我国主粮作物的化学农药用量及其温室气体排放估算

现代农业中化学农药在提高作物产量中发挥着重要的作用,但是我国普遍存在过量用药现象,导致环境污染和危害食品安全.基于2012年的全国性农户问卷调查,本研究分析了2011年我国水稻、小麦和玉米使用农药现状,并估算了它们的温室气体排放.结果表明: 这3种作物至少使用了54种杀虫剂、24种杀菌剂和50种除草剂,其中32%的水稻种植农户使用了生物农药.全国3种作物使用了30.8 kt杀虫剂、16.5 kt杀菌剂和58.3 kt除草剂,它们的温室气体排放总量为1.5 Tg Ce,杀虫剂、杀菌剂和除草剂的排放分别占23.8%、16.9%和59.3%.南方区的农药用量占全国用量的51%;全国水稻、小麦和玉米的单位产量农药用量分别是0.22、0.18和0.24 g·kg^-1粮食,3种作物用药总量分别为44.4、21.4和39.7 kt,温室气体排放分别为665.5、250.1和547.5 Gg Ce;在不同农药种类中,有机磷类杀虫剂占我国所用杀虫剂总量的69%,苯丙咪唑类、有机磷类、唑类和有机硫类等杀菌剂占杀菌剂总量的87%,酰胺类、有机杂环类和有机磷类等除草剂占除草剂总量的85%.因此,减少农药用量,对于我国粮食安全和环境安全及减少农业温室气体排放都具有重要意义.

Estimations of application dosage and greenhouse gas emission of chemical pesticides in staple crops in China.

Chemical pesticides play an important role in improving crop yield in modern agriculture. However, commonly overuse of pesticide in China leads to serious environmental problems and food safety hazards. Based on a national questionnaire survey of farmers across China in 2012, the situation of pesticide applications to rice, wheat, and corn in 2011, and their corresponding greenhouse gas (GHG) emissions were investigated. The survey showed that at least 54 types of insecticide, 24 types of fungicide, and 50 types of herbicide were in use across three crops. 32% of rice farmers applied biological pesticides in China. The amounts of pesticides applied to the three cereal crops were 30.8, 16.5, and 58.3 kt for insecticides, fungicides, and herbicides, respectively. The total GHG emission from these pesticides was 1.5 Tg Ce, and the GHG emissions from these insecticides, fungicides, and herbicides accounted for 23.8%, 16.9%, and 59.3% of the total emission, respectively. In south China, the amounts of pesticides applied occupied 51% of the national total. For the production of each kilogram of grain, the amounts of pesticides applied were 0.22, 0.18, and 0.24 g for rice, wheat, and corn, respectively. Therefore, the sums of pesticides applied by crop types were 44.4 kt for rice, 21.4 kt for wheat, and 39.7 kt for corn. Meanwhile, the GHG emissions of pesticides were 665.5, 250.1, and 547.5 Gg Ce for rice, wheat, and corn, respectively. For pesticide types, organophosphorus insecticides accounted for 69% of total insecticide use in China, while benzimidazole, organophosphorus, azole, and organic sulfur fungicides together contributed 87% of total fungicide use. In addition, the use of anilide, organic heterocyclic, and organophosphorus herbicides contributed 85% of the total herbicide application. Therefore, the reduction of pesticide use would play an important role in food safety and environmental safety, and GHG mitigation in agricultural sector in China.