The Value of Stabilizing Fertilizer under Carry‐Over Conditions
用动态规划模型研究磷肥施用不均对产量和利润的影响，发现土壤磷储备低时，减少施肥变异的技术价值高，尤其对低残留肥料（如氮、钾）用户和土地贫瘠的农民。
Abstract This paper develops a dynamic programming model to examine the effects on yield and profitability of variability in spread of phosphate fertilizer under carry‐over conditions and the value of technology which reduces this variability. The cost of uneven spread is high, if the plant‐available soil phosphorus reserve is low. Therefore, the value of technology reducing variability in spread is high to farmers with less‐developed land where soil phosphorus reserve is low. This value is also high to users of low carry‐over fertilizers, i.e., nitrogen and potassium.