冬水田区杂交中稻蓄留再生稻的氮肥盈余对次年头季稻的节氮效应

Nitrogen-saving effect of nitrogen fertilizer residue in hybrid middle rice stored for regeneration on the following year’s first season rice in winter paddy area

  • 摘要: 为了提高杂交中稻蓄留再生稻田的氮肥施用效率, 研究了上年氮素残留对次年头季稻的节氮效果, 以期为再生稻田合理的氮肥管理策略奠定理论基础和实践依据。于2021—2023年在川南冬水田区开展3年定位试验, 以优质杂交中稻品种‘旌3优6150’为试材, 设置再生稻季疏穴0、25%、50%、75%、100%和预留次年头季稻氮肥用量的处理, 通过再生稻发苗盛期疏穴塑造再生稻产量差, 导致稻田不同氮素残留量, 探究上年氮素残留与次年头季稻节氮关系。研究表明, 氮残留量与再生稻产量呈极显著负相关。头季稻的氮素干物质生产效率比再生稻高15.48%, 而稻谷氮素生产效率和氮收获指数则分别比再生稻低5.56%和16.51%。头季稻与再生稻的氮利用率呈正相关。粒芽肥(15N)大部分被当年头季稻吸收, 间接促进再生芽发苗, 直接被再生稻吸收利用较少, 并残留于土壤中供次年头季稻利用。次年头季稻节氮量与上年氮残留量呈极显著正相关(r=0.955**), 上年再生稻氮残留量和次年头季稻节氮量均随着上年再生稻疏穴率增加而增加。次年头季稻节氮量与上年再生稻产量呈极显著负相关关系。上年再生稻产量在0~4 125 kg∙hm−2范围内, 次年头季稻可按当地高产施氮水平减少施氮量99.11~0.11 kg∙hm−2。与头季稻相比, 再生稻氮素干物质生产效率下降, 而氮素稻谷生产效率和氮收获指数增加, 说明次年头季稻节氮量与上年氮残留量具有协同作用, 因此, 提高再生稻产量是减少稻田氮盈余的关键。

     

    Abstract: To improve the nitrogen (N) fertilization efficiency of hybrid middle rice -retained regeneration paddies, the N-saving effect of N residue in the previous year on the next year’s first season rice was investigated with the aim of laying a theoretical foundation and a practical basis for a reasonable N fertilizer management strategy in regeneration paddies. In 2021–2023, a three-year positioning experiment was performed in the winter paddy area of South Sichuan, using the high-quality hybrid medium rice variety ‘Jing 3 you 6150’ as the test material. Treatments were set up with 0, 25%, 50%, 75%, 100% thinning of regeneration rice and reserving N fertilization for the following year’s first season rice, to shape the N-saving relationship between N savings and N conservation of the previous year’s first season rice through thinning of regeneration rice at the peak of seedling stage and the different N sinking balance of the paddy caused by the difference of regeneration rice yield. Furthermore, this study aimed to explore the relationship between N residue in the previous year and N savings in the following year’s first-season rice through the regeneration of rice seedling season sparse hole shaping to regeneration rice yield difference to different N residue in the rice field. The results indicate that N residue was significantly negatively correlated with the yield of regenerated rice. The N dry matter production efficiency of first-season rice was 15.48% higher than that of regenerated rice, whereas the N rice production efficiency and N harvest index were 5.56% and 16.51% lower, respectively, than those of regenerated rice. Most of the regenerated rice grain sprout fertilizer (15N) was absorbed by the first season rice of the current year, indirectly promoting the regeneration of buds and seedlings, and was directly absorbed and utilized by the regenerated rice to a lesser extent, and residues in the soil for the use of the first season rice in the following year. N saving in the following year’s first season rice was significantly and positively correlated with the previous year’s N sinking residue (r=0.955**), and both paddy sinking residue and N saving in the following year’s first season rice increased with an increase in the previous year’s regeneration rice thinning rate. The N content of the first-season rice in the following year was significantly negatively correlated with the yield of regenerated rice in the previous year. The yield of regenerated rice in the previous year was within the range of 0−4 125 kg∙hm−2, and the N application rate for the first season of rice in the following year could be reduced by 99.11−0.11 kg∙hm−2 according to the local high-yield N application level. Compared with the first-season rice, the N dry matter production efficiency of regenerated rice decreased, whereas the N rice production efficiency and N harvest index increased. This indicated that the N content of the first-season rice in the following year had a synergistic effect with the N sink balance of the previous year. Therefore, increasing the yield of regenerated rice is the key to reducing the N sink balance in rice fields.

     

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