Neutron Physics Considerations in Moisture Probe Design
Neutron physics can be used to characterize most of the know behavior of neutrons in the soil. Scattering, absorption and slowing down are the principal processes affecting moisture probe...
Factors Affecting Neutron Gauge Calibration
Neutron gauge characteristics and soil chemistry affect gauge calibration. External factors also influence gauge calibration and should be considered in the calibration procedure. Gauge...
Access Tube Characteristics and Neutron Meter Calibration
Neutron meter calibration was found to be influenced by material type, thickness and size of access tube. Meter counts were decreased by an average of 15% for a 20% increase in tube diameter...
Relationship of Soil Type and Chemicals to the Calibration of Neutron Meters
Theory of neutron scattering and moderation in matter explains many of the characteristics of calibration curves of neutron moisture probes. Characteristics include effect of atomic species...
Using Neutron Probes to Aid Irrigation Scheduling
Neutron soil moisture measurements are used to supplement irrigation forecasts on the 60,000 acre sprinkler-irrigated Navajo Indian Irrigation Project (NIIP). Weekly irrigation forecasts...
An Assessment of Input Variables to the Penman-Monteith Equation Using Canopy Reflectance Measurements
Observing the form of the Penman-J.L. Monteith equation, it can be seen that several terms could be potentially estimated from remotely sensed data. These include: net radiation, canopy...
Stream Standards for Toxics and Irrigated Agriculture Using New Mexico as a Case Study
New Mexico follows a policy of 'antidegradation' with respect to the existing quality of a stream, but its standards specifically exclude return flows from irrigated...
Management Practice Effects on Water Quality
An array of resource conservation and water quality issues are providing research challenges and opportunities in soil and water, irrigation, and drainage. The key to addressing these...
Field Calibration of Neutron Gauges: SCS Method
Field calibration of neutron gauges is easy and requires very little time under normal circumstances. Special soil sampling equipment is required that can be fabricated by most machine...
Comparison of ET Measured with Neutron Moisture Meters and Weighing Lysimeters
The neutron moisture meter (N.M.) method of determining crop water use is frequently used in research and irrigated agriculture. This study was conducted to compare crop evapotranspiration...
Application of Neutron Soil Surface Water Monitoring for Plant Establishment
Soil surface water content measurements are tedious and time consuming, and to improve on such tasks, a neutron surface moisture probe was modified by using cadmium shielding. This prevented...
Practical Approaches Used in Neutron Meter Moisture Monitoring
This paper describes a practical, appropriate methodology for utilizing neutron meter soil moisture measurements to provide irrigation management information to farmers. A neutron meter...
Neutron Meters in Statewide Irrigation Programs
These programs have ranged from University demonstrations of new technologies on through completely locally funded and operated programs. The most significant interest has been from those...
The Colorado River Salinity Program?An Overall Perspective
Economic losses resulting from increases in salinity in the Colorado River system were estimated to be $311 million annually in 1986. As a result of protests by Mexico to the United States...
The USDA Colorado River Salinity Control Program
Approximately 37 percent of the salt contribution in the Colorado River can be attributed to irrigation activities in the river basin. The United States Department of Agriculture (USDA),...
Computation of Unsaturated Soil Parameters Using Upward Infiltration Empirical Data
The relationship between soil moisture content and hydraulic conductivity with the soil tension be defined to simulate unsaturated flow in a porous media. Direct measurements of these...
Impact of Agriculture on Ground-Water Quality on the Delmarva Peninsula
Both pesticides and nitrates have been detected in the ground water on the Delmarva Peninsula. Highest nitrate concentrations have been found on well-drained soils. Poultry manure is one...
Research Need on Integrated System for Water and Pest Management to Protect Groundwater Quality
Research is urgently needed to develop the technology for integrating the methodologies for managing soil, water, ground cover, pesticide applications, and fertilizer applications in such...
Influence of Method of Fertilizer Application on Groundwater Pollution
Researchers at New Mexico State University have been looking for methods to improve the efficiency of fertilizer application in irrigated agriculture. Preliminary results obtained in the...
Soil Water Movement in Glacial Till: A Case Study in Central South Dakota
Between 1985 and 1987, the CENDAK Drainage Steering Committee conducted several investigations to assess the drainage needs for a proposed large-scale irrigation project in central South...
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