现阶段作物生产的生态与经济效益评估 ——以江苏省为例

通过成本、效益比较和土壤养分投入产出分析,对江苏省现阶段的作物生产状况进行了生态与经济效益评估。结果表明:在农业劳动力多而耕地少的地区,棉花与玉米、小麦、油菜接作均可获得较高经济效益;在劳动力紧缺、规模化生产的地区,种植水稻 玉米、水稻 小麦、水稻 油菜为宜,不仅省工,且可获得较高的经济效益和产品能,水稻 玉米种植模式还能获得较高的秸秆能。在当前条件下,5种作物的N肥投入均大于产出,P肥产投接近平衡,而K肥投入远远小于产出。为兼顾经济效益和生态效益,维持土壤肥力平衡,水稻施N量应减少165～225 kg/hm2,小麦应减少75～105 kg/hm2,玉米应减少90～165 kg/hm2,棉花应减少120 kg/hm2,油菜应减少60～90 kg/hm2。棉花施K量应增加120 kg/hm2,而其余作物可通过秸秆还田来补充土壤K,维持K的产投平衡。

Evaluation of ecological and economic benefits of crop production in Jiangsu Province

Economic benefits, energy output and soil NPK output/input for current crop production in Jiangsu Province were studied. Results show that cotton in combination with corn, wheat or rape can yield high economic benefits in the regions with intensive labor, small-scale production. Rotating rice and corn, wheat or rape can not only save labor, but also yield high economic and energy benefits in the region with low labor, large-scale production. For five crop types, N input is larger than N output, P input and output is basically in balance and K input is lower than output. In reference to ecological and economic benefits and soil fertility equilibrium maintenance, N fertilizer input should be reduced to 165- 225 kg/hm^2 for rice,75--105 kg/hm^2 for wheat,90--165 kg/hm^2 for corn, 120 kg/hm^2 for cotton and 60--90 kg/hm^2 for rape;and K fertilizer input should be increased to 120 kg/hm^2 for cotton. For the other crops,soil K may be supplemented by plowing crop straw/stalk back to field.