Effect of alfalfa on subsurface (tile) nitrogen and phosphorus loss in Ohio, USA. Issue 6 (2nd November 2022)

• Record Type: Journal Article
• Authors: Arrueta, Lourdes D.; Hanrahan, Brittany; King, Kevin; Kalcic, Margaret
• Is Part Of: Journal of Environmental Quality. Volume 51:Issue 6(2022)
• Page Start: 1181
• Page End: 1197
• Publication Date: 2022-11-02
• Subjects: Agricultural ecology -- Periodicals; Environmental engineering -- Periodicals; Pollution -- Periodicals; 630
• DOI: 10.1002/jeq2.20414
• Languages: English
• ISSNs: 0047-2425

Abstract

Abstract: Growing annual crops such as corn ( Zea mays L.) can lead to considerable nutrient losses through subsurface drainage in agricultural fields, posing a serious threat to surface water quality in the midwestern United States. Perennial crops have the potential to reduce these nutrient losses. However, more comprehensive data are needed on the nutrient loss effect of perennial crops. We examined the effect of alfalfa ( Medicago sativa L.) on nitrate‐nitrogen (NO3 − –N), total nitrogen (TN), dissolved reactive phosphorus (DRP), and total phosphorus (TP) in subsurface drainage using a before–after‐control‐impact (BACI) experimental design with one control field (with annual crops) and one impact field (with alfalfa) each on two farms (Sites A and B) located in northwestern Ohio. The "Before" period (prior to planting alfalfa at the impact field) extended for 4 yr (2013–2017) at Site A and 6 yr (2011–2017) at Site B; the "After" period extended for an additional 2 yr at both sites. Reductions in the mean monthly discharge and loads of NO3 − –N, TN, DRP, and TP were significant at Site A, whereas the only significant change at site B was a reduction in the mean monthly TP load. Significant reductions in NO3 − –N loads were observed during spring and winter at Site A. In addition, alfalfa reduced the variability of discharge and nutrient loads through subsurface drainage at both sites. Our findings suggest that introducing alfalfa into annual crop rotations has the potential to reduce subsurface nutrient loads and increase the resiliency of agricultural systems. Core Ideas: A BACI approach was used to assess the effect of alfalfa on subsurface discharge and nutrient loads. Alfalfa reduced subsurface discharge, NO3 − –N, TN, DRP, and TP loads at one site, but only TP at the second site. Alfalfa reduced NO3 − –N loads during spring and winter at one site. Alfalfa reduced the variability of subsurface discharge and nutrient loads by dampening extremes.