Engineering Commons^™

Water Conservation's Role In California Water Transfers, Charles M. Burt

BioResource and Agricultural Engineering

This paper describes various irrigation district water transfer projects. Water transfers have been of many types, including agriculture to agriculture, agriculture to urban, and agriculture to environment. In each case that will be described, the unique circumstances of each district will be described. Typical actions include developing a water balance to determine if “wet water” truly exists for conservation, then identifying the sources of that wet water. Subsequent actions include developing designs that will conserve the water, achieving board approval, and constructing and implementing the conservation measures.

Variability Within Irrigated Fields, Charles M. Burt, Byron Clark

BioResource and Agricultural Engineering

In agricultural production and research, it is common to represent fields as uniform areas. For example, fertilizers, soil amendments, and other inputs have traditionally been applied uniformly (or as uniformly as possible) based on estimated needs for the field as a whole (or as an “average”).

Of course, it is also recognized that fields are not truly uniform with respect to soil characteristics, uniformity of applied water, pest pressures, fertility needs, crop growth and yield, and other characteristics. With the emergence and refinement of variable rate application technology, many growers now attempt to maximize returns by “prescribing” variable amounts of …

Evaluation Of Magnetic Meters For Irrigation Pipeline Measurement, Stuart Styles, Bryan Busch

BioResource and Agricultural Engineering

Magnetic flow meters are used to measure the flow rate of a liquid in a closed pipeline. This type of meter is becoming increasingly popular for measurement with agriculture applications. Electromagnetic meters were tested by the Irrigation Training and Research Center in pipelines located less than the 10 diameters upstream of disturbances with good results. Results show that location guidelines for placing a magnetic meter can be decreased even for turbulent conditions. This paper will discuss how a magnetic flow meter works, advantages and disadvantages of this type of meter, test results, and new guidelines for field applications.

Crop Coefficients And Water Use For Cowpea In The San Joaquin Valley Of California, William R. Detar

William R DeTar

To improve irrigation planning and management, a modified soil water balance method was used to determine the crop coefficients and water use for cowpea (Vigna unguiculata (L.) Walp.) in an area with a semi-arid climate. A sandy 0.8-ha field was irrigated with a subsurface drip irrigation system, and the soil moisture was closely monitored for two full seasons. The procedure used was one developed for cotton by DeTar [DeTar, W.R., 2004. Using a subsurface drip irrigation system to measure crop water use. Irrig. Sci. 23, 111–122]. Using a test and validate procedure, we first developed a double sigmoidal model to …