稻虾共作对稻田土壤耕作层养分的影响——基于益阳市南县的实证分析

为探明稻虾共作模式对土壤耕作层养分的影响,选择湖南省南县稻虾共作模式实施1年、2年、3年及以上的稻田,以一季中稻单作为对照,分析其纵向变化趋势和横向变化差异.结果表明,相对于中稻单作,稻虾共作模式1年、2年、3年及以上的土壤pH提高了8.95%~11.42%;全氮、全磷分别提高了18.33%~35.05%、3.13%~25.71%;碱解氮、有效磷、速效钾分别提高了3.32%~22.22%、29.94%~34.12%、8.74%~15.02%;稻虾共作模式土壤有机质含量呈先降后升趋势,较中稻单作模式第1年降低12.28%,第2年、3年及以上分别提高了29.39%、38.87%.稻虾共作模式提高了土壤耕作层养分含量,促进了土壤中氮、磷、钾元素的固定和转化吸收,改善了中稻单作模式养分流失的问题.

Effects of Rice-Shrimp Co-cultivation on the Nutrients in the Topsoil Layer of Paddy Field:Based on the Empirical Analysis of Nan County,Yiyang City

In order to find out the effect of rice - shrimp co-cultivation on soil nutrients,rice fields with rice - shrimp co-cultivation mode for 1,2,3 years or more in Nanxian county of Hunan province were selected,the longitudinal and horizon-tal variation trends of rice - shrimp co-cultivation mode were analyzed with single season as control, The results showed that the soil pH value increased by 8. 95%-11. 42% in the rice - shrimp co-cropping mode for 1 ,2,3 years or more. Total nitrogen and total phosphorus increased by 18.33%-35. 05% and 3. 13%-25.71% respectively. Alkali - hydrolyzed nitrogen .available phosphorus and available potassium increased by 3. 32%-22.22%,29.94%-34. 12% and 8.74%- 15. 02% respectively. The soil organic matter content in the rice - shrimp co-cropping mode decreased first and then increased .which wras 12. 28% lowrer than that in the middle - rice single - cropping mode in the first year.29. 39% higher than that in the second year,38. 87% higher than that in the third year. The co-cropping mode of rice - shrimp improved the nutrient content in the soil tillage layer,promoted the fixation and conversion of nitrogen ,phosphorus and potassium in the soil.and improved the nutrient lass in the single cropping mode of medium rice.