化肥N (F5)、10%有机肥N+90%化肥N (Y1)、30%有机肥N+70%化肥N (Y3)、50%有机肥N+50%化肥N (Y5)7个试验处理,系统研究了不同比例腐殖酸、有机肥替代化肥对小麦产量及产量构成和土壤碳、氮组分含量的影响。结果表明:F3、F5、Y3和Y5处理,分别较HF显著提高9.7%,8.0%,9.2%和18.2%。同时,Y5对土壤中各种活性有机碳、氮组分含量的提高均有显著促进作用,提高幅度在36.8%~114.4%和27.8%~105.4%;Y3处理下可溶性、水溶性、微生物有机碳、氮和轻组有机碳、氮组分的含量较HF显著提高21.1%~156.8%;F3和F5处理下土壤中可溶性、微生物和轻组有机碳、氮组分含量较HF显著提高25.4%~119.3%。可溶性有机碳、微生物有机氮、轻组有机氮与籽粒产量呈极显著正相关;可溶性有机氮通过促进公顷穗数增加而提高冬小麦产量;总有机碳、水溶性有机碳和微生物有机氮则通过提高穗粒数达到增产效果。综上,在黄土旱塬冬小麦种植区进行30%~50%的有机肥和腐殖酸替代化肥后,可达到显著增产效果,同时提高土壤中活性碳、氮组分的作用。其中,50%有机肥替代处理的增产与培肥地力效果更为显著,适宜在当地推广应用。

Effects of Different Organic Substitutes on Soil Organic Carbon and Nitrogen Fractions and Winter Wheat Yield in Dryland of Loess Plateau

In order to discuss the influence of different organic fertilizers substitute chemical fertilizer nitrogen on wheat yield and soil carbon and nitrogen components in winter wheat area of the Loess Plateau, provide theoretical basis for reducing the application of chemical nitrogen fertilizers, promote wheat quality and efficiency and sustainable agricultural green development in this area, the effects of different ratios of humic acid and organic fertilizers substitute chemical fertilizers on wheat yield and yield composition and soil carbon and nitrogen content were systematically studied. The experiment set up 7 experimental treatments in the winter wheat planting area of Shanxi Loess Plateau in 2019:100% chemical fertilizer N treatment (HF), 10% humic acid N+90% chemical fertilizer N (F1), 30% humic acid N+70% chemical fertilizer N (F3), 50% humic acid N+50% chemical fertilizer N (F5), 10% organic fertilizer N+90% chemical fertilizer N (Y1), 30% organic fertilizer N+70% chemical fertilizer N (Y3), 50% organic fertilizer N+50% chemical fertilizer N (Y5). The results showed that F3, F5, Y3, and Y5 treatments significantly improved 9.7%, 8.0%, 9.2% and 18.2% compared with HF, respectively. At the same time, Y5 significantly promoted the increase of the content of various active organic carbon and nitrogen components in the soil, and the increase range was between 36.8%~114.4% and 27.8%~105.4%; The content of soluble, water-soluble, microbial organic carbon, nitrogen and light organic carbon and nitrogen components under Y3 treatment was significantly increased by 21.1%~156.8% compared with HF. Compared with HF, the soluble, microbial, light organic carbon and the nitrogen content in the soil under F3 and F5 treatments were significantly increased by 25.4%~119.3%. At the same time, soluble organic carbon, microbial organic nitrogen, light group organic nitrogen had very significant positive correlations with grain yield. The soluble organic nitrogen could increase winter wheat yield by promoting the increase of ears per hectare. Total organic carbon, water-soluble organic carbon, and microbial organic nitrogen could increase yield by increasing the number of grains per spike. In conclusion, when 30%~50% organic fertilizer and humic acid were used for substitution of chemical fertilizer in winter wheat growing area of loess plateau, significant yield increase could be achieved, and the effects of active carbon and nitrogen components in soil could be improved. Among them, the 50% organic fertilizer replacement treatment has more significant effects on increasing yield and improving fertility, which is suitable for local promotion and application.