Sustainable High Yields on Poorly Drained Soils For presentation: Water for Food Conference Lincoln, Nebraska May 1-3, 2011 R. Wayne Skaggs

Drainage in United States (Million Ha) Total Cropland 170 Cropland Requiring Drainage 43 (25%)

Cropland Needing Drainage500 Million Ha (33% of Total Cropland) DRAINAGE WORLD-WIDE (Smedema et al. 2004)

Million Ha All Cropland500 (33%) Irrigated Cropland150 (55%) Rainfed Cropland350(28%) CROPLAND NEEDING DRAINAGE (Smedema et al. 2004)

Avg. annual nitrogen yield Mississippi River of streams for Drainage Basin Hypoxic Zone

Nitrogen Losses in Drainage Water Increase with Intensity of Subsurface Drainage

Natural Slow Dr. ModerateIntensive Total Nitrogen (kg/ha/yr) TOTAL NITROGEN

DWM Structures for Subsurface Drains

Potential Effect of DWM in the Midwest on N Load to Gulf of Mexico 50,000 ton N per Year Based on 8.3 million Ac of drained corn and soybean land in the states of Iowa, Indiana, Illinois, Ohio and Minnesota (Jaynes et al., 2008) NRCS recently (March, 2011) announced a major initiative to promote DWM and related practices in the upper Midwest to reduce N losses to the Mississippi River and Gulf of Mexico.

A grosphere AMPLIFY is a initiative enabling public and private sector scientists to partner with producers to achieve high yield in an environmentally and economically sustainable manner. A MPLIFY Modelingfor ProducingLargeIncreases inFoodYield

Potential to Increase Sustainable Yields on Drained Soils in Humid regions

23%

Hypothesis Drought stresses can be substantially reduced and yields increased by increasing root depths in poorly drained soils in humid regions

Methods to Increase Root Depth Increase pH to > 5.5 to depths of > 60 cm Incorporate Organic Matter Genetic Manipulation