生物质炭和秸秆施用对黄褐土生化性质及小麦产量的影响

Effects of Biochar and Straw Application on Soil Biochemical Properties and Wheat Yield in Yellow-cinnamon Soil

以位于河南省方城县的黄褐土田间定位试验为平台,监测生物质炭和秸秆连续施用4 a后小麦拔节期和成熟期土壤性质变化及其与成熟期籽粒产量的关系,明确影响小麦产量的主要土壤生化因子。试验包含6个处理,即分别在不施用生物质炭(–B)和施用生物质炭(+B)条件下各设置3个处理:(1)对照(CK),(2)单施化肥(NPK),(3)秸秆还田配施化肥(NPK+S)。结果表明:生物质炭和秸秆施用对土壤生化性质和籽粒产量的影响基本上不存在交互作用。连续4a施用生物质炭后,小麦产量平均降低了17.4%。尽管NPK+S与NPK处理间平均产量没有显著差异,但它们比CK处理产量分别增加了33.8%和37.4%。采用偏最小二乘法路径模型(PLS–PM)分别分析了拔节期和成熟期的土壤速效养分、活性有机质和酶活性对产量的影响,发现小麦拔节期的土壤速效养分含量,特别是氮素的供应是直接影响产量的最为重要因子;而成熟期土壤生化性质对作物产量的影响比较小。因此,为防止黄褐土上施用生物质炭和秸秆后小麦产量降低,需要特别注意小麦拔节期土壤氮素的补充。

A four-year field experiment was conducted in Fangcheng County of Henan Province to disclose the relation between crop yield and soil properties at jointing and maturity stages of winter wheat planted with biochar application(+B) or not(–B), and both contained three treatments of chemical fertilizers(NPK), chemical fertilizers plus straw(NPK+S), and an amended control(CK). The results showed that biochar and straw had no interaction effect on wheat yield. The average wheat yield was reduced by 17.4% following continuous application of biochar for 4 a. Compared to CK, wheat yield of NPK+S and NPK treatments increased by 33.8% and 37.4%, respectively, while no significant differences in wheat yield existed between NPK+S and NPK treatments. Relationships between wheat yield and soil properties at jointing or maturity stages were obtained using PLS-PM model, and it was found that wheat yield was affected mostly by N supply at jointing stage, while soil properties had less effect on wheat yield at maturity stage. In conclusion, more attentions should be paid to N supply at jointing stage of wheat in the yellow-cinnamon soil to prevent yield decrease after biochar and straw are applied.