Grazing Management Effects on Non-point Source Pollution of Pasture Streams J.R. Russell 1, D.A. Bear 1, K.A. Schwarte 1, and M. Haan 2 1 Iowa State University, Ames, IA 2 Michigan State University, Hickory Corners, MI

IMPAIRMENTS TO IOWA’S WATER RESOURCES 2008 Impaired Waters List (357 streams & 77 lakes) (Iowa DNR, 2008)

ANNUAL SEDIMENT, PHOSPHORUS, AND NITROGEN LOADING OF ROCK CREEK LAKE FROM TRIBUTARIES WITH DIFFERENT PROPORTIONS OF PASTURELAND (Downing et al., 2000)

PHOSPHORUS DELIVERY TO THE GULF OF MEXICO (Alexander et al., 2008) /

HYPOTHETICAL ROUTES OF NONPOINT SOURCE POLLUTION BY GRAZING CATTLE Direct manure deposition Stream bank erosion or is it cut bank erosion? Surface run-off

CONCENTRATIONS OF NITRATE-N, TOTAL P,TOTAL SUSPENDED SOLIDS, AND E. COLI IN WATER SAMPLES TAKEN DURING HIGH FLOW EVENTS UPSTREAM AND DOWNSTREAM OF A 10-ACRE PASTURE (Vidon et al., 2007)

CONCENTRATIONS OF NITRATE-N, TOTAL P,TOTAL SUSPENDED SOLIDS, AND E. COLI IN WATER SAMPLES TAKEN DURING HIGH FLOW EVENTS UPSTREAM AND DOWNSTREAM OF A 10-ACRE PASTURE GRAZED BY 25 COWS YEAR-ROUND (Vidon et al., 2007)

FACTORS CONTROLLING THE EFFECTS OF GRAZING ON WATER QUALITY Location of grazing Timing of grazing Intensity of grazing Length of grazing (CAST, 2002)

EFFECTS OF COW DISTRIBUTION ON DISTRIBUTION OF FECES AND URINE IN PASTURES

MODEL FOR QUANTIFYING THE EFFECTS OF GRAZING MANAGEMENT ON NONPOINT SOURCE POLLUTION OF PASTURE STREAMS Pollutant concentration or frequency Cattle #s Grazing DaysStream Length Cow-days/ft Diet intake and indigestibility Fecal Pollutant Load or Incidence Distribution Grazing management Plant species Shade distribution Stream Riparian zone Open area Congregation area Transport in runoff Transport in runoff Stream Climate Off-stream water

EFFECTS OF AMBIENT TEMPERATURE ON THE PROBABILITY OF GRAZING COWS BEING IN AND WITHIN 100 ft OF A STREAM OR POND IN PASTURES ON FIVE FARMS OVER THREE YEARS

EFFECTS OF PASTURE SIZE ON THE CONGREGATION OF GRAZING COWS IN AND WITHIN 100 ft OF A PASTURE STREAM OR POND ON SIX PASTURES OVER THREE YEARS y = x x 2 (r 2 =0.61)

IMPLICATIONS OF PASTURE SIZE AND SHAPE ON CATTLE TEMPORAL/SPATIAL DISTRIBUTION RESEARCH Ref. (State)Approx. pasture size, ac TreatmentEst. distance from treatment to stream, ft Stream and/or riparian effects Sheffield et al., 1997 (VA) Offstream water 37Reduced congregation Porath et al., 2002 (OR) 30Offstream water 1600Reduced congregation Byers et al., 2005 (GA) 42Offstream water 296Reduced congregation “35Offstream water 263No significant effect on congregation Agouridis et al., 2005 (KY) 5 – 7.5Offstream water 230No effect on congregation Line et al., 2000 (NC) 104Offstream water 338No effect on NPS

IMPLICATIONS OF PASTURE SIZE AND SHAPE ON CATTLE TEMPORAL/SPATIAL DISTRIBUTION Regulatory Treatments to control NPS of pasture streams seem likely to be most effective on small or narrow pastures.

PERCENTAGE OF TIME GRAZING CATTLE ARE IN AND WITHIN 110 ft OF A PASTURE STREAM IN TWO YEARS 30 ac pastures 463 ft stream reach (Haan et al., 2010) CSU = Continuous stocking unrestricted

EFFECT OF RESTRICTING STREAM ACCESS TO STABILIZED CROSSING ON CONGREGATION OF CATTLE IN OR NEAR PASTURE STREAMS IN TWO YEARS (Haan et al., 2010) CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted

EFFECT OF RESTRICTING STREAM ACCESS BY ROTATIONAL GRAZING ON CATTLE CONGREGATION IN OR NEAR PASTURE STREAMS IN TWO YEARS (Haan et al., 2010) CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

EFFECT OF SHORT- TERM ACCESS TO OFFSTREAM WATER AND MINERAL SUPPLEMENTATION ON CONGREGATION OF CATTLE IN OR NEAR PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted w/W or open = with offstream water and mineral

EFFECT OF OFF-STREAM WATER OR RESTRICTED STREAM ACCESS ON CONGREGATION OF CATTLE WITHIN 110 FT OF A PASTURE STREAM IN 10 (small) OR 30 (large) ACRE PASTURES OVER 5 MONTHS (2010)

RELATIONSHIP BETWEEN THE PROPORTION OF TIME THAT CATTLE ARE WITHIN 110 FT OF A STREAM AND THE PROPORTION OF PASTURE AREA WITHIN THAT AREA

CONSIDER ENVIRONMENTAL FACTORS

EFFECTS OF BLACK GLOBE TEMPERATURE-HUMIDITY INDEX ON THE PROBABILITY OF CONGREGATION OF CATTLE WITHIN 33 m OF A PASTURE STREAM IN TWO GRAZING SEASONS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted

EFFECT OF THE TEMPERATURE-HUMIDITY INDEX ON THE AMOUNTS OF TIME CATTLE WERE IN THE RIPARIAN AREAS OF BERMUDAGRASS-TALL FESCUE PASTURES WITH OR WITHOUT OFFSTREAM WATER (Franklin et al. 2009)

EFFECTS OF AMBIENT TEMPERATURE ON THE PROBABILITY OF COWS SEEKING SHADE (Haan et al., 2010)

EFFECTS OF PASTURE SIZE ON THE PROBABILITIES OF CATTLE PRESENCE IN SHADE IN THE TOTAL PASTURE OR RIPARIAN ZONE

EFFECTS OF GRAZING MANAGEMENT ON NONPOINT SOURCE POLLUTION OF PASTURE STREAMS

EFFECTS OF STOCKING RATE BETWEEN MEASUREMENT PERIODS ON STREAM BANK EROSION MEASURED QUARTERLY ON 13 FARMS IN THE RATHBUN LAKE WATERSHED OVER THREE YEARS

EFFECTS OF GRAZING MANAGEMENT ON ANNUAL EROSION/DEPOSITION ACTIVITY AND NET EROSION OF STREAM BANKS IN 2008 AND 2009

GRAZING MANAGEMENT MAY NOT ALWAYS PREVENT STREAM BANK EROSION

EFFECTS OF STOCKING RATE BETWEEN BIMONTHLY MEASUREMENTS OF THE PROPORTION OF BARE AND MANURE- COVERED GROUND WITHIN 50 FT OF STREAMS IN 13 PASTURES y = x – 0.314x 2 (r 2 =0.16) y = x – 0.009x 2 (r 2 =0.35)

GRAZING SYSTEM EFFECTS ON PROPORTIONS OF BARE AND MANURE-COVERED GROUND WITHIN 15 TO 110 FT OF PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

GRAZING SYSTEM EFFECTS ON PROPORTIONS OF APPLIED PRECIPITATION AND AMOUNTS OF SEDIMENT AND P TRANSPORTED IN RUNOFF FROM SIMULATED RAIN APPLIED TO BARE AND VEGETATED SITES ON STREAMBANKS AT 7.5 cm/hr (P < 0.10) aa a a a a b b b b b b cc c

CONTRIBUTIONS OF PRECIPITATION RUNOFF, DIRECT FECAL DEPOSITION, AND CUT BANK EROSION TO ANNUAL SEDIMENT LOADING OF PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

CONTRIBUTIONS OF PRECIPITATION RUNOFF, DIRECT FECAL DEPOSITION, AND CUT BANK EROSION TO ANNUAL SEDIMENT LOADING OF PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

CONTRIBUTIONS OF PRECIPITATION RUNOFF, DIRECT FECAL DEPOSITION, AND CUT BANK EROSION TO ANNUAL PHOSPHORUS LOADING OF PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

CONTRIBUTIONS OF PRECIPITATION RUNOFF, DIRECT FECAL DEPOSITION, AND CUT BANK EROSION TO ANNUAL PHOSPHORUS LOADING OF PASTURE STREAMS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

GRAZING SYSTEMS EFFECTS ON STREAM BANK EROSION SUSCEPTIBILITY (1 – 60) OVER FIVE YEARS CSU = Continuous stocking unrestricted CSR = Continuous stocking restricted RS = Rotational stocking

ROLE OF GRAZING CATTLE ON PATHOGEN LOADING OF PASTURE STREAMS

STOCKING RATE EFFECTS ON MEAN CONCENTRATIONS OF TOTAL COLIFORMS IN BIWEEKLY WATER SAMPLES FROM UP- AND DOWNSTREAM SAMPLING SITES IN 13 PASTURES OVER 3 YEARS

STOCKING RATE EFFECTS ON THE INCIDENCES OF BOVINE ENTEROVIRUS (BEV), CORONAVIRUS (BCV), AND ROTAVIRUS (BRV) IN BIWEEKLY WATER SAMPLES FROM STREAMS IN 13 PASTURES FOR THREE YEARS BEV: y = x x 2 (r 2 =0.0101) BCV: y = x-0.015x 2 (r 2 =0.0345) BRV: y = x x2 (r 2 =0.0708)

CONCLUSIONS Stream bank erosion is primarily related to hydrologic processes that supersede possible grazing effects Improper grazing management may increase: –Bare ground near pasture streams –Manure concentration near pasture streams –Sediment and nutrient loading of precipitation runoff Pathogen loading of pasture streams by grazing cattle is: –Poorly related to presence of total coliforms Bovine enterovirus may be a better indicator –Confounded by upstream loading Domestic and wildlife species –Rare and controlled by: Seasonal incidence of shedding of the pathogens Manure distribution Transport of the pathogens to the stream

CONCLUSIONS Risks of grazing on nonpoint source pollution of pasture streams may be controlled by maintaining streamside vegetation through use of: –Stabilized crossings with riparian buffers –Rotational grazing –Off-stream shade? –Off-stream water and/or nutrient supplementation???

BOTTOM LINE The Best Management Practices to control nonpoint source pollution on individual pastures will be site specific. –Small, narrow pastures will likely need more restrictive practices to control distribution of grazing cattle than large, wide pastures –Other characteristics to consider Cattle stocking rate Cattle breed, age, and physiological state Distance to off-stream water Shade distribution Botanical composition Stream order and evolution

Acknowledgements: This project is supported in part by: The Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Award No The Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Award No The Leopold Center for Sustainable Agriculture Iowa Beef Center Rathbun Land and Water Alliance

EFFECTS OF PRESENCE OR ABSENCE OF CATTLE IN PASTURES FOR 0 TO 6 DAYS PRIOR TO SAMPLING ON THE INCIDENCES OF BOVINE ENTEROVIRUS, CORONAVIRUS, AND ROTAVIRUS IN UP- OR DOWNSTREAM WATER SAMPLES FROM 13 PASTURES FOR 3 YEARS

INCIDENCE OF BOVINE ENTEROVIRUS AND CORONAVIRUS SHED BY 90 GRAZING COWS IN 3 MONTHS OVER TWO YEARS (No E. coli O157:H7 or Bovine rotavirus shed)

INCIDENCE OF BOVINE ENTEROVIRUS IN RUNOFF FROM RAINFALL SIMULATIONS ON STREAM BANKS OF PASTURES WITH UNRESTRICTED STREAM ACCESS IN TWO YEARS (No E. coli O157:H7, Bovine coronavirus, or Bovine rotavirus observed )