Overview. Irrigated Pasture. Practices. Rangeland. Grazing Intensity 10/28/2010. Effective Grazing Land Conservation Supporting Research

Transcription

1 Effective Grazing Land Conservation Supporting Research Ken Tate, UCD Plant Sciences CA NRCS All Employees Conference, Sacramento October 27, 21 Overview Grazing conservation practices: under scrutiny. Report some current research results. Introduce some new projects. L. Roche, R. Atwill, R. Dahlgren, T. O Geen, D. Lewis, B. Jones, D. Lile, N. McDougald, D. Dudley Practices : intensity, season, frequency of grazing; rest Irrigated Pasture Grazing Facilities: water, fencing Filter Strips: trap pollutants in runoff Brush Management: conversion to grass Rangeland Plants, soil, water, habitat Grazing intensity is a critical conservation tool Sustainab bility Intensity (AU/ac or AU/ac/yr) 1

2 Bulk Density (g cm - 3 ) No grazing 2+ years Light grazing, >12 lb/ac RDM Moderate grazing, g, 8 lb/ac RDM Heavy grazing, <5 lb/ac RDM NO L M H Stream Water Quality Sediment mg/l Nitrate mg/l E. Coli cfu/1ml None lb/ac RDM Moderate 8 lb/ac RDM Heavy 5 lb/ac RDM Timing of grazing is a critical conservation tool Microbial pollutants decline exponentially in fecal pats during Spring, Summer, Fall days E. coli reduced by rest from grazing before irrigation i (cfu/1 ml) E. coli 5, Above Wetland 4, Below Wetland 3, 2, Off set timing of grazing and 1, irrigation rotational grazing Days Since Grazed Late season use detrimental to plants such as aspen and willow Earlyseasonuse and infrequent rest from grazing OK 2

3 Conclusions Rest Rotation Grazing System Aspen Pasture Year 1: graze early season Year 2: graze mid season Year 3: graze late season Year 4: rest if needed, or graze early season Year 5: graze mid season Etc. aspen Grazing distribution is a critical conservation tool Grazing and meadow stream health Time spent distributing livestock away from riparian area increases stream health Stream He ealth and Frequency Number of Taxa 3 25 Total Taxa 2 Cobble Gravel Fines Livestock Distribution Effort (days/yr) 6% of cattle fecal loading is near livestock attractants (e.g., shade, water) Vegetative Filter Strips A critical conservation tool 3

4 Annual rangeland filter strips Attenuation of pollutants in irrigated pasture runoff by small wetlands >9% of E. coli retained in the fecal pat or trapped within 1 ft Rainfall An additional 7% to 99.9% trapped within ihi 1 yard of pat pat duction Percent red Functioning wetland Channelized wetland -6 E. coli Sediment (TSS) NO 3 -N Total N Total P PO 4 -P Agricultural Benefit Production data: UC SFREC Stocking Rate acre/auy Brush Management Treatment 26 none oak woodland 13 thin to 3% oak cover 7 thin to 1% oak cover Brush Management A practice with trade offs 6 thin to % oak cover Oaks, shrubs important to maintaining ecosystem services balance forage increase w/ conservation Metric Oak Woodland Grassland Total N Total C 52 3 Infiltration Diversity to Restore Rangeland Soil Quality, Plant Diversity, Water Quality, and Agricultural Productivity N. pulchra (plants/m 2 ) Distance from blue oak (dripine radius) Oak recruitment K. Tate, L. Roche, V. Eviner, J. Derner, T. O Geen, M. Lubell, M. George 4

5 Manage for many outcomes, not just one, nor one at a time Mail survey to 2 CA and WY ranchers about their Mail survey to 2 CA and WY ranchers about their Mail survey to 2 CA and WY ranchers about their Ten year, 3 acre adaptive grazing management experiment at UC SFREC Mail survey to 2 CA and WY ranchers about their California Rangeland Watershed Laboratory Ten year, 3 acre adaptive grazing management experiment at UC SFREC Develop on-line grazing conservation effectiveness decision support and interactive learning tool 5