Irrigation and fertigation practices in small-scale family farming systems for water and nutrient efficiency in semi-arid Mediterranean areas

Efficient use of water and nutrients in irrigation system is important in arid and semi-arid regions, where water is a limiting resource. This study aims to analyze irrigation and fertigation practices for a widespread crop (pepper, Capsicum annuum) in Tunisia, in a context of highly diverse agricultural practices. The study took place in the irrigated plain of the Merguellil river in Central Tunisia, characterized by its high diversity of crops and practices. In 2019, irrigation and fertilization practices involved in pepper crop cultivation watered by drip irrigation, were compared on fourteen plots. This was carried out through an approach coupling semi-directive surveys with farmers and monitoring of irrigation, done using a temperature logger installed on the irrigation pipes and allowing the detection of irrigation duration. The study covered the three main seasons of pepper cultivation (Spring, Summer and late Summer). The results showed globally an opposition of two main logics. On the one hand, there are strategies aiming to a significant water supply during the first days after planting, followed by a non-irrigated period, forcing the plant to "tap into the soil water reserves", then irrigation at regular rates (once every three to five days or more) thereafter, sometime alternate with fertigation. On the other hand, there are strategies of regular water and nutrients supply, taking into account crop requirements: low water inputs at the beginning (on daily or once every two to four days rate), followed by a progressive increase. In this strategy, application of fertilizers through the drip irrigation occurred right after the first irrigations, the farmer alternating up to three irrigations for one fertigation. Commonly, fertilization was fractioned and application was done in the last quarter of watering time in order to avoid/reduce nutrient leaching. The number of splits varied significantly from a farmer to another and from a strategy to another. These irrigation and fertigation practices may have different effects on the system outputs, mainly on water and nitrogen efficiency and yield

The logics of farming practices: Mapping innovative and alternative practices with agroecological potentials in three irrigated plains in North Africa

In the irrigated plains of North Africa, the sustainability of productive resources is subject to several threats linked to the productivist model of irrigated agriculture. These threats prompt farmers to mobilize depleting productive resources. In order to reduce vulnerabilities and sustain their farming systems, farmers can update their adaptive strategies by setting-up innovative, alternative, farming practices that in conjunction enable them to sustain farm profitability. This study aims at mapping and analyzing such existing local farming practices with agroecological potentials. Our approach is based on direct observations combined with interviews with farmers in three irrigated plains in the Maghreb: the Merguellil, Upper Cheliff and Saiss plains, respectively in Tunisia, Algeria and Morocco. This study shows that, while intensive agricultural practices do characterize most farming systems, there co-exists, at the same time, a wide range of alternative practices that valorize ecological processes in some way or another. The most common practices are developed to improve soil fertility management (production of diluted liquid manure, organic fertilization, integration of leguminous plants into the rotation), to enhance land use efficiency (crop rotation, intercropping, relay intercropping, agroforestry) or to provide multiple ecosystem services (diversification, livestock integration). For example, and in the sense of “hitting two targets with one shot ”, farmers combine two or more crops on the same plot in order to (1) increase land-use efficiency to face land fragmentation linked to inheritance issues; (2) diversify their cropping strategy and spread out market-related risks; (3) reduce expensive production costs related to irrigation, chemical fertilization, etc. Our analysis of farmers' logics shows that economic reasons undoubtedly take precedence overall environmental concerns. This is why these innovative practices are considered as (1) access to low-input and low-cost strategies for small farmers; (2) as a pathway to international markets for agribusiness farmers, rather than agroecological practices per se. In plains like those of the Maghreb, intensive and conventional practices, associated with environmental threats, coexist with a wide variety of practices with agroecological potentials. Putting the farmer first and mobilizing their extensive local knowledge can contribute to the field of agroecology. Such practices may pave the way for a more sustainable agricultural development