Project Number: 3096-13000-010-000-D
Project Type: In-House Appropriated
Start Date: Feb 15, 2022
End Date: Feb 14, 2027
Objective 1: Determine changes in the factors associated with soil health across agroecosystems that are transitioning to dryland agriculture. Our aim is to provide new information on changes of soil organic matter that result in water conservation leading to better soil health-based management decisions. Sub-objective 1A: Validate a method and categorize soil health across a range of management strategies by simultaneous measurements of key enzyme activities affecting soil biochemistry. Sub-objective 1B: Examine effects of diverse management practices on microbial soil health and functions related to soil biogeochemical cycling and organic matter dynamics. Sub-objective 1C: Define and measure soil degradation in various agroecosystems resulting from vegetation change and disturbance and how those factors affect soil crusting, surface erodibility, precipitation capture efficiency, and microbial transport on the fugitive dust. Objective 2: Assess effects of climatic factors on water limited biotic and abiotic agroecosystem characteristics and processes affecting crop, water, and soil health management. Sub-objective 2A: Use crop models to evaluate irrigation strategies that maximize water use efficiency and profits in US Southern High Plains cotton production. Sub-objective 2B: Test whether nighttime CO2 enrichment or high frequency, short-term pulses of CO2 affect plant growth, leaf area or crop water use. Sub-objective 2C: Define and inspect the theoretical dryland crop production limits achieved by soil management. Sub-objective 2D: Model conservation agriculture (CA) effects on US Southern High Plains dryland cotton production. Objective 3: Fundamental investigations of the quality and quantity of various sources of water for agricultural production in the Southern High Plains including groundwater, surface water, and rainwater. Sub-objective 3A: Develop a method for assessing the value of rainfall, groundwater, and surface water for agricultural uses based upon water chemistry. Sub-objective 3B: Assess the effects of salty irrigation water on soil surface crusting, erodibility, and soluble dust emissions.
The challenges that confront Southern High Plains (SHP) agricultural producers are associated with the rapid decline of the Ogallala Aquifer (OA) water table and intermittent rainfall that often is less than the amount required to sustain crop production. The water table’s decline combined with the region’s semi-arid climate is driving a transition from partially irrigated to almost entirely dryland agricultural production. In both marginally irrigated and dryland systems crop management will shift towards optimizing the remaining irrigation resources and adopting innovative crop and soil management approaches. The problems confronting SHP producers during this transition will require solutions that are specific to semi-arid agriculture, minimize risk, and support economic and environmental sustainability. In addition to identifying solutions appropriate for current climate conditions, management decisions will also depend on new knowledge of soil and crop interactions in an evolving CO2 environment. Thus, our project addresses climate factors associated with current highly variable SHP precipitation patterns and rising CO2 levels. Our research will quantify and provide a better understanding of the impacts of soil degradation, climate uncertainty, and changing water availability and quality in semi-arid agriculture. Specifically, we will: 1) develop and validate methods for soil health metrics and use them to evaluate management practices that promote water conservation; 2) account for climate variability when evaluating management practices that affect crop yield, water use and soil health; and 3) develop a method for evaluating water quality of the various sources of water used for production and increase understanding of soil salinity effects on surface crusting, erodibility, and hygroscopic dust emissions emanating from such surfaces. Our results will provide the knowledge needed to sustain agricultural production during the transition to dryland systems in the SHP and in other semi-arid production regions.