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

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。

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

To explore mechanisms on biochar application-induced changes in crop yield, relationships between crop yield and various soil properties measured at harvest stage were usually conducted, which will prevent us to adjust soil properties timely if negative effect of biochar application happens. Here, based on a four-year field experiment located in Fangcheng County, Henan Province, we tried to relate crop yield with soil properties measured at both jointing and maturity stages of winter wheat under planting with biochar application (+B) or not (-B), both contained three treatments of chemical fertilizer (NPK), chemical fertilizer plus straw (NPK+S), and an amended control (CK). Our 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 four years. Relative to CK, the yield from the NPK+S and NPK treatments increased by 33.8% and 37.4%, respectively, while no significant differences in yield were found between the NPK+S and NPK treatments. Relationships between the wheat yield and soil properties obtained from jointing or maturity stage were conducted, using PLS-PM model. It was found that capacity of N availability from the jointing stage was the most important factor affecting the wheat yield, while soil properties from the maturity stage had less effect on wheat yield. Our results suggested that N supplementation at the jointing stage of wheat should be particularly paid more attention in the yellow-cinnamon soil following biochar and straw application.