有機農法採用之影響因素與經濟效果－以花蓮縣富里鄉稻農為例

Abstract

農業不僅提供穩定與優質的糧食供給來源，同時也可維持生態環境並保留鄉村純樸的農家生活。近年來，隨著社會大眾對於食物安全的要求逐漸升高及都市居民休閒方式的改變，再加上環境保育比過去更受重視，有機農法已成為最為風行的農業生產方式。臺灣的有機農業於近十餘年間蓬勃發展，其中，東部的花蓮縣玉里鎮、富里鄉以及臺東縣池上鄉、關山鎮等地區，一直都是臺灣稻米的重要產區，又由於臺灣東部所受到的環境汙染較其他地區為少，因此在有機產業的發展上也相當穩定而快速。在學界，有機農業也是近年來被廣為討論的議題，而農業經濟領域相關文獻多著重於有機農法採用影響因素的檢視，少部分研究則探討有機農民與慣行農民在生產效率或生產力上之差異。本文的主要目的是結合近期技術採用文獻在方法論上的發展，以臺灣有機發展早，且成長穩定快速的花蓮縣富里鄉羅山有機村及周圍村鎮的有機稻農與慣行稻農為研究母體，分三方面探討有機農法採用的態度形成、影響因素以及經濟效果。 首先，利用 Ajzen（1985）及 Ajzen and Madden（1986）提出的計畫行為理論，本文討論該理論各構面間之關聯性，亦即將重點放在態度、社會規範與行為控制間的關係，以了解農民有機農法之態度形成，並進一步比較有機農民與慣行農民在態度形成上之差異。其次，考量農民對於有機農法經濟影響的看法可能與一般態度構面的影響有所不同，同樣在計畫行為理論的架構下，本文檢視經濟考量及計畫行為理論各構面對於農民有機農法採用所造成之影響。本文的第三個主要目的在於探討有機農法採用所為農民帶來的經濟效果。本文利用Rosenbaum and Rubin（1983）提出的傾向分數法以處理技術採用經濟效果評估不可避免的自我選擇問題，在 Neyman-Rubin 虛擬事實因果推論的架構下，估算採用有機農法的農民在採用與不採用時之收入、成本與利潤等之差距，即所謂的受試者平均試驗效果（average treatment effect for the treated，ATT）。 在實證分析部分，本文依據主要研究目的區分為三個相互連貫的子題。第一子題的實證結果發現，對環境與健康的態度不同，會對有機農民與慣行農民的正向有機態度形成造成不同的影響。對慣行農民而言，對環境與健康的態度i越正向，其持正向有機態度的機率越高；然而，對有機農民而言，此正向影響之程度則相當小。若進一步將有機農民依採用時點區分為早採用與晚採用之農民，本文發現，相對於慣行農民，對環境與健康的態度對早採用農民形成正向有機態度會產生負向影響，但晚採用農民與慣行農民之間則並未呈現顯著差異，這樣的結果說明有機產業在早期所面臨的發展問題。第二子題的結果顯示，在計畫行為理論的架構下，富里鄉稻農對資訊的態度會對其採用有機農法的機率產生正向影響，而環境與健康態度與採用機率之間並無顯著關係，主觀社會規範則呈現顯著的負向影響。本文亦發現與多數文獻的結果一致，經濟考量是影響農民採用有機農法的主要因素之一；再將有機農民依採用時點加以區分，則可發現早採用農民與晚採用農民最明顯的區別在於，影響早採用農民採用決策的因素主要來自態度構面，而經濟考量則是影響晚採用農民的主要因素。本文在第三子題應用共變數調整與傾向分數配對兩種方法估算有機農法採用的經濟效果；結果發現，有機農法採用平均而言造成富里鄉稻農單位面積收入減少約24,000 元，而單位面積利潤則減少約 2,500 元。 本文依據主要研究結果提出具體建議。首先，營造對有機農法友善的社會氛圍或舉辦活動以促使農民與消費者之間產生更緊密的連結，將會有助於有機農法的推廣。其次，本文發現經濟因素是影響農民採用有機農法的主要因素，而採用有機農法會降低農民之收入與利潤，因此，就誘因設計而言，農政單位可以透過提高有機稻穀收購價格，以增強農民採用有機農法之意願。最後，相關單位應該再加強有機農產品的監管機制，以避免不肖農民或業者的投機行為造成農民對有機農法信心的喪失。

As a stable source of quality food, agriculture also has the function of maintaining ecological environment and preserving the pristine lifestyle of rural residents. In recent years, in addition to fastening their eyes on environmental issues, the public are attaching more importance to food safety; organic farming has thus become a new mainstream of farming methods. As well, organic farming in Taiwan has experienced fast growth during past decades since the government put efforts in promoting the adoption of this “ecological production management system”, as defined by USDA National Organic Standards Board (NOSB) in April 1995. Eastern areas, especially Yuli and Fuli in Hualien County as well as Chihshang and Guanshan in Taitung County, are the major rice production areas in Taiwan. Because the problem of environmental pollution has been less severe in those areas, organic farming keeps growing steadily in eastern Taiwan. Based on the survey data of Fuli Township in Hualian County, this thesis attempts to provide a synthesis of recent methodological developments in the literature to examine the attitude formation, adoption determinants as well as economic impacts of organic farming. The major objectives of this thesis are three-folded. First of all, making use of the theory of planned behavior (TPB) developed by Ajzen (1985) and Ajzen and Madden (1986), this study aims at finding out the association between the elements of TPB, that is, the relationships between attitudes, perceived social norm and perceived behavioral control. Secondly, taking into account the different effects of TPB constructs and economic concerns, this study assesses the separate influences of these two determinants on the adoption of organic farming. The third objective of this study is to evaluate the economic impacts of adopting organic farming. Applying the propensity score methods proposed by Rosenbaum and Rubin (1983), this study solves the self-selection problem encountered in effect evaluation of technology adoption. Within the context of Neyman-Rubin counterfactual causal inference framework, the so-called average treatment effect for the treated (ATT) is calculated by measuring the differences in income, cost and profit resulting from organic farming. The empirical results are summarized as the following according to the three major objectives. First is that attitude toward environment and health has differential effects on organic and conventional farmers in terms of forming positive attitude toward organic farming. For the conventional farmers, the positive attitude toward environment and health increases the probability of holding positive attitude toward organic farming. However, for the organic farmers, this positive effect is quite small. Dividing the organic farmers into early and late adopters indicate that, relative to the conventional farmers, early adopters’ attitude toward environment and health has negative effect on forming positive attitude toward organic farming, while no significant effect is observed for the late adopters. This result reveals some problem in the development of organic industry at the early stage. The empirical results in the second part of this thesis suggest that, within the context of TPB, Fuli rice farmers’ positive attitude toward information will increase their probability of organic farming adoption. Moreover, while attitude toward environment and health has no significant influence on the adoption decision, perceived social norm exhibits negative effect. The results also indicate economic concern is the major determinant of rice farmers’ adoption of organic farming. A further division of the organic farmers reveals considerable differences between early and late adopters. The results suggest the main motivation of early adopters comes from the attitudinal factors, while economic concern is the major determinant of late adopters’ adoption decision. In the third part, this study applies both covariate adjustment and propensity score matching methods to investigate the economic effects of organic farming. As a result of adopting organic farming, Fuli rice farmers’ income per hectare decrease, on average, by $24,000 NT, and profit per hectare decrease by $2,500 NT as well. Based on the findings of this thesis, some policy implications for the promotion of organic farming can be inferred. First of all, creating a pleasant atmosphere of organic farming or holding some events and festivals to bridge a close connection between the farmers and consumers will help promoting organic farming. Secondly, the empirical results reveal that economic concern is one of the main factors driving farmers’ adoption decision, and organic farming will reduce both income and profit significantly. Raising the purchasing price of organic-certified rice will therein create a stronger incentive for farmers to adopt organic farming. Last, but not the least, the governmental authorities should reinforce the monitoring and traceability system of organic products to prevent the cheating or misconduct of a small number of organic rice farmers.