IWRA Proceedings

AbstractLa Laguna region, which is located at the Northern part of Mexico at 26° N latitude and 103° W longitude, undergoes an important water scarcity due to the amount of water extracted from the subsurface aquifer is around 40 % higher of that entering into the aquifer. In turn, this causes a decreasing in water availability for different uses, such as domestic, industry and agriculture. Is in the last use where around 85 % of water extracted is applied. However, the level of irrigation efficiency is not as high as needed for preserving this important natural resource. Based on this problem, a field experiment was carried out in order to obtain information regarding to irrigation water saving using subsurface drip irrigation in comparison to the traditional surface irrigation method; and about growth and yield of alfalfa (Medicago sativa L.) under subsurface drip irrigation conditions. Four irrigatión depths were evaluated. These were calculated from pan evaporation readings (EV) using four percentages, 50, 65, 80, and 100 %. Treatments were allocated in the field and statistically analyzed based on a randomized complete block design with four replications. Specific differences between treatments were calculated using the Duncan method (p= 0.05). Irrigation was applied twice per week using the subsurface drip method. Accumulated dry matter of six harvests of alfalfa (cv. Excelente) was analyzed. Likewise, four plant growth variables, leaf area index (LAI), net assimilation rate (NAR), relative growth rate (RGR), and crop growth rate (CGR) were measured. Both, total irrigation water applied and water saving in comparison to the surface irrigation method, were also measured. Water saving was obtained from the treatments that received less than 100 % of the EV at levels of 43.9, 32.0 y 19.4 % for the 50, 65 y 80 % EV treatments, respectively. Both, NAR and CGR resulted higher in the treatment that received the highest irrigation depth, whereas the level of LAI and RGR did not vary throughout the range of irrigation depth studied. Crop dry matter was higher at the most irrigated treatment (20.82 ton ha-1). As compared to the average commercial dry forage yield with surface irrigation in the Comarca Lagunera, all of the treatments produced a higher value.