Water saving vs. farm economics in cotton surface irrigation: An application of multicriteria analysis

Abstract

Improving surface irrigation systems for cotton in Ras-El-Ain district, Northeast Syria, needs finding alternative solutions that provide for both water saving and farm economic benefits in a context of small and family farms. Multicriteria analysis was used to evaluate and rank a set of furrow and border irrigation alternatives, with and without precise land leveling, that were created with the decision support system SADREG. This approach allowed to consider various criteria, mainly water saving and farm economics. Results show that both graded furrow and border alternatives are acceptable, with a slight advantage for graded furrows. Alternatives without land leveling have shown to be more appropriate when focusing farm economic results, while alternatives including land leveling were selected when priorities were assigned to water saving. These results relate with higher costs of alternatives that consider land leveling. Equipment for appropriate control of inflow rates was considered for all cases. The improved alternatives may lead to savings of 20-28% of irrigation water and increasing the irrigation water productivity from present 0.31 to 0.44 kg m −3. When the same alternatives were ranked for a 20% deficit irrigation their rankings changed, with reduced ranks of alternatives requiring land leveling. This is due to the fact that yields and yield values are reduced with deficit irrigation, thus making it less favorable to select alternatives that imply higher costs. The study shows that adopting more advanced but more costly irrigation technologies aimed at water saving requires appropriate economic incentives, training of farmers and an institutional framework able to support the sustainable use of water in irrigation.

Economic Performance of Traditional and Modern Rice Varieties under Different Water Management Systems

“…A five-year mean [22] was used to evaluate rice prices in order to reduce the impact of price volatility that characterizes the rice sector (Figure 1). To go further on the economic analysis, it is possible to evaluate the Economic Water Productivity Ratio (EWPR) [23][24][25] where IWC (€) is the irrigation water costs…”

Comparing Sprinkler and Surface Irrigation for Wheat Using Multi-Criteria Analysis: Water Saving vs. Economic Returns

“…Soil water content at 30 kPa (field capacity) is 0.37 cm 3 ·cm −3 and at 1550 kPa (permanent wilting point) is 0.23 cm 3 ·cm −3 , resulting in a total available water of 140 mm. The soil infiltration characteristics were analyzed in a previous study [23], and the resulting Kostiakov infiltration curve is: Z = 0.0118τ 0.3227 + 0.000167τ (1) where Z is the cumulative infiltration per unit width of the borders (m 3 ·m −1 ) and τ is the infiltration opportunity time (min). The observed soil basic infiltration rate is 4.1 mm·h −1 [23].…”

“…Supplemental irrigation is often applied, generally using traditional graded borders. The actual surface irrigation performances and respective potential improvements have been recently analyzed [23]. For the present study, a wheat season of 165 days was considered, the sowing date being 1 January.…”

“…Considering results previously obtained [23], this application focused on graded border irrigation with and without precision land levelling, respectively GB PL and GB NPL . Contrary to GB PL , GB NPL has reduced investment, but does not allow achieving high distribution uniformity and good irrigation performances.…”

“…The alternatives resulted from the combination of different field lengths (50 m, 100 m and 200 m) with various inflow rates per unit width (0.8, 1.2, 1.6, 2.0, 2.8 and 3.6 L·s −1 ·m −1 ). Hydraulic computations were performed using a Manning's roughness coefficient of 0.16 s·m −1/3 as described by Darouich et al [23].…”