长期施用秸秆生物炭对土壤养分及作物生长的影响

于2011—2020年在山西榆次区开展田间定位试验，设不施肥(CK)、不施肥施生物炭(CK+B)、施氮磷钾肥(NPK)和氮磷钾肥配施生物炭(NPK+B)共4个处理，种植模式为玉米-高粱轮作，研究有机碳施用5 a和10 a对0～20 cm土层土壤有机质、全氮、有效磷、速效钾含量和土壤蔗糖酶、脲酶、碱性磷酸酶、过氧化氢酶活性的影响，及各处理累积秸秆干物质量、养分积累量和籽粒产量的变化。结果表明：(1)生物炭施用5 a和10 a后，与CK比较，CK+B处理土壤有机质含量分别提高了46.3%和61.2%;与NPK比较，NPK+B处理土壤有机质含量分别提高了67.8%和77.7%。施用10 a后CK+B处理全氮含量显著高于CK处理，但NPK+B和NPK处理土壤全氮含量间没有显著差异。生物炭对土壤速效钾含量提升效果显著，施用10 a后CK+B和NPK+B处理土壤速效钾含量较CK和NPK处理提升86.4%～46.6%。(2)生物炭施用10 a显著提升了土壤蔗糖酶和碱性磷酸酶的活性，增幅分别为11.4%～11.9%和7.9%～16.2%,但对脲酶、过氧化氢酶和有效磷没有影响。(3)生物炭施用10 a明...

Effects of long|term application of straw biochar on soil nutrient and crop growth

Long|term field experiments were carried out from 2011 to 2020 with four treatments of without fertilizer (CK), without fertilizer plus biochar only (CK+B), nitrogen, phosphorus, and potassium fertilizer (NPK), and NPK fertilizer plus biochar (NPK+B). Maize and sorghum were rotated. This experiment was conducted to study the influences of organic carbon continuous application with 5 years and 10 years on soil organic matter, total N, available P and available K contant, as well as soil sucrase, urease, alkaline phosphatase, and catalase enzyme activities in 0~20 cm soil layer, along with changes in biomass, nutrient accumulation and yield. The result showed that: (1) Compared with CK, CK+B enhanced soil organic matter by 46.3% and 61.2% after biochar applying 5 and 10 years, respectively; meanwhile they were increased by 67.8% and 77.7% induced by NPK+B relative to NPK, respectively. 10-year biochar application resulted in a higher soil total N content when fertilizer was withdrawn, whereas no difference was noticed under conditions of fertilization. Soil available K contents were enhanced significantly by 86.4% and 46.6% for CK+B and NPK+B, compared with CK and NPK, respectively. (2) Biochar applying continuous for 10 years significantly increased the activities of sucrase by 11.4%~11.9% and alkaline phosphatase by 7.9%~16.2%, but had no effect on soil urease, catalase, and available P. (3) The positive effect of biochar on accumulative P and K uptake both at heading and maturity was observed, but there was no effect on N accumulative uptake at the maturity after 10-year’s application. Biochar did not enhance grain yield irrespective fertilization treatment. Obviously, long|term application of straw biochar promoted soil organic matter and soil available K significantly whereas there were relative low influences on soil total N and available P. Biochar application improved the uptake both P and K. Therefore, when biochar was applied, N should be supplied to maintain crop growth, and decrease K dose.