关键词: 饲料作物, 温室气体, 生命周期评价, 粮改饲

Abstract: This study aims to delineate the disparities in greenhouse gas (GHG) emissions from the cultivation of food and forage crops,and to pinpoint significant emission sources. Drawing on 738 valid household questionnaire surveys executed in Gansu and Ningxia from 2018 to 2021,the GHG emissions from four principal crops (wheat,maize,alfalfa,and forage maize) were assessed using the Life Cycle Assessment method. The research revealed that the per-hectare dry matter yields of wheat,maize,alfalfa,and forage maize were 6.45,16.81,6.28,and 17.05 tons,respectively;while the per-hectare crude protein yields were 0.52,1.08,0.79,and 1.22 tons,respectively. Besides,the GHG emissions per hectare of wheat,maize,alfalfa,and forage maize were 3.89,5.14,1.12,and 4.34 tons of CO₂ equivalent,respectively. With dry matter and crude protein as functional units,forage crops,especially alfalfa,demonstrated lower emissions. Sensitivity analysis revealed that fertilizers and agricultural machinery were the primary contributors to GHG emissions,collectively representing an average of 75.29% and 11.51%,respectively. Hence,we propose substituting food crops with forage crops to facilitate herbivorous animal husbandry in the study area. Implementing improved crop fertilization management and increasing mechanical efficiency can significantly contribute to GHG mitigation in herbivorous animal husbandry.

Key words: Forage crop, Greenhouse gases, Life cycle assessment, Cereal shift to forage production