Engineering Commons^™

Bulk Density Of A Sandy Loam: Traffic, Tillage, And Irrigation-Method Effects, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Modern crop production creates a cycle between soil compaction caused by traffic and alleviation of this condition by tillage or natural processes such as freezing and thawing. The objective of this study was to evaluate important management practices as they relate to changes in bulk density of a tilled sandy loam soil. Practices evaluated were irrigation method, time between tillage and traffic, tire pressure and wheel load of applied traffic, and controlled traffic. Relationships among bulk density, penetration resistance, and infiltration rate were determined. Experiments were conducted in the San Joaquin Valley of California, on a sandy loam soil (Entisol) …

Real-Time Irrigation Scheduling Of Cotton With An Automated Pan Evaporation System, Claude J. Phene, William R. Detar, David A. Clark

William R DeTar

High frequency irrigation control necessitates real-time

monitoring of soil water, plant water status or atmospheric

evaporative demand. The research objective was to

determine the suitability of real-time control of subsurface

drip irrigation using automated evaporation pan

measurements.

Hourly electronic measurement of water loss from an

evaporation pan was a critical feedback control element in

the irrigation scheduling of a high frequency subsurface

drip system (SDI) used to irrigate cotton. The water level

in the class "A" pan was monitored continuously using a

micrologger to measure the output of the electronic water

level sensor. The crop water needs were calculated by …

Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke

Douglas D. Stokke

Wood is a major industrial raw material, with U.S. consumption approaching that of aluminum, plastics, cement, and steel combined. Partially as a result of the magnitude of wood and wood products in use, these products constitute a substantial portion of the solid waste stream. In order to reduce the amount of wood and wood fiber disposed in landfills, efforts to recycle these materials into useful products such as structural composites are needed. The success of such conversion depends in part on knowledge of the morphological characteristics of various sources of secondary wood and wood fibers, and the influence of wood …

Feeding Patterns Of Growing Pigs At Warm Constant And Cyclic Temperatures, Hongwei Xin, James A. Deshazer

Hongwei Xin

Feeding behavior of ad libitum-fed^ 39-kg, crossbred gilts was investigated under mean ambient temperatures of 30.8° C with 0, 7, and 16.6° C cycles. Average meal size, 160 to 170 g/pig; meal duration, 13.3 to 14.3 min; and ingestion rate, 12.2 g/min-pig did not appear to be influenced by the temperature conditions. However, meal frequency, 9 to 11 per day, tended to be reduced by elevated hours of exposure to high temperatures. Consequently daily feed intake of the pigs was signiflcantly less in the 16.6° C cycle treatment than in the 0 or 7° C cycle treatments (P<0.01). Feed consumed during the lighting period (0600 h to 2100 h) accounted for 75%, 61%, and 37% of daily feed intake for the 0, 7, and 16.6° C cycle treatments, respectively. Pigs under the 0° C cycle had most feeding activities in the afternoon and evening (55% of daily feed intake). In contrast, pigs under the 16.6° C cycle had most feeding events at night and early morning (91 % of daily feed intake).

Responses Of Pre-Fasted Growing Turkeys To Acute Heat Exposure, Hongwei Xin, James A. Deshazer, Mary M. Beck

Hongwei Xin

Nicholas turkeys at the age of 15 to 16 weeks were fasted for 24 hours in a moderate environment and then subjected to acute heat exposures of various dry-bulb and wet-bulb temperatures (T^u, and T^jj). Total feed intake was not influenced by T^^ of 32*' C, 36"* C or 40° C (P > 0.10), although differences existed in dynamic feeding profiles. Total heat production rate (THP) varied quadratically with T^^, and respiratory quotient (RQ) decreased linearly with T^u,. The lower RQ values at the higher T^i^ levels may have resulted from reduced feed assimilation. No differences were detected on feed intake, …

Object-Oriented Methodology For Analyzing And Allocating Resources For Field Operations, Steven A. Freeman, A. Dale Whittaker

Steven A. Freeman

An object-oriented methodology for machinery management was developed by combining knowledge system techniques with conventional problem solving techniques. The methodology developed here, if incorporated into a machinery management tool, provides the farmer with the ability to evaluate the physical feasibility of an overall farm plan (regarding field operations) being considered for the future and to identify possible solutions when the farmer is unable to complete this overall farm plan using current resources. The developed methodology also provides the farmer with the ability to assess the progress being made toward completion of the defined calendar as a result of changes in …

Effects Of Hurricane Hugo On Agricultural Structures, Jay D. Harmon, George F. Grandle, Clyde L. Barth

Jay D. Harmon

A tour of damage to agricultural structures by hurricane Hugo was conducted. Empty grain bins which exhibited improper anchorage tended to fail. Post-frame buildings that were improperly anchored, braced or fastened failed, while others that were designed and constructed using sound engineering practices generally withstood hurricane winds.

Infiltration Rate Of A Sandy Loam Soil: Effects Of Traffic, Tillage, And Plant Roots, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar, A. L. Urie

William R DeTar

Settling and trafficking of a soil after tillage causes rapid changes in the soil physical condition until a new equilibrium is reached. In the soil studied, a Wasco (coarse-loamy, mixed, nonacid, thermic Typic Torriorthent) sandy loam, soil compaction reduces infiltration rates, which under grower conditions could result in inadequate infiltration of irrigation water to supply crop requirements. Our objective was to evaluate important management practices as they relate to changes in the infiltration rate of a sandy loam soil. Factors evaluated were traffic, tillage between crops, and the formation of channels by roots of perennial crops. Tillage between crops increased …