In a collaborative work between the Agricultural
Research Service (ARS) Soil and Water Management
Research, the University of Castilla-La Mancha
(UCLM) in Spain, West Texas A&M University, and
Texas A&M AgriLife, researchers adapted a crop
model for use in the Texas High Plains to simulate
crop water use and corn yield to help producers
adjust center-pivot irrigation strategies and
maximize profitability with limited water.
Crop producers in this semi-arid region of the Texas
High Plains largely depend on groundwater irrigation.
Each season, crop producers in the region evaluate how
much land area could be irrigated under the pivot with
limited water. Addressing this is not straightforward
because producers must consider reducing irrigated
areas, which influences grain yield, input costs, and
the timing of the irrigation applications.
To help producers with these decisions, researchers
completed a study that uses 25 years of climatic data
to simulate corn production using a range of irrigation
capacities, the maximum amount of water that can be
delivered to an irrigated acre in a day, to evaluate
water allocation strategies that could increase profitability
and improve the efficient use of water.
Many crop producers in the Texas High Plains irrigate
crops using a center-pivot, equipment that often needs
five or more days to complete a single revolution around
the field. When evaluating strategies to maximize profit
under limited irrigation capacities, the study considers
the time factor of moving the center-pivot because this
influences how much water can be applied and the end-of-season yield.
The model showed that for irrigation capacities
representative of the region and a growing season with
average rainfall, maximum profitability was achieved by
irrigating about 75% of entire pivot area with the remaining
area in fallow (unplanted field) or dryland cotton.
Concentrating water generated greater net returns because
of lower seed and fertilizer costs and greater corn yields
that compensated for lack of production in fallow areas.
In years with seasonal drought, the irrigated area would
need to be further constrained to avoid crop failure and
"Results from this adapted model allow producers to
evaluate how best to allocate the limited water that
is available to a fraction of the land area under the pivot
that, over the long term, maximizes profitability and
utilizes water resources more efficiently," said Soil
Scientist Robert Schwartz with Soil and Water Management
Research. "Some scenarios in the study even demonstrated
that profitability could be maximized by irrigating a
fraction of the area but using less water compared to
irrigating the full pivot circle, thereby conserving
groundwater for future use."
"This study has demonstrated that the crop water use model
MOPECO can be adapted to many different scenarios and is
a useful tool for improving the environmental and economic
sustainability of agricultural systems where water is
limiting," said Alfonso Domínguez researcher of the Centro
Regional de Estudios del Agua (CREA) of UCLM. "A simplified
version of this model is being tested in many semiarid
areas of the Mediterranean basin and the Americas with
the objective of making it available to the farm sector
through an online platform."
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System