Abstract

Background

Nutrient balance in rice paddy fields can change under different tillage management practices; however, the extent of the change may differ for various rice varieties. A field experiment was conducted over 2 successive years to clarify the effects of no-till and rice varieties on the apparent balance of nitrogen (N) and phosphorus (P). Four treatments: no-till/japonica rice (NTJ), no-till/glutinous rice (NTG), conventional tillage/japonica rice (CTJ), and conventional tillage/glutinous rice (CTG) with three replicates of each were established to test the hypothesis that no-till and japonica rice can improve the apparent balance of nutrients.

Results

The tillage method and rice variety had interactive effects on the apparent balance of N and P. After the 2-year experiment, total N and P pools in the 20 cm surface soil layer were highest under the NTJ treatment (4757.0 kg N ha⁻¹, 2428.5 kg P ha⁻¹) and lowest under the CTG treatments (4726.3 kg N ha⁻¹, 2412.0 kg P ha⁻¹). Under no-till conditions, japonica rice had higher grain yield but lower straw biomass than that of glutinous rice. NTG treatment significantly increased the N and P content in rice grains and straw. The environmental losses of N and P in the rice fields mainly occurred during the rice season. Based on nutrient balance estimation, N losses in the NTJ, NTG, and CTJ treatments were reduced by 15.03 kg N ha⁻¹, 11.55 kg N ha⁻¹, 6.72 kg N ha⁻¹, respectively, as compared with that of the CTG treatment. The corresponding P losses were reduced by 8.02 kg P ha⁻¹, 7.84 kg P ha⁻¹, and 3.96 kg P ha⁻¹. In terms of economic benefits, NTJ also resulted in the highest actual income (2724.25 US dollars) and the highest ratio of production investment (6.40).

Conclusion

No-till was more likely to maintain soil N and P nutrients than conventional tillage, and this advantage was most significant when planting japonica rice. In addition, no-till was conducive to N and P uptake by rice, but only japonica rice exhibited increased grain yield. Consequently, the NTJ treatment was recommended to improve the N and P balance.

中文翻译：

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免耕和水稻品种对稻田氮磷平衡的影响

摘要

背景

不同耕作管理方式下稻田的养分平衡可能发生变化。但是，不同水稻品种的变化程度可能有所不同。连续2年进行了田间试验，以阐明免耕和水稻品种对氮（N）和磷（P）的表观平衡的影响。建立了四个处理：免耕/粳稻（NTJ），免耕/糯米（NTG），常规耕作/粳稻（CTJ）和常规耕作/糯米（CTG），每组三个重复进行测试免耕和粳稻可以改善养分表观平衡的假设。

结果

耕作方法和水稻品种对氮和磷的表观平衡具有交互作用。两年的试验后，在NTJ处理下20 cm表层土壤层中的总氮和磷库最高（4757.0 kg N ha ^-1，2428.5公斤P公顷^-1）和下CTG处理最低（4726.3千克ñ公顷^-1，2412.0公斤P公顷^-1）。在免耕条件下，粳稻的产量高于糯米，但秸秆的生物量却较低。NTG处理显着提高了稻米和稻草中的N和P含量。稻田中氮磷的环境损失主要发生在水稻季节。根据养分平衡估算，NTJ，NTG和CTJ处理中的氮损失减少了15.03 kg N ha^-1，11.55千克氮公顷^-1，6.72千克氮公顷^-1，分别作为与该CTG治疗相比。相应的P损失是8.02公斤P公顷降低^-1，7.84公斤P公顷^-1，3.96公斤P公顷^-1。在经济利益方面，NTJ还创造了最高的实际收入（2724.25美元）和最高的生产投资比率（6.40）。

结论

没有-直到更有可能保持土壤氮，磷营养成分比传统耕作，而这种优势是最显著当种植粳稻。此外，免耕有利于水稻吸收氮和磷，但只有粳稻表现出增加的籽粒产量。因此，建议使用NTJ处理来改善氮磷平衡。