LUBBOCK, Texas -- The Texas Tech University Plant and Soil Science Department has received a $10,000 grant from the High Plains Underground Water Conservation District No. 1 in Lubbock to evaluate the feasibility of applying phosphorus through center pivot sprinkler systems, as well as defining water quality constraints which may limit or even prevent phosphorus applications through center pivots. Phosphorus is an essential element in cotton production.
The project goal is to determine the proper relationship between fertilizer solutions applied through center pivot sprinkler systems (fertigation) and the range of groundwater qualities that exist throughout the High Plains Water District.
The native groundwater quality in the area has varying quantities of calcium and magnesium that can potentially cause problems when mixed with phosphorus. Chemical reactions between phosphorus, calcium, and magnesium cause precipitates, or solids, to fall out of solution and clog nozzles used in center pivot sprinkler systems.
The initial portion of the project will be conducted in a plant and soil science department laboratory where different combinations and quantities of fertilizer will be mixed with water having various levels of calcium and magnesium to determine the ratio at which precipitates become a problem. Researchers will then use Texas Water Development Board data to identify areas of the High Plains Water District that have water quality factors that may necessitate special consideration when applying phosphorus fertilizers through fertigation. Research may show that phosphorus cannot be applied through a sprinkler system without clogging in certain areas of the district with high levels of calcium and magnesium in the groundwater.
"We believe that fertigation offers the producer a better approach to manage one of his most expensive inputs and to ensure that nutrient supply does not limit yield and water use efficiency of his crop," said Dr. Dan Krieg, professor of crop physiology. Krieg is heading the research project, which began March 1 and ends Dec. 15, 1999.
Ultimately, producers could use maps identifying the water quality in the area of their farms and the data gained by Dr. Krieg's research team to guide them in setting the correct flow rate of their injector pumps when applying phosphorus through their center pivot sprinkler systems.
Applying phosphorus through center pivot sprinkler systems would be an efficient and effective method to supply proper amounts of phosphorus in a timely manner to satisfy the needs of growing crops, according to High Plains Water District Manager A. Wayne Wyatt.
"This appears to be a more efficient method to apply fertilizer than banding or sidedressing," said Wyatt. "In many instances, plant feeder roots are cut during sidedress fertilizer applications. As a result, the plants must focus energy on regenerating the roots rather than valuable reproductive growth for fruit production."
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