不同稻田生态种养模式对土壤理化性质及综合肥力的影响

Effects of Crop/Animal Co-cultivations on Physiochemical Properties and Fertility of Rice Paddy Soil

[目的]定量评价不同生态种养模式对稻田土壤理化性状及综合肥力的影响,以期为华南地区稻田生态种养模式的选择提供理论依据。[方法]通过主成分分析法定量评价稻鸭(RD)、稻鱼(RF)、稻虾(RS)3种生态种养模式和常规种植(CK)稻田模式的土壤综合肥力的差异,明确影响稻田土壤综合肥力的主要影响因子。[结果]不同生态种养模式均可有效降低土壤容重,提高土壤孔隙度,缓解土壤酸化,对提高土壤养分和有机碳含量也具有较为显著的效果,其中0–10 cm表层土壤的孔隙度、有机碳、全氮、全磷、全钾、碱解氮、速效磷、速效钾含量均为RD最高或并列最高。土壤综合肥力主成分分析结果显示,0–10 cm表层土壤肥力得分排序为RD>RF> RS> CK,10–20 cm亚表层土壤为RD> RF> CK> RS,并且土壤容重、有机碳、孔隙度、胡敏素碳、全氮和碱解氮为稻田土壤肥力的主要贡献性指标,全钾、pH、速效钾、全磷、富里酸碳、胡敏酸碳和有效磷为次要贡献性指标。[结论]整体来看,RD为培肥稻田土壤的最佳模式,RF其次,RS的效果较差。因此,华南地区稻田土壤培肥可将RD作为优先考虑的对象,或者结合现实情况合理选择其他生态种养模式。

【Objective】Effects of ecologically friendly co-cultivation of crops and animals on the physiochemical properties and fertility of soil on rice paddy fields were analyzed.【Methods】Principal component analysis(PCA)was used to study the effects on the soil of paddy fields in South China under 4 types of co-cultivation that combined rice-growing and duck-raising(RD),rice-growing and fish-aquaculture(RF),or rice-growing and shrimp-aquaculture(RS)in comparison to the conventional mono-crop practice on a rice paddy field(CK).Bulk density,porosity,acidification,and nutrient contents of the soil were determined.【Result】All co-cultivations significantly reduced bulk density,improved porosity,alleviated acidification,and increased contents of nutrients and organic carbon in the soil.Of the 3 methods,RD rendered the greatest porosity,organic carbon,total nitrogen,total phosphorus,total potassium,alkali-hydrolyzable nitrogen,available phosphorus,and available potassium in the 0-10 cm surface paddy soil.The fertility scores on the co-cultivations as ranked by PCA were RD>RF>RS>CK for the surface soil and RD>RF>CK>RS for the 10-20 cm sub-surface soil.The primary factors contributing to the soil fertility included bulk density,organic carbon,porosity,humin carbon,total nitrogen,and alkali-hydrolyzable nitrogen,while the secondary factors,total potassium,pH,available potassium,total phosphorus,fulvic acid carbon,humic acid carbon,and available phosphorus.【Conclusion】On a paddy field,cultivating rice with ducks(RD),or fish(RF)as the second choice,effectively improved the soil conditions and fertility.Nonetheless,under specific local considerations such maneuver could also be combined with other means to achieve an ecologically beneficial rice farming in South China.