Corn Yield and Water Use Efficiency Under Contrasting Irrigation Application Methods: An Aquacrop Study Contrasting Subsurface Drip and Sprinkler Irrigation Methods

Abstract

Grain corn (Zea mays, L.) is sensitive to soil water availability, which can be influenced by irrigation application method. Four facts
motivate deficit irrigation of corn in this region. First, declining Ogallala aquifer well yields limit water availability and thus the area of land
that can be irrigated fully. Second, mild reductions of irrigation have been shown to increase yield since the full irrigation practice in this
region often results in over irrigation and loss of nutrients to deep percolation. Third, the water use efficiency of corn has been shown
to increase with mild deficit irrigation. Fourth, it is known that evaporative losses from the soil surface are reduced with subsurface drip
irrigation (SDI) in the semiarid
Southern High Plains, and deficit irrigation may be practiced with less risk using SDI. A study
contrasting sprinkler and SDI irrigation of corn was conducted in 2013 on four conjoined 4.4ha
fields, each containing a large weighing
lysimeter for energy and water balance measurements. Two fields were sprinkler irrigated and two had SDI. The study was conducted
on a Pullman silty clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) at Bushland, TX (35°11′ N, 102°6′ W, 1174 m above
MSL). Fields were fertilized for a 16.7 Mg ha1
(250 bushel per acre) yield goal, and irrigated to replace crop water use to field capacity
on a weekly basis. Weather was measured at an adjacent research weather station over mowed grass. AquaCrop was run using soilspecific
hydraulic and physical properties, the recorded and quality controlled weather data, and input data on plant stand and
fertilization. The presentation will discuss the differences between fieldmeasured
crop water use and water use efficiency and those
estimated using AquaCrop, including whether or not AquaCrop was able to estimate the 1.57 Mg ha1
(25 bushel per acre) yield
advantage achieved using SDI