About this Research Topic
Worldwide agricultural production in semiarid climates is a high-risk endeavor given the uncertainty of rainfall distribution and amount. For example, the semiarid region of the Texas High Plains has an average rainfall where the monthly coefficient of variation is greater than 70% and the introduction of irrigation in the 1950’s provided year-to-year stability in crop yields. The source of the irrigation water is an underground aquifer, Ogallala, that extends from Texas north to the Dakota’s. In the Texas High Plains, the aquifer has diminished, reaching water levels that in certain areas can only supply a limited amount of water that is well below the crop’s water requirements, i.e., deficit-irrigation. Current irrigation technology, such as sub-surface drip and overhead sprinkler has improved the efficiency of applying water while minimizing losses and have extended the application of water from a declining water table. As a result, there is a transition being experienced from deficit-irrigation to dryland crop production. The rate of this transition is unknown and varies across the region and is a function of crop grown, irrigation system used and other agronomic management factors.
Dryland production relies on stored soil water and thus agronomic management practices must maximize the amount of rain that infiltrates, i.e., effective rain, into the soil and minimize losses due to runoff and evaporation from the soil. Previous field studies in dryland production indicate that traditional experimental designs do not always capture the inherent spatial variability in soil properties that is required to develop relations that can predict crop yield as a function of effective rainfall and stored soil water. The alternative are experiments in large plots and over long-time scales, i.e., landscape scale (>20 ha) with multiple years, to quantify agronomic management effects on production. Further, experimental results combined with simulation models can be used to evaluate multiple scenarios. While the problems associated with dryland production are general, the solutions are site-specific and require a systems approach.
Questions of interest:
- What are short-term and long-term economic implications of the transition from deficit-irrigation to dryland production?
- What is the economics of dryland production under different management schemes?
- What management practices improve rainfall capture for dryland production?
- What is impact of agronomic management cultural practices, e.g., cover crops, tillage, plant population, crop rotations, etc. on dryland production?
- How does rain frequency, intensity and amount affect the water balance (inputs = outputs) of dryland production fields?
This Research Topic welcomes a series of research articles related to the above issues. The following themes would be considered:
- What is dryland agriculture? History of dryland production.
- Economics of dryland agriculture, short- and long-term implications.
- Sustainability of dryland agriculture.
- Rainwater harvesting. The water balance of dryland agriculture. How to increase soil water storage?
- Landscape scale studies – experimental design of dryland production.
- Role of plant breeding (drought and temperature stress) in dryland production.
- Role of simulation models to evaluate dryland cropping systems.
Keywords: Semiarid climate, Crop stability, Dryland crop production, Deficit-irrigation, Dryland agriculture, Sustainablity, Climate change, Cropping systems, Agronomic management
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