Biomedical Engineering and Bioengineering Commons^™

Nutrient Concentrations Of Runoff During The Year Following Manure Application, John E. Gilley, Bahman Eghball, D. B. Marx

Biological Systems Engineering: Papers and Publications

Little information is currently available concerning temporal changes in nutrient transport following the addition of manure to cropland areas. This study was conducted to measure nutrient transport in runoff as affected by tillage and time following the application of beef cattle or swine manure to a site on which corn (Zea mays L.) was grown. Rainfall simulation tests were initiated 4, 32, 62, 123, and 354 days following land application. Three 30 min simulated rainfall events, separated by 24 h intervals, were conducted at an intensity of approximately 70 mm h-1. Dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus …

Nitrogen And Phosphorus Concentrations Of Runoff As Affected By Moldboard Plowing, John E. Gilley, Bahman Eghball, David B. Marx

Biological Systems Engineering: Papers and Publications

The excessive application of manure on cropland areas can cause nutrients to accumulate near the soil surface. This study was conducted to measure the effects of moldboard plowing on the redistribution of nutrients within the soil profile and nutrient transport by overland flow. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha^-1 to a silty clay loam soil and then incorporated by disking. Selected plots were moldboard plowed 244 days later to a depth of approximately 23 cm. Soil samples for analysis of water‐soluble phosphorus, Bray and Kurtz No. 1 …

Reducing Long-Term Atrazine Runoff From South Central Nebraska, Walter Scott Gorneau, Thomas G. Franti, Brian L. Benham, Steve D. Comfort

Biological Systems Engineering: Papers and Publications

Heavy reliance on chemical weed control in field crops of South Central Nebraska has resulted in the appearance of atrazine at concentrations greater than established drinking water standards. Our objective was to evaluate the best management practices for atrazine runoff for the tillage and herbicide management practices common to the region under study. Field experiments were performed to measure edge–of–field atrazine and water loss from disk–till, ridge–till, and slot plant (no–till) management systems. Results indicated less water runoff from no–till (34% less) and ridge–till (36% less) than from disk–till. Similarly, atrazine loss was also less: 24% less for no–till and …

Sediment Movement Within A Strip Intercropping System, John E. Gilley, L. A. Kramer, R. M. Cruse, A. Hull

Biological Systems Engineering: Papers and Publications

This study was conducted to identify sediment movement within a strip intercropping system in southwestern Iowa during the third year of a three-year crop rotation. Soil loss, resulting from the application of simulated rainfall to a Monona silt loam soil, was measured from individual corn (Zea mays L.), soybean (Glycine max (L.) Merr), and winter wheat (Triticum aestivum L.) strips, and from multiple strips which included all three crops. Because of the crop rotation and residue management procedures, used at the study site, a substantial amount of surface cover and vegetative mass was present on each of …

Tillage Effects On Soil Erosion Potential And Soil Quality Of A Former Conservation Reserve Program Site, John E. Gilley, J. W. Doran

Biological Systems Engineering: Papers and Publications

This study was conducted to determine the effects of tillage on soil erosion potential and soil quality characteristics of a former Conservation Research Program (CRP) site. Following tillage, the study area in northern Mississippi was maintained in a fallow condition for nine months. Soil loss from simulated rainfall events was minimal on recently tilled plots and an adjoining, undisturbed CRP area. In contrast, soil loss from the former CRP site which had been tilled nine months previously was similar to values obtained before the CRP program when the area had been cropped for several years. Tillage and over-winter fallowing caused …

Tillage And Planting System, Stalk Chopper, And Knife Applicator Influences On Corn Residue Cover, David P. Shelton, Stephen D. Kachman, Elbert C. Dickey, K.T. Fairbanks, Paul J. Jasa

Biological Systems Engineering: Papers and Publications

Percent corn (Zea mays L.) residue cover remaining on the soil surface after planting was measured for 11 tillage and planting systems that included combinations of the use, and timing, of a stalk chopper and/or a knife-type fertilizer applicator. Tillage, as well as use of a stalk chopper or knife applicator, significantly reduced residue cover. Only 27 of the 69 stalk chopper/knife applicator/tillage and planting system treatment combinations that were evaluated could be classified as conservation tillage by having at least 30% residue cover remaining after planting.

Hydraulic Roughness Coefficients As Affected By Random Roughness, John E. Gilley, S. C. Finkner

Biological Systems Engineering: Papers and Publications

Random roughness parameters are used to characterize surface microrelief. In this study, random roughness was determined following six selected tillage operations. Random roughness measurements agreed closely with values reported in the literature.

Surface runoff on upland areas is analyzed using hydraulic roughness coefficients. Darcy-Weisbach and Manning hydraulic roughness coefficients were identified in this investigation on each soil surface where random roughness values were determined. Hydraulic roughness coefficients were obtained from measurements of discharge rat巳and flow velocity.

The experimental data were used to derive regression relationships which related Darcy-Weisbach and Manning hydraulic roughness coefficients to random roughness and Reynolds number. Random …