长期冬种绿肥对双季稻种植下红壤性水稻土质量的影响及其评价

Effect of Long-term Winter Planting-Green Manure on Reddish Paddy Soil Quality and Its Comprehensive Evaluation under Double-rice Cropping System

利用非线性评价模型对28a双季稻种植下连续冬种绿肥对土壤质量的影响进行量化,以农业部衡阳红壤环境重点野外科学观测基地长期冬种绿肥稻田为平台,分析了28a冬种不同绿肥的红壤性水稻土质量的变化情况,选择土壤容重(BD)、最大持水量(MWHC)、孔隙度(POR)、标准化平均重量直径(MNWD)、pH、阳离子交换量(CEC)、有效养分、土壤有机质(SOM)、微生物生物量碳(MBC)、土壤酶和作物生产力等项目作为评价指标,并根据不同指标所具有的功能归纳为:抗物理退化,养分供应和贮藏,抗生物化学退化和保持作物生产力的能力,以这4项功能为基础划分土壤质量指数(SQI)。冬种绿肥处理条件下土壤抗物理退化、土壤养分供应和贮藏、抗生物化学退化和保持作物生产力的功能都明显强于冬闲处理。稻-稻-黑麦草(R-R-RG)处理土壤抗物理退化功能最强;稻-稻-紫云英(R-R-MV)处理土壤养分供应和贮藏功能最强;抗生物化学退化功能,R-R-MV处理和稻-稻-油菜(R-R-RP)处理最强;R-R-RP处理保持作物生产力功能最强。4个处理的SQI等级范围为0.552(稻-稻-冬闲(R-R-WF)处理)到0.632(R-R-MV处理),R-R-MV处理的SQI值和土壤功能等级最高,3个冬种绿肥处理都明显高于冬闲处理。长期冬种绿肥翻压能明显地改善红壤性水稻土质量。

A non-linear assessment model was used to quantify effects of 28 years＇ successively winter planting-green manure on reddish paddy soil quality under double-rice cropping system.The reddish paddy soil quality under different winter-planting green manure experimental plots was analyzed based on a 28-year experiment in Key Field Monitoring Experimental Station for Red Soil Eco-environment of Ministry of Agriculture,Qiyang county,China.A soil quality index（SQI） based on four soil functions（i.e.the soil ability to resist physical degradation,supply plant nutrients and storage,resist biochemical degradation and sustain crop productivity） was derived for each treatment using bulk density（BD）,maximum water holding capacity（MWHC）,porosity（POR）,normalized mean weight diameter（NMWD）,pH,cation exchange capacity（CEC）,plant available nutrients,soil organic matter（SOM）,microbial biomass,soil enzymes and rice yield.The soil ability to resist physical degradation,to supply plant nutrients and storage,to resist biochemical degradation and to sustain crop productivity of winter green manure treatments was much stronger than the winter fallow treatment.The soil ability to resist physical degradation of R-R-RG treatment was the strongest.The soil ability to supply plant nutrients and storage of R-R-MV treatment was the strongest.The soil ability to resist biochemical degradation of R-R-RP treatment and R-R-MV treatment were the strongest.The ability to sustain crop productivity R-R-RP treatment was the strongest.Soil quality index ratings ranged from 0.552（R-R-WF treatment） to 0.632（R-R-MV treatment） among the four treatments.SQI and soil functional grade of R-R-MV treatment were the highest,the three winter green manure treatments were higher than the winter fallow treatment obviously.It was suggested that long-term winter planting-green manure should be an importent measure to promote reddish paddy soil quality.