Biological Engineering Commons^™

Hydraulic Characteristics Of Rills, John E. Gilley, E. R. Kottwitz, J. R. Simanton

Biological Systems Engineering: Papers and Publications

Rill density and rill flow rates were determined during rainfall simulation tests conducted at 11 sites located throughout the eastern United States. A mean rill density of 1.0 rills/m was found for the study locations. From measurements of the relative distribution of flow rates, a procedure is identified for partitioning flow between individual rills.

Regression equations were developed for relating rill width and hydraulic roughness coefficients to flow rate. Equations were also derived for predicting mean flow velocity from visually determined measurements of advance velocity. Information reported in this study can be used to estimate hydraulic characteristics of rills.

Ridge Plant Systems: Fertility, Richard B. Ferguson, Charles A. Shapiro, Elbert C. Dickey, Gary W. Hergert

Biological Systems Engineering: Papers and Publications

The Soil Sample

The starting point for any fertilizer program, regardless of the tillage system, is obtaining a representative soil sample. Without knowing which nutrients are needed, the questions of what fertilizer and how much to apply become irrelevant. Two types of soil samples should be obtained: the traditional, zero to 8-inch sample for general fertility (pH, phosphorus, potassium, organic matter, etc.) and deep, subsoil samples for nitrate. Subsoil samples for nitrate should be taken to a depth of at least 3 feet.

The problem of how to obtain a representative soil sample is particularly relevant in ridge-tilled fields. On …

Using The Line-Transect Method To Estimate Percent Residue Cover, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, Roger Kanable, Susan Smydra Krotz

Biological Systems Engineering: Papers and Publications

Crop residue left on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. ~ Research in Nebraska and other Midwestern states shows ' that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by as much as one half of what it would be from residue-free conditions. Greater amounts of residue cover further limit soil erosion, Figure 1.

Residue reduces erosion in two ways. First, the residue dissipates raindrop impact energy, reducing the amount of soil that is detached. Residue also forms a …

Stress Cracking And Breakage Susceptibility As Affected By Moisture Content At Harvest For Four Yellow Dent Corn Hybrids, Curtis Weller, M. R. Paulsen, M. P. Steinberg

Biological Systems Engineering: Papers and Publications

Four hybrids of yellow dent com were harvested at three levels of moisture content. After drying, samples were analyzed for stress cracking and susceptibility to breakage in Wisconsin (WBT) and Stein (SBT) breakage testers. Significant differences in stress cracking and breakage susceptibility as determined with the WBT and the SBT were observed among the four hybrids. Breakage susceptibility as measured with the WBT and SBT significantly increased as the harvest moisture increased. Stress cracks increased significantly as harvest moisture increased within the drying air temperatures of 49, 71, and 93° C. WBT breakage susceptibility significantly increased as drying air temperature …

Adsorption Of Bromide Tracers Onto Sediment, John E. Gilley, S. C. Finkner, John W. Doran, E. R. Kottwitz

Biological Systems Engineering: Papers and Publications

Information concerning hydraulic parameters on upland areas could be greatly expanded through the use of tracing techniques. If bromide is used as a tracer, adsorption of bromide onto sediment may be of concern. Therefore, a laboratory study was conducted to identify the effects of sediment content and initial bromide concentration on adsorption of bromide for selected soils.
When bromide solutions were used within the appropriate instrument measurement range, neither soil texture, liming, nor sediment content were found to significantly affect adsorption of bromide. In contrast to systems using fluorescent dyes, correction factors for estimating adsorption of bromide are unnecessary. Since …