1. Correlating Soil Moisture with Forage Quality in Sierra Valley and Goodrich Creek 26 February 2007 Quincy, CA Laura A. Murphy University of California, Davis

2. Outline Objectives Motivation Study Plan –Location –Site and sampling design Preliminary results –Biomass utilization (palatability) –Crude Protein –TDN (energy) –Depth to water table

3. Objectives Investigate the correlation between soil moisture conditions and forage quality (palatability and nutrition): Is there an optimal soil moisture condition for this area? Consider whether irrigation management for optimal soil moisture condition is economically worthwhile, in terms of enhanced forage.

4. Why do we think irrigation is linked to forage quality? –Bridgeport Valley example (from: K. Tate)

5. Study Plan Locations –3 ranches in SV; 1 ranch in GC Layout –1 m 2 cage to exclude grazing –1 observation well (to 1 meter where possible) –4 soil moisture sensors: 2 at 10”; 2 at 20” Well Data logger Sensors

6. Study Plan (ct’d.) What was monitored and when (May-Sept) –Depth to water table (WT): 1 per month –Soil moisture: 1 per hour, continuous –Biomass in and outside cages (Ocular estimate calibrated by clipped sample): 1 per month –Forage biomass samples taken for forage quality analysis, including: crude protein, fiber, fat, energy, Ca, Mg, K, P, Na, Fe, Mn, Zn, Cu: 1 per month

7. Cages in the field

8. Preliminary Results

13. Preliminary conclusions Utilization by cattle appears to be correlated with both soil moisture conditions and crude protein content Forage with higher crude protein throughout season is more utilized than forage with lower/decreasing crude protein Higher utilization of forage where water table is below surface but maintained throughout season