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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Research Project #432342
Research Project: Improving the Sustainability of Irrigated Farming Systems in Semi-Arid Regions

Location: Water Management and Systems Research

2022 Annual Report


Accomplishments
1. Developed global-level understanding of crop drought response traits. Through the application of field, greenhouse, and laboratory experiments, ARS scientists in Fort Collins, Colorado, identified key drought response mechanisms (physiological and structural “traits”) in maize, sorghum, and sunflower. This research, conducted in close collaboration with scientists in the United States, France, Australia, India, Mexico, and China, has meaningfully improved our scientific understanding of drought physiology (specifically water-carbon exchange processes), plant growth modeling (during drought), and soil-plant interactions. These traits and their connections represent uniquely coordinated networks that confer improved performance either when water is limiting or when it is non-limiting. These identified trait networks are a blueprint for geneticists and breeders on how whole plants (i.e., not single traits in isolation) could be manipulated to improve performance in contrasting environments. These important advances have produced high-impact publications, numerous invitations to high-profile national and international scientific meetings, and invitations to present research findings at prestigious universities and private labs (e.g., Harvard University). These important contributions, as part of a long-term international effort to improve dryland and irrigated crop production, represent potentially revolutionary advances in crop science and plant breeding.

2. Improved mapping of spatially variable crop water stress and water use with remote sensing. Agricultural water supplies in arid and semi-arid regions in the U.S. are experiencing uncertainty and limitations due to climate variability and extreme drought, wildfires, interstate compacts/agreements, declining aquifers, and water delivery restrictions. These water limitations intensify the need to manage irrigation on an optimized spatial and temporal basis, instead of traditional uniform irrigation practices. While both spatial data and variable-rate irrigation systems exist, there is a large knowledge gap preventing farmers from effectively using the data and technology. ARS scientists in Fort Collins, Colorado, successfully used unmanned aerial vehicle (UAV)-based remote sensing technology to map the spatial variability of crop growth and water stress at a farm scale. The UAV-based remote sensing techniques coupled with multiple imagery sources provide accurate maps of crop water use, representing an important integration of remote sensing and variable-rate irrigation technologies to support the irrigation industry. New remote sensing data and technologies were also harnessed to address farmers’ concerns regarding managing irrigation in response to within-field soil variability. ARS scientists in Fort Collins, Colorado, in collaboration with other ARS units, and universities in the U.S. and China, demonstrated that maize canopy temperature is not only related to crop water stress but more closely to the interaction of water availability and soil characteristics. Also, a remotely sensed soil salinity-related vegetation index and canopy temperature-based stress index enhanced crop yield prediction for water-stressed maize during reproductive and maturation stages. This work bridges the gap between data collection and irrigation decisions with limited water at scales not previously realized. Such technology will be valuable to irrigation system manufacturers, agronomists, and farmers with the need to optimize crop production with limited water.

3. Economic impacts of strategic deficit irrigation on maize grain yield. Globally, almost half (40%) of agricultural production comes from irrigated lands with demands on water availability increasing and many farmers facing limited water for irrigation. There is urgent need to find solutions to avoid global food shortages. ARS scientists in Fort Collins, Colorado, reduced crop water use by 15-17% and maintained yield by applying moderate shortfalls during the crop late-vegetative stage (prior to flowering) followed by near full irrigation for the remainder of the growing season. Furthermore, late-vegetative irrigation shortfalls protected crops from dramatic yield losses in response to late-season water shortfalls, compared to crops that were fully irrigated through much of the season but were water limited at season end. In collaboration with agricultural economists at Colorado State University, we also identified the price of water needed for producers to benefit from intentionally applying less irrigation. Water lease prices in the range identified are beginning to be found in regions with high demands on water. This research provides a cost-effective water management strategy for irrigated maize production in water limited regions. It identified the critical need for late season irrigation for optimal regional management of limited irrigation water; and economic thresholds for policies to balance agricultural and municipal water interests for water conservation districts and policy makers.

4. Discovered potential long-term effects of water limitation on soil function. Water limits crop production in arid and semi-arid regions around the world but also degrades soil health through several interacting processes. While conserving water resources is critical, little was known about how shortfalls in irrigation impacted crop roots and critical soil characteristics. ARS researchers in Fort Collins, Colorado, along with collaborators at Colorado State University assessed the impacts of soil water availability on corn root growth, soil carbon storage, and soil microbial communities across deficit irrigation treatments. When water was limited early in the season, root growth increased deeper in the soil profile and resulted in increased soil organic carbon stores deep in the soil profile. Cumulative years of deficit irrigation reduced microbial biomass, but, importantly, shifted microbial communities to more drought tolerant groups. Limited water availability early in the season had lasting effects, regardless of water availability during the rest of the season, indicating potential impacts beyond the relatively short timeframe during the season that treatments were in effect. This research shows that water availability affects crop root growth and distribution, carbon dynamics, and soil biological activity in critical ways that should be considered alongside potential water savings when setting irrigation management goals. This highly-cited scientific advancement provides valuable considerations for policy formulation (e.g., Natural Resources Conservation Service Farm Bill programs) and management guidelines (e.g., State Extension programs and soil health non-governmental organizations).


Review Publications
Costa-Filho, E., Chávez, J.L., Zhang, H., Andales, A.A. 2021. An optimized surface aerodynamic temperature approach to estimate maize sensible heat flux and evapotranspiration. Agricultural and Forest Meteorology. 311. Article e108683. https://doi.org/10.1016/j.agrformet.2021.108683.
 Zhang, L., Zhang, H., Han, W., Niu, Y., Chávez, J.L., Ma, W. 2022. Effects of image spatial resolution and statistical scale on water stress estimation performance of MGDEXG: A new crop water stress indicator derived from RGB images. Agricultural Water Management. 264. Article e107506. https://doi.org/10.1016/j.agwat.2022.107506.
 Strand, E.J., Bihar, E., Gleason, S.M., Han, S., Schreiber, S.W., Renny, M.N., Malliaras, G.G., McLeod, R.R., Whiting, G.L. 2021. Printed organic electrochemical transistors for detecting nutrients in whole plant sap. Science and Technology of Advanced Materials. 8(4). Article e2100853. https://doi.org/10.1002/aelm.202100853.
 Veettil, A.V., Mishra, A.K., Green, T.R. 2022. Explaining water security indicators using hydrologic and agricultural systems models. Journal of Hydrology. 607. Article e127463. https://doi.org/10.1016/j.jhydrol.2022.127463.
 Flynn, N.E., Stewart, C.E., Comas, L.H., Del Grosso, S.J., Schnarr, C., Schipanski, M., Von Fischer, J.C., Stuchiner, E.R., Fonte, S.J. 2022. Deficit irrigation impacts on greenhouse gas emissions under drip-fertigated maize in the Great Plains of Colorado. Journal of Environmental Quality. 51(5):877-889. https://doi.org/10.1002/jeq2.20353.
 Katimbo, A., Rudnick, D.R., DeJonge, K.C., Lo, T.H., Qiao, X., Franz, T., Nakabuye, H.N., Duan, J. 2022. Crop water stress index computation approaches and their sensitivity to soil water dynamics. Agricultural Water Management. 266. Article e107575. https://doi.org/10.1016/j.agwat.2022.107575.
 Flynn, N.E., Comas, L.H., Stewart, C.E., Fonte, S.J. 2020. Deficit irrigation drives maize root distribution and soil microbial communities with implications for soil carbon dynamics. Soil Science Society of America Journal. 85(2):412-422. https://doi.org/10.1002/saj2.20201.
 Zadworny, M., Comas, L.H., Bagniewska-Zadworna, A. 2021. Root anatomy. New Phytologist. 232(3):1028-1037. https://doi.org/10.1111/nph.17572.
 Mommer, L., Comas, L.H., Weigelt, A. 2021. Root spatial distribution. New Phytologist. 232(3):1017-1021. https://doi.org/10.1111/nph.17572.
 Flaster, D., Gallagher, R., Wenk, E., Wright, I., Indiarto, D., Lawson, J., Allen, S., Gleason, S.M., Blackman, C.J. 2021. AusTraits, a curated plant trait database for the Australian flora. Scientific Data. 8. Article e254. https://doi.org/10.1038/s41597-021-01006-6.
 Trout, T.J., DeJonge, K.C. 2021. Evapotranspiration and water stress coefficient for deficit-irrigated maize. American Society of Civil Engineers Journal of Irrigation and Drainage. 147(10). https://doi.org/10.1061/(ASCE)IR.1943-4774.0001600.
 Niu, Y., Han, W., Zhang, H., Zhang, L., Chen, H. 2021. Estimating fractional vegetation cover of maize under water stress from UAV multispectral imagery using machine learning algorithms. Computers and Electronics in Agriculture. 189. Article e106414. https://doi.org/10.1016/j.compag.2021.106414.
 Zhang, H., Zhang, L., Niu, Y., Han, M., Yemoto, K.K. 2020. Comparison of water stress coefficient using three alternative canopy temperature-based indices. International Journal of Precision Agricultural Aviation (IJPAA). 3(2):28-34. https://doi.org//10.33440/j.ijpaa.20200302.78.
 Hunter, C., Ware, M.A., Gleason, S.M., Pilon-Smits, E., Pilon, M. 2022. Recovery after deficiency: Systemic copper prioritization and partitioning in the leaves and stems of hybrid poplar. Tree Physiology. Article etpac038. https://doi.org/10.1093/treephys/tpac038.
 Gleason, S.M., Barnard, D.M., Green, T.R., Mackay, D.S., Wang, D.R., Ainsworth, E.A., Altenhofen, J., Banks, G.T., Brodribb, T.J., Cochard, H., Comas, L.H., Cooper, M., Creek, D., DeJonge, K.C., Delzon, S., Fritschi, F.B., Hammer, G., Hunter, C., Lombardozzi, D., Messina, C.D., Ocheltree, T., Stevens, B.M., Stewart, J.J., Vadez, V., Wenz, J.A., Wright, I.J., Zhang, H. 2022. Physiological trait networks enhance understanding of crop growth and water use in contrasting environments. Plant, Cell & Environment. 45(9):2554-2572. https://doi.org/10.1111/pce.14382.
 Delfin, E.F., Drobnitch, S.T., Comas, L.H. 2021. Plant strategies for maximizing growth during water stress and subsequent recovery in Solanum melongena L. (eggplant). PLoS ONE. 16(9). Article e0256342. https://doi.org/10.1371/journal.pone.0256342.