秸秆利用循环模式的能值效率和持续发展能力

Comparison of emergy efficiency and sustainable development capability between different agricultural circulation modes with straw utilization

用能值法分析了不同农业循环模式的能值效率和可持续发展能力,以期找到适合本地区发展的农业循环模式。以小麦玉米两熟农田、奶牛饲养系统和沼气发酵系统为研究对象,以常规施肥为对照模式(CK),设置玉米秸秆粉碎还田的农田循环模式、沼液还田的农沼循环模式和有机肥还田的农牧循环模式3种循环模式,用能值方法比较4种循环系统的能值效率和可持续发展能力。结果表明,4种模式的净能值产出率(EYR)都大于1,农田、农沼和农牧循环模式的EYR分别是对照模式的1.13倍、54.22%和50.2%,农田、农沼和农牧循环模式的能值投资率(EIR)分别是对照模式的80.88%、4.25倍和5.85倍,农田、农沼和农牧循环模式的环境负载率(ELR)分别是对照模式的78.95%、3.71倍和1.76倍,农田循环模式对环境的压力最小,农沼循环模式对环境的压力较大,4种模式的ELR都在可接受范围内。农牧循环模式的产品安全性指标(EIPS)为-0.015,最接近于0,其产品安全性最高,而对照模式的产品存在一定的安全隐患。种植模式中农田循环模式可持续发展能力优于对照模式,复合循环模式中农牧循环模式要优于农沼循环模式。综上所述,农牧循环模式的发展潜力最大,是最适合本地区的秸秆利用循环模式。

Using emergy evaluation method, this paper compared the emergy efficiency and sustainable development capability of the different circular agriculture modes in North China. The emergy evaluation on four modes were conducted, which including wheat-maize cropping system with conventional fertilization （control）, cropping system with crushed straw （farmland circulation mode ）, cropping- feeding （dairy cattle ） system with dung used as fertilizer （farmland-livestock mode）, and cropping- feeding- biogas system with biogas slurry used as fertilizer （farmland-biogas slurry mode ）. The results showed that the emergy yield ratios （EYR） of the 4 modes were higher than 1, the emergy yield ratios （EYR） of the farmland circulation mode, farmland-biogas slurry circulation mode, and farmland-livestock circulation mode, which were respectively 1.13 times, 54.22%, and 50.2% as much as those of control mode, whereas emergy investment ratios of the farmland circulation mode, farmland-biogas slurry circulation mode, and farmland-livestock circulation mode were respectively 80.88%, 4.25 and 5.85 times as much as those of control mode. The environmental loading ratios （ELR） of thefarmland circulation mode, farmland-biogas slurry circulation mode, and farmland-livestock circulation mode were respectively 78.95%, 3.71 and 1.76 times as much as those of control mode. The environmental pressure of farmland circulation mode was the lowest, the farmland-biogas slurry circulation mode was the highest. But the ELRs of 4 modes were acceptable. The emergy index of product safety of the farmland-livestock circulation mode were -0.015, its safety was the highest, the products of the control mode had some safety loophole. The farmland circulation mode had the strongest sustainable potential in 2 planting modes, the farmland-livestock circulation mode had the strongest sustainable potential in 2 comprehensive circulation modes. In conclusion, farmland-livestock mode has the strongest sustainable potential and is an ideal circular agricuhure mode, which should be popularized in the region.