陕西省小农户作物生产的减肥潜力及经济效益评价

【目的】小农户在农业生产中投入的生产资料普遍过高,随种植业结构演变,肥料投入也势必会发生变化。明确小农户经营模式下粮食、油料和经济作物的施肥现状和经济效益,能为小农户作物生产的养分管理、肥料减施和经济效益提高提供参考。【方法】2018年对陕西省的主要农作物生产情况进行问卷调查,以粮食(小麦、玉米、水稻、谷子、马铃薯)、油料(油菜、大豆)、经济(苹果、西红柿、烤烟)作物为研究对象,共获得1 709份调研问卷。基于此调研结果,以产量水平为分类依据,分析小农户的施肥现状、减肥潜力和经济效益。【结果】小麦、玉米、水稻、谷子和马铃薯的平均产量分别为4.6、7.3、8.3、3.7和19.8 t·hm^-2,氮肥用量分别为177、247、186、255和209 kg N·hm^-2,磷肥用量分别为102、103、88、142和125 kg P₂O₅·hm^-2,钾肥用量分别为37、47、64、53和110 kg K₂O·hm^-2。油菜和大豆的平均产量分别...

Fertilizer Reduction Potential and Economic Benefits of Crop Production for Smallholder Farmers in Shaanxi Province

【Objective】The material input of agriculture production is generally high for smallholder farmers, and the application rate of chemical fertilizers will change with the evolution of crop structure. Understanding the situation of nutrient input and economic benefits of smallholder to cereal crop, oil crop and cash crop could help guide scientific fertilization and improve economic benefits. 【Method】In 2018, a questionnaire survey was conducted on the production of major crops in Shaanxi Province. The cereal crop (wheat, maize, rice, millet, and potato), oil crop (canola and soybean), and cash crop (apple, tomato, and flue-cured tobacco) were considered as targeted crops, and a total of 1 709 questionnaires were obtained. Further, the fertilization status of smallholder, the potential of fertilizer reduction, and economic benefits according to yield level of different crops were evaluated. 【Result】For the production of wheat, maize, rice, millet, and potato, the mean yield was 4.6, 7.3, 8.3, 3.7, and 19.8 t·hm^-2, respectively; the mean nitrogen (N) fertilizer rate was 177, 247, 186, 255, and 209 kg N·hm^-2, respectively; the mean phosphate (P) fertilizer rate was 102, 103, 88, 142, and 125 kg P₂O₅·hm^-2; mean potassium (K) fertilizer rate was 37, 47, 64, 53, and 110 kg K₂O·hm^-2, respectively. For canola and soybean production, the mean yield was 2.4 and 2.7 t·hm^-2, N fertilizer rate was 156 and 99 kg N·hm^-2, P fertilizer rate was 80 and 63 kg P₂O₅·hm^-2, K fertilizer rate was 56 and 26 kg K₂O·hm^-2, respectively. For the production of apple, tomato, and tobacco, the mean yield was 23.8, 93.5, and 2.7 t·hm^-2, respectively; N fertilizer rate was 731, 471, and 118 kg N·hm^-2, P fertilizer rate was 482, 387, and 118 kg P₂O₅·hm^-2, K fertilizer rate was 535, 447, and 132 kg K₂O·hm^-2, respectively. N and P fertilizers were usually over-applied, while both over-application and under-application of K fertilizer coexisted. The potential of N, P, K fertilizer reduction ranges from 28% to 60%, 52% to 66%, and 11% to 51% for cereal crop, 33%, 37% and 46% for canola, respectively. However, the application rate of P and K fertilizer needed to increase by 11% and 28% for soybean production, respectively. The potential of N, P, and K fertilizer reduction ranged from 41% to 67%, 65% to 70%, and 49% to 64% for apple and tomato production, respectively. For tobacco production, the application rate of P fertilizer could decrease by 53%, while the application rate of N fertilizer needed to increase by 22% and 11% for farmers with medium and high-yielding, respectively. The source of N was mainly compound fertilizers and urea, and the sources of P and K were mainly compound fertilizers. For the way of chemical fertilizer application, most of N fertilizer was applied as basal fertilizer, and a small part was supplemented by topdressing, while almost all P and K fertilizers were applied as basal fertilizer. For cereal crop, oil crop, and cash crop, the cost of fertilizer application accounted for 31%-52%, 57%-59% and 48%-65% of total input, respectively, and the net economic benefit ranged from 0.44×10⁴to 1.63×10⁴, 0.75×10⁴to 0.84×10⁴, and 4.19×10⁴ to 15.05×10⁴yuan/hm², respectively. Because the net economic benefit of high-yielding in cash crop, e.g., apple and tomato, was higher than that of cereal crop and oil crop, smallholder farmers were more inclined to grow them. However, the substantial application of chemical fertilizer in cash crop production brought great environmental risks. 【Conclusion】The main target of fertilizer reduction and benefit improvement was smallholder with low and middle-yielding level. Compared with cereal crop and oil crop, the economic benefit of cash crop, especially for apple and tomato, was higher, while their potential of fertilizer reduction was also higher due to substantial application of chemical fertilizer. Notably, the result of the study also demonstrated that there was also insufficient application of fertilizer in crop production, e.g., soybean and tobacco. In conclusion, the fertilizer management of smallholder varied greatly. Improving the level of fertilizer management for smallholder was conducive to increasing both yield and economic benefits, and thus contributing to sustainable crop production.