Abstract

Within the Lower Mississippi Alluvial Valley, conservation practices are being utilized to mitigate nutrient loading to streams from agricultural landscapes. This study was conducted to determine the potential to use solids, phosphorus (P) and nitrogen (N) captured by tailwater recovery (TWR) systems for reuse onto production fields through irrigation applications. Seven TWR systems were assessed for seasonal changes in nutrient concentrations and application loads. Samples were collected every three weeks from 2013 to 2015 for seasonal analyses and weekly during the 2014 and 2015 growing seasons for nutrient load analyses. Water samples collected in spring contained greater concentrations of solids than samples collected in winter and summer. In addition, spring samples contained greater concentrations of nitrate–nitrite than samples collected in all other seasons, and spring samples also contained higher ammonium than summer and fall samples. Mean nutrient loads per hectare recycled onto the landscape for an irrigation season were 325.10 kg ha−1 solids, 0.86 kg ha−1 P, and 7.26 kg ha−1 N, with the N being 77% organic. TWR systems can be used to recycle solids, P and N onto agricultural landscapes through irrigation events; however, nutrient loads will not be sufficient to alter agronomic fertilizer recommendations.

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