Transcript mowing or pasturing - College of Agriculture & Natural Resources

www.pastures
why, where and when
of
Pasture Management
Willie Lantz
Extension Educator
Ag and Natural Resources
Garrett County, Maryland
What is a pasture?
• A collection of plants
• Area used for feeding livestock
• Area used to house livestock
• Your definition of a pasture may depend
on many factors such as land area
available, stocking density, and
management.
Managing Pastures
• Goals
– Provide forage to meet the animals needs
during the grazing season.
– What is your animals needs?
• Horses require about 1.5% of Body Weight as a
forage.
• 1000 lbs horse = 15 lbs of forage Dry
Matter/day
• 240 days grazing X 15lbs/day = 3600lbs
DM/year
• A two ton yield should be an achievable yield
since most hay systems expect 2-4 ton yields
from grasses.
• How much dry matter will a
pasture produce?
– This will depend on several
factors:
•
•
•
•
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Species
Fertility of the Soil
Soil Type
Utilization
Other Environmental factors
such as rainfall.
• The table at right indicates
the amount of expected
dry mater from various
species at three levels of
productivity
2007 Penn State Agronomy Guide
Does what the animals eat matter?
• Forage quality changes with changes in
grass & legumes as they mature
Table 1.8-1. Chemical composition of legumes and legume-grass mixtures at
advancing stages of maturity.
Chemical composition
% (DM basis)
Brief
description
CP
ADF
NDF
Relative
feed value
CP = crude protein, ADF = acid detergent fiber, NDF = neutral detergent fiber
Legume, prebloom
>19
<31
<40
>151
Legume, early bloom
<20% grass, vegetative
17-19
31-35
40-46
125-151
Legume, mid bloom
<30% grass, early head
14-16
36-40
47-53
103-124
Legume, full bloom
<40% grass, head
11-13
41-42
54-60
87-102
Legume, full bloom
<50% grass, head
8-10
43-45
61-65
75-86
Mostly grass, head
<8
>45
>61
<75
2007 Penn State Agronomy Guide
Let look at two different Horses
A mature horse weighing 1,100 pounds requires 1.4
pounds of Protein/Day
A two year old growing horse requires 2.5 lbs of
Protein per day
Lets Look at the what would be provided from two
different pastures.
A mid bloom legume/grass pasture will have about
15% crude protein therefore a horse consuming
1.5% of the body weight will get 2.25 lbs of
Protein/Day
A mature grass pasture in full head will have about 8%
crude protein. A horse consuming 1.5% of its body
weight will get 1.2 lbs of protein per day.
Goals of Growing Pasture
• Keep the pasture species growing and
in the vegetative stage
• Keep Soil Fertility in the Optimum
Range
• Control Weeds
Growing & Harvesting Grass
• No matter which method of harvesting
grass (mowing or pasturing), when you
harvest is critical for grass to be
productive.
• Grass must produce 4-5 leaves before
it is not dependent on stored
carbohydrates for growth.
• Allow most cool season grasses such
as Orchard Grass to get 6” – 8” before
grazing
Rotate Pastures
• Rotate Pastures to force animals to eat less
desirable plants resulting in an increase in
the utilization of the pasture.
– If allowed to graze large areas, animals will
select their preferred species of
grasses/legume.
– This allows other species to get over mature
and become less desirable.
– Animals will return to desirable species and
overgraze.
• This will reduce these species ability to recover and
eventually weaken the stand.
Grass Growth
• Grasses grow from a crown (short stem at or
below the soil surface)
• After harvest or pasturing, the grass must
pull needed sugars for respiration from
storage areas in the crown to supplement the
sugars being made in the few remaining
leaves.
• If continuously overgrazed, the plants
reserves will be depleted and the plant will
recover slowly leading to poor production
• Slowly recovering pastures are more prone
to weed infestations.
Seasonal Growth of Grass Species
Pasture Rotation
• Set up a pasture rotation that allows
the grass to recover.
• Start grazing with grass pasture reach
6-8 inches of height and stop at 3-4
inches.
• More paddocks will be needed in the
summer
– Consider grazing hay fields
– Supplement with hay or grain
Table 1.8-9. Suggested paddock sizes (A/animal unit) based on grazing period and
available pasture in intensive rotational grazing system.
To calculate paddock size, multiply the suggested acres per unit by the animal units (see Table 1.8-7) in your grazing
group.
1.One animal unit = feed requirements of a 1,000 -lb dry cow (25 lb dry matter/day).
2.These are estimates of the percentage of pasture actually consumed. Utilization is usually improved as grazing pressure
is increased.
Available pasture (lb dry matter/A)
Grazing period, days
% Pasture
utilization2
750
1000
1500
--- A/animal unit 1 ---
1
80
0.042
0.031
0.021
2
75
0.089
0.067
0.044
3
75
0.133
0.100
0.067
4
70
0.190
0.143
0.095
5
65
0.256
0.192
0.128
6
60
0.333
0.250
0.167
7
60
0.389
0.292
0.194
Fertilize Pastures
Fertilize pastures yearly
• Why
– For maximum plant growth plants will require
more nutrients than they get from the soil.
– Most grasses require 150 pounds of Nitrogen for
optimum growth. 20-40 pounds is converted from
organic mater and other sources on a yearly
basis.
– Legumes (clovers/alfalfa/trefoil) does not require
Nitrogen but will require additional Potassium.
Fertilization cont.
• Fertilize according to your nutrient
management plan.
– Soil test every three years (P, K, pH)
– Split applications of Nitrogen
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•
•
Apply 1/3 in early spring (March)
Apply 1/3 early summer (Mid June)
Apply 1/3 in early fall (late August)
Apply just before a rain
– Apply P & K in the fall
pH Management - Liming
Lime pastures with two ton of lime every
third year
• Why
– maintain a pH of 6.0-6.5
• Desirable range for soil microbes
• Low pH ranges tie up plant nutrients
• Soil Test before liming – follow
recommendation on soil tests or nutrient
management plan
Mowing Pastures
Mow pastures after rotating to a new
pasture
• Why – needed if grasses have went to
head.
– The seed head produces an auxin which is
a plant hormone that prohibits additional
stem and leaf development.
– If headed grasses are left stand it will
reduce yield and recovery times.
– If animals are not rotated they will not eat
mature grasses which causes animals to
over graze other areas of the pasture.
Mowing Pastures cont.
• When to mow:
– If the grass gets ahead of the animals and
starts to come into head.
– If rotating pasture, mow the paddock only
if more than 20% of the pasture area has
grass that is in head.
– If not rotating, mow about ¼ of the pasture
per week if more than 25% of the pasture
has mature plants
– Do not mow any shorter than 6”
Controlling Weeds
• Why Control Weeds?
– Reduce crop yield by removing water
and nutrients
– May Shade out desirable plants
– Take up space of productive plants
– Some plants are poisonous
How to Control Weeds
• Do everything discusses earlier first
– Rotate Pastures
– Adjust pH and Fertility
– Mow Pastures
• After those factors have been
corrected, eliminate problem weeds
– Know the weed and the weed’s life cycle
you are trying to control
• Control most weeds when they are in a
growing part of their life before they go
to seed
Renovate Pastures
Must answer this question first:
Why do you need to renovate the
pasture?
Correct these factors before evaluating if you need
to renovate the pasture!
Pasture Management Resources
• University of Maryland, Maryland Forages
Program (Horse Pasture Publications)
– http://www.mdforages.umd.edu/publ.cfm
• University of Maryland, Maryland Cooperative
Extension Publications
– http://extension.umd.edu/publications/Category.cfm?ID=C
• 2007-2008 Penn State Agronomy Guide
– http://agguide.agronomy.psu.edu/
• ATTRA – National Sustainable Agriculture Information
Service
– http://attra.ncat.org/livestock.html#Grass