Bioresource and Agricultural Engineering Commons^™

Comparison Of Sensors And Techniques For Crop Yield Mapping, Stuart J. Birrell, Kenneth A. Sudduth, Steven C. Borgett

Stuart J. Birrell

The implementation of site-specific crop management is dependent on the variations in yield and yield potential within a field. Crop yield maps are important for both the implementation and evaluation of site-specific crop management strategies. Management decisions and evaluations based on yield maps must take into consideration the accuracy and resolution of the maps.

An impact-based yield monitor and a volumetric yield monitor were compared. The effect of different dynamic models of combine grain flow on the calculated instantaneous yields were investigated. Both simple time delay models and first order models could be used to model the grain flow. In …

Vegetative Filter Strip Design For Grassed Areas Treated With Animal Manures, Dwayne R. Edwards, Tommy C. Daniel, Philip A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Vegetative filter strips (VFS) are a low-cost management option that have been demonstrated to be effective in reducing runoff transport of fertilizer constituents applied to grassed areas (pasture or meadow). Runoff quality studies involving fertilizers applied to grassed areas suggest that VFS can be designed by assuming that (1) only infiltration is responsible for pollutant removal, (2) the first post-application runoff event is most important from a water quality perspective (enabling a design event approach), and (3) no pollutant build-up that degrades VFS performance will occur. The purpose of this study was to develop a VFS design algorithm for grassed …

Poultry Litter-Treated Length Effects On Quality Of Runoff From Fescue Plots, Dwayne R. Edwards, Philip A. Moore Jr., Tommy C. Daniel, Puneet Srivastava

Biosystems and Agricultural Engineering Faculty Publications

Using experimental data and/or mathematical simulation models to identify practices that reduce pollution from manure-treated areas is sometimes perceived as limited by the unknown validity of extrapolating plot-scale data to larger areas and by uncertainties in modeling transport of various pollutants. The objectives of this study were to assess the effect of length of manure treatment on runoff concentrations of poultry litter constituents and to define the modes of transport (particulate versus soluble) for nitrogen (N), phosphorus (P), carbon (C), and solids. Poultry litter was applied to three 1.5- x 18.3-m fescue (Festuca arundinacea Schreb.) plots with runoff collection …

Quality Of Runoff From Four Northwest Arkansas Pasture Fields Treated With Organic And Inorganic Fertilizer, Dwayne R. Edwards, Tommy C. Daniel, John F. Murdoch, Philip A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Long-term land application of animal manures, even at agronomic rates, can promote accumulation of soil phosphorus (P) which can, in turn, contribute to increased P loadings to downstream waters. The objective of this study was to assess the soil and runoff effects of replacing animal manure as a soil amendment with inorganic fertilizer (ammonium nitrate, NH₄NO₃) on fields that had been treated previously with animal manures. Runoff from two pairs of small fields (0.57 to 1.46 ha) was sampled from September 1991 to April 1994. All fields had been treated previously with animal manures; after runoff …

Performance Of Vegetative Filter Strips With Varying Pollutant Source And Filter Strip Lengths, Puneet Srivastava, Dwayne R. Edwards, Tommy C. Daniel, Philip A. Moore Jr., Thomas A. Costello

Biosystems and Agricultural Engineering Faculty Publications

Vegetative filter strips (VFS) can reduce runoff losses of pollutants such as nitrogen (N) and phosphorus (P) from land areas treated with fertilizers. While VFS effectiveness is considered to depend on lengths of pollutant source and VFS areas, there is little experimental evidence of this dependence, particularly when the pollutant source is manure-treated pasture. This study assessed the effects of pollutant source area (fescue pasture treated with poultry litter) length and VFS (fescue pasture) length on VFS removal of nitrate N (NO₃-N), ammonia N (NH₃-N), total Kjeldahl N (TKN), ortho-P (PO₄-P), total P (TP), …

Simulation Of Runoff Transport Of Animal Manure Constituents, Yang Wang, Dwayne R. Edwards, Tommy C. Daniel, H. Don Scott

Biosystems and Agricultural Engineering Faculty Publications

Runoff losses of land-applied animal manure constituents can adversely affect the quality of downstream waters. Reliable mathematical simulation models can help estimate runoff losses of animal manure constituents and identify management measures to reduce these losses. The objective of this study was to develop and calibrate an event-based simulation model to describe the runoff transport of solids (soil and manure particles) and nutrients (nitrogen and phosphorus) from areas treated with animal manure. The resulting model, consisting of linked hydrology, soil/manure transport, and nutrient transport components, is process-oriented and uses measurable parameters to the greatest degree possible. The three components of …

A Direct, Approximate Solution To The Modified Green-Ampt Infiltration Equation, Puneet Srivastava, Thomas A. Costello, Dwayne R. Edwards

Biosystems and Agricultural Engineering Faculty Publications

Accurately predicting the rainfall-runoff process is of vital importance for water quality models as well as for correct design of various types of hydraulic structures. This article presents a method of describing the cumulative infiltration process as an explicit function of time using an approximation to the modified Green-Ampt equation given by Mein and Larson (1971). The resulting equation is helpful in predicting cumulative infiltration and therefore infiltration capacity for computer simulation models. The proposed method takes about 50% less time than the usual iterative technique for the same degree of accuracy. The maximum error due to approximation was 1% …

Development Of A Biologically Based Aerobic Composting Simulation Model, Dennis P. Stombaugh, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

A relatively simple dynamic model based on microbial process kinetics has been developed for aerobic composting. Differential equations describing microbial, substrate, and oxygen concentrations, as well as moisture and temperature profiles have been derived as a function of vessel size and aeration rate. Microbial biomass growth was described using Monod growth kinetics as a function of degradable substrate concentration, oxygen concentration, moisture content, and compost temperature. Facility and fan operating costs have been included to permit economic optimization of the process. Predicted results demonstrated the ability of the model to quantify and describe the influence of multiple interacting factors (temperature, …

Application Of Simplified Phosphorus Transport Models To Pasture Fields In Northwest Arkansas, Dwayne R. Edwards, C. T. Haan, Andrew N. Sharpley, John F. Murdoch, Tommy C. Daniel, Philip A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Runoff transport of phosphorus (P) is often predicted from simple equations with parameters determined from data applicable primarily to row-cropped and fallow cover conditions. The applicability, accuracy, and precision of such P transport prediction equations under pasture situations are less well defined. The objectives of this study were to determine parameters of simplified runoff P transport equations for pasture fields and to assess the accuracy and precision of the equations. Runoff, sediment yield, soluble P transport, and particulate P transport data were collected from four pasture fields in northwestern Arkansas. Runoff event enrichment ratios and extraction coefficients were computed, and …

Evaluation Of The Crop Growth Component Of The Root Zone Water Quality Model For Corn In Ohio, Sue E. Nokes, Feliks M. Landa, Jon D. Hanson

Biosystems and Agricultural Engineering Faculty Publications

The Root Zone Water Quality Model (RZWQM) is a computer model developed to simulate water, chemical, and biological processes in the root zone of agricultural management systems. As of this writing RZWQM is in the beta-testing phase of development. This article reports on a parameterization and evaluation study performed in Ohio on field corn for the crop growth component of RZWQM. The generic crop growth model in RZWQM had not previously been parameterized or tested on field corn. This article reports the results of such a study. One year of data was used to calibrate RZWQM, and two additional years …

Evaluation Of Gps For Applications In Precision Agriculture, Steven C. Borgelt, John D. Harrison, Kenneth A. Sudduth, Stuart J. Birrell

Stuart J. Birrell

Location coordinate information is needed in precision agriculture to map in-field variability, and to serve as a control input for variable rate application. Differential global positioning system (DGPS) measurement techniques were compared with other independent data sources for sample point location and combine yield mapping operations. Sample point location could be determined to within 1 m (3 ft) 2dRMS using C/A code processing techniques and data from a high-performance GPS receiver. Higher accuracies could be obtained with carrier phase kinematic positioning methods, but this required more time and was a less robust technique with a greater potential for data acquisition …

Nutrient Mapping Implications Of Short-Range Variability, Stuart J. Birrell

Stuart J. Birrell

Successful site specific nutrient application depends on accurate soil nutrient maps, which are generally developed from grid samples. The implication of short range variability for soil nutrient mapping is investigated. Interpretation of soil nutrient maps must consider the level of confidence associated with estimated values.

Analysis Of Spatial Factors Influencing Crop Yield, K. A. Sudduth, S. T. Drummond, Stuart J. Birrell, N. R. Kitchen

Stuart J. Birrell

The spatial relationship between crop yields and soil and site parameters was modeled using several methods. Yield maps estimated by projection pursuit regression and neural network analysis agreed well with measured yields. These methods also allowed generation of response curves for estimated yield as a function of each of the input parameters. These response curves were useful for investigating the relationship between yields and individual soil and site parameters.

Missouri Precision Agriculture, N. R. Kitchen, K. A. Sudduth, Stuart J. Birrell, S. C. Borgelt

Stuart J. Birrell

A number of projects related to different facets of precision agriculture are being carried out by an interdisciplinary team of scientists and engineers with the University of Missouri and the USDA Agricultural Research Service. This paper provides an overview of those projects.