Sanjay Shukla is an associate professor in the Agricultural and Biological Engineering Department working at IFAS's Southwest Florida Research and Education Center in Immokalee, Florida. Shukla's primary interest is water quality and supply issues, and his location in Immokalee puts him in the center of one of the most delicately balanced environments of the country, South Florida. This is a large area of extensive agricultural operations that coexist with environmentally unique and sensitive regions, and at its edges are Florida's densely populated coasts and I-4 corridor. At the center of the region is the Southeast's largest freshwater lake, Lake Okeechobee. Shukla's many projects look at managing water and nutrient discharges from the agricultural and ranching operations in terms of how to conserve water and reduce the nutrient loads to the Northern Everglades region that contain the Lake Okeechobee and the Everglades.
To understand Shukla's work, it is necessary to understand the natural system he is working with. Northern Everglades region of South Florida is a large watershed that encompasses Lake Okeechobee in the north and the Everglades in the south. Water from much of the land south of Orlando flows down to the lake. Originally, water from the lake was carried south in a wide shallow swath to Florida Bay. Water also moves from this area to the west coast of Florida through Caloosahatchee River, where it mixes with salt water in coastal estuaries.
In the 1920s, a levee was built around Lake Okeechobee as a flood control measure, and subsequent drainage of the area through a series of canals reduced the area of the Everglades by over 50% to make more land available for agricultural and urban development. And South Florida is ideal for agriculture. With its shallow water table and year-round warm weather, a wide variety of crops are grown in the area. Major land uses in the area include sugarcane, citrus, vegetables crops, and beef cattle ranches.
The high demands on South Florida's available water, the re-engineering of the region on massive scale, and the high levels of nutrients flowing into the system have contributed to a gradual environmental degradation of the region. Too much and too little summarize south Florida woes. The region experiences water extremes caused by periodic droughts and tropical storms/hurricanes. These extremes combined with massive drainage of the region have forced a re-examination of every aspect of management in the region. Wetlands like the Everglades were once considered useless, but now, their critical role in the health of the regional ecology is better understood. Restoration of the Everglades is a key to the long-term sustainability of the area, and a large-scale effort is underway, but under any scenario, natural and human uses of South Florida will have to coexist.
Shukla's research plays a vital role in finding a sustainable path for this coexistence. The key issue that Shukla must address is the nutrients, nitrogen (N) and phosphorus (P), that are collected from agricultural lands by rain and irrigation water and carried throughout the watershed. These elements are essential plant nutrients, and as fertilizers, are important to local farming. They are also introduced by the animal wastes produced on South Florida's extensive ranch lands.
Shukla explains that excess N and P that run off into local waters often impact local ecologies by promoting the growth of algae that rob the water of oxygen, resulting in ecological damage to water bodies. The repercussions are felt throughout the ecosystem. Only through a concerted effort on the part of government agencies, agricultural producers, and researchers has the condition of the Lake Okeechobee and other linked waterbodies such as the Caloosahatchee River been improved.
An important way of reducing N and P discharges is through a program called Best Management Practices, or BMPs. These are practical, science-based recommendations that agricultural producers can use to minimize the loss of agricultural chemicals by managing the water and fertilizers inputs as well as managing their discharge to the environment. The water management practices include both irrigation and drainage. Irrigation management involves applying the right amount of water while the drainage management involves careful pumping and storage to avoid flooding of the farm. Nutrient management strategies involve using the right amount that is needed by the crops. BMPs have also been developed for ranchers to retain water and nutrient on ranchlands through practices such as installing culverts to reduce the flows and hydrate the wetlands and ditch fencing to reduce the animal waste discharges. Shukla is working on a long-term evaluation of the effectiveness of BMPs on Florida's cattle ranches. Shukla has paid special attention to fencing BMP and a BMP involving increasing the on-ranch storage by storing water in the ditches and isolated wetlands. Wetlands slow down the movement of nutrient laden water on its way to water bodies, and they are rich with plant life which can use up excess nutrients. The study indicates that these methods can reduce P discharges, and study continues in order to understand how these recommendations work in different settings. A key to the effectiveness of BMPs is that they are matched to individual situations rather than taking a "one size fits all" approach.
Shukla is excited about what he describes as a novel approach to ecosystem restoration through a program called Payment for Ecosystem (or Environmental) Services, PES. Shukla’s research is contributing to a program called Florida Ranchland Environmental Services Program (FRESP), a joint effort of World Wildlife Fund (WWF), state agencies, Ranchers, and UF/IFAS. This is an entrepreneurial approach in which landowners are paid by the state for providing the services of water storage and phosphorus treatment in the Northern Everglades region. For example, if the rancher decides to partly restore the storage capacity of the wetlands by flooding part of pasture they take a risk of affecting their production but are paid by the state for reducing the flows and treating phosphorus because they help store water and treat it. The state figures out what the ecosystem service is worth -- in this case, the water storage and cleaning activity of the wetlands -- and pays the rancher to keep the wetlands close to their natural state.
Ecosystem services is a term used to describe the work that ecosystems perform, such as the way wetlands remove P, as described in the previous paragraph. These functions are natural for a wetland, but they are important "services" to the environment -- in the wetlands' case, to the groundwater which supplies most of irrigation and drinking water needs. Calling this natural function of wetlands a "service" is a way of thinking about its value more concretely. If the water isn't available or is of poor water quality, taxpayers pay to store and clean in some other way.
Reimbursing producers for ecosystem services has many positive aspects. By explicitly valuing the ecological contribution of land, landowners have another option in how to use land. PES gives landowners and those who benefit from their land, a more exact understanding of what is gained when natural systems are preserved or restored. PES gives producers a positive role as preservers of the environment. This approach has been used in many settings around the world. Landowners are paid to keep wetlands, forests, streams, and other natural features in their original state or to improve lands and preserve their role in maintaining the quality of the environment.
The success of PES depends on determining how much service a landowner provides and what it is worth. Shukla is part of a muliti-institutional project led by the World Wildlife Fund to accomplish this. The FRESP is a six -year pilot program working with eight Florida ranches to modify water management to retain water for natural treatment. Shukla says that this is one of the few programs in the country to implement PES, and it is showing promising results.
Shukla has a project specifically aimed at quantifying P treatment from stormwater impoundments such as reservoirs and farm ponds. Discovering how much P these impoundments can treat is a first step to understanding how to enhance the treatment effect and reduce net P discharge from farms and ranchlands. How soil retains water and adjusting inflows of water are just two of the issues that control how effective impoundments are. His study showed that while the impoundments can reduce the phosphorus loads by 20%, the treatment can be increased by modifying the impoundments. In another related project, Shukla showed that the impoundments can also become an alternative source of water supply by supplying almost three months of agricultural irrigation needs in south Florida.
Another area of Shukla’s research program is specifically targeted towards quantifying the effects of BMPs for the row crops such as vegetable and sugarcane in saving water and reducing the nutrient losses from the farm. Among several crops in south Florida, nutrient losses from vegetable crops are highest because of its intensive operation. In a jointly funded project by Florida Department of Agriculture and Consumer Services (FDACS) and Southwest Florida Water Management District (SWFWMD), Shukla has evaluated the effectiveness of water and fertilizer BMPs in reducing the nitrogen and phosphorus losses. He showed that adoption of these BMPs can reduce the nutrient loads. In another project, Shukla showed that use of soil moisture sensors for irrigation management can reduce the water use of vegetable crops by 36% compared to traditional irrigation management. In addition to water conservation benefits, nutrient losses are also reduced.
While many of Shukla's projects look at nutrient discharges, he is also interested in water use. Agriculture is a major user of water in South Florida, and the limited regional water supply must be managed to meet the needs of both extensive agricultural operations and the cities and towns of the area. In recent decades, water conflicts and water shortages have become major issues in several regions of Florida, and these issues have been made more complex by recurrent droughts. Producers need more information about the precise water needs of the crops they grow, and Shukla is working with an ingenious system to precisely quantify these needs.
The device is called a lysimeter, and while the name suggests some kind of hand-held device, it is actually a large metal tank installed in the middle of a field of active crop production. The tank is 12 feet wide, 16 feet long, and 4.5 feet deep, and it is used to estimate crop water use. Water input (rainfall an irrigation) and output (drainage and runoff) to the lysimeters are measured. Any water that is not accounted for in these measurements is the water used by the plant. Shukla makes these measurements under many conditions and develops a precise picture of how environmental conditions and the plant's growth pattern relate to its water use. Placing the tank in a working field puts the plants in their most natural context for these experiments. Using lysimeters, Shukla has measured the water use for two vegetable crops, watermelon and pepper as part of two grants from the SWFWMD. The results from these two studies are being used by producers to schedule irrigation for these two crops to ensure optimum production while conserving Florida’s water resources. Results are also being used by the state agencies in proper allocation of water to the producers.
Shukla has received grants through UF/IFAS innovation award program and the SWFWMD to use the lysimeter to study the water needs of several crops that are promising for supplying the feedstock for biofuels, another very active UF program. He and his collaborators are working with sugarcane, switchgrass, and sweet sorghum to compare their water needs, nutrient loads, and energy and understand how extensive cultivation of these crops would impact the water resources in the region. Of course, he will also be interested in the N and P discharges from these crops. Through this kind of research, a precise understanding of the environmental impact and the cultural needs of crops can be evaluated and planned for in advance, making agriculture a better partner with the environment it depends on.
Dr. Shukla specializes in evaluation of effects of agricultural practices on water quality and quantity.
Research and Extension
- Evaluation of cow-calf BMPs in the Lake Okeechobee basin
- Modeling water dynamics of stormwater impoundments for water supply in South Florida
- Evaluation of water and nutrient BMPs for vegetables
- Ground water recharge, upflux, and nutrient loadings from vegetable fields
- Ph.D. Biological Systems Engineering, Virginia Tech, December 2000
- M.S. Agricultural Engineering, Virginia Tech, February 1995
- B.S. Agricultural Engineering, University of Allahabad, India. January, 1990(1st Rank in the Graduating Class of 50, Passed with distinction)
Associate Professor, ABE Department, University of Florida.
Assistant Professor, Agricultural and Biological Engineering (ABE) Department, University of Florida.
Senior Research Assistant, Biological Systems Engineering (BSE) Department, Virginia Tech
Graduate Research Assistant, BSE Dept., Virginia Tech
Awards and Honors
- 2007 ASCE Journal of Hydrologic Eng- Best Technical Note Award for the Paper "Accuracy of Hydrodynamic Modeling of Flood Detention Reservoirs"
- 2006 Dallas B. Townsend Extension Term Professorship Award,
- 2005 USDA-CSREES Southern Region Applied Research Award.
- 2005 Young Extension Worker, ASAE Florida Section
- Outstanding Graduate Student Award, Alpha Epsilon
- Merit Award, University of Allahabad, for 1st rank in graduating class
- Alpha Epsilon
- Phi Kappa Phi
- Gamma Sigma Delta
Other Professional Activities
- American Society of Agricultural & Biological Engineers (ASABE)
- American Water Resources Association (AWRA)
- American Geophysical Union (AGU)