College of Resource Environment and Tourism, Capital Normal University, 100048, Beijing, China.
Department of Environmental Engineering, University of Seoul, 02504, Seoul, Korea.
Sci Rep. 2020 Jun 1;10(1):8837. doi: 10.1038/s41598-020-65796-2.
Biochar is widely used as a soil amendment. Enzyme activity is an important factor that reflects soil metabolic activity, and is involved in biochemical processes such as organic matter decomposition and nutrient cycling in soils. However, the effects of biochar prepared for different straw materials on soil enzyme activity and soil nutrients are rarely studied. Through pot experiments, the effects of different straw (wheat, rice, maize) biochars (obtained by pyrolysis at 500 °C) on soil organic carbon, nitrogen, available phosphorus, and enzyme activity were studied in paddy soil. The results showed that the addition of biochar increased the soil organic carbon content, which gradually decreased with the extension of the rice growth period. The soil ammonium nitrogen content gradually decreased as the rice growth period continued; however, the soil nitrate nitrogen content first decreased and then increased over the rice growth period. Soil invertase, phosphatase, and urease activity first increased and then decreased, and the enzyme activity was the highest at the heading stage of rice. At this time, there were also significant correlations between enzyme activity and carbon, nitrogen, and phosphorus levels, except in the case of soil urease activity. The geometric mean of the investigated enzyme activities was the highest after amendment with rice straw biochar. These results indicate that the response of enzyme activity to biochar depends on the biochar feedstock and the rice growth stage.
生物炭被广泛用作土壤改良剂。酶活性是反映土壤代谢活性的重要因素，参与土壤中有机质分解和养分循环等生化过程。然而，对于不同秸秆材料制备的生物炭对土壤酶活性和土壤养分的影响却鲜有研究。通过盆栽试验，研究了不同秸秆（小麦、水稻、玉米）生物炭（在 500°C 热解制备）对水稻土有机碳、氮、有效磷和酶活性的影响。结果表明，生物炭的添加增加了土壤有机碳含量，随着水稻生长周期的延长而逐渐减少。土壤铵态氮含量随水稻生长周期的延长而逐渐减少；然而，土壤硝态氮含量先减少后增加。土壤转化酶、磷酸酶和脲酶活性先增加后减少，在水稻抽穗期达到最高，此时酶活性与碳、氮、磷水平之间也存在显著相关性，除土壤脲酶活性外。经水稻秸秆生物炭改良后，所研究的酶活性的几何平均值最高。这些结果表明，酶活性对生物炭的响应取决于生物炭的原料和水稻的生长阶段。
