Showing papers in "Transactions of the ASABE in 1987"

GLEAMS: Groundwater Loading Effects of Agricultural Management Systems

Abstract: GLEAMS (Groundwater Loading Effects of Agricul-tural Management Systems) is a mathematical model developed for field-size areas to evaluate the effects of agricultural management systems on the movement of agricultural chemicals within and through the plant root zone. This paper describes the concepts of the hydrology, erosion, and pesticide components of GLEAMS. Results of sensitivity analysis and validation with observed bromide and pesticide data are given. The validation includes comparisons of model simulations and observed soil concentrations in the root zone, and simulated and observed leaching losses.

Revised slope steepness factor for the universal soil loss equation

Abstract: Areanalysis of historical and recent data from both natural and simulated rainfall soil erosion plots has resulted in new slope steepness relationships for the Universal Soil Loss Equation. For long slopes on which both interrill and rill erosion occur, the relationships consist of two linear segments with a breakpoint at 9% slope. These relationships predict less erosion than current relationships on slopes steeper than 9% and slopes flatter than about 1%. A separate equation is proposed for the slope effect on short slopes where only interrill erosion is present. For conditions where surface flow over thaw-weakened soil dominates the erosion process, two relationships with a breakpoint at 9% slope are presented.

storm Erosivity Using Idealized Intensity Distributions

Abstract: EQUATIONS were derived that compute storm rainfall energy, maximum thirty-minute intensity, and erosivity directly from rainfall amount, storm duration, and tabulated factor values. The method was based on the assumption of idealized rainfall intensity distributions where intensities were arranged in descending order. Several observed storms were evaluated to determine how well the distributions fit observed data and to determine parameter values for individual rainfall events. Each distribution was described by a nonuniformity coefficient, which was defined by a relationship between peak and average intensity. A revised unit energy equation was also developed and used to compute storm energy values by this method. These values were very close to those computed by standard procedures for the Universal Soil Loss Equation (USLE). The method tends to overestimate maximum 30 min intensity, which in general gives larger rainfall erosivity values than does the USLE procedure. Please view the PDF for the complete article. The text below is only to aid searches. It is unformatted and incomplete, lacking figures, tables, and equations.

Using volatile fatty acid relationships to predict anaerobic digester failure.

Abstract: DURING recent years, a number of observations have been made in the literature regarding the level and ratio of certain organic acids and the correlation of these acid relationships with anaerobic digester performance, either complete failure or operation in a stressed state. It is an accepted fact that levels of organic acids are important in digestion for two reasons: (a) organic acids (particularly acetic) are the immediate precursors in the metabolic chain leading to methane formation and (b) if present in high concentration, acids are known to cause stress in the microbial population and can ultimately lead to complete process failure. The recent literature (approximately the last 7 years) was searched for digester performance data and organic acid levels. Seventy observations were used in arriving at a relationship between acetic acid level and propionic to acetic acid ratio and digester failure or success. Methane productivity (L CH4/g VS added) was used as the parameter determining digester performance. A defmite trend was recognized that suggests acetic acid levels in excess of 800 mg/L or a propionic to acetic acid ratio greater than 1.4 indicate impending digester failure. A laboratory scale study was then conducted to verify this phenomenon.

Crop Coefficients Derived from Reflected Canopy Radiation: A Concept

Abstract: SIMILARITIES between the crop coefficient curve and a vegetation index showed potential for modeling a vegetation index into a crop coefficient. Therefore, the possibility of directly estimating the crop coefficient from measured reflectance properties of a crop/soil scene was investigated. Reflected canopy radiation in the 0.63 to 0.69 jwm and 0.76 to 0.90 jjim band widths was measured normal to and two meters above corn (Zea mays L.), and the normalized difference (ND) vegetation index was computed. The seasonal ND curve was curvilinear and resembled the basal crop coefficient (K^b) curve for corn. Leaf area index and canopy shading were 3.2 and 77.6%, respectively, when the ND reached its maximum valvue. A linear transformation of the ND was developed by equating the ND at effective cover and for dry, bare soil at the experimental site to the K^b at effective cover and for dry soil evaporation, respectively. This transformation produced a seasonal curve very similar to the basal crop coefficient curve and was named the basal spectral crop coefficient (K^J. Crop coefficients derived from spectral measurements are independent of the usual time base parameters, planting date and effective cover date, associated with traditional crop coefficients. Thus, the basal spectral crop coefficient is a real-time crop coefficient that permits the crop to express its response to weather, management practices, and stresses.

Dry Matter Level Effects on Alfalfa Silage Quality I. Nitrogen Transformations

Abstract: The effect of initial dry matter (DM) level on the nitrogen tranformations occurring in alfalfa silage was studied. Four dry matter (DM) levels (from unwilted to 64% DM) during three harvests (early June, mid-July and late August) were harvested using a mower-conditioner and forage chopper and ensiled in mini-silos. Silages were analyzed after 0, 1, 2, 3, 4, 5, 7, 10, 14 and 60 days for pH, moisture, and various nitrogen forms. With the exception of some of the unwilted silages, the final concentrations of non-protein nitrogen, free amino acids and ammonia decreased with increasing dry matter within a harvest. Initial proteolysis rate decreased linearly with increasing DM level. However, the proteolysis rate decreased exponentially with time at a rate independent of DM level (0.0456 h-i). Ammonia formation was reduced by increasing DM level although differences among harvests affected ammonia levels as well.

Effects of Oven Drying Temperature and Drying Time on Rough Rice Moisture Content Determination

Abstract: THE effects of oven drying temperature and drying time on whole-kernel, long-grain rough rice moisture content determination were investigated for different moisture content levels ranging from approximately 9 to 22% (w.b.). The results showed that a simplified oven method can be used for rapid moisture measurement with accuracy comparable to that of a standard Association of Official Analytical Chemists (AOAC) method. An equation was developed that relates the apparent moisture content determined using a given drying time and temperature to the moisture content determined by the standard AOAC method.

Cone Penetrometer Applications — A Review

Abstract: THIS report provides a history of cone penetrometers, a description of the various types, an explanation of the factors affecting the penetration resistance, and a discussion of possible applications of cone penetrometers.

Soil Roughness Changes from Rainfall

Abstract: CHANGES in soil surface roughness were measured for three tillage systems following the application of a series of simulated rainstorms. Tillage systems were chisel, chisel + disking, and chisel + disking + harrowing. Rain with an intensity of 50 mm-h-i and an energy rate of 0.0275 kJ-m~2 per mm of water was applied in storms of 0.3, 0.5, 0.7, 1.5, 3.0 and 6 h durations. Soil surface roughness was expressed by a parameter R which represented the effect of clod size and frequency. Roughness changes could be described by the function R = Cj + C2 exp( —C3-r) where r is the cumulative rainfall. Autocorrelation analysis showed substantial variation in the spatial dependency of (a) the roughness parameter R among tillage systems and (b) the measured elevations on a transect following different rainstorm events.

A Stress State Transducer for Soil

Abstract: Atransducer was developed that measured normal pressures in six predetermined directions to provide data for mathematically determining the complete stress state in soil. The stress state transducer was evaluated under hydrostatic loading in both a sand and a clay. All six sensing elements registered within 6% of the applied pressure.

The Roles of Rainfall and Runoff in the Sediment Transport Capacity of Interrill Flow

Abstract: Alaboratory study was conducted to examine the transport capacity of interrill flow. Experiments were performed in flows with and without rainfall to isolate the contributions to transport capacity from surface runoff and raindrop impact. Theory and measurement indicated that the runoff contribution was determined by discharge and bedslope. The transport capacity was greatly enhanced by raindrop impact, and the enhancement depended on rainfall intensity and bedslope. Rainfall momentum and kinetic energy fluxes were also significant in explaining the transport enhancement. Interrill transport capacity equations based on the separate runoff and raindrop impact contributions were developed. Simpler equations, with the two contributions lumped, were also investigated. Rainfall-disturbed flows were better able to transport the larger particles of the sediment mixture. However, observations of restricted flow competence suggested that the transport capacity of interrill flow is dependent on soil, as well as on hydraulic and rainfall properties.

Enhancement of Subsoiling Effect on Soil Strength by Conservation Tillage

Abstract: THE effects of deep tillage are believed to differ for conventional vs. conservation tillage in the sandy Ultisols of the southeastern Coastal Plains of the United States. To test this, cone indices were measured for a conventional tillage and a conservation tillage treatment before and after in-row subsoil-planting. In the first year of the study, the conservation tillage treatment had a significantly higher moisture content (15.1 vs 12.1% on a dry weight basis) and a mean soil strength that was 0.70 MPa less than the conventional treatment. In the second year, the conservation tillage treatment had a lower moisture content (13.2 vs. 14.9%) and a mean soil strength that was 0.29 MPa greater than the conventional treatment. However, after conventional treatment strengths were corrected for soil moisture content differences, the mean strengths were about the same. The differences in the distribution of the strengths favored the conservation tillage treatment which was evenly distributed while the conventional tillage treatment had areas of higher strength that could more easily inhibit root growth.

Color Vision in Robotic Fruit Harvesting

Abstract: THIS report discusses the use of chrominance information in natural scenes to enhance digital color images used to control a robotic manipulator for fruit harvest. By exploiting the natural high contrast in color between fruit and other objects in a color image the ability to differentiate citrus fruit from background leaves, soil, and sky is demonstrated.

Infiltration Response to Kinetic Energy

Abstract: THE effect of water droplet kinetic energy and application intensity on exposed and covered, dry and wet soil surfaces was investigated on a mixed Udic HaploboroU Vienna loam soil in eastern South Dakota. A modified Purdue type infiltrometer was used to produce different rainfall energy and intensity levels of tilled soil. Soil surface seal development was evident in the reduction of water infiltrated after given time periods and in the reduced infiltration rates with increasing kinetic energy levels of the applied water. The droplet energy flux density level at incipient runoff may help quantify the surface sealing reaction of the soil..

Thermal Environment Effects on Growing-Finishing Swine Part I—Growth, Feed Intake and Heat Production

Abstract: SIXTY crossbred gilts were reared two per pen in five pens each at environmental temperatures of 5, 10, 15, 20, 25 and 30°C Animals initially weighed an average of 436 kg and were slaughtered at an average weight of 867 kg Statistically, growth rate was unaffected by temperature from 5 to 20°C However, there was a trend toward decreased growth rate from 20 to 5°C and substantial decreases above 20°C Feed intake decreased as temperature increased from 5 to 30°C and was related to temperature by a polynominal function Heat production per unit weight decreased with increasing temperature and increased with increasing feed intake and body weight The heat production data were fitted to a multiple linear regression equation Conversion of feed to gain was most efficient at 20 and 25°C The data define a broad range of acceptable thermal conditions rather than a singluar optimal environmental temperature

Simulating subsurface drainage in the lower Mississippi Valley with DRAINMOD.

Abstract: DATA from a subsurface drainage-runoff-erosion field experiment near Baton Rouge, LA, were used to evaluate the water managment model, DRAINMOD, for simulating subsurface drainage in the lower Mississippi Valley. Predicted and measured surface runoff, subsurface drain flow, and water table depth were compared for 3 years, 1981, 1982 and 1983 which were, respectively, normal-to-wet, drier than normal, and very wet in growing season soil water conditions. Model predicted runoff, drain flow, and water table depth compared more closely with the field measured (observed) values during the wettest year, 1983. For the drier-than-normal year, 1982, runoff and drain flow were significantly overpredicted because evapotranspiration (ET) was underestimated by the model. Assumed deeper rooting for corn in 1982 increased soil water withdrawal by ET and significantly improved predictions of water table depth.

Sensitivity of spectral vegetative indices to crop biomass

Abstract: THE sensitivity of three commonly used spectral vegetative indices—ratio (R43), normalized difference (ND43), and greenness (GR43); to plant canopy variables was compared for four row crops. An exponential equation was fitted to nontransformed spectral and canopy variable values and a linear equation was applied to normalized data values to describe the spectral vegetative index (VI)—canopy variable relations. R43 asymptotic values for the exponential relationship were highest; however, ND43 and GR43 were more highly correlated with LAI and ground cover over the complete range of values. Relative rates of change (normalized derivatives) of the exponential equations relating the VI to LAI were smallest for ND43. The normalized linear equations indicated that R43 had greater sensitivity to biomass and LAI than GR43 and ND43. The sensitivity of all VI was highest to ground cover, but the sensitivity of ND43 was lower than that of R43 and GR43. Overall R43 is more sensitive to high levels of biomass and LAI, but when crops are small ND43 and GR43 may be the best estimators of LAI and ground cover.

Measurement of Low Pressure Sprinkler Evaporation Loss

Abstract: EVAPORATION loss from low pressure spray type sprinklers was investigated using the potassium ion as a chemical tracer in the irrigation water. Potassium ion concentrations were monitored in surface caught water and in the atmosphere 60-m downwind from a line source simulating a continuously moving irrigation machine. Evaporation losses ranged from 0.5 to 1.4% for smooth spray plate sprinklers and from 0.4 to 0.6% for coarse serrated sprinklers. Measured evaporation values for the smooth spray plate sprinklers were highly correlated (R2 = 0.98) with calculated values from Kinzer and Gunn's (1951) laboratory work.

Numerical Modeling of Natural Convection Heating in Canned Liquid Foods

Abstract: Amathematical model was developed for the first time for predicting detailed flow patterns and temperature profiles during natural convection heating of canned liquids. Finite difference methods were used to solve the governing Navier-Stokes equations in axisymmetric cylindrical coordinates. A vorticity-stream function formulation of the equations was used. Details of the numerical techniques used are discussed. Plots of transient isotherms, streamlines and velocities are provided. From the standpoint of food processing, the slowest heating points migrated within the bottom 15% of the can with no particular pattern of migration.

Technical Notes: Estimation of Gross Heating Values of Biomass Fuels

Abstract: EXPERIMENTAL data reported in the literature for gross heating values of various types of biomass were correlated with heating values that were estimated using the Boie equation This equation was originally developed to estimate the gross heating values of fossil fuels from their respective compositions of carbon, hydrogen, oxygen, nitrogen, and sulfur The estimated heating values agreed within 50% of the experimental data for 47 types of plants and crop residues and within 8% for cattle feedlot manure of normal quality This correlation makes it possible to accurately predict the gross heating values of most biomass fuels of known ultimate composition and ash content

statistical Approach for Drip Lateral Design

Abstract: A design technique was developed using a statistical approach. This technique is based upon the coefficient of variation of pressure head along a lateral line and the variations of emitter flow caused by manufacturer. Considering the proportionality factor K, and the pressure head H in the emitter flow equation, q = KH^ as two random variables, an equation for mean emitter flow can be derived using Taylor's theorem. The coefficient of variation of K indicates the manufacturer's variation. The coefficient of variation of pressure head is determined statistically from the average and variance of pressure head which is affected by friction and slope changes along the lateral line. Once a design criterion of an emitter flow variation (expressed as the coefficient of variation) is set and a type of emitter is selected, the required coefficient of variation of pressure head for the lateral line can be calculated and the design length can be determined.

Fruit location in a partially occluded image

Abstract: .D IGITA Limage analysis with a modified circular ^ Hough transform proved able to locate tomatoes based on shape and not color, even when the scenes contained substantial background noise and the fruit were partially hidden from view.

optimization of Pimiento Pepper Lye-Peeling Process Using Response Surface Methodology

Abstract: RESPONSE Surface Methodology (RSM) was used to evaluate the effect of lye concentration (4 to 12% NaOH), process temperature (80 to 100°C) and time (1.5 to 6.5 min) on the yield, peeling loss and unpeeled skin, in a lye-peeling process of pimiento peppers {Capsicum annum L. cv. Truhart'). Optimization of the process was performed to result maximum removal of the skin and minimum loss of edible fruit. Computer generated response surfaces, canonical analysis and contour plot interpretation revealed that relatively high lye concentration (12% NaOH) combined with short processing time (1.6 to 2 min) at a moderate temperature of around 90°C should yield an optimum process with practically all the skin removed and peeling loss as low as 20%.

Determination of peach firmness by analysis of impact force

Abstract: IMPACT forces of peaches striking a rigid surface were analyzed as a means for prediction of firmness and, hence, maturity. The impact force characteristics C2 (peak force/(time to peak force)^) and F295 (295 Hz spectrum magnitude) were highly correlated with fruit elastic modulus and penetrometer measurements of flesh firmness, and poorly correlated with mass and radius. These characteristics could be used to distinguish immature and mature peaches from threshold mature fruit, but the firmness sorting resolution was affected by variations in impact location. A band-pass filter circuit was constructed and tested to automatically sense the desired frequency components of the impact force signal.

Thermophysical Properties of Meat Products: General Bibliography and Experimental Values

Abstract: Experimental values for thermophysical properties of different kinds of meats are here presented such as: thermal conductivity, enthalpy, heat capacity, thermal diffusivity and density. All these values were obtained from an extensive selection of the existent bibliography. They correspond to measurements made at the normal temperature range during cooling and freezing processes. In the present work a complete and detailed table of bibliography is presented in order to facilitate the attainment of information about experimental data, measurement techniques and mathematical equations.

Moisture and Storage Effects on Dry Matter and Quality Losses of Alfalfa in Round Bales

Abstract: ALFALFA (Medicago sativa L.) hay storage in round bales has increased in recent years in the North Central region. Experiments were conducted to measure alfalfa moisture concentration and storage method effects on dry matter and quality losses during storage either inside or outside. Acid detergent fiber concentration immediately after baling increased as moisture decreased indicating significant effects on leaf loss during baling. However, alfalfa baled at higher moisture had a higher percentage of its N in the acid detergent insoluble-N fraction after 3 months of storage. Bales stored outside lost 9.1% of their initial DM and 13.6% of m vitro digestible DM compared with 3.8 and 7.5%, respectively, for similar bales stored inside. Round and rectangular bales stored inside were similar in quality before storage and had similar DM losses during storage. However, round bales were higher in neutral detergent fiber after storage than rectangular bales in most cases, but did not differ in N concentration. Weathered hay from bales stored outside was much lower in nonstructural carbohydrates and higher in fiber than samples of the entire package. Alfalfa treated with 10 kg Mg ' of a propionic:acetic acid mixture (80/20 w/w) had storage losses similar to those for dry hay baled with no treatment.

Control of orchard spraying based on electronic sensing of target characteristics

Abstract: Aconventional air-carrier orchard sprayer was retrofitted with a microcomputer-based sprayer control system. A foliage volume measurement system, based on ultrasonic range trandsucers was interfaced to a computer. Three 3-nozzle manifolds on each side of the sprayer were controlled by the computer using control algorithms based on spray deposition studies. Use of the full control system resulted in spray volume savings ranging from 28 to 35% and 36 to 52% in peaches and apples, respectively. A simple intermittent control system resulted in savings from 10 to 17% in peaches and 21 to 28% in apples. In orchard comparisons between controlled vs. uncontrolled sprayer operation, spray deposition from the controlled sprayer was found to be reduced at some locations.

Modeling Potato Tuber Mass with Tuber Dimensions

Abstract: THIRTEEN models for predicting potato tuber mass from tuber dimensions were identified and used to evaluate theoretical limits of performance for mechanical and electronic potato tuber sorting devices. The models were divided into three classes based on: (1) single and multiple variable regression of the tuber length, width and height, (2) approximation of tuber shape by an ellipsoid, and (3) approximation of tuber shape by summation of thin disks. Tuber silhouettes were recorded and analyzed using digital imaging equipment and techniques. Class 3 models were most accurate, followed by Class 2 and Class 1 models. Class 1 models were the most simple, Class 3 most complex. Class 3 models could predict tuber mass within 25 g only 70% of the time, Class 2 models, 90% of the time and Class 1 models over 99% of the time..

Measurement of Soil Bulk Density and Moisture

Abstract: BULK density and moisture content of soil influence the soil conditions created by tillage, vehicle trafficability, soil compaction caused by vehicles, water infiltration and drainage, and crop growth. Measurement and description of soil conditions are necessary for correct management decisions to create soil conditions that will maximize short- and long-term crop production. Techniques for measurement of soil bulk density and soil moisture are reviewed and advantages and disadvantages of each method discussed. Although the physical properties of the surface layer of soil are very important, properties in that layer are the most difficult to measure. There are no quick, easy, and accurate methods for determination of soil bulk density or soil moisture content. However, there are several methods for each that may be used successfully.

Study of Impact and Compression Damage on Asian Pears

Abstract: RESULTS of impact and compression tests on Chojuro, Twentieth Century, Tsu Li, and Ya Li varieties of Asian pears indicate that Chojuro pears are the firmest and most resistant to mechanical damage. At the time of harvest, Tsu Li and Ya Li pears could resist mechanical damage nearly as well as Chojuro pears, but they become more susceptible to bruising in cold storage. Twentieth Century pears are most sensitive to impact and compression bruising. Increased time in the ripening room produces more softening and increased bruise resistance of Chojuro and Twentieth Century pears than of Tsu Li and Ya Li pears.