Citation: Chang, K.-F.; Wu, P.-I.;Liou, J.-L.; Yang, S.-L. Contract Owner’s Best Commanding for Sweet Potato Farming Based on the Theory of Planned Behavior. Agriculture 2022, 12, 1221. https://doi.org/10.3390/ agriculture12081221 Academic Editor: Giuseppe Timpanaro Received: 8 July 2022 Accepted: 10 August 2022 Published: 14 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). agriculture Article Contract Owner’s Best Commanding for Sweet Potato Farming Based on the Theory of Planned Behavior Ke-Fen Chang 1 , Pei-Ing Wu 2, *, Je-Liang Liou 3 and Shou-Lin Yang 4 1 Overseas Business Department, Uncle Sweet Co., Ltd., Yunlin County 65242, Taiwan 2 Department of Agricultural Economics, National Taiwan University, Taipei 10617, Taiwan 3 Center for Green Economy, Chung-Hua Institution for Economic Research, Taipei 10672, Taiwan 4 Department of Logistics Management, National Kaohsiung University of Science and Technology, Kaohsiung 82454, Taiwan * Correspondence: piwu@ntu.edu.tw; Tel.: +886-2-3366-2663 Abstract: The purpose of this study is to examine and compare different psychological and sociode- mographic factors for contracting sweet potato production for farmers with different statuses based upon the theory of planned behavior (TPB). Sustainable production provides contract owners with a sufficient amount of both food crops and a source of bioethanol clean energy. The impact of such factors on potential farmers based on the TPB for a particular contract type is estimated with the data collected in three major sweet potato production cities/counties in Taiwan through the probit model and multinomial logit model. The average size of the surveyed farms is 1.64 ha. The results consistently show that the factors of attitude toward the advantages of contract farming, subjective norms regarding contract farming, perceived contract farming control, and behavior intention have very significant impacts on the selection of contract farming types for professional farmers and brokers. These results indicate that the contract owners will gain the greatest advantage through commanding any factor in TBP for these two groups of farmers, as they have an incentive to manage the sources of sweet potatoes at the best conditions before they have the agreement with the contract owners, either as the supply of bioethanol energy raw materials, supply of food crops, or supply of food processing materials. Keywords: psychological factors; sociodemographic factors; multinomial logit model; marginal effect; contract owner; bioethanol 1. Introduction Agricultural production is apparently affected by all kinds of climate factors. Under globalization, it has become increasingly difficult for small-scale agricultural management to compete with similar agricultural products imported from countries with large-scale agricultural operations. Contract farming is one way for those countries with small scales operations to engage in agricultural production that is part of a planned scheme. This can help maintain a balance between production and marketing and further reduce farmers’ possible losses due to market risk [1]. Moreover, food security, agricultural development, provision of bioethanol energy, and utilization of a guaranteed number of products on hand can also be maintained via contract farming [2]. Contract farming means that the contract owner and farmer enter into an agreement whereby one side offers the other side land and labor and provides it with a variety of promises regarding the quality, required size, quantity, and price of the contract items [3]. From the contract owner’s viewpoint, it is likely to achieve an efficient utilization and allocation of resources with a sufficient amount of production. This normally results in a long-term cooperation between the contract owner and the farmer and in both sides being better off [4,5]. Agriculture 2022, 12, 1221. https://doi.org/10.3390/agriculture12081221 https://www.mdpi.com/journal/agriculture