Ron Fleming and Malcolm MacAlpineUniversity of Guelph Ridgetown Campus,

Ridgetown, ON, N0P 2C0

Paper No. CSBE08-142

BackgroundNMA sets limits on spreading rates based

on:Land slopeHydrologic Soil GroupApplication method (e.g. incorporated)Distance to surface water

Factors influencing runoff risk:Soil textureSoil structureLand slope Soil management Vegetative cover Soil moisture level

Risk of rainfall after spreading

Frost in soil Manure DMRate of application Application method

Objectives• Develop maximum land application rates

for liquid manure.• Assess the impact of post application

rainfall events on runoff on different field slopes

• Propose maximum land application rates on pre-tilled and untilled land surfaces

SetupSmall plots – 1 m x 1 mDifferent land slopesDifferent manure typesSurface-applied manureHSG: C or DSimulated rainfall on some plots

SetupFactors Number DetailsLiquid applied 3 Swine, dairy, waterLand slope 3 3 to 5%, 6 to 8%, > 9% Application rate 3 46.7, 93.5 and 140.2 m3/ha Tillage 2 Un-tilled vs tilledReplications 3Total plots 162

Site 1, un-tilled section, 2.9% slope

Site 1, tilled section, 2.7% slope

Rainfall simulation1 in 5 year storm

(25.5 mm in 30 minutes)

24 hours after manure applied

On 2/3 of plots

Site 2, tilled section, 4.7% slope

ResultsSpreading after wheat harvest in August &

SeptemberSoil: silt loamHSG: mostly CDairy manure: 7.4% DMSwine manure: 2.5% DM

Site 1 - 2.8% slope

Site 2 – 5.0% slope

Site 3 – 15.1% slope

Results (cont.)

Results (cont.)Average volume of runoff was highest at

steepest slope (Site 3) – other 2 sites not significantly different

Average volume of runoff higher for swine manure than for dairy manure

dairy swine water

Median Plot with 95.0% Confidence Intervals

Liquid Applied

0

100

200

300

400

Run

off V

olum

eRunoff volume – all plots – median

& 95% confidence intervals

Results (cont.)140 m3/ha resulted in significantly more

runoff than lower two rates (97 & 47 m3/ha)Applic. rate 140 m3/ha; runoff = 963 mLApplic. rate 94 m3/ha; runoff = 253 mLApplic. rate 47 m3/ha; runoff = 97 mL

Results (cont.)Pre-tillage did not lead to a “significant”

reduction in the volume of liquid runoff Mean runoff - tilled sites was 309 mLMean runoff - un-tilled sites was 523 mLSimilar for individual sites, for individual

liquids and for each application rateImpact of vegetative cover?

Results (cont.)After simulated rainfall, Runoff Volume:

Influenced by site (more at Site 2), but not by slope

Influenced by liquid application rate – the higher the initial rate, the more rainfall runoff

Not influenced by initial liquid applied

ConclusionsLowest application rate met NMA

standards in all cases and highest rate exceeded in all cases

Lots of variability in runoffNo runoff on 25% of plotsRunoff highest for steepest slope (15.1%)

ConclusionsMore runoff for Swine manure (DM=2.5%)

than Dairy manure (DM=7.4%)Nutrients in runoff similar to applied liquidFollowing simulated rainfall, nutrients in

runoff much lower than initial liquids

This yearSlope

Plots 1 m wide by 4 m long – manure on 3 m length

FundingOntario Ministry of Agriculture, Food &

Rural Affairs – Nutrient Management Research Program

Questions