Forage Quantity and Quality Dynamics Due to Weathering over the Dry Season on California Annual Rangelands

Livestock obtain forage by grazing on rangeland. In California annual rangelands, residual dry matter is commonly used to determine proper levels. Rangeland biomass and quality can degrade dramatically during the dormant summer period. We examined 25 sites across an rainfall gradient (183–492 mm) over 3 contrasting yr (2015–2017) that varied from 57% 152% of average precipitation. Overall fractional loss was 54.4% (range = 46.5–61.5%) with greater losses occurring in years. Biomass were related amount peak standing crop plant composition—both a function Fractional seasonal 2015 962 kg/ha (61.5% seasonal; 9.7% monthly), 2016 1 541 (55.0% 8.7%monthly) 2017 923 (46.5% 7.3%, monthly). Forage metrics strongly affected weathering processes. Crude protein concentrations decreased 33.6%, 27.7%, 21.0% 2015, 2016, 2017, respectively. contrast, relative fiber lignin (acid detergent [ADF] cellulose + lignin) weathered showed increases for ADF: 44.6% (2015), 32.2% (2016), 24.1% (2017). Increased varied: 3.4% 23.9% 28.0% 2017. While ADF (weathered biomass, kg/ha) increased process, stock 39.3% (ADF) 46.6% (lignin), compared overall CP 67.1%. The significant aboveground as processes occurred throughout period affects livestock strategies. nutrient through season should be considered when determining strategies achieve levels supplementation regimes before onset rainy season.