Research > Geospatial Hydrology

Summary

Recent News from the Lab

The ever-increasing pressure for land and water resources requires their efficient use to meet various agricultural and non-agricultural needs. The overall goal of the Geospatial Hydrology research program is to develop and evaluate climate-resilient, regenerative agricultural strategies for conserving soil and water, enhancing crop water productivity, and protecting soil and water quality in diverse agroecosystems. We accomplish this goal by using hydrologic, ecosystem, and crop growth models and data analysis approaches.

Major focus areas of our research program, in crop and rangeland settings, include:

  1. Assessing hydrologic and environmental impacts of changes in land use and management
  2. Improving crop water use efficiency and development of irrigation decision support tools
  3. Assessing climate change impacts on crop production and evaluation of adaptation strategies
  4. Improving soil health and enhancing ecosystem services
  5. Characterization of groundwater quantity and quality

Current Research Projects

Assessing grazing management impacts on hydrology, and soil and water quality at the ranch and watershed scales

Both rural and urban populations depend on ecosystem services provided by rangelands. Ecosystem services can include maintaining stable and productive soils, delivering clean water, and sustaining plants, animals and other organisms that support livelihoods and human aesthetic and cultural values. It is therefore important for ranch/land managers to adopt management practices that maintain or restore soil and ecosystem health and resilience. Grazing management practices have a significant influence on water catchment functions and soil health.

The overall goal of this project is to assess the ranch and watershed scale impacts of traditional continuous grazing and alternate adaptive multi-paddock grazing practices on key ecosystem services provided by rangelands, and suggest best grazing management practices using the SWAT and APEX models. The specific objectives are to:

  1. Evaluate the impacts of light and heavy continuous, and adaptive multi-paddock grazing management practices on water storage, water erosion, water quality, nutrient retention, soil carbon sequestration and downstream flooding risk in selected watersheds in the Southern and Northern Great Plains.
  2. Assess the impacts of climate variability and change on water catchment functions, sediment and nutrient losses, and streamflow characteristics under different grazing management practices, and suggest potential climate change adaptation/mitigation strategies.

Study Results

Results from the Clear Creek watershed (71% rangelands) study in north central Texas indicated that the simulated annual surface runoff, and sediment and nutrient losses reduced by about 31%-40% under the adaptive multi-paddock grazing when compared to traditional heavy continuous grazing. Adaptive MP grazing has also reduced the simulated highest annual streamflow by 25% and hence demonstrated the potential to reduce the risk of flooding downstream.

Results from the Apple watershed study in North Dakota and the Lower Prairie Dog Town Fork Red watershed in northwest Texas are curerntly being analyzed to assess the impacts of grazing management on hydrology, water quality and soil carbon sequestration.

Development and evaluation of efficient irrigation and crop management strategies for crop production under current and future climatic conditions

Agriculture in the semi-arid Texas High Plans and Rolling Plains region is facing many challenges from rapid declines in groundwater levels, recurring droughts in the recent times, and projected warmer and drier summers in the future. We use the DSSAT Cropping System Model to develop and evaluate environmentally and economically sustainable cropping systems and production practices for the region under the current and future climate change scenarios.

The specific objectives of this study are to:

  1. Develop and evaluate efficient irrigation and crop management strategies for crop production, and formulate decision support tools using the evaluated crop modules. Some examples include:
    • Determine the optimum periods for terminating irrigation for cotton in the Texas High Plains.
    • Evaluate efficient crop-growth-stage-based deficit irrigation strategies for cotton and grain sorghum production in the Texas High Plains.
    • Evaluate the feasibility of growing winter wheat cover crop in cotton production systems of the Texas High Plains and Rolling Plains and determine optimum cover crop termination dates.
  2. Development and evaluation of a novel sensor- and crop-model based decision support tool for efficient irrigation management
  3. Assess potential yield increases through management of soil hydrologic processes in semi-arid dryland agricultural systems
  4. Assess the impacts of historic and future climate variability and change on crop production, water use and soil carbon sequestration, and suggest climate change mitigation/adaptation strategies.

Study Results

  • The first and second weeks of September (118 and 125 days after planting, respectively) were identified as ideal irrigation termination periods for cotton under full and deficit irrigation, respectively, in normal-rainfall years. Compared to normal years, ideal irrigation termination periods were found to be a week earlier in wet years and a week later in dry years.
  • Cotton peak bloom growth stage was found to be the most sensitive stage to water stress. In contrast, water stress during early growth stages of germination, seedling emergence and squaring, and final growth stages of cutout, late bloom and boll opening had little effect on seed cotton yield. In case of grain sorghum, irrigating during the early reproductive stages resulted in the most efficient use of limited water.
  • The 20% irrigation deficit strategy was found to be an ideal irrigation strategy for grain sorghum production in the Texas High Plains under both current and future climatic conditions. This strategy resulted in a substantially higher water use efficiency than full irrigation with only a minor (<11%) yield loss.
  • Among eight grain sorghum virtual cultivars simulated for climate change adaptation, an ideotype with high yield potential trait (10 % higher partitioning to the panicle, radiation use efficiency, and relative leaf size than the reference cultivar) resulted in maximum grain sorghum yield gains in the future under both irrigated (6.9%–17.1% increase) and dryland (7.5%–17.1% increase) conditions, when compared to the reference cultivar. Enhancing drought tolerance by increasing root density at different soil depths also resulted in a significantly higher irrigated grain sorghum yield than the reference cultivar. A longer maturity cultivar will likely increase irrigation water use and, therefore, is not recommended for water limited conditions.
  • A novel sensor- and crop-model based irrigation management decision support mobile app, idCROP (irrigation decision support system for Conserving Resources and Optimizing Crop Production) is currently being developed. This cutting-edge real-time crop irrigation scheduling tool uses historic and short-term forecasted weather data, in conjunction with crop management information provided by the user, to suggest efficient irrigation strategies, so users can choose a strategy that best fits their well capacity and yield/economic goals.

Assessing the impacts of biofuel-induced land use change on watershed hydrology and water quality

The increasing demand for land for biofuel production in the U.S. has led to increased competition for productive agricultural land, shifts in land use among different crops, and conversion of land from other uses into biofuel production. About half of the targeted second-generation biofuels for 2022 is identified to be produced in the Southeastern Region of the U.S, which includes several states traditionally in the U.S. Cotton Belt. USDA estimates that approximately 11.4% of existing croplands and pastures in this region will be required for second-generation biofuel production. The overall goal of this study is to assess the hydrologic and water quality impacts associated with the change in agricultural land use to biofuels-dominated cropping systems in the semi-arid Southwestern U.S. Cotton Belt region using the SWAT, APEX and Integrated SWAT-APEX models. The specific objectives are to:

  1. Assess the impacts of potential land use change from cotton to cellulosic bioenergy crops such as Alamo switchgrass, Miscanthus, big bluestem and biomass sorghum on water balances and water quality at the landscape and watershed scales.
  2. Study the effects of historic and future climate variability on water balances, sediment and nutrient loads, and crop yields under baseline and biofuel-induced land use change scenarios.

Study Results

Results from the Double Mountain Fork Brazos watershed in the Southern High Plains of Texas indicated that Miscanthus and switchgrass would serve as ideal bioenergy crops for the dryland and irrigated systems, respectively. This is due to their higher water use efficiency, better water conservation and water quality improvement effects, greater biomass and biofuel production potential, and minimum crop management requirements.

Replacing cotton with perennial grasses (switchgrass in irrigated areas and Miscanthus in drylands) decreased simulated annual surface runoff, total nitrogen load through surface runoff and nitrate leaching to groundwater by 88%, 86% and 100%, respectively and increased percolation by 28%. The climate change analysis indicated that the simulated annual irrigation water use and total nitrogen load under the future perennial grass land uses would reduce by 60% and 30%, respectively, when compared to future cotton land use.

Assessment of spatio-temporal variability of groundwater quality and availability in Texas

Texas is largely dependent upon groundwater resources. About 59% of state’s total water supply and about 99% of the rural household needs are met from the groundwater extracted from 9 major and 21 minor aquifers of the state. Future projections, however, indicate about 30% reduction in water availability over the next few decades due to adverse climatic conditions and depletion of major aquifers. Numerous studies have documented groundwater quality degradation in several parts of the state, which threatens community welfare and sustainable development.

In the face of snowballing crises of water availability and water quality deterioration, the overall objective of this study is to identify long-term spatio-temporal trends in groundwater levels and groundwater quality across the state and unravel the nexus between the two.

We integrate different geochemical, graphical, and statistical techniques within a geospatial environment to seek answers to questions such as:

  1. Where are the hotspots of groundwater contamination and groundwater level declines?
  2. Is groundwater contamination a manifestation of changes in groundwater levels?
  3. What are the potential causes of groundwater contamination and groundwater level declines?
  4. What are the effects of different agricultural and land management practices on groundwater quality and availability?
  5. What are the best management practices for conserving groundwater resources and protecting water quality?

Study Results

Our long-term assessment of groundwater quality (nitrates, fluoride and salinity) in several major and minor aquifers of Texas has provided more insights into various factors that affected groundwater quality and led to identification of groundwater quality degradation hotspots. We have also delineated spatially associated zones of groundwater level declines in Texas, and identified hotspots that warrant implementation of appropriate management strategies. The state-wide decadal median groundwater levels in Texas were found to decline from about 14 m from land surface in the 1930s to about 36 m in the 2000s. Groundwater level declines across the state, however, mostly followed logarithmic trends marked by levelling-off phenomena in recent times due to implementation of conservation measures and regulatory strategies.

Quantification of improvements in ecosystem services from adoption of soil health promoting practices

Maintenance of healthy soil ecosystems is a key for ensuring water, food and energy security for current and future generations. The health of soils is determined by the ecosystem services they provide on the farm/ranch, across the watershed and downstream of the watershed, which include harvestable phytomass, soil carbon sequestration, rainfall infiltration and retention, soil fertility, plant nutrient acquisition and nutrient cycling, and disease resistance. Practices such as conservation/no-tillage and cover crops reduce soil erosion, add organic matter to soil, increase infiltration and soil water holding capacity, increase nutrient retention, reduce leaching, break pest cycles, provide resources for beneficial insects, and thereby improve soil health.

The overall goal of this project is to simulate field- and watershed-scale improvements to ecosystem services (e.g. reduction in peak flows, which influence the chances of occurrence of floods; reduction in runoff/sediment/nutrient losses; increase in soil water storage, plant available water, and nutrient retention) due to long-term adoption of soil health promoting practices in the lower and middle Brazos River Basin in Texas.

Enhancing soil ecosystem health and resilience through pasture cropping

Pasture cropping is a farmer-initiated, relatively new, and innovative land management system that integrates direct seeding of annual crops into dormant perennial grasses. Although the U.S. Southern Great Plains region provides an excellent platform for this regenerative approach that originated in Australia, studies evaluating soil health benefits of pasture cropping are lacking.

The overarching goal of this study is to evaluate improvements in soil-dependent ecosystem services when grasslands are pasture cropped. We have initiated pasture cropping field experiments at the Pittman Ranch near Muenster, TX and the Nance Ranch near Canyon, TX. We will evaluate soil ecosystem service benefits of pasture cropping at the ranch- and watershed-scales using the APEX model and we will analyze short- and long-term profitability implications of pasture cropping in comparison to conventional practices. Our study will provide first quantitative measures in the US regarding the effects of pasture cropping on soil health and profitability of perennial grasslands and changes in on- and off-site ecosystem services. Other potential outcome is enhanced rancher awareness about the soil health and climate change mitigation effects of pasture cropping.

Dr. Srinivasulu Ale

Photo of Srinivasulu Ale

Associate Professor and Geospatial Hydrologist at the Texas A&M AgriLife Research Center at Vernon.

He has extensive research experience in hydrologic, water quality and crop growth modeling, and he has lead or contributed to various research projects in the USA, India, and the Netherlands.

Download CV

Team Members

  • Dr. Jasdeep Singh, Postdoctoral Research Associate
  • Dr. Arun Bawa, Postdoctoral Research Associate
  • Ms. Qiong Su, Ph.D. Candidate, Water Management and Hydrologic Sciences (WMHS) Program, TAMU, College Station (co-advised by Dr. Vijay Singh and Dr. Srinivasulu Ale).
  • Mr. Sayantan Samanta, Ph.D. Candidate, WMHS Program, TAMU, College Station (co-advised by Dr. Srinivasulu Ale and Dr. Cristine Morgan).
  • Mr. Rene Francis Simbi Mvuyekure, M.S. Student, WMHS Program, TAMU, College Station (co-advised by Dr. Srinivasulu Ale and Dr. Vijay Singh).
  • Mr. Montana Caise, M.Eng. student, Dept. of Biological & Agricultural Engineering (BAEN), TAMU, College Station (co-advised by Dr. Srinivasulu Ale and Dr. Salvatore Calabrese).

Publications

Please refer to my homepage on Google Scholar or Research Gate for a complete list of publications.

[1Post-Doc supervisee; 2Graduate Student advisee (Chair/Co-Chair); 3Graduate Student advisee (Committee member)]

  1. Himanshu1, S.K., S. Ale, J.P. Bordovsky, J. Kim1, S. Samanta2, N. Omani1, and E.M. Barnes. 2021. Assessing the impacts of irrigation termination periods on cotton productivity under strategic deficit irrigation regimes. Scientific Reports. 11, 20102 (2021)
  2. Ale, S., S.K. Himanshu1, S.A. Mauget, D. Hudson, T.S. Goebel, B. Liu, R.L. Baumhardt, J.P. Bordovsky, D.K. Brauer, R.J. Lascano, and D. Gitz III. 2021. Simulated dryland cotton yield response to selected scenario factors associated with soil health. Frontiers in Sustainable Food Systems. Vol. 4, 617509
  3. Kothari2, K., S. Ale, J.P. Bordovsky, C.L. Munster, V.P. Singh, J. Nielsen-Gammon, G. Hoogenboom. 2021. Potential genotype-based climate change adaptation strategies for sustaining cotton production in the Texas High Plains: A simulation study. Field Crops Research. Vol. 271, 108261.
  4. Himanshu1, S.K., Y. Fan, S. Ale, and J.P. Bordovsky. 2021. Simulated efficient crop-growth-stage-based deficit irrigation strategies for maximizing cotton yield, crop water productivity and net returnsAgricultural Water Management. Vol. 250, 106840
  5. Ale, S., D. R. Harmel, A.P. Nejadhashemi, K. DeJonge, S. Irmak, I. Chaubey, K.R. Douglas-Mankin. 2020. Global water security: Current research and priorities for action. Transactions of the ASABE. 63(1): 49-55.
  6. Ale, S., N. Omani1, S.K. Himanshu1, J.P. Bordovsky, K.R. Thorp, and E.M. Barnes. 2020. Determining optimum irrigation termination periods for cotton production in the Texas High Plains. Transactions of the ASABE Special collection on Global Water Security. 63(1): 105-115. [Invited Paper]
  7. Kothari2, K., Ale, J. Bordovsky, K. Thorp, D. Porter, C. Munster, and G. Hoogenboom. 2020. Potential benefits of genotype-based adaptation strategies for grain sorghum production in the Texas High Plains under climate change. European Journal of Agronomy. Vol. 117, 126037.
  8. Harmel, R.D., I. Chaubey, Ale, A.P. Nejadhashemi, S. Irmak, K. DeJonge, S. Evett, E.M. Barnes, M. Catley-Carlson, S. Hunt, and I. Mani. 2020. Perspectives on Global Water Security. Transactions of the ASABE Special collection on Global Water Security. 63(1): 69-80. [Invited Paper]
  9. Kothari2, K., Ale, J.P. Bordovsky, and C.L. Munster. 2020. Assessing the climate change impacts on grain sorghum yield and irrigation water use under full and deficit irrigation strategies. Transactions of the ASABE Special collection on Global Water Security. 63(1): 81-94. [Received 2021 ASABE Superior Paper Award]
  10. Himanshu1, S.K., Ale, J.P. Bordovsky, and M. Darapuneni. 2019. Evaluation of crop-growth-stage-based deficit irrigation strategies for cotton production in the Southern High Plains. Agricultural Water Management Special Issue on “Managing the Ogallala”. Vol. 225, 105782.
  11. Kothari2, K., Ale, J. Bordovsky, K. Thorp, D. Porter, and C. Munster. 2019. Simulation of efficient irrigation management strategies for grain sorghum production over different climate variability classes. Agricultural Systems. 170: 49-62.
  12. Chen2, Y., Ale, and N. Rajan. 2018. Implications of Biofuel-Induced Changes in Land Use and Crop Management on Sustainability of Agriculture in the Texas High Plains. Biomass and Bioenergy. 111: 13-21.
  13. Adhikari1, P., N. Omani1, Ale, P.B. DeLaune, K. R. Thorp, E.M. Barnes, and G. Hoogenboom. 2017. Simulated effects of winter wheat cover crop on cotton production systems of the Texas Rolling Plains. Transactions of ASABE Special collection on Crop Modeling Applications in Agricultural Water Management. 60(6): 2083-2096.
  14. Chen2, Y., Ale, N. Rajan, and C.L. Munster. 2017. Assessing the hydrologic and water quality impacts of biofuel-induced changes in land use and management. Global Change Biology – Bioenergy. 9(9): 1461-1475.
  15. Park1, J., Ale, W.R. Teague, and J. Jeong. 2017. Evaluating the ranch and watershed scale impacts of using traditional and adaptive multi-paddock grazing on runoff, sediment, and nutrient losses in North Texas. Agriculture, Ecosystems and Environment. 240: 32-44.
  16. Park1, J., Ale, W.R. Teague, and S.L. Dowhower. 2017. Simulating hydrologic responses to alternate grazing management practices at the ranch and watershed scales. Journal of Soil and Water Conservation. 72(2): 102-121.
  17. Modala2, N.R., Ale, D. Goldberg, M. Olivares, C. Munster, N. Rajan and R. Feagin. 2017. Climate change projections for the Texas High Plains and Rolling Plains. Theoretical and Applied Climatology. 129(1): 263-280.
  18. Chaudhuri1, S. and Ale, 2014. Long-term (1930-2010) trends in groundwater levels in Texas: Influences of soils, landcover and water use. Science of the Total Environment. 490: 379-390.
  19. Chaudhuri1, S. and S. Ale, 2014. Lon-term (1960-2010) trends in groundwater contamination and salinization in the Ogallala aquifer in Texas, USA. Journal of Hydrology. 513: 376-390.

Grants

Current Grants

  1. Lewis, K., Berthold, T., Wagner, K., Bell, J., DeLaune, P.B., McCallister, D.M., Ale, S., Mirchi, A., Rocateli, A., McCarl., A., Bagnall, D., Keeling, W., Smith, G., Roquette, M., Smith, J., Gentry, T., Sharma, S., Wyatt, B., Gregory, L., Warren, J., Kimura, E., Maeda, M., Jilling, A., Byrd, S., Pinchak, W., Guerrero, B., Keeling, W.,  and Dunn, C.. Sustainable agricultural intensification and enhancement through the utilization of regenerative agricultural management practices. USDA-NIFA Sustainable Agricultural Systems (SAS) program. $9,999,947 (2021-2026).
  2. Ale, S., Teague, W.R., DeLaune, P.B., Wang, T., and Steffens, T. Enhancing soil ecosystem health and resilience through pasture cropping. USDA-NIFA Foundational Program. $499,992 (2021-2024).
  3. Ale, S., Himanshu, S.K., Bell, J., Fan, Y., Bordovsky, J., and Gitz, D. Evaluation of efficient crop-growth-stage-based deficit irrigation strategies for cotton and grain sorghum production in the Texas High Plains. USDA-ARS Ogallala Aquifer Program, $35,000 (2020-2022).
  4. Ale, S., Adams, C., Biggers, K., Wall, J., Kimura, E., and Fan, Y. Development and evaluation of a novel sensor- and crop-model based decision support tool for efficient irrigation management. Texas A&M Water Initiative. $276,474 (2020-2021).
  5. Swanson, C., Stoleru, R., Fipps, G., and Ale, S. Creation of an AI-powered next generation home irrigation controller. Texas A&M Water Initiative. $318,284 (2020-2021).
  6. Ale, S., DeLaune, P.B., and Himanshu, S.K. Evaluation of soil health benefits of cover crops in cotton production systems of the Texas Rolling Plains. Cotton Incorporated. $40,000 (2020-2021).
  7. Gopal Naik, M., Ale, S., Gupta, H., Jaber, F., Lai, J.S., and Huang, J.C. Planning and development of climate resilient water sensitive urban designs: A case study of Hyderabad Metropolitan City. Scheme for Promotion of Academic and Research Collaboration (SPARC), A Government of India Initiative, INR 7,700,000 (2019-2022).
  8. Morgan, C.L.S., Woodward, R., McIntosh, W.A., and Ale, S. Actionable links between soil function, ecosystem services, and stakeholder perceptions to overcome barriers to improved soil management. USDA-NIFA Foundational Program, $496,000 (2018-2022).
  9. Adams, C., Trostle, C., Ale, S., DeLaune, P., Park, S., Hoogenboom, G., and Boote, K. Enhancing ecosystem services through integration of guar into wheat cropping systems of the Southern Great Plains. USDA-NIFA Foundational Program, $445,000 (2018-2022).
  10. Gitz, D., Hudson, D., Ale, S., Mauget, S., Lascano, R., and Goebel, T. Assessment of potential yield increases and economic risk avoidance through management of soil hydrologic processes in semi-arid rain fed systems. USDA-ARS Ogallala Aquifer Program, $110,822 (2018-2022).
  11. Wang, T., Feng, H., Hennessy, D.A., Ale, S., and Park, J. Saving grassland of the Great Plains: Is management intensive grazing (MIG) a socioeconomically viable option? USDA-NIFA Foundational Program, $499,985 (2017-2022).