Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2013
Publication Date: 12/13/2013
Publication URL: http://handle.nal.usda.gov/10113/59373
Citation: Mikha, M.M., Stahlman, P.W., Benjamin, J.G., Geier, P.W. 2013. Remediation/restoration of degraded soil II: Impact on crop production and nitrogen dynamics. Agronomy Journal. 106:261-272. Interpretive Summary: Loosing topsoil rich with organic materials, particularly by wind erosion, influences many aspects of soil properties and productivity in the central Great Plains Region. This study evaluates (i) the addition of beef cattle manure and no-till on restoring the productivity for the eroded land and (ii) monitors soil available N to 4 ft depth. The eroded site was located at the Agriculture Research Center, near Hays, KS. From 2006 to 2011, cropping sequences were grain sorghum (Sorghum bicolor L.), forage oat (Avena sativa L.), winter wheat (Triticum aestivum L.), and proso millet (panicum miliaceum L.). Four out of six years, the productivity was negatively influenced by low precipitation and/or high ambient temperature. In any year, the productivity increased with manure than commercial fertilizer. High soil available N was observed below 2 ft especially with high dosage of manure and fertilizer, double the crop N requirement. This was because of the excess amounts of N added and low productivity in some years. The low dosage of manure, equivalent to crop N requirement, had less productivity and less soil available N below 2 ft than the high dosage of manure treatments. Overall, manure could have the benefit of increasing yields of the eroded land. However, the advantage of increasing the productivity and the risk of soil available N below 2 ft with high dosage compared with the low dosage of manure needs to be addressed in subsequent years.
Technical Abstract: Soil erosion influences many aspects of soil properties and productivity as a consequence of loosing topsoil rich with organic materials. The objectives of this study were to restore the productivity and evaluate nitrogen (N) loss of eroded land as influenced by tillage practices, N types, and N rates. The eroded site was an Armo silt loam soil (fine-loamy, mixed, mesic, Entic Haplustolls) located at the Agriculture Research Center, Hays, KS. Tillage practices were no-tillage (NT) and conventional tillage (CT). Nitrogen types were beef manure (M); urea or anhydrous ammonia, as commercial fertilizer (F); and no-N control (C) at two rates low (L) and high (H). Cropping sequences were grain sorghum (Sorghum bicolor L.), forage oat (Avena sativa L.), winter wheat (Triticum aestivum L.), and proso millet (panicum miliaceum L.). Grain yield and soil inorganic nitrogen (SIN) at 0- to 120-cm depth were evaluated. Grain yields were not influenced by tillage practices, except in 2006 when NT had greater yields than CT. Manure addition increased grain yields compared with F and C treatments. The SIN leached down the soil profile was observed with FH and MH due to the excess amounts of N added and low productivity. The ML exhibited less productivity and less SIN loss than MH treatment. Overall, M could be the N source that can improve the productivity of the eroded site. However, the benefits of increasing the productivity and the risk of N loss with MH compared with ML need to be addressed in subsequent