To learn more and register email Ogallala Water project manager Amy Kremen

Led by presenters:

Verónica Acosta-Martínez,
Soil Microbiologist/Biochemist, USDA-ARS,
Wind Erosion & Water Conservation
Research Unit,
Cropping Systems Research Laboratory, Lubbock, TX

Rajan Ghimire,
Assistant Professor of Cropping Systems,
New Mexico State University
Dept of Plant and Environmental Sciences,
Agricultural Science Center, Clovis, NM

About this presentation: The goal of the Ogallala Water Coordinated Agricultural Project is to identify best management practices for optimizing water use across the Ogallala Aquifer region (OAR) through multidisciplinary efforts. Our team has been conducting soil health assessments across the OAR to identify the complex interactions of management, soil, and climate that increase the soil microbial component and organic matter pools as indicators of improved essential soil functions related to biogeochemical cycling and soil water dynamics.

During this presentation, we will present on the indicators and methods we are using to provide a soil health assessment within the OAR, focusing in particular on soils in transition from irrigated to dryland production collected from the Southern High Plains states of Texas and New Mexico.

In Texas, we are working with three growers near Littlefield, TX who were provided NRCS funding in 2017 to offset the cost of installing subsurface drip irrigation prior to the 2018 growing season to split their land into center pivot, subsurface drip irrigation, and dryland production to better use water. Each grower site represents a unique scenario on how to best distribute their limited water across their land to maximize production, with cotton being the primary crop, and corn, sorghum, and winter wheat being secondary. Undisturbed land under the Conservation Reserve Program (CRP), considered here to be an ideal soil health system, had 3 times greater microbial community size and 10 times greater levels of a marker for arbuscular mycorrhizae (AMF) compared to the sites under crop production. Soil samples were taken in October 2018 and 2019, and we will sample again in October 2020 to determine if and how management and crop choices help compensate for the transition to dryland production, and how soil health is improved under CRP.

In eastern New Mexico, research plots were established in Fall 2015 with eight cover crop treatments (fallow, pea, oat, canola, and mixtures of pea+oat, pea+canola, pea+oat+canola, pea+oat+canola+barley+hairy vetch+radish) in winter wheat-sorghum rotations with no-tillage management. The response of selected soil health indicators increased with cover cropping. For example, there was greater fungal abundance (12-40%), labile organic matter (17-20%), and AMF abundance (47-49%) under cover crops than under fallow plots in 2018 and 2019. Similarly, integrating livestock with crops increased labile organic matter and resulted in a shift in the microbial community structure.

Our studies show how efforts to improve soil health in hot, dry, semiarid regions of the Southern High Plains are possible with the adoption of management practices that diversify cropping systems and aim to conserve soil and water, and/or involving the integration of livestock with crop production and cover cropping.