Khaled Bali

Water Application Under Varying Soil and Intake Opportunity Time

ABSTRACT ADVANCE trajectories and irrigation performance resulting from volume balance model simulation with spatially averaged and spatially varying infiltraion characteristics were compared with actual irrigation results. Field measured water application uniformity was lower than uniformity simulated with a volume balance model which allowed for spatially varying infiltration function characteristics. Measured and simulated advance trajectories were in close agreement.

Comparison of ALARM and SEBAL Evapotranspiration of Irrigated Alfalfa

Estimating crop evapotranspiration (ETc) is essential for effective agricultural water management and water resources planning. The objective of this study was to compare two methods for estimating daily crop ET (ETc). The first method used the Analytical Land Atmosphere Radiometer Model (ALARM) and the dimensionless temperature (DT) (ALARM-D) procedure, while the second method used the Surface Energy Balance Algorithm for Land (SEBAL). A study was conducted on an irrigated alfalfa field in southern California in summer 2008. Standard meteorological data from a weather station and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Moderate Resolution Imaging Spectroradiometer (MODIS) surface temperature were used to estimate ETc. Observed hourly and daily ETc were determined using surface renewal meteorological method. On average, the relative error of the ASTER 90-m pixel hourly and daily ETc was 8 and 1.2 and -10.3 and -16.3 % for ALARM-D and SEBAL, respectively. For 1-km pixels, MODIS and ASTER (upscaled) ALARM-D daily ET estimates were higher than SEBAL and ASTER ALARM-D and SEBAL daily ETc was greater than MODIS ALARM-D and SEBAL daily ETc. These initial results suggest that the performance of ALARM-D and SEBAL was comparable in hourly ETc estimation while ALARM-D outperformed SEBAL in daily ETc.. More studies in diverse locations and environmental conditions are needed before solid conclusions can be drawn about how ALARM-D and SEBAL compare in hourly and daily ETc estimation.

Estimating Evapotranspiration of Fully-and Deficit-irrigated Alfalfa in Commercial Fields with the Eddy Covariance and Surface Renewal Methods

Evapotranspiration (ET) of fully irrigated and deficit irrigated (no irrigation in July, August, and September) was measured in four commercial alfalfa fields with the eddy covariance (EC) and surface renewal (SR) energy balance methods. Both EC and SR methods were used in the fully irrigated part of the fields, while the SR method only was used in the deficit irrigated part. Deficit irrigation reduced ET, but the amount of reduction was highly site specific. Good agreement was found between the EC and SR methods. However, patterns of the daily differences between the EC and SR methods differed between the four fields.

Management Practices for Phosphorus and Sediment Reduction in the Salton Sea Watershed

Abstract — Nutrients, sediment and silt in drainage waters have been identified as the leading cause for water quality impairments in rivers and waterbodies in California. Approximately one-third of applied irrigation water leaves irrigated field as surface runoff and subsurface drainage. In this project, we implemented seven standard and improved irrigation and fertigation management practices on a commercial alfalfa field to reduce the load and concentration of phosphorus and sediment in drainage waters. Reducing the amount of surface runoff after the application of P fertilizer is a key factor in reducing the load of P in drainage waters. The loads of P in runoff waters were reduced by as much as 75% compared to normal irrigation and fertigation practices. Water-run application of P increased the concentration and load of P in runoff water by almost 100% compare to broadcast P applications. Avoiding water-run applications can reduce the load of P in runoff water by more than 50%.

Mid-Summer Deficit Irrigation of Alfalfa as a Strategy for Saving Water

Alfalfa is California’s single largest agricultural water user due to its large acreage and long growing season, using 4 to 5.5 million acre feet of water each year. Because of this water use, the California Department of Water Resources is interested in deficit irrigation of alfalfa for providing water for transfer elsewhere. One strategy is to terminate irrigation during July and August when alfalfa yields are relatively small and use the “saved” water for nonagricultural uses. The amount of transferable water would be the difference in the evapotranspiration (ETc) of a fully-irrigated field and that of a deficit-irrigated field; however, no information exists on the potential ETc differences. Evapotranspiration was determined in a commercial field using the eddy covariance and surface renewal energy balance methods in a fully irrigated part of the field, and the surface renewal method in the deficit irrigated part of the field. In addition, alfalfa yield, applied water, canopy coverage and plant height measurements were made in both parts of the field. Deficit irrigation greatly reduce alfalfa yield in 2003, 2004, and 2005. Yield reductions due to deficit irrigation generally ranged from 41 to 88% of the fullyirrigated treatments. Cumulative ETc in 2005 was 48.1 inches for the fullyirrigated treatment. Deficit irrigation (no irrigation) started on July 25. Cumulative ETc between July 25 and December 6 (end of measurement period) was 20.8 inches for the fully irrigated treatment and 11.4 inches for the deficit irrigated treatment for a difference of 9.4 inches. INTRODUCTION Water transfers from the water-rich agricultural areas of northern California are ______________________ 1 Extension Irrigation and Drainage Specialist, Dept. of Land, Air and Water Resources, University of California, Davis, CA; brhanson@ucdavis.edu 2 Extension Forage Specialist, Dept. of Plant and Environmental Sciences, University of California. Davis, CA; dhputnam@ucdavis.edu. 3 Extension Biometeorology Specialist, Dept. of Land, Air and Water Resources, University of California, Davis, CA; rlsnyder@ucdavis.edu

Midsummer deficit irrigation of alfalfa as a strategy for providing water for water-short areas.

Alfalfa is California’s single largest agricultural water user due to its large acreage and long growing season. As a result, interest exists in midsummer deficit irrigation (no irrigation in July, August, and September) of alfalfa in water-rich areas to provide water for water-short areas with the amount of transferred water equal to the difference in the evapotranspiration (ET) between fully-irrigated and deficit irrigated alfalfa. However, little data exists on the ET of midsummer deficit-irrigated alfalfa. Commercial fields were selected for fully-irrigated and deficit-irrigated irrigation treatments of alfalfa. The fullyirrigated alfalfa was irrigated according to the irrigator’s normal practices. The deficit irrigation treatments were no irrigation in July through to September. Alfalfa ET was measured using the eddy covariance and surface renewal energy balance methods. Deficit irrigation of alfalfa during the midsummer reduced both ET and yield. The amount of reduction, however, was very site-specific. The Davis site showed the largest reduction in ET (198 mm), while the other sites showed much smaller reductions (5 to 62 mm).

Small Grain Production Manual (complete)

Author(s): Jackson, Lee; Fernandez, Bonnie; Meister, Herman; Spiller, Monica; Jackson, Lee; Williams, Jack; Kearney, Tom; Marsh, Brian; Wright, Steve; Jackson, Lee; Munier, Doug; Kearney, Tom; Pettygrove, G S; Brittan, Kent; Mathews, Marsha; Jackson, Lee; Fulton, Allan; Bali, Khaled; Mousli, Zak; Jackson, Lee; Jackson, Lee; Godfrey, Larry; Natwick, Eric; Wright, Steve; Jackson, Lee; Whisson, Desley; Salmon, Terrell; Jackson, Lee; Canevari, Mick; Orloff, Steve; Vargas, Ron; Wright, Steve; Wilson, Rob; Cudney, Dave; Jackson, Lee; Collar, Carol; Orloff, Steve; Mathews, Marsha; Wright, Steve; Jackson, Lee; Mitchell, Jeff; van Horn, Mark; Munier, Doug; Jackson, Lee; Marsh, Brian; Jackson, Lee; Kearney, Tom; Garcia, Sergio; Jackson, Lee; Canevari, Mick; Vargas, Ron; Wright, Steve; Jackson, Lee | Abstract: The Small Grain Production Manual is a 14-part free online publication that presents essential information on producing wheat, barley, oat, triticale, and rye, from growth and development through seedbed preparation, fertilization, and irrigation, to pest management, crop rotation, cover cropping, and harvesting and storage. The manual also includes an overview of small grain production in California, as well as a handy troubleshooting guide. Color photographs, drawings, charts, graphs, tables, and references. This download includes all 14 parts of the Small Grain Production Manual.