英文文献：Profitability Of Fertilizer Use On Maize By Small-Scale Farming Households In Zambia-赞比亚小规模农户在玉米上使用化肥的利润
英文文献作者：Xu, Zhiying,Jayne, Thomas S.,Black, J. Roy,Govereh, Jones
英文文献摘要：
Multi-year nationwide survey data is used to estimate maize yield response functions and determine profitability of fertilizer use by small-scale farmers in Zambia. Most previous research on economics of fertilization used estimates of yield response to nutrients based on experimental or simulation data and seldom investigated region-specific and management-specific effects. In this paper we address the main issues arising from using large survey data and estimate maize yield response functions for different groups of households that have various management practices and soil conditions in two major agro-climatic zones. Profitability of fertilizer use is determined for each group in each zone and the results provide the following messages. First, households that obtained fertilizer on time and used animal draught power or mechanical power for land preparation are more likely to find fertilizer use profitable than other groups of households located in the same district. Second, farmers' proximity to the provincial centers has a significant impact on the profitability of fertilizer use. Greater distances and transport costs from provincial centers erode the profitability of fertilizer use. Third, high time preferences for money also reduce the profitability of fertilizer use. Thus, despite achieving relatively high physical crop response rates to fertilizer use in some areas, small farmers may find fertilizer use unprofitable until efforts are made to reduce transportation costs and implicit interest rates as well as to ensure more timely delivery of fertilizer.

多年的全国调查数据用于估计玉米产量响应函数，并确定赞比亚小规模农户使用化肥的盈利能力。以往的施肥经济学研究大多是根据试验或模拟数据估计产量对养分的响应，很少研究特定区域和特定管理的效应。在这篇论文中，我们讨论了利用大量调查数据和估计在两个主要农业气气区中具有不同管理方法和土壤条件的不同家庭群体玉米产量响应函数所产生的主要问题。每个区域的每一组的肥料使用利润是确定的，结果提供了以下信息。首先，按时获得肥料并使用畜力或机械力进行土地整地的家庭比同一地区的其他家庭群体更有可能发现使用肥料有利可图。其次，农民靠近省级中心对肥料使用的盈利能力有显著影响。由于距离省中心较远，运输成本也较高，化肥使用的盈利能力受到削弱。第三，对资金的高度时间偏好也降低了化肥使用的盈利能力。因此，尽管某些地区的作物对化肥使用的物理响应率相对较高，但小农户可能会发现，除非采取措施降低运输成本和隐性利率，并确保更及时地交付化肥，否则化肥使用将无利可图。