Abstract:

【Objective】 It is important to clarify the mutual effects of reduced chemical fertilizer application on the quality and nutrient uptake of early rice and soil fertility after planting and utilizing Chinese milk vetch, and lay a scientific basis for fertilizer application of rice in red-soil paddy field. 【Methods】 With red-soil paddy field as the subject, the effects of planting and utilization of Chinese milk vetch on the growth, development as well as nutrient uptake and utilization of early rice in paddy field in Gaoan, Jiangxi Province were investigated from 2015 by setting six experimental treatments: 1)control treatment without fertilization (CK); 2)green manure application with 22 500 kg/hm² Chinese milk vetch returning (G); 3)100% chemical fertilizer application (N₁₀₀); 4)Chinese milk vetch (22 500 kg/hm²) returning + 100% chemical fertilizer application (GN₁₀₀); 5)Chinese milk vetch (22 500 kg/hm²) returning + 80% chemical fertilizer application (GN₈₀); 6)Chinese milk vetch (22 500 kg/hm²) returning + 60% chemical fertilizer application (GN₆₀). 【Results】 Chinese milk vetch returning and reduced chemical fertilizer application by an appropriate amount (20%) could promote rice yield, guarantee the N and P nutrition of rice and increase the contents of soil organic matters and alkali-hydrolysed nitrogen. Chinese milk vetch combined with chemical fertilizer application could improve head rice rate, chalkiness and gel consistency of early rice but reduce protein content. The yield, brown rice rate, head rice rate, chalky grain rate and protein content of early rice were significantly positively correlated with grain N content while significantly negatively correlated with grain Si content. A significantly positive correlation was found between grain Mg content and head rice rate. The uptake of P, Ca and Mg in grains showed a positive effect on milling quality, protein content and chalky grain rate but negatively affected gel consistency. Soil alkali-hydrolysed nitrogen presented an indirectly positive effect on grain N content but indirectly negatively affected grain Si content. Alkali-hydrolysed nitrogen, available phosphorus and available potassium had an indirect positive effect on N, P and K uptake in grains. The pH’s effects on grain Ca and P contents and those of exchangeable Ca and Mg contents on grain P content were indirectly negative. 【Conclusion】 Chinese milk vetch returning to the field (22 500 kg/hm²) and chemical fertilizer application reduced by 20% can promote rice yield and improve rice quality.

Key words: Chinese milk vetch, early rice, rice quality, nutrient uptake, soil nutrient

摘要：

【目的】阐明紫云英种植利用后减施化肥对早稻品质、养分吸收及土壤肥力的相互影响,为红壤稻田施肥提供科学依据。【方法】以红壤稻田为研究对象,2015年开始在江西高安大田定位研究种植利用紫云英对早稻生长发育及养分吸收利用的影响。设置6个试验处理：1)不施肥对照处理(CK);2)绿肥处理(G),即紫云英量22 500 kg/hm²;3)100%化肥处理(N₁₀₀);4)紫云英翻压22 500 kg/hm²+100%化肥处理(GN₁₀₀);5)紫云英翻压22 500 kg/hm²+80%化肥处理(GN₈₀);6)紫云英翻压22 500 kg/hm²+60%化肥处理(GN₆₀)。【结果】紫云英配施全量及减施适量(20%)化肥能提高水稻产量,保障水稻N、P营养,提高土壤有机质和碱解氮含量。紫云英配施化肥能提高早稻整精米率、垩白与胶稠度但降低蛋白质含量。早稻产量、糙米率、整精米率、垩白粒率、蛋白质与籽粒含N量呈显著正相关,与籽粒含Si量呈显著负相关;籽粒含Mg量与精米率呈显著正相关。籽粒P、Ca、Mg吸收量对碾米品质、蛋白质含量和垩白粒率是正效应,对胶稠度是负效应。土壤碱解氮对籽粒含N量是间接正效应,对籽粒含Si量是间接负效应;碱解氮、有效磷、速效钾对籽粒N、P、K吸收量是间接正效应;pH对籽粒Ca、P含量以及交换性Ca、Mg对籽粒P含量均为间接负效应。【结论】紫云英22 500 kg/hm²还田并减施20%化肥能提高水稻产量,提升稻米品质。

关键词: 紫云英, 早稻, 稻米品质, 养分吸收, 土壤养分