摘要:作物秸秆和畜禽粪肥是有机肥资源的主要组成。研究等氮施肥下稻秸-有机肥联合还田对南方黄泥田水稻产能、化肥替代与养分吸收利用的影响, 可为南方丘陵稻田改土培肥、增产提质增效提供依据。基于连续4年田间定位试验, 设置6个处理, 有机物料联合还田氮素投入分别占农田总氮投入的0 (RO0)、20% (RO20)、40% (RO40)、60% (RO60)、80% (RO80)与100% (RO100), 其中RO20、RO40、RO60、RO80和RO100处理稻秸干物量(kg?hm?2)投入分别为750、1500、2250、3000和3750, 氮素不足部分有机肥补足, 分析了水稻产量、养分吸收利用以及肥力因子变化。结果表明, 连续4年, RO20、RO40、RO60与RO80处理的水稻籽粒平均产量较RO0增幅8.4%~13.9%(P<0.05), 但随着有机物料配施比重的提高, 产量增幅呈下降趋势, RO100处理与RO0产量基本持平。在产量组成因子中, 配施有机物料处理的有效穗增加最为明显。RO20和RO40处理的水稻效益分别较RO0增加2204元?hm?2和527元?hm?2。除RO100处理外, 其他有机物料联合还田处理的水稻地上部植株氮、磷和钾养分吸收量较RO0分别显著增加8.5%~14.9%、8.5%~14.8%和8.6%~16.9% (P<0.05), 均以RO20处理最高; 有机物料联合还田处理的氮素回收率较RO0提高6.5~11.4个百分点, 其中RO20显著高于RO80和RO100处理(P<0.05)。有机物料联合还田不同程度提高了籽粒钙、镁、锌含量, 但降低了铁含量。此外, 有机物料联合还田提高了土壤pH、有机质、全氮、有效磷、速效钾含量以及微生物量碳、氮及脲酶活性, 降低了土壤容重。综上, 连续4年, 稻秸-有机肥联合还田提高了黄泥田产能与养分利用水平, 有机物料联合还田可替代化肥。综合考虑水稻增产效应、化肥减施、效益与肥力提升效果, 等氮施肥下, 稻秸-有机肥联合还田, 以替代20%化肥效果最佳, 其次为替代40%化肥效果较好。
关键词:黄泥田/
稻秸还田/
有机肥/
氮肥回收率/
化肥替代/
水稻产能/
养分吸收
Abstract:Crop straw and livestock manure, the main components of organic fertilizer resources, play important roles in the improvement of soil fertility and reduction of chemical fertilizer. To provide a basis for improving the soil fertility, crop yield and benefits of rice in a southern hilly area, various amounts of combined rice straw and organic fertilizer were returned to yellow-mud paddy soils under uniform total N input conditions and the effects on the rice production capacity, chemical fertilizer substitution, and plant nutrient uptake were studied. The field experiment was conducted in a yellow-mud paddy field in Minqin County, Fujian Province over four consecutive years. The experiment involved six treatments with uniform total N input but varying percentages of replacing N from a mix of rice straw and organic fertilizer (RO); that was, 0 (RO0, CK), 20% (RO20), 40% (RO40), 60% (RO60), 80% (RO80), and 100% (RO100) of N input. The dry amounts of rice straw applied in treatments of RO20, RO40, RO60, RO80, and RO100 were 750 kg?hm?2, 1500 kg?hm?2, 2250 kg?hm?2, 3000 kg?hm?2, and 3750 kg?hm?2, respectively; and the shortage of N was supplied by organic ferilizer. The variations in rice yield, nutrient uptake, and soil fertility factors were analyzed. As a result, the 4-year average yield of rice grains of RO20, RO40, RO60, and RO80 treatments significantly increased by 8.4%–13.9% relative to the yield of CK (P<0.05). However, the increasement of yield tended to decline with the increased application rates of organic materials, as the rice yield of RO100 was comparable to that of CK. Among the yield components, the effective spike significantincreased by RO treatments. The benefits of rice of RO20 and RO40 treatments were 2204 ￥?hm?2 and 527 ￥?hm?2 higher than that of CK, respectively. The uptake of N, P and K by rice plants under various RO treatments significantly increased by 8.5%?14.9%, 8.5%?14.8% and 8.6%?16.9%, respectively, compared with CK, except for RO100 treatment. The recovery rate change of N in all RO treatments increased by 6.5?11.4 percentage points, with the differences between RO20 and RO80 or RO100 were statistically significant (P<0.05). Although the contents of Ca, Mg and Zn in rice grains increased, the content of Fe decreased following the return of organic materials. The RO treatments increased soil pH and the contents of organic matter, total N, available P, available K, microbial biomass C, microbial biomass N and urease activity; but decreased the soil bulk density. In conclusion, the combined return of rice straw and organic fertilizer to yellow-mud paddy soil for 4 consecutive years improved rice productivity and fertilizer uptake. In this study, the combination of organic materials can completely replace the chemical fertilizers. Based on the rice yield, reduction of chemical fertilizer use, and improvement of farmer earnings and soil fertility, RO20 treatment was considered as the best fertilization regime, followed by RO40 treatment.
Key words:Yellow-mud paddy soil/
Straw incorporation/
Organic fertilizer/
Nitrogen recovery rate/
Chemical fertilizer substitution/
Rice productivity/
Nutrient uptake
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