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为阐明不同施肥模式下南方黄泥田土壤-水稻碳(C)、氮(N)、磷(P)生态化学计量特征,探讨C、N、P计量比对水稻N、P养分供应状况的指示意义,基于黄泥田长期施肥28年后的4个年份收获期数据,研究了不施肥(CK)、单施化肥(NPK)、化肥+牛粪(NPKM)与化肥+全部稻草还田(NPKS)处理收获物水稻植株和土壤有机C、全N、全P含量及其生态化学比值。结果表明:1)与CK相比,长期不同施肥土壤有机C、全N、全P含量分别增幅11.3%~39.1%、19.3%~43.1%、34.5%~69.0%,均以NPKM处理最高。土壤有机C、全N、全P相互间均呈显著正相关,且三者与籽粒、秸秆产量均呈显著正相关;土壤全N、全P也分别与对应的植株全N、全P呈极显著正相关,土壤有机C与植株有机C呈显著负相关;2)不同处理籽粒N:P变化范围为4.99~6.29、秸秆N:P变化范围为7.28~11.76。随着外源N、P的补充,各施肥均不同程度地降低了籽粒与秸秆C:N、N:P、C:P,与NPK处理相比,NPKM与NPKS处理籽粒、秸秆的上述比值呈进一步降低趋势,NPKM降幅尤为明显;3)不同施肥模式下水稻植株N:P及C:P与土壤P素、植株产量均呈显著负相关,显示黄泥田各施肥不同程度地受到P素限制而N素供应相对丰富,这与土壤养分化学诊断结果基本一致。上述说明,土壤有机C、全N、全P总量供应水平是影响黄泥田生产力的重要指标,NPKM处理对黄泥田定向培肥效果最为明显。植株N:P与产量关系对揭示该类稻田N、P限制有较好的指示作用,即较高的植株N:P而较低的产量暗示土壤P素供应相对N素缺乏。表征黄泥田水稻P素限制的植株N:P阈值范围可能较湿地生态系统(14~16)低。
In order to elucidate the ecological stoichiometry of soil C and N and P in the yellow soil in southern China, the significance of the C, N and P stoichiometry in supplying nutrients to N and P in rice was explored Based on the harvest data of four years after long-term fertilization for 28 years in Huangdi, the effects of non-fertilization (CK), NPK, NPKM and NPKS treatment were studied Harvesting of rice plants and soil organic C, total N, total P and its ecochemical ratio. The results showed that: 1) Compared with CK, the contents of organic C, total N and total P in long-term different fertilization soils increased by 11.3% -39.1%, 19.3% -43.1% and 34.5% -69.0%, respectively. Soil organic C, total N and total P were significantly and positively correlated with each other, and the three were significantly and positively correlated with the grain and straw production. The soil total N and total P were also correlated with the corresponding N, P There was a significant positive correlation between soil organic C and plant organic C; 2) The N: P ranged from 4.99 to 6.29 and the N: P ranged from 7.28 to 11.76. With the supplementation of exogenous N and P, the fertilization reduced the C: N, N: P and C: P of grain and straw at different degrees. Compared with NPK treatment, the above ratio of NPKM and NPKS treatment of grain and straw was (P <0.05) .3) The N: P and C: P of rice plants under different fertilization modes were significantly negatively correlated with soil P and plant yield, which indicated that P fertilization was limited to different degrees in different fertilization treatments N supply is relatively abundant, which is basically the same with soil nutrient chemistry diagnosis. The above description, soil organic C, total N, total P total supply level is an important indicator of the productivity of yellow muddy fields, NPKM treatment of the effect of directional fertilization is the most obvious. The relationship between plant N: P and yield showed a good indicator of N and P limitation in this kind of paddy field, ie higher plant N: P and lower yield suggested that P supply in soil was relative to N deficiency. The range of N: P thresholds characterizing P-limited rice in yellow paddy soil may be lower than in wetland ecosystems (14-16).