油菜季施磷结合秸秆还田提高油菜–水稻轮作体系的产量和磷肥利用率

【目的】探究秸秆还田和减磷处理对油–稻轮作周年物质生产和磷素利用的影响。【方法】田间试验在四川绵阳进行，种植制度为油菜–水稻复种。设置秸秆不还田(T1)和秸秆还田(T2)两种模式，4个施磷模式：油–稻两季均不施磷(P1)、油菜施P₂O₅ 120 kg/hm²–水稻季施P₂O₅ 90 kg/hm² (P2)、油菜季施P₂O₅ 120 kg/hm²–水稻季不施磷(P3)、油菜季不施磷–水稻季施P₂O₅ 90 kg/hm² (P4)。分析了油菜、水稻及周年干物质积累、产量以及磷素利用。【结果】施磷显著提高了油–稻轮作周年产量、干物质积累量和吸磷量。与P2相比，P3提高了油–稻两季干物质积累量、花后茎叶干物质转出量和吸磷量，其油–稻周年的产量、干物质积累量和吸磷量分别提高10.14%～27.65%、8.39%～9.71%、1.86%～...

Phosphorus application and straw incorporation increase yield and phosphorus utilization in a rape-rice rotation system

  【Objectives】  We assessed the appropriate combination of straw incorporation and phosphorus application for the efficient production and phosphorus utilization in a rape-rice rotation system.  【Methods】  Field experiment was conducted for two years in Mianyang, Sichuan Province, under the rape-rice rotation system. The treatments were: P application with straw returning (T2) and without straw returning (T1), no P application in both rape–rice seasons (P1), application of 120 kg/hm2 P₂O₅ on rape and 90 kg/hm2 P₂O₅ on rice (P2), application of 120 kg/hm2 P₂O₅ only on rape (P3), and application of 90 kg/hm2 P₂O₅ only on rice (P4). At heading and maturing stage of rape and rice, plant samples were collected for the analysis of dry matter accumulation (DM), yield and P content.  【Results】  Among the four treatments, P3 recorded the highest yield, DM and P uptake of rape, two rice cultivars and the rotation system. Compared with P2, P3 increased the yield, DM, post-flowering dry matter transfer and P uptake of rape and rice in two seasons by 10.14%–27.65%, 8.39%–9.71%, and 1.86%–5.65% respectively. Compared with the P2 treatment, P4 treatment increased the DM, post-flowering transport amount and yield of rice, but decreased the DM of rape and P absorption and the rotation system. Compared with P2, P3 increased the apparent P fertilizer efficiency of the system by 92.70%, while P4 did not exhibit significantly higher P efficiency. Under the same P treatment, straw returning improved the yield, DM and P uptake of rape, rice and rotation system and increased the translocation of DM and P accumulated before flowering stage of rape and rice than T1.  【Conclusions】  In rape-rice rotation system, applying P on rape could satisfy the P nutrition for rape season, the P returned to field by rape straw could be absorbed and used more efficiently by the following rice than P fertilizer, thereby increasing the P use efficiency, dry matter production and translocation, and yield of the rotation system. On the contrary, application of P only in rice season, no matter rice straw returning to field or not, does not provide enough P for rape, and decreases the yield and P efficiency of the system. Therefore, application of P on rape combined with straw incorporation is the best P application mode.