|Tour Stop #8: Upland Erosion Control Research|
Upland erosion control research is being conducted at Holly Springs and the Nelson Farm. This research includes field studies on plots (0.01 to 0.1 ha) and watersheds (2 to 4 ha). Yields and economic returns are evaluated to determine practicality of alternative agronomic and engineering practices. Runoff, soil loss, and changes in soil properties are measured to determine environmental impacts. On erodible loessal soils with slopes ranging tom 2 to 6%, typical of many DEC soil resources currently in pasture of CRP land uses, yield levels and profitability of cotton, soybean, wheat grain sorghum, and corn have been greater or equal with no-fill management than with conventional tillage. Continuous corn, (doublecrop) wheat-soybean rotated with corn, and cotton no-fill planted into a killed wheat cover crop have been the most profitable cropping systems studied at the Nelson Farm. At Holly springs, long-term soybean yield response to tillage, progressive erosion, and landscape position has been monitored since 1983. No-till management has reduced erosion by at least 75% on plots and by 90 to 96% on watersheds compared to conventional tillage. Ridge-tillage and reduced tillage were intermediate. Runoff has sometimes also been reduced. Runoff and erosion data are being used to refine RUSLE and WEPP erosion prediction models. Cover crops have enhanced the ability of no-tillage to reduce runoff and erosion. Research has identified cover crops that can reseed themselves, making them more attractive to producers.
Combinations of engineering and agronomic practices have been needed to control concentrated-flow erosion in watershed studies. Grass hedges are inexpensive vegetative barriers that can slow runoff and help control concentrated flow erosion. Terraces, waterways, and grass hedges can complement conservation tillage to provide a comprehensive runoff and erosion control system. Ongoing research seeks to optimize the combination of these practices in the most economical and effective manner for variable landscapes.
These research findings show that several conservation management systems are capable of keeping soil losses below tolerance limits for row-crops on fields with steepnesses and lengths typical of those on DEC watersheds. Farmers could respond to commodity prices and convert CRP or pasture land to row-crops using no-tillage techniques, without sacrificing yields or profits and without increasing runoff or sediment yields.
Key Words:Erosion control, No-till, Profitability, RUSLE, Soil loss, Surface runoff, Tillage, Watersheds
Publications:Dabney, S. M., J. D. Schreiber, C. S. Rothrock, and J. R. Johnson. 1996. Cover crops affect seedling growth. Agron. J. 88(6):961-970.
McGregor, K. C., Mutchler, C. K., Johnson, J. R., and Pogue, D. E. 1996. USDA and MAFES Cooperative Conservation Studies at Holly Springs-I 956-1996. Mississippi Agricultural and Forestry Experiment Station Bulletin 1044, Mississippi State, MS. 21 pp. 1996.
McGregor, K. C., Bingner, R. L., Bowie, A. J., and Foster, G. R. Erosivity index values for northern Mississippi. Trans. of ASAE 38(4):1039-1047.1995.
Triplett G. B., S. M. Dabney, and J. H. Siefker. 1996. Tillage systems for cotton on silty upland soils. Agron. J. 88(4):507-512.