关中小麦-玉米轮作农田磷肥减施增效研究

在关中冬小麦-夏玉米轮作体系下,通过合理的磷肥减施结合调控措施来减少土壤磷累积对于提高磷肥施用效率和降低土壤磷淋溶风险具有重要意义。利用田间试验比较不同施磷水平和调控措施对作物产量、磷效率和土壤磷库状况的影响。与CK相比,采用撒施的RF与CF处理玉米产量显著提高,但小麦和年度作物总产量没有显著差异。RF基础上减磷15%的JF处理(撒施改为条施)相对于CF和RF产量有下降趋势,但差异不显著,磷回收率和偏生产力显著高于CF。相对于JF,减磷结合调控措施(秸秆包裹或铵态氮肥硫铵代替尿素)中的JFT2和JFT3处理能够显著提高小麦籽粒产量;JFT1、JFT2和JFT3的回收率和偏生产力较JF处理均有所提高,其中JFT3提高显著。JFT1、JFT2和JFT3的土壤速效磷和微生物量磷也均有所提高,其中JFT1和JFT2的微生物量磷显著高于JF处理。RF处理的回收率略高于CF处理,但没有显著性差异,JFT3处理的磷肥回收率显著高于其他处理,除CF和RF处理,其余处理的磷素均处于亏缺状态,随着减磷量的增加,磷素亏缺逐渐增加。在目前关中农田土壤速效磷质量分数相对较高的情况下,RF较CF处理能够减少磷肥施用12.5%,可获得较好产量并提高磷肥利用率,且能够维持土壤磷水平稳定,是相对比较优化的施磷量。于推荐施肥基础上减磷15%结合秸秆包裹或生理酸性肥(硫铵)调控措施是值得推介的磷肥减施增效方案,但其长期可行性还需要进一步田间验证。

Application Rate Reduction and Use Efficiency Improvement of Phosphate Fertilizer on Farmland under Wheat-maize Rotation System in Guanzhong Area of Shaanxi

Under the condition of winter wheat-summer maize rotation system in Guanzhong area,reasonable reduction of phosphorus application combined with regulation measures is important to decrease soil phosphorus accumulation for improving the use efficiency of phosphate fertilizer and reducing the risk of soil phosphorus leaching. The effects of crop yield, phosphorus use efficiency and soil phosphorus pool status were compared under different phosphorus levels and regulation measures by field experiments in this study. Compared with CK, RF and CF treatment of broadcast application method increased the seed yield of maize significantly, but it could not increase yield of winter wheat and the total annual seed yield. Yield of JF treatment (15% reduction on the basis of RF, and the application method was changed from broadcasting into localized application of strip) showed a decline tendency compared with CF and RF, although the difference was not significant each other. The phosphorus recovery rate and partial productivity of JF were significantly higher than that of CF. Compared with JF, JFT2 and JFT3 could significantly increase wheat grain yield among all 3 treatments of phosphorus reduction combined with regulation measures (straw-enwrap or/and ammonium sulphate instead of urea). Compared with JF treatment, the phosphorus use efficiency, recovery rate and partial productivity of JFT1, JFT2 and JFT3 were all relatively improved, in which of JFT3 was significantly improved. The soil available phosphorus and microbial biomass phosphorus (MBP) of JFT1, JFT2 and JFT3 were also relatively improved, in which the MBP of JFT1 and JFT2 was significantly higher than that of JF. The recovery rate of RF treatment was slightly higher than that of CF treatment, but there was no significant difference. The recovery rate of JFT3 was significantly higher than other treatments.Except for CF and RF treatments, Phosphorus was in a state of deficit, and as the amount of phosphorus decreased, the phosphorus deficiency increased gradually.Under the condition of relatively high soil available phosphorus mass fraction of farmland in Guanzhong area at present, RF was a relatively optimized phosphorus application rate to reduce the application rate of phosphate fertilizer by 12.5%, and it obtained better yield and increased the utilization rate of phosphate fertilizer, and basically maintained the level of soil phosphorus fertility compared with CF. The schemes of 15% phosphorus reduction combined with regulation measures of straw-enwrap or ammonium sulphate instead of urea are worthy of recommendation to reduce phosphorus fertilizer application rate and to improve the phosphorus use efficiency, but its long-term feasibility needs to be validated further in the fields.