Assessment of a Large Subsurface Controlled Drainage and Irrigation System: I. Design, Soil Properties, and Attendant Crop Performance.

Controlled subsurface drainage irrigation systems have been designed to promote agronomic performance and to limit overland transport of nutrients during high rainfall events. However, drainage systems may promote nutrient transport through the drainage tiles, potentially impacting surface water resources. In this manuscript we describe the design of a 40 ha controlled subsurface drainage irrigation system, describe the soil resource and describe the performance of corn (Zea mays L.) and soybean (Glycine max. L.), with a special focus on nutrient uptake. In companion manuscripts we describe nutrient concentrations from tile drain effluent and note their potential impact on surface water resources. Crop yields approach regional yield thresholds, and the soil water contents were maintained between field capacity and the maximum allowed soil water deficit, thus optimizing crop growth and development. Nitrogen, P, K uptake patterns are described and are demonstrated to be an important reservoir for limiting nutrient leaching.

Key Words:     Drainage, Irrigation, Nutrient Uptake, Corn, Soybeans