Contemporary row-crop practices in the mid-southern, USA contribute to declining water tables and impairment of downstream waters, threatening the sustainability of irrigated agriculture and vital ecosystem services. This research was conducted to determine if various conservation practices and technologies can economically reduce negative environmental consequences of regional corn (Zea mays L.) production. The environmental, agronomic, and economic effects of implementing cover crops, manipulating traffic pattern, and integrating irrigation water management (IWM) technologies (computerized hole selection, surge irrigation, and soil moisture sensors) were investigated at either the small plot or field scale in the Delta region of Mississippi. Cover crop effects on runoff, water quality, corn grain yield, and net returns were primarily neutral or negative. Under furrow irrigation, cover crops did not affect runoff or nitrogen and phosphorus transport, but decreased erosion 16%. No cover crop decreased rainfall-induced runoff, erosion, or N and P transport. Over the four years of the experiment, cover crops maintained or decreased yield, net returns, and water use efficiency. Eliminating equipment traffic from furrows largely maintained or reduced runoff and subsequent contaminant transport. For both furrow irrigation and simulated rainfall, runoff and erosion were consistently less from nontraffic furrows than traffic furrows. Traffic effects on nutrient transport was more variable. Transport of some phosphorus constituents was decreased in the absence of furrow traffic; however, rainfall-induced nitrogen transport was greater from nontraffic furrows during the late-season event. Irrigation water management technologies improved corn grain yield, net returns, and irrigation water use efficiency across multiple locations in the mid-southern USA. Relative to standard production practices, implementing IWM technologies reduced total water applied 40% and increased corn grain yield 6.5 bu acre-1, which constituted a 51% increase in irrigation water use efficiency. The decrease in cost for irrigation water applied and increase in returns from yield gains exceeded the cost of the IWM technologies and resulted in an increase in net returns across a range of pumping depth and diesel price scenarios. Of the evaluated conservation strategies, reducing equipment traffic and implementing IWM technologies will most consistently improve the sustainability of irrigated agriculture and ecosystem services in the mid-southern USA.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-6213 |
| Date | 06 August 2021 |
| Creators | Spencer, Gene David |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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