Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 2013
Publication Date: June 11, 2013
Citation: Shipitalo, M.J., Owens, L.B., Bonta, J.V., Edwards, W.M. 2013. Effect of no-till and extended rotation on nutrient losses in surface runoff. Soil Science Society of America Journal. 77(4):1329-1337. DOI:10.2136/sssaj2013.01.0045. Interpretive Summary: No-till crop production usually reduces soil erosion, but concern has been raised that this crop management practice might increase losses of nutrients in water that runs off fields when surface-applied fertilizers are not incorporated. In this 16-year study, we compared nutrient and soil losses in runoff from fields in a corn-soybean rotation and farmed with no-till and chisel tillage. We also investigated whether using less mineral fertilizer by growing wheat and red clover after soybean and applying manure before planting corn as part of a three-year, extended rotation with disk tillage could reduce nutrient losses. The results indicated that losses of most nutrients were less from no-till than from chisel-tilled fields. The extended rotation produced crop yields similar to those for no-till and chisel tillage, but generally resulted in greater nutrient and soil losses. Therefore, with the specific fertilizer and crop management practices investigated, no-till did not have a greater impact on water quality than chisel tillage. An extended rotation that included tillage and manure application but less nitrogen fertilizer, however, had a greater negative impact on water quality than a two-year rotation with no-till or chisel tillage. Farmers will benefit from this information by knowing that they can maintain runoff water quality with properly managed no-till crop production without having to occasionally till to incorporate fertilizers.
Technical Abstract: No-till crop production can reduce soil erosion compared to conventional tillage, but there is concern that lack of fertilizer incorporation will increase loss of dissolved nutrients in surface runoff. Therefore, we compared nutrient and sediment loss from two no-till and two chisel-till small (0.45-0.79 ha) watersheds managed in a 2-yr corn (Zea mays L.)/soybean [Glycine max (L.) Merr]-rye (Secale cereale L.) cover crop rotation for 16 crop years. We also investigated the effect of replacing some of the mineral N with manure and red clover by monitoring runoff from three watersheds in a 3-yr corn/soybean/wheat-red clover (Triticum aestivum L. - Trifolium pratense L.) extended rotation. Manure was added to these reduced-input watersheds prior to corn planting and they were disked in corn and soybean years. For all tillage treatments, nitrate-N losses were greatest with corn and averaged from 3.7 (no-till) to 5.5 kg/ha/yr (chisel) for all crop years. Average dissolved P losses were 0.21 kg/ha/yr (chisel), 0.32 kg/ha/yr (no-till), and 0.84 kg/ha/yr (reduced-input). Total P losses were lowest from no-till (0.79 kg/ha/yr), intermediate for chisel (0.84 kg/ha/yr), and greatest for reduced-input watersheds (1.68 kg/ha/yr). Soil loss was lowest from no-till (807 kg/ha/yr), intermediate from chisel (1073 kg/ha/yr), and highest from reduced-input watersheds (1177 kg/ha/yr). Thus, no-till had only slightly higher dissolved P losses compared to chisel, but had lower soil, nitrate-N, and total P losses. The higher dissolved and total P losses, as well as greater soil loss, compared to chisel and no-till watersheds, indicated that there was no surface water quality benefit to the reduced-input, extended, rotation.