湖南双季稻区耕作模式的环境影响评价

Assessment of Environmental Impact on Different Conservation Tillage Patterns in Double-crop Rice Area in Hunan Province

以湖南双季稻区双季稻-马铃薯(CT1)、双季稻-黑麦草(CT2)、双季稻-紫云英(CT3)、双季稻-油菜(CT4)、双季稻双免栽培(CT5)5种保护性耕作模式为例,应用生命周期评价方法,从单位面积投入、单位面积产量、单位经济效益的环境影响三个角度评价不同保护性耕作模式的环境潜在影响。结果表明:从单位面积物质投入的角度评价结果显示,CT3模式的潜在环境影响综合指数较对照模式(双季稻-冬闲,CK)低4.72%,而其他模式则比CK高出11.95%-45.20%,平均增加了29.02%;从单位面积产量的角度评价结果显示,CT5模式的潜在环境影响综合指数比CK高34.55%,而其他模式则比CK低1.57-45.93%,平均降低24.29%;从单位经济效益的角度评价结果显示,CT5模式的潜在环境影响综合指数比CK高23.93%,而其他模式则比CK低29.07-49.06%,平均增加了24.88%。综合考虑,与CK对比,CT3和CT4模式对环境的潜在影响较小,CT2居中,CT5和CT1模式则较大。

This paper focused on five conservation tillage patterns （ double-crop rice-potato （ CT1 ）, double-crop rice-ryegrass （ CT2）, double-crop rice-Chinese milk vetch （ CT3 ）, double-crop rice-rape （ CT4 ） and double-crop rice with no-tillage （ CT5 ） ） applied in double-crop rice regions in Hunan Province and with double-crop rice with winter fallow as the contrast. Life cycle assessment in terms of input, production and economic benefit was used to synthetically assess the potential environment impact of the five conservation tillage patterns. Results show that, in the aspect of input, integrated index of environmental impact （IIEI） of CT3 is 4.72% lower than that of double-crop rice with conventional tillage （CK） , while the others are higher than CK, ranging from 11.95% to 45.20% , with an average rate of 29.20%. From the point of production, IIEI of CT5 is 34.55% greater than that of CK but the others are lower than CK, accounting for 1.57% to 45.93%, with a mean rate of 24.29%. In the aspect of economic benefit, IIEI of CK is 23.93% lower than that of CT5, While the others are lower than CK, ranging from 29.07% to 49.06%, with a mean rate of 24. 88%. Compared to CK, CT3 and CT4 contribute less to potential environment impact, while CT1 and CT5 have more serious environmental risk. And CT2 is in the middle of the two extremes.