Tuesday, November 6, 2007 - 4:00 PM
230-17
Saline Drainage and Waste Water Use and its Effects on Forages and Livestock.
Shallow saline water tables in the western San Joaquin Valley result from regional water management and irrigation. Since 1999, saline-sodic drainage and other waste waters (range: ECiw: 2-10 dS m-1) have been used to irrigate Bermuda grass (Cyanodon dactylon) grazed rotationally by cattle at a 30 ha acre site in Kings County . Forage yield and quality and livestock performance have been monitored. Forage sampling occurred at sites selected to reflect varying soil salinity across the site measured as ECe (range: 7 to 30 dS m-1). Bermuda grass grew up to ECe levels of approximately 22 dS m-1. Biomass available at the start of grazing cycles during summer varied from 1.5 Mg DM ha-1 to 2.5 Mg DM ha-1. On a hay basis, forage CP contents averaged 9.0 %, (range: 4.2 to 22.1%), ADF: 29.6 % (range: 20.7 to 42.3), B: 245.4 mg kg-1 DW (range: 73 to 1004), Mo: 1.44 mg kg-1 DW (range: 0.3 to 5.3). Cu:Mo ratios averaged 5.2. CP and trace element content were greater in the upper portion of the canopy selected by cattle; Na content was greatest in the lower portion of the canopy. Forage Na and S contents were correlated with soil analyses. Intake by beef cattle varied from 40 to 60 % of standing biomass, depending on variable stocking rates, time of year and management. Non-supplemented average daily gains ranged from 0.1 to 0.75 kg d-1, depending on stocking rate, which varied over a three year study period depending on the objectives of the grazer. No adverse livestock health effects were observed.
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