Research > Cropping Systems and Physiology


In the Cropping Systems and Physiology program at Texas A&M AgriLife Research in Vernon, we are focused on making advancements in agriculture that results in higher crop profitability, reduced environmental impact, and resource security.

We study crops at the systems level to understand how they interact with environmental and management factors over the course of time. We study the physiology of crop plants, at the whole-plant level, to better understand their functional traits in the context of stress and under varied management.

Topics of interest:

  • Root system biology
  • Nitrogen fertility
  • Crop stress responses
  • Cropping system diversity and sustainability

Focus crops include food, fiber, and other bio-based product crops.

Grain Legumes (Pulses): Cropping Systems and Nitrogen Fixation

Grain legumes, also known as pulses, are grown for their seeds and often as green manure. Legume seeds can be produced for food and feed, with generally high nutritional value, and some are produced for their industrial uses. A unique and valuable aspect of legumes is their ability to associate with soil bacteria to “fix” atmospheric nitrogen. The process of fixing nitrogen makes atmospheric nitrogen available to the legume as fertilizer and enriches soil fertility.

Guar is one important legume crop in the Southern Great Plains region, though it has received relatively little research attention. The plant produces a seed containing viscous galactomannan gum, which is used in a variety of food and industrial applications as a lubricant, binder, thickener, and hardener. Guar is extremely drought and heat tolerant, requires few inputs, and considered beneficial in semi-arid cropping systems. We are engaged in USDA-NIFA-funded research focused on integrating guar into regional cropping systems, including collaboration to develop an original DSSAT model for guar and understanding soil nitrogen dynamics in integrated systems.

We are also working to understand developmental, environmental, and management factors that impact nitrogen fixation in guar and other regionally important grain legumes. This is important work, because producers and scientists are unsure about efficiency of legume nitrogen fixation in semi-arid regions and little is known about how to manage for it.

These research projects are expected to promote pulse production and growth of pulse industries in this region, and to generate information that will expand nitrogen fixation in cropping systems in semi-arid regions.

Organic Wheat Cropping Systems

Organic agriculture is nearly absent in the Southern Great Plains region of Texas, despite large demand for organic products that could be produced in the area. The region is nationally recognized for its grain-only and dual-purpose (pasture- and grain-producing) wheat cropping systems. We are conducting collaborative research, funded by the USDA-NIFA Organic Transitions program, to introduce regional producers to organic production in these systems, focused on expanding economic, health, and environmental opportunities in the region.

In our research project, we are utilizing a systems approach to directly compare conventional grain-only and dual-purpose wheat cropping systems to transitional organic systems with management practices customized for the region. The research is occurring at the West Walker Ranch south of Vernon, TX at a large field scale of about 100 acres. Through our project activities we will develop and validate management practices for organic production of wheat and beef; compare the economics, soil health, and productivity of conventional and organic systems; and provide extension outreach and education.

Crop Stress Physiology and Phenotyping

A tremendous amount of cotton is produced in Texas, much of it irrigated with increasingly scarce irrigation water resources and the remainder grown in stressful dryland conditions. We are invested in efforts to improve physiological knowledge and selection of cotton varieties that use water more productively. We are engaged in a collaborative, state-wide effort funded by Cotton Inc. to develop an effective ground-based high-throughput phenotyping system that utilizes rapid sensor measurements for identification of superior cotton germplasm. We are also running pilot studies to explore the responses of the cotton root system, in terms of physical and hydraulic characteristics, to irrigation and other management factors.

We are working to better understand stress physiology in wheat, especially responses to drought. Wheat is among the top-consumed agricultural products in the world, but scientific progress in improving wheat yields has stalled in recent years. This may be partially attributed to lack of knowledge of the physiological mechanisms contributing to yield, especially in stressful growing conditions, and poor management practices. In our collaborative research, which is funded by the Texas Wheat Producers Board, we investigate season-long associations among crop development, growth, photosynthesis, senescence, and yield. We are working to identify trait combinations that will allow continued progress in improving wheat yields. We are also researching the use of enhanced-efficiency fertilizers in wheat nitrogen management.

Curtis Adams

Photo of Curtis Adams

Assistant Professor

Curriculum Vitae

Team Members

Gordon Raymos, Research Technician

Philip Hinson, Graduate Research Assistant

Rajan Shrestha, Graduate Research Assistant

Jennifer MacMillan, Graduate Research Assistant


Adams, C., S. Thapa, E. Kimura. 2019. Determination of a plant population density threshold for optimizing cotton lint yield: A synthesis. Field Crops Research 230:11-16.

Thapa, S., C. Adams, C. Trostle. 2018. Root nodulation in guar: Effects of soil, Rhizobium inoculants, and guar varieties in a controlled environment. Industrial Crops and Products 120:198-202.

Adams, C., S. Thapa, Y. Fan, S. Park. 2018. Agronomic and economic effects of two enhanced-efficiency urea fertilizer technologies on Southern Great Plains winter wheat. Agronomy Journal 110:1-6.

Liang, Xi, Y. Liu, J. Chen, C. Adams. 2018. Late-season photosynthetic rate and senescence were associated with grain yield in winter wheat of diverse origins. Journal of Agronomy and Crop Science. 204:1-12.

Adams, C., J. Erickson. 2017. Yield enhancement by short-term imposition of severe water deficit in the vegetative growth stage of grain sorghum. Journal of Agronomy and Crop Science 203:307-314.

Adams, C., J. Frantz, B. Bugbee. 2013. Macro- and micronutrient-release characteristics of three polymer-coated fertilizers: Theory and measurements. Journal of Plant Nutrition and Soil Science 176:76-88.