Groundwater contribution to irrigated potato production in the Canadian Prairies.

Abstract

Potato is a moisture sensitive crop with soil water deficit/excess causing yield reduction. In Southern Manitoba, potato producers are experiencing wetter and drier conditions within the soil profile during the growing season leading to poor quality and inconsistent yields. The objective of this study was to compare the effect of groundwater contribution under overhead irrigation and no-irrigation treatments; on water availability within the potato root-zone and potato yield in a fine sandy loam soil in Southern Manitoba. Data on precipitation, irrigation depth, soil water content by depth, and potato yield were collected during the 2013 and 2014 growing seasons to assess the impact of groundwater contribution on potato production, water table depth, and volumetric soil water content. Although, the overhead-irrigated plots had a marginally higher yield, the difference was not statistically significant compared to the control in both years. Potato yields from both treatments were significantly negatively correlated with the average groundwater depth. A water balance analysis was conducted within the root-zone during rainy and rain-free periods, which showed that groundwater contribution might have met some of the crop water demand. The deeper the groundwater table the lower the upward flux to the root-zone from the water table which shows that groundwater level had a significant influence on potato yield. High yield even under non-irrigated conditions shows the importance of upward migration of water from the shallow groundwater table. Since upward flux is a major contributor to potato water uptake, the quality of groundwater should be monitored to ensure the quality of potatoes.