Conservation Buffers to Minimize Pesticide Losses One more reason to promote buffers!
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Transcript of Conservation Buffers to Minimize Pesticide Losses One more reason to promote buffers!
Conservation Buffers to Conservation Buffers to Minimize Pesticide LossesMinimize Pesticide Losses
One more reason to One more reason to promote buffers!promote buffers!
Buffer impacts...Buffer impacts...
Trap sediment (and adsorbed and Trap sediment (and adsorbed and absorbed pesticides)absorbed pesticides)
Slow runoff (for sheet flow)Slow runoff (for sheet flow) Increase infiltrationIncrease infiltration Biological degradationBiological degradation Cuts down on drift and Cuts down on drift and
oversprayingoverspraying
Many studies...Many studies...
Trapping efficiencies of 50% or Trapping efficiencies of 50% or moremore
Increasing water infiltration is the Increasing water infiltration is the most important factor in trapping most important factor in trapping pesticidespesticides
Without buffers, edge of field Without buffers, edge of field losses can range from 1 to as losses can range from 1 to as much as 10%much as 10%
““Conservation buffers are not a Conservation buffers are not a substitute for careful pesticide substitute for careful pesticide selection and use”selection and use”
““They are a tool to further improve They are a tool to further improve water quality…when used along water quality…when used along with other practices”with other practices”
……Not the total solutionNot the total solution
Types of buffers...Types of buffers...
Grassed waterwaysGrassed waterways Contour buffer stripsContour buffer strips Vegetative barriersVegetative barriers Tile inlet buffersTile inlet buffers Field bordersField borders Filter strips and filter areasFilter strips and filter areas Riparian forest buffersRiparian forest buffers
Other specialty buffers...Other specialty buffers...
Constructed wetlandsConstructed wetlands Windbreaks & shelterbeltsWindbreaks & shelterbelts Cross wind trap stripsCross wind trap strips Herbaceous wind barriersHerbaceous wind barriers Set-aside and special use areas Set-aside and special use areas
(CRP fields, wood lots, diversion (CRP fields, wood lots, diversion backslopes, ditchbanks, wildlife backslopes, ditchbanks, wildlife habitat plantings)habitat plantings)
Pesticide trapping...Pesticide trapping...
Function of how tightly the pesticides Function of how tightly the pesticides are adsorbed to soil particles (Kare adsorbed to soil particles (Kococ))
Pesticides with low KPesticides with low Kococ values values (generally less than 500) tend to (generally less than 500) tend to move more in water that on sedimentmove more in water that on sediment
To trap low KTo trap low Koc oc pesticides effectively, pesticides effectively, buffers need to increase water buffers need to increase water infiltration and max. contact with soil infiltration and max. contact with soil and vegetation.and vegetation.
Some research results...Some research results...
Group Koc
Percentpesticidetrapped
Pesticide
Highlyadsorbedpesticides
1,1008,000
72-100%86-96%
LindaneTrifluralan
Low toModeratelyadsorbedpesticides
20100600
70%11-100%65%
2,4-DAtrazineNorflurazon
Designing buffers for Designing buffers for efficient pesticide efficient pesticide
trapping...trapping... location, location, locationlocation, location, location water must run through the system water must run through the system
by sheet flow, not concentrated flowby sheet flow, not concentrated flow grading may be necessarygrading may be necessary maintenance should be plannedmaintenance should be planned wider strips encourage sheetflow wider strips encourage sheetflow
and infiltrationand infiltration most effective at the top of the most effective at the top of the
watershed!watershed!
Considerations...Considerations...
greatest volume of runoff enters the greatest volume of runoff enters the watershed from the small streamswatershed from the small streams
intermittent and 1st and 2nd order intermittent and 1st and 2nd order streams require more buffer protectionstreams require more buffer protection
relatively little “new” water enters 3rd relatively little “new” water enters 3rd and 4th order streams over banksand 4th order streams over banks
buffers along larger streams have buffers along larger streams have many other benefits but less for many other benefits but less for pesticide interception and water qualitypesticide interception and water quality
Dealing withDealing withconcentrated flow...concentrated flow...
level spreaderslevel spreaders gradinggrading waterbarswaterbars vegetated barriers perpendicular vegetated barriers perpendicular
to the flowto the flow remove the “natural” berms along remove the “natural” berms along
the field edgethe field edge
How wide?How wide?
subject of considerable debatesubject of considerable debate factorsfactors
– soil type (drainage, permeability, zone soil type (drainage, permeability, zone of seasonal saturation, % organic of seasonal saturation, % organic matter)matter)
– antecendent moistureantecendent moisture– soil structure and compactionsoil structure and compaction– climate and storm eventsclimate and storm events– slopeslope– condition of vegetation, etc.condition of vegetation, etc.
Research findings...Research findings...
10 to 650 feet10 to 650 feet under most conditions at least 50 feetunder most conditions at least 50 feet NRCS draft standardNRCS draft standard
– min. 30 ft. for trapping sediment and min. 30 ft. for trapping sediment and adsorbed pesticidesadsorbed pesticides
wider is not always better, depends on wider is not always better, depends on soils, climate, vegetation, & pesticide!soils, climate, vegetation, & pesticide!
Relatively narrow buffers can still have Relatively narrow buffers can still have big impacts (narrow is better than none)big impacts (narrow is better than none)
Check this web site...Check this web site...
www.ftw.nrcs.usda.gov/tpham/www.ftw.nrcs.usda.gov/tpham/buffer/akey.htmbuffer/akey.htm
offers assistance in selection and offers assistance in selection and sizing of bufferssizing of buffers
NRCS standards & specifications:NRCS standards & specifications:www.ftw.nrcs.usda.gov/nhcp_2.htmlwww.ftw.nrcs.usda.gov/nhcp_2.html
Vegetation…Vegetation…
many optionsmany options zonation considerationszonation considerations 3 zone riparian buffer3 zone riparian buffer
– Zone 1 undisturbed forest (closest to Zone 1 undisturbed forest (closest to stream)stream)
– Zone 2 management forestZone 2 management forest– Zone 3 vegetative filter for runoff controlZone 3 vegetative filter for runoff control
maintenance considerationsmaintenance considerations
Economics...Economics...
““giving up land”giving up land” incentive paymentsincentive payments tax exemptionstax exemptions cost of installation and maintenancecost of installation and maintenance some limited income potentialsome limited income potential environmental and good neighbor environmental and good neighbor
benefitsbenefits may be a “compliance” requirementmay be a “compliance” requirement
Maintenance matters...Maintenance matters... periodic sediment removalperiodic sediment removal mowing (at proper height)mowing (at proper height) harvest to remove accumulated harvest to remove accumulated
nutrientsnutrients potential reseedingpotential reseeding avoid oversprayingavoid overspraying avoid use as turning areas and avoid use as turning areas and
drivewaysdriveways weed & insect controlweed & insect control
Integrating buffersIntegrating bufferswith other BMPs with other BMPs
IPMIPM pesticide selectionpesticide selection pesticide timingpesticide timing banded applicationsbanded applications soil incorporation (?)soil incorporation (?) conservation tillageconservation tillage nutrient nutrient
managementmanagement subsurface drainagesubsurface drainage
contour farmingcontour farming stripcroppingstripcropping crop rotationcrop rotation terracesterraces detention pondsdetention ponds irrigation timingirrigation timing irrigation water irrigation water
managementmanagement compaction compaction
reductionreduction
Many references availableMany references available NRCS/SWCD officesNRCS/SWCD offices Banks and Buffers,Banks and Buffers, A Guide to A Guide to
Selecting Native Plants for Selecting Native Plants for Streambanks and Shorelines.Streambanks and Shorelines. Tennessee Valley Authority. CD-Tennessee Valley Authority. CD-ROM. Call 423-751-7338ROM. Call 423-751-7338
Watch for: Watch for: Conservation Buffers to Conservation Buffers to Reduce Pesticide LossesReduce Pesticide Losses (NRCS) (NRCS)
www.nhq.nrcs.usda.gov/CCS/www.nhq.nrcs.usda.gov/CCS/Buffers.htmlBuffers.html
For an Electronic Copy:For an Electronic Copy:
Conservation Buffers to Reduce Pesticide Losses
NRCS National Water and Climate Center’s website: http://www.wcc.nrcs.usda.gov
go to: /water/quality/common/pestmgt/files/newconbuf.pdf
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