Development of the research, education, and extension farm included several phases. These phases allowed for many considerations to be taken into account.
- Protection of the farm’s natural resources. Conservation plans were prepared to assure protection of the farm’s outstanding live oaks. Conservation tillage practices have been used whenever feasible to maximize entry of irrigation and rainfall into the soil and minimize wind and water erosion. Pine trees that were not removed during development of the facility are being managed according to accepted forestry best management practices.
- Background site and soil characterization. A detailed topographic and aerial survey was completed using tractor-mounted GPS navigation equipment in order to make the most effective use of the topography, soil, resources, and natural beauty of the farm. A background soil fertility map was created using point samples on 1 acre grids with separated 0 to 6 and 6 to 12 inch deep layers. Waters Agricultural Laboratory in Camilla provided an analysis of the 200 samples taken.
- Selection and layout of the major experimental units. The primary design criteria for the farm included accommodations for experiments that the University of Georgia cannot do on its existing farms throughout the Coastal Plain. Therefore, comparisons of separate irrigation rates, times of application, and depth of irrigation control zones were assigned as the major experiments at SIRP. Competition for water highlights the importance and demand of water sources. Efficiency in all phases of irrigated agriculture – from irrigation of most productive land, elimination of off-target spray, and in-field variable rate adjustments for crop needs, to application efficiency and scheduling methodology – will be needed to maintain current levels of production. There are a variety of field sites located at SIRP. These sites include small center pivots with an emphasis on application efficiency and pivot and end gun controls. A 4-tower pivot system has been used to design and test precision control and variable rate irrigation technology. Two linear systems with variable rate controls supply water to replicated plot designs. Several subsurface drip irrigation (SDI) areas have been used in replicated field designs for vegetable and row crop use, as well as chemigation studies.
- Selection, design, and purchase of irrigation equipment. To facilitate testing on a variety of manufacturers’ equipment and controls, researchers selected four matched 2-tower center pivot systems (approximately 260 feet), one each from T-L, Lindsay, Reinke, and Valley. For each pivot purchased, we included the manufacturer’s state-of-the-art control panels (which have since been upgraded) and an attached end gun. This variety gives us maximum flexibility in testing new controls, nozzle packages, and end gun operations.
A 4-tower, 600 foot Valley center pivot was purchased for work with precision application and variable rate controls (VRI). The system has provided an outstanding test platform for continuing development of VRI by FarmScan, Computronics, and Design Feats (all of Australia) and Advanced Ag Systems (Dothan, AL).
Two 4-tower Valley lateral move systems were installed with precision valve controls. These controls allow for the creation of a rectangular field with replicated, randomly assigned irrigation plots and blocks for use in studies of rates of application, timing of irrigation, and scheduling methods for row and selected vegetable crops. Originally, the zone control was by manual switching of electrical solenoid valves. In 2012, Advanced Ag Systems installed VRI controls on these two systems for automated zone management with on/off controls. Drip and subsurface drip (SDI) systems have been implemented in various designs to fit specific research needs. In one field, buried submains and risers as well as control wires were installed on 80 ft centers to allow flexible layout of drip and drip under mulch. At each riser, four pressure-regulated flow and valve systems can be attached and controlled at a central panel. Three other fields have SDI systems with drip tape buried at either 12 inches or 3 inches below the surface. Each of these fields have multiple zones established for replicated studies.
Engineering plans for water and power supply and distribution.
Three 8-inch wells (AAA Well Drilling, Albany, GA) and 6-inch PVC pipe and electric power supply (United Irrigation Supply, Inc., Quitman, GA) were arranged in a loop to form the backbone of the water and power distribution network. Pressure regulated flow valves are installed on each well pump as an alternative to maintain varying flow at system design pressures. A variable frequence drive was added to one of the wells to allow direct power and performance comparisons between VFD and pressure-regulated valves for variable flow control systems. Recently, a 4-inch well (Harvey Well Drilling, Albany, GA) was added to supply water to the subsurface drip irrigation field.
Design, construction, and layout of multipurpose headquarters building
The Stripling Irrigation Research Park has two structures. One building is a strand steel building 60 by 125 feet. About two thirds of the building are air conditioned and used for office, work, and meeting rooms. The remainder serves as a shop and assembly area, clean storage areas, drying and preparation areas for plant and soil samples, and covered equipment shelter. A separate steel structure acts as a protected chemical mixing and tank rise area with an associated sprinkler system to safely distribute rinsate.
Plans for management, maintenance and operations, and upgrades
With aid from the Assistant Dean for the UGA-CAES Campus at Tifton, operating budgets have been established. With input from the Advisory Committee and equipment dealers and manufacturers, the Superintendent and staff are responsible for maintenance as well as upgrades.