**1. Introduction**

Farmers today are facing climate hazards such as floods, droughts and/or frost. In central and southern Europe, farmers are experiencing an increase in the frequency of droughts, with negative impacts on crop productivity [1]. In France, 2011 has been one of the ten driest years in 50 years so far, with a hydric deficit mean of more than 10% and a mean temperature exceeding the reference by 2.6 ◦C (1971–2000) [2]. The context of agricultural production has become increasingly volatile and unpredictable [3]. Farmers need to adapt to a changing environment with new constraints, such as water scarcity [4]. Their decisions regarding irrigation strategies directly influence the quantity and quality of natural resources [5]. The impact of droughts is particularly severe for summer-irrigated plants, such as maize (*Zea mays* L.).

In France, grain maize is the second most frequently produced cereal after wheat (*Triticum aestvum*), with a national production of 13.5 million t in 2020 [6] over an area of just over 1 million ha, 35% of which was irrigated [7]. The decrease in rainfall directly affects maize yield since it is sensitive to hydric deficit, especially at reproductive development stages. Adaptation strategies, such as changing the amount, timing and frequency of irrigation, can avoid yield losses and make it possible to save water [8,9]. The start of the

**Citation:** Albert, M.; Bergez, J.-E.; Couture, S.; Faivre, R.; Willaume, M. Decision-Making Process Factors Explain Some of the Heterogeneity of Irrigation Practices among Maize Farmers in Southwestern France. *Water* **2021**, *13*, 3504. https:// doi.org/10.3390/w13243504

Academic Editors: Alban Kuriqi and Luis Garrote

Received: 8 October 2021 Accepted: 5 December 2021 Published: 8 December 2021

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**Copyright:** © 2021 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/).

irrigation season is a key element for crop development and is a milestone that should not be missed; it will make it possible to target high yields and ensure the continuation of irrigation practices. Focusing on the date of first irrigation is therefore a major challenge for farmers in terms of water management. The date of first irrigation for maize usually varies with the region. However, it may also vary from farm to farm in a similar context of water availability. Understanding explicative factors of this heterogeneity is key to enhancing adaptation in agriculture.

Many studies have sought to explain the heterogeneity of farmers' practices. Most of them considered structural and material factors such as farm characteristics and agricultural practices. Several studies attempted to understand farming system management based on the level of resources [10], intensity of agricultural practices [11,12], equipment and socioeconomic aspects [13]. However, practices remain heterogeneous even when farmers have similar production situations [14]. For example, differences in chemical input practices have been explained in part by farmers' personal characteristics and their production situation [15,16]. Moreover, farmers' decisions are not completely based on structural and material factors [17]. Recent studies have hypothesized that, in addition to structural and material factors, psychological factors could also explain the heterogeneity of practices among farmers [18]. It appears that two types of psychological factors can explain such heterogeneity: risk preference (i.e., a farmer's degree of reluctance to perform potentially risky practices [19,20]), and decision-making process factors (i.e., psychological factors specific to the decision-making process). The decision-making process is the process by which an individual commits to following a choice when alternatives exist, even when these alternatives are not known or analyzed [21]. Few studies have focused on the influence of decision-making process factors on the heterogeneity of practices [22–25]. Some studies modeled the decision-making process in order to better understand farmers' behavior [18,25,26]. Daydé (2017) developed a conceptual model of the decision-making process and hypothesized that the heterogeneity of the process among farmers explained the heterogeneity of practices. His case study focused on fungicide doses applied to wheat. In Daydé's (2017) model, the farmer's decision-making process was based on three decisionmaking process factors: reactivity (i.e., the farmer's capacity to change his plans), assistance (i.e., amount of external information used by the farmer), and deliberation (amount of internal information used by the farmer).

Our study aimed to explain the heterogeneity of the date of first irrigation of maize farmers in southwestern France. Our objectives were to study the role of structural and material factors as well as psychological factors through risk preferences and the three decision-making process factors (reactivity, assistance and deliberation). Our study was based on semi-directed interviews with maize farmers. We begin by describing the conceptual framework, survey design and the methods for analyzing the survey data. We then present and discuss the main results, with particular focus on psychological factors specific to the decision-making process and their influence on farmers' decisions to start irrigating.
