A reduction of chemical fertilizers and improving fertilizer utilization rate are important for ensuring a balance between plant growth and minimizing the degradation of the black soil. We conducted a 2-year pot experiment with four treatments during 2019 and 2020, including T0: no fertilizer, T1: conventional use of chemical fertilizer, T2: 15% reduction of the chemical fertilizer combined with 400 kg·hm-2 of humic acid bio-fertilizer (HABF), and T3: 30% reduction of the chemical fertilizer combined with 600 kg·hm-2 of HABF, to examine the effect of reduction rates of chemical fertilizers combined with the HABF on soil microbial abundance, enzyme activity and nutrient content in maize cultivation. The results showed that the application of HABF significantly increased the abundance of soil bacteria and fungi, with the number of microbial colonies being positively correlated with the amount of HABF. When measured at the tassel stage of maize growth, T2 and T3 treatments significantly increased the activities of urease, sucrase, and catalase in soil by 11.4%-21.6%, 34.9%-46.7%, and 6.5%-13.4%, respectively. The available nitrogen contents in T2 and T3 treatments were higher than that in the T1 treatment by 8.2%-18.1%, which ensured the sufficient nitrogen supply to maize after the tassel stage. Soil available phosphorus and available potassium contents increased by 17.1%-121.0% and 9.6%-57.3%, respectively, compared with T1 treatment. With the increases of the amount of HABF, the activation effects of soil phosphorus and potassium and dry matter mass per plant increased significantly in T2 and T3 treatments compared with T1 treatment. In conclusion, HABF promoted the proliferation of soil bacteria and fungi, improved activities of catalase, urease, and sucrase, soil nutrient contents, and dry matter mass per plant. The 15% reduction of chemical fertilizer combined with 400 kg·hm-2 of HABF is the most suitable nutrient management strategy for maize production in black soil.
降低化肥施用量、提高肥料利用率是稳定粮食产量、缓解黑土退化的有效途径。本研究以玉米为对象,采用2年室内盆栽试验,设置化肥减量配施腐植酸生物肥4个处理[T0:不施肥;T1:常规化肥用量;T2:化肥减量15%配施腐植酸生物肥(400 kg·hm-2);T3:化肥减量30%配施腐植酸生物肥(600 kg·hm-2)],研究腐植酸生物肥对土壤微生物数量、酶活性和养分含量的影响,以明确退化黑土对腐植酸生物肥的响应,为黑土土壤保护提供参考。结果表明: 与单施化肥相比,腐植酸生物肥的施用显著增加了土壤细菌和真菌数量,菌群数量随着腐植酸生物肥用量的增加而增加。与T1处理相比,T2处理可显著提高土壤脲酶、蔗糖酶和过氧化氢酶活性,玉米抽雄期以后脲酶、蔗糖酶和过氧化氢酶活性分别显著增加了11.4%～21.6%、34.9%～46.7%和6.5%～13.4%。T2、T3处理土壤碱解氮含量较T1处理升高了8.2%～18.1%,保障了抽雄期后土壤的供氮能力;土壤有效磷和速效钾含量分别较T1处理显著增加了17.1%～121.0%和9.6%～57.3%,随着腐植酸生物肥用量的增加,土壤磷素和钾素活化效果更显著。与T1处理相比,T2、T3处理玉米单株干物质量显著增加。可见,施用腐植酸生物肥增加了土壤细菌和真菌的数量,提高了过氧化氢酶、脲酶、蔗糖酶活性和土壤养分含量,增加了玉米单株干物质量。本试验条件下常规化肥减量15%配施400 kg·hm-2腐植酸生物肥是黑土玉米生产最适宜的养分管理策略。.
Keywords: bio-fertilizer; biological property; chemical fertilizer reduction; humic acid.