A Response to Sustainable Crop Production In a Region Facing a Decline In Groundwater Aquifer Levels

Climate change has resulted in a steady decline of the unconfined groundwater aquifer in the San Luis Valley of Colorado. Growers face limited water supply for potato (Solanum tuberosum L.) production. An alternative and more efficient system of irrigating potato is needed. Drip irrigation supplies the required amount of water close to the plant root, and avoids the potential of water loss through drift and evaporation which are some of the inefficiencies in the conventional overhead irrigation system.

Studies were conducted in Colorado to reduce the amount of irrigation water pumped for potato production by using drip irrigation. The effect of drip irrigation on potato tuber yield and quality was also evaluated. Treatments consisted of surface drip irrigation (drip tapes buried at 5 to 7.5 cm below the soil surface), subsurface drip irrigation with drip tapes buried at 20 and 35 cm below the soil surface, and an overhead irrigation system which served as the control. Between 68 to 74 % of overhead irrigation water was used in the drip irrigation system for potato production.

Surface drip irrigation produced 11% more marketable size (114 to 454 g) tubers and 91% more large marketable size (284 to 454 g) tubers, compared to overhead irrigation for the cultivar Rio Grande Russet. Drip irrigation produced 92% more tubers with diameter > 5 cm and > 284 g in weight and 18% more longer (> 8.8 cm) tubers, compared to overhead irrigation. Tuber specific gravity was high (1.090) under drip irrigation, compared to overhead irrigation (1.085).

Results of this study indicate that potato production can be sustained in the San Luis Valley with about 26 to 32% less irrigation water through the use of drip irrigation system. This technology can improve the production of premium size and quality tubers.