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 …