台灣氮肥需求及其污染之經濟分析

An Economic Analysis of Nitrate Demand and Pollution in Taiwan

自1950年起，台灣農業因化學肥料的使用而提升了作物生產力及農家收入，然而，大量施用肥料也形成許多環境問題。本文建立化學肥料之需求體系，導出各種氮肥之自身價格彈性，發現結果為正數，這是由於政府長久以來對肥料價格進行補貼，且各種肥料價格的變動均為同向所致。其次，複合肥料與尿素之間有輕微替代性，但其交叉彈性偏低，而硫酸錏與複合肥料之交叉彈性較高，為互補關係，硝酸錏鈣與複合肥料之交叉彈性亦高，也是重要的互補品。由於近年來複合肥料的使用以遞增速度增加，因此建議應嚴格限制其經濟誘因，避免過度使用。文中亦探討已開發國家之肥料相關政策，特別討論肥料施用之誘因與反誘因。由於農家施肥的種類、數量及方式，實際上受到產量、氣候、耕作方式及其他種種變數之影響，行政上不易控制其使用，因而也可以考慮以課稅或補貼之經濟誘因抑制未來之肥料使用，本文提出其他各種適於台灣農業之政策性建議，期待決策者除了以政策干預也能應用市場機能減少肥料之使用。 The application of chemical fertilizers, particularly since 1950, have improved Taiwan's crop productivity and farmer's income significantly. Yet, the extensive application of fertilizers poses numerous environmental problems. This paper developed the demand system for fertilizers and indicated that own price elasticities of nitrogenous fertilizers are all positive because all fertilizer prices have been highly subsidized and price changes always move in the same direction. Combined Fertilizers and Urea are slightly substitutable, while the cross-price elasticities are quite low. Ammonium Sulphate and Combined Fertilizers are complementary, while the estimated cross-price elasticities are high. Calcium Ammonium Nitrate and Combined Fertilizers are substantial complements, while the estimated cross-price elasticities are also high. Since the application of Combined Fertilizers has been increasing at an increasing rate, it is recommended that the economic incentives to use Combined Fertilizers should be strictly constrained. Fertilizer related policies available to developed countries are discussed. The incentives and disincentives of fertilizer use are emphasized. Direct control over fertilizer application can be changed from year to year in response to production levels, climate variations, farming patterns and other variables. However, the administration of the quantity regulation is quite complicated. As for the economic instrument, taxation and subsidy could be effective ways of reducing the application of fertilizers in the future. This paper discusses alternative policy tools for Taiwan's agriculture with a hope that government intervention as well as market mechanism will curb fertilizer use in the future.

The application of chemical fertilizers, particularly since 1950, have improved Taiwan's crop productivity and farmer's income significantly. Yet, the extensive application of fertilizers poses numerous environmental problems. This paper developed the demand system for fertilizers and indicated that own price elasticities of nitrogenous fertilizers are all positive because all fertilizer prices have been highly subsidized and price changes always move in the same direction. Combined Fertilizers and Urea are slightly substitutable, while the cross-price elasticities are quite low. Ammonium Sulphate and Combined Fertilizers are complementary, while the estimated cross-price elasticities are high. Calcium Ammonium Nitrate and Combined Fertilizers are substantial complements, while the estimated cross-price elasticities are also high. Since the application of Combined Fertilizers has been increasing at an increasing rate, it is recommended that the economic incentives to use Combined Fertilizers should be strictly constrained. Fertilizer related policies available to developed countries are discussed. The incentives and disincentives of fertilizer use are emphasized. Direct control over fertilizer application can be changed from year to year in response to production levels, climate variations, farming patterns and other variables. However, the administration of the quantity regulation is quite complicated. As for the economic instrument, taxation and subsidy could be effective ways of reducing the application of fertilizers in the future. This paper discusses alternative policy tools for Taiwan's agriculture with a hope that government intervention as well as market mechanism will curb fertilizer use in the future.