Sarah Kenyon Agronomy Specialist 417-967-4545 …extension.missouri.edu/ozark/documents/2014... ·...
Transcript of Sarah Kenyon Agronomy Specialist 417-967-4545 …extension.missouri.edu/ozark/documents/2014... ·...
Plant Growth or Yield
Quality
Putting it Together
Plant Growth or Yield
Sun
CO2
H2O
O2
CHO
Mineral Nutrients
9 Macronutrient elements:
C H O N K P Ca Mg S
8 Micronutrient elements:
Mn Zn Cu Cl B Fe Mo Ni
Some other elements that are beneficial:
Na Si V Co Al
Grass Anatomy
Iowa State University Extension PM 1791
Tillers
Initially, tillers depend on carbohydrates developed the previous fall. Then as leaf area explodes with additional tillers, new sugars are made
Legume Anatomy
Iowa State University Extension PM 1791
3 primary stages of forage development
1. Vegetative
Tillers emerge from buds in the crown
Tiller growth uses stored carbohydrates
Plants begin making new sugars
Most new sugars supplement carbohydrates to help growth
Very little if any is put into storage
Leaves get longer
New tillers grow from buds, tillers branch
More leaf area speeds up photosynthesis
Some new sugars continue to be used in growth
Some new sugars stored as carbohydrates
3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing
Leaf growth slows down
Photosynthesis continues making sugars
Most new sugars stored as carbohydrates
Reproductive tillers begin to elongate
3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing
3. Reproductive
Leaf growth stops, formation of stems and reproductive structures
Photosynthesis continues making sugars
Most new sugars used for seed production
Little stored carbohydrates used for seed development
Perennial ◦ Production of Seeds
◦ Vegetative
Tillers
Rhizomes
Annual ◦ Production of Seeds
Iowa State University Extension PM 1791
3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing
3. Reproductive
In Tall Fescue – growing point are not removed
In Tall Fescue – residual stubble contains chloroplasts
In Alfalfa – many auxiliary buds (growing points) are removed
In Alfalfa – most chloroplasts are gone
In both plants – regrowth seen in light green
In Tall Fescue – regrowth from intact growing points
In Tall Fescue – regrowth uses some stored carbohydrates
In Alfalfa – regrowth from basal buds
In Alfalfa – regrowth uses most stored carbohydrates
Dry Matter Yield at Various Cutting Heights
0
2000
4000
6000
8000
10000
12000
Per. Ryegrass Tall Fescue
Species
Dry
Matt
er
Yie
ld (
lb/a
cre
)
1 inch
2 inches
3 inches
4 inches
5 inches
6 inches
% Leaf Removed
% Root Growth Stopped
10 0
20 0
30 0
40 0
50 2 to 4
60 50
70 78
80 100
90 100
Stops root growth 12 days
Stops root growth 18 days
To remain healthy,
30% of grass root
systems must be
replaced annually.
Dry Matter Yield at Various Cutting Heights
0
2000
4000
6000
8000
10000
12000
Per. Ryegrass Tall Fescue
Species
Dry
Matt
er
Yie
ld (
lb/a
cre
)
1 inch
2 inches
3 inches
4 inches
5 inches
6 inches
Overgrazing is removing too much of the canopy too often
Cool Season Grasses ◦ Tall Fescue
◦ Orchardgrass
Warm Season Grasses ◦ Native Grasses
◦ Bermudagrass
Annuals ◦ Pearl Millett
◦ Winter Wheat
Take Half / Leave Half Residual
Allows plant to recover completely after grazing ◦ Recovery of shoots and roots
Allows for plant and stand persistence
During grazing periods: control stubble height • Keep growing points
• Provide for good photosynthesis
• Keep roots growing
Between grazing periods: schedule rest periods • Allows for photosynthesis
• Allows leaves to regrow
• Vegetative reproduction can occur
Short-lived perennials reseed ◦ Red Clover
Annuals reseed ◦ Annual Lespedeza, Crabgrass
Grasses are given the chance to spread ◦ Bermudagrass
Plants are allowed to thicken naturally by reseeding
www.agriseed.co.nz
Incorporates a grazing strategy and rest periods ◦ Quality & quantity increases
◦ Enhanced forage utilization
◦ Persistence increases
Quality
Working definition:
“high protein, low fiber”
Measured Components
• Acid Detergent Fiber (ADF) = cellulose & lignin
• Neutral Detergent Fiber (NDF) =
total cell walls =
cellulose, lignin & hemicellulose
• Nitrogen
• Minerals
• Antiquality
Calculated Components
• Net Energy (NE) calculated from ADF
• Total Digestible Nutrients (TDN) calculated from ADF
• Digestible Dry Matter (DDM) calculated from ADF
• Dry Matter Intake (DMI) calculated from NDF
• Relative Feed Value (RFV)
calculated from NDF & ADF
• Crude Protein (CP) calculated from Nitrogen
1. Maturity
CP = 13 – 14% CP = 5 - 6%
The sharpest decrease in quality occurs during the reproductive phase. During this growth phase plants lose quality by the hour!
What is the boot stage?
Changes in botanical composition and forage quality of forage groups at different maturity stages.
Forage Group Leaves CP NDF
------------------------% DM-----------------------
Grasses
Vegetative > 50 > 18 < 55
Boot 40 - 50 13 - 18 55 - 60
Heading 30 - 40 8 - 12 61 - 65
Mature 20 - 30 < 8 > 65
Legumes
Vegetative 40 - 50 > 19 < 40
Bud 35 - 45 17 - 19 40 - 46
Early Flower 25 - 40 13 - 16 47 - 51
Late Flower < 30 < 13 > 51
Source: Schroeder, 1996
•When 4th leaf emerges, the first leaf begins to die •Most grasses will have no more than 3 live leaves any point in time •Pasture quality begins to decline and is wasted
The 3 to 3½ leaf stage is the optimum stage for grazing
www.agriseed.co.nz
Iowa State University Extension PM 1791
1st bite: leaves with low fiber
2nd bite
3rd bite: stems with high fiber
1. Maturity 2. Plant Part
1st bite: leaves low fiber 27.4 38.5 0.79
2nd bite 22.9 44.6 0.76
3rd bite: stems high fiber 14.0 60.0 0.67
CP NDF NeL
Crude Protein Content of Pastures
12-Paddock Rotation
Variation in Milk Production Between Pastures
Dry Matter Yield at Various Cutting Heights
0
2000
4000
6000
8000
10000
12000
Per. Ryegrass Tall Fescue
Species
Dry
Matt
er
Yie
ld (
lb/a
cre
)
1 inch
2 inches
3 inches
4 inches
5 inches
6 inches
Dry Matter Yield at Various Cutting Heights
0
2000
4000
6000
8000
10000
12000
Per. Ryegrass Tall Fescue
Species
Dry
Matt
er
Yie
ld (
lb/a
cre
)
1 inch
2 inches
3 inches
4 inches
5 inches
6 inches
1. Maturity 2. Plant Part 3. Species
Annual & Perennial
Cool-Season & Warm-Season
Grasses & Legumes
Forbs & Browse
Palatability of Cool-Season Forage Grasses – Univ. of Wisconsin
Specie Variety Palatability*
Orchardgrass TAKENA 4.3
Timothy CLIMAX 4.3
Perennial Ryegrass KEMAL 4.2
Orchardgrass BARIDANA 4.0
Orchardgrass DAWN 4.0
Perennial Ryegrass ANACONDA 4.0
Smooth bromegrass BLIZZARD 3.8
Orchardgrass BENCHMARK 3.7
Timothy DOLINA 3.7
Orchardgrass HAYMATE 3.5
Orchardgrass WARRIOR 3.0
Smooth bromegrass ALPHA 2.3
Tall fescue KY 31 1.4
Tall fescue BRONSON 1.2
Tall fescue SEINE 0.6
*Palatability rating 0=0% grazed, 1=20%, 2=40%, 3=60%, 4=80%, 5=100% grazed. Palatability of grasses under grazing is determined by visual estimation of percent defoliation of plots. The visual determination is made midway during mob grazing by beef cows of the grass plots for yield determination.
1. Maturity 2. Plant Part 3. Species 4. Anti-quality Factors
Nutrient Deficiency ◦ Grass Tetany
Weeds
Poison Compounds ◦ Nitrate Poisoning
◦ Prussic Acid
Bloat
Fescue Toxicosis
Early spring production Medium to high yield Excellent persistence Good tolerance to: ◦ Poor drainage ◦ Low soil fertility ◦ Drought ◦ Heat stress ◦ Cold temperatures ◦ Insects ◦ Nematodes
Fungus found in stem, leaf sheaths & seed
Increases progressively season long
Minimized in young growth
Cannot survive outside of the plant host
Roberts and Andrae, 2004
www.agricom.co.nz
Mutualistic Symbiosis ◦ Plant providses habitat and nutrition for the
endophyte
◦ Endophyte (fungus) provides plant with multiple benefits
Drought Tolerance
Insect Resistance
Increase Nutrient Acquisition
Grazing Tolerance
Others
Produces alkaloids which confer pasture pest resistance but can also cause animal health problems ◦ Peramine
◦ Lolines
◦ Ergovaline
Medicinal Alkaloids ◦ Morphine, quinine, atropine, vincristine
Addictive Alkaloids ◦ Cocaine, heroin, caffeine, nicotine
Very toxic in small amounts ◦ Strychnine, coniine
Lower conception rates
Reduced milk production
Reduced feed intake
Rough hair coat
Increased core body temperature in summer (leads to heat stress)
Frozen nose, ears, tails, etc (in winter)
Fescue foot
US beef industry over $600 million annually
Missouri beef industry over $160 million annually
All US livestock sectors over $1 billion (Roberts and Andrae, 2010)
Test < 20% = Low Infection
> 55% = High Infection
(West, 1998)
Endophyte generally necessary for
persistence south of this line
Bouton et al., 2002 www.noble.org
Non-toxic endophytes (Novel or Friendly) ◦ Retain persistent qualities
◦ Animal performance similar to E-
Available Varieties: ◦ Jesup Tall Fescue with MaxQ
◦ Advance with AR37
◦ Bar-Optima with E34
◦ Others
AR4 E- E+ Location Average Daily Gain (lb) Fayetteville, AR 1.43 1.55 0.93 Mt. Vernon, MO 1.21 1.21 0.55
West et al., 1998
Roberts and Andrae, 2004
1. Maturity 2. Plant Part 3. Species 4. Anti-quality Factors
Plant Growth or Yield
Quality
Putting it Together
Monitor forage before, during and after the grazing event ◦ Determines forage
availability for livestock
◦ Identifies which paddocks to graze, rest, and cut for hay
◦ Helps to prevent overgrazing
◦ Helps to identify weak pasture stands
Monitor pastures at least twice a month ◦ Weekly is better
Walking is better than driving
Forage available for livestock in KNOWN
Able to construct pasture budgets and establish paddock rotations
Able to Adjust: ◦ Forage Allocation
◦ Number of Cattle in Paddock
◦ Number of Days for Grazing
Write down pasture measurements and management decisions ◦ Rest Periods
◦ Number of Cattle on Pasture/ Days Cattle are on Pasture
◦ Forage Demand
◦ Paddock Rotation Schedule
◦ Many More
Write down pasture measurements and management decisions
Grazing Wedge ◦ http://plantsci.missouri.edu/grazingwedge/
Ranchers should adopt the philosophy that pasture production is their business.
Therefore, the health of the pastures is the most important aspect of ranching.
THANK YOU!
Observe pasture growth regularly ◦ Yield
◦ Stand Density and Health
◦ Over time can help to identify:
Low producing paddocks
Need to weed control
Management strengths and weaknesses
Allow adequate rest between grazing for plant recovery
Begin Grazing at the 3 – 3 ½ leaf stage Harvest hay during the boot stage Manage stands for improved pasture quality
Keep pasture records!!!
Questions?