Irrigation Analysis Based on Long-Term Weather Data

Mahan, J. R.; Lascano, Robert J.

doi:10.3390/agriculture6030042

Cited by 10 publications

(10 citation statements)

References 41 publications

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“…In the THP, the Ogallala Aquifer is largely a closed system where withdrawals exceed recharge leading to a decline of the water table [3] [4] [6] [8]. In certain areas of the THP, the decline in the Ogallala Aquifer water table is leading to well capacities that yield less water than the daily water requirements, evapotranspiration demand, of the crops grown in this area [9] [10].…”

Section: Introductionmentioning

confidence: 99%

Irrigation Termination Thermal Time and Amount on Cotton Lint Yield and Fiber Quality

Lascano¹,

Baumhardt²,

Goebel³

et al. 2017

OJSS

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Cotton irrigation in the Texas High Plains (THP) is often dictated by the well capacity and not by the water needs of the crop. The source of irrigation-water is the Ogallala aquifer and in many areas of the THP, the water table has declined to well capacities that deliver 1.3 to >7.6 mm/d. There is plenty of information on cotton responses to irrigation frequency and amount; however, information on when to terminate irrigation and its effect on cotton lint yield and fiber quality is scarce. Our objective was to evaluate over a 4-year period three irrigation termination thermal times corresponding to cumulative daily heat units (∑HU) of 890 ˚C, 1000 ˚C and 1110 ˚C from crop emergence, and three levels of irrigation (2.5, 5.1 and 7.6 mm/d) on cotton lint yield and fiber quality. Irrigation was applied with a sprinkler system on a 3-day frequency in Lubbock, TX. Results showed that on average the 7.6 mm/d level produced the most cotton lint yield regardless of the irrigation termination thermal time. Terminating cotton at 1000−˚C ∑HU resulted in water savings of 25 to 50 mm for the 2.5 and 5.1 mm/d levels without significantly affecting lint yield. For the 7.6 mm/d and terminating at 890−˚C ∑HU resulted in water savings of 100 to 115 mm. Average fiber length statistically increased with termination thermal time and level. This effect was most significant in years with the least rain and warmer air temperature. Micronaire increased with the termination thermal time in years with >500 mm of rain. Average fiber length uniformity and fiber strength were minimally affected by termination thermal time. As irrigation level increased, the average micronaire decreased, and fiber strength increased for the 5.1 and 7.6 mm/d irrigation. We concluded that in the THP for well capacities that deliver 2.5-5.1 mm/d irrigation can be terminated when the ∑HU reaches about 1000 ˚C from emergence without impacting cotton lint yield.

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Section: Introductionmentioning

confidence: 99%

Irrigation Termination Thermal Time and Amount on Cotton Lint Yield and Fiber Quality

Lascano¹,

Baumhardt²,

Goebel³

et al. 2017

OJSS

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“…In ENWATBAL the evaporative flux is solved from a combination of the surface energy balance and an aerodynamic model of the turbulent air above the soil surface. The unknown value of the surface energy balance is the soil surface temperature (T s ) in Equations 7and (9) and this value is found by iteration until the surface energy balance of zero is numerically met. At each time step (Δt), ENWATBAL, begins by finding, from the previous values of the soil water content and temperature of each soil layer, the corresponding soil hydraulic potentials and the water and conductivity values.…”

Section: Enwatbal Modelmentioning

confidence: 99%

“…In the THP, the Ogallala aquifer is classified as a closed system, where withdrawals exceed recharge, and thus over the years the depth to the water table has increased [4] [5] [6] [7]. The major withdrawal of water is mainly due to irrigation of crops and has resulted in a depletion of groundwater to the extent that in several parts of the THP existing irrigation wells can only supply <50% of the daily water requirement of crops [8] [9]. This decline of the groundwater here and elsewhere has prompted considerable research on irrigation scheduling, i.e., when and how much water to apply, and on the development of irrigation systems suited for this region.…”

Section: Introductionmentioning

confidence: 99%

“…In the THP, the average decline of the depth to the water table of the Ogallala aquifer is about 0.3 m/year and on average has dropped about 15 m since measurements started in 1969 [21] [22]. The introduction of more efficient irrigation systems and attempts to monitor crop water use via evapotranspiration networks [9] have extended the lifespan of the Ogallala aquifer. However, an outcome not expected by the introduction of more efficient irrigation systems is the so-called "paradox of irrigation efficiency" where the rate of groundwater depletion actually increases due to irrigation [23].…”

Section: Introductionmentioning

confidence: 99%

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Water Balance of Two Major Soil Types of the Texas High Plains: Implications for Dryland Crop Production

Lascano¹,

Leiker²,

Goebel³

et al. 2020

OJSS

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Crop production in the Texas High Plains is shifting from irrigated to dryland due to the increase of the depth to the water table from the Ogallala aquifer in regions where the saturated thickness of 9 m, the minimum to sustain irrigation, has been reached. Our objective was to use the mechanistic model ENWATBAL to evaluate the daily and annual water balance for three scenarios of rainfall in this region, a dry (189 mm), an average (449 mm) and a wet (669 mm) year. These three scenarios were applied to two major soil series of this region, Pullman and Amarillo. In all simulations, we used hourly input weather data for a location near Lubbock, Texas and used measured soil hydraulic properties to simulate the water balance for each soil series and the three rainfall scenarios. Results showed that in years with average and wet rain, storage of rainfall occurred in the Pullman but not in in the Amarillo soil series. However, storage of water could be enhanced by combining furrow dikes with minimum tillage along with crop covers that provide a surface residue. The implications of our results for dryland crop production in the semiarid climate of the THP suggest that for years with average and wetter rainfall soils in the Pullman series could store water that would be available for crop use. However, this was not the case for the Amarillo soil series and these soils represent a higher risk for dryland crop production.

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“…Decreases in saturated thickness in the southern portion of the High Plains aquifer (McGuire, 2017) are reducing well yields and thereby limiting irrigation flow capacities and the ability to meet peak crop water requirements. Scheduling irrigation to maintain soil water above a certain stress threshold is usually not attainable under these conditions except during periods with above‐average precipitation (Mahan & Lascano, 2016). In the Texas High Plains (THP), maize ( Zea mays L.) pollination and the early reproductive growth stages usually coincide with the period of greatest irrigation requirements and consequently a limited irrigation pumping capacity during this critical stage can markedly affect seed set and grain yield (Howell et al., 1989; Musick & Dusek, 1980; Schwartz et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

Response of maize hybrids under limited irrigation capacities: Yield and yield components

et al. 2022

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Grain yield of maize (Zea mays L.) in the semiarid Texas High Plains (THP) is greatly reduced when irrigation cannot meet peak water requirements. Drought‐tolerant hybrids may mitigate yield losses resulting from water deficits. We examined the effect of irrigation capacity (8.47 and 4.23 mm d–1) and planting rates (74,000 and 95,000 seeds ha–1) during three growing seasons (2016–2018) on grain yield and yield components of three maize hybrids, two of which were considered drought tolerant. Crop water deficits at the low irrigation level usually extended temporally from seventh leaf collar to dough stage. Mean grain yields varied from 5.2 Mg ha–1 under the low irrigation level to 19.9 Mg ha–1 at the high irrigation level. Hybrid did not influence grain yield and aboveground biomass in all 3 yr. Although kernel number and kernel mass were significantly influenced by hybrid across all years, this did not result in grain yield differences because greater kernel mass compensated for reduced kernel number. Harvest index did not significantly differ between conventional and drought‐tolerant hybrids. In 2016, grain yield was significantly influenced by plant density only at the low irrigation level, with 44% greater yields at the low plant density. For the patterns and level of water stress observed during these three growing seasons, the three hybrids performed similarly. Besides using hybrids well adapted to the region, mitigation of yield reductions under limited irrigation capacities in the THP can be achieved by concentrating irrigation on less land area and optimizing planting rates.

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Irrigation Analysis Based on Long-Term Weather Data

Cited by 10 publications

References 41 publications

Irrigation Termination Thermal Time and Amount on Cotton Lint Yield and Fiber Quality

Irrigation Termination Thermal Time and Amount on Cotton Lint Yield and Fiber Quality

Water Balance of Two Major Soil Types of the Texas High Plains: Implications for Dryland Crop Production

Response of maize hybrids under limited irrigation capacities: Yield and yield components

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