Converting Marginal Sands into Sustainable Agricultural Production and Ecosystem Services.

Water deficits are key factors restraining crop yield and quality, exacerbated by the changing climate in many regions of the world. Frequent water limitations to plants in humid regions comprise one of the greatest abiotic deterrents to achieving maximum genetic potential of crop yield. Drought conditions can no-longer be viewed solely as a biophysical phenomenon addressed only by breeding drought-resistance cultivars or management practices requiring often very tardy supplemental irrigation. Additionally, since the majority of highly productive soils are currently farmed, innovative hydropedological approaches are needed to convert large tracts of highly permeable sandy soils into long-term sustainable agriculture production. Current projections of localized droughts combined with reductions in stored surface water and receding groundwater levels demand new water storage technologies for improving water use efficiency. A Soil Water Retention Technology (SWRT) was developed at Michigan State University which includes installing engineered subsurface water retention membranes into sandy soils which double soil water holding capacities in plant root zones. Greater quantities of plant available water and nutrients in the root zones provide plant resilience to drought resulting in maize production of 325 bushels (17.5 MT/ha) of grain. Enhanced irrigation water use efficiency produces higher biomass for soil carbon sequestration and renewable cellulosic biofuels. Greater retention of water reduces irrigation energy and CO2. Greater retention of N and K nutrients in the root zone reduces deep leaching and groundwater contamination. Therefore, SWRT membranes have the potential to alleviate plant droughts, improve cropping systems resilience to climate change and offer significant numbers of ecosystem services to communities where sandy soils have been converted to sustainable agricultural production.