Submitted to: National Sunflower Research Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 22, 2004
Publication Date: February 27, 2004
Citation: Merrill, S.D., Tanaka, D.L., Zobeck, T.M., Stout, J.E., Krupinsky, J.M., Hagen, L.J. 2004. Effects of tillage and fallowing on wind erosion in sunflower stubble land. In: Proceedings of the 26th Sunflower Research Workshop Forum. Jan. 14-15, 2004. National Sunflower Association, Bismarck, ND. Available: http://www.sunflowernsa.com Technical Abstract: Crop agriculture in the dryland portions of the northern Great Plains has undergone considerable evolution over the past 10-20 years as the traditional wheat-dominated crop-fallow system has given way to crop intensification (elimination of fallow) and diversification of crop species included in rotations. A number of crops alternative to wheat leave considerably smaller amounts of crop residue covering the soil after harvest as compared to small grain crops themselves. We set up an experiment in sunflower in which direct measurements of wind erosion were made under a 'worst case' but realistic agronomic scenario. Land that had been under conservation tillage and that contained sunflower stubble from the previous year was subjected to three levels of spring, pre-plant tillage: no-till, a medium level of conventional tillage, and a heavier level as required for certain crops. No crop was planted, but, in simulation of a producer decision to not plant, the land was fallowed by multiple application of glyphosate, the most used herbicide. On a generic silt-loam soil, we found that soil in the tilled treatments became increasingly more wind-erodible during the mid-summer and early fall period. Winter wheat seeding in later September served to stop the erosion. Cumulative soil losses of approximately 5 to 15 tons per acre were measured, which is at a level that has immediate serious implications for spreading of suspended load (fine particles with negative health and water quality implications) off field. The no-till management was found to be generally soil protective, but wind driving forward soil particles detached from the surface by higher-energy rainfall ('rain splash erosion') resulted in moderate degrees of erosion occurring in the wetter, late spring period.