Abstract
This study is targeted to improve surface irrigation performance of durum wheat in swelling soils. For this purpose, furrow and border irrigation trials were carried out and evaluated under different soil water depletion rates, furrow spacing and unitary inlet discharges. Irrigation was triggered whenever the soil water depletion rate reached a predetermined threshold. A comprehensive irrigation evaluation produced hydraulic, agronomic and economic indicators, such as application efficiency, distribution uniformity, crop yield, gross margin and water productivity. Experimental results showed that supplied water depths exceeded soil water deficits, inducing relevant vertical and lateral water losses. Al- though border and furrow irrigation crop yields were virtually tantamount (about 5.5 Mg/ha), furrow irrigation was the system of choice. An irrigation strategy based on a furrow spacing of 150 cm, an inlet discharge of 2 l/s/furrow and a soil water depletion rate of 30% required a gross water depth of 4300 m3/ha/yr and generated an optimum crop yield of 58 qx/ha. In the analyzed range of soil water depletion, the gross margin and water value amounted to 1064 - 1390 Tunisian Dinar per hectare (TD/ha) and 0.39 - 0.44 TD/m3, respectively, for a furrow spacing of 150 cm.
Highlights
Water requirements of irrigated areas are endlessly growing because of irrigation intensification and the concomitant expansion of irrigated acreages
These results show that furrow irrigation of wheat is an adequate alternative to border irrigation in the local swelling soils
These results show that the soil water deficit (WD) and the mean applied water depths (MAWD) increased gradually as the soil became dry
Summary
Water requirements of irrigated areas are endlessly growing because of irrigation intensification and the concomitant expansion of irrigated acreages. Acreages served by surface irrigation have witnessed a noticeable worldwide regression during the last decade. Despite public subsidies to curb excessive water use, surface irrigation is still practiced on more than 54% of irrigated area in Tunisia. Improper surface irrigation strategies on cracked soils are synonymous of noteworthy water and nutrients losses. These are generated by the so-called bypass or funnel flow which results in a preferential flow within cracks [6]. Donahue et al [8] estimated the area covered by vertisols to 1.8% of the world area In these soils, the change of volume in the vertical direction induces the subsidence phenomenon, whereas the change of volume in the lateral direction causes the formation of cracks [9].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
