Slide1: Forage Fertility
New Mexico Crop Production Assoc.
Ruidoso, NM
January 24, 2006 Mike Stewart
Potash & Phosphate Institute
www.ppi-ppic.org
All cattle for New Mexico and Texas, 1995-2005: All cattle for New Mexico and Texas, 1995-2005
Cattle on feed for New Mexico and Texas, 1995-2005: Cattle on feed for New Mexico and Texas, 1995-2005
Milk cow numbers for New Mexico and Texas, 1995-2004: Milk cow numbers for New Mexico and Texas, 1995-2004 NM is the fastest growing milk production state in the U.S.
Benefits of forage fertilization: Benefits of forage fertilization
Greater water use efficiency
More resistance to disease and insects
Improved winterhardiness and drought tolerance
Greater efficiency of other inputs Increased yield
Improved quality
Higher profit potential
Animal production… a function of forage quantity and quality: Animal production… a function of forage quantity and quality Therefore
Animal/A x product/animal= product/A Forage yield (quantity)
expressed in animals/A
Forage quality
expressed in product/animal
Product= beef, milk, wool, etc. Source: Sollenberger and Cherney. Forages Volume II. p. 98
“Forage quality is the extent to which a forage, whether pasture, hay or silage, has the ability to produce the desired animal response.” Garry Lacefield, U. of Kentucky Progressive Farmer, March 1999 : “Forage quality is the extent to which a forage, whether pasture, hay or silage, has the ability to produce the desired animal response.” Garry Lacefield, U. of Kentucky Progressive Farmer, March 1999 Forage quality…
best defined in terms of animal performance
Several factors affect forage quality: Several factors affect forage quality Plant species
Stage of maturity
Fertility
Climate
Forage species affects quality: Forage species affects quality Pratt
Law of the minimum (1862) Justus von Leibing Crop yield will be determined by the most limiting nutrient in a system. Or, in other words, an excess of one nutrient cannot overcome the deficiency of another.: Law of the minimum (1862) Justus von Leibing Crop yield will be determined by the most limiting nutrient in a system. Or, in other words, an excess of one nutrient cannot overcome the deficiency of another.
Some cool season forage crop examples: Some cool season forage crop examples Balanced fertility…. nutrient interactions affect forage productivity
Wheat forage yield response to N and P fertilization: Wheat forage yield response to N and P fertilization lb P2O5/A Sanders et al. 1991.
Better Crops Magazine. Vol 75. No 3. irrigated wheat
Texas Panhandle
Wheat forage and N fertilization… forage to beef conversion: Wheat forage and N fertilization… forage to beef conversion Each ton of wheat forage requires about 60 lb total N
Therefore, 30 lb of N will produce about 1000 lb forage
Assuming a general conversion of 10 lb forage to produce 1 lb beef,
wheat pasture requires about 30 lb N/A for each 100 lb beef produced
From personal communication, E. Funderburg
The Noble Foundation
Sulfur fertilizer affects cool season forage S content: Sulfur fertilizer affects cool season forage S content lb S/A
Nitrogen and S fertilizer affect cool season forage protein: Nitrogen and S fertilizer affect cool season forage protein lb S/A
Value of protein increase in forage due to S fertilizer (based on cotton seed meal): Value of protein increase in forage due to S fertilizer (based on cotton seed meal) A nutrient input can have value far beyond what we might at first expect
Alfalfa: Alfalfa
Slide18: Follet and Wilkinson, 1995
Alfalfa Nutrient Uptake and Removal: Alfalfa Nutrient Uptake and Removal Alfalfa has higher demand for nutrients
than most crops
Nutrient Amount removed, lb/ton
P2O5 15
K2O 60
Ca 30
Mg 6
S 6
N (through fixation) 60
Slide20: Alfalfa Root Development
Most lateral roots are near the soil surface for the first year, but more deep lateral roots develop as the plant ages.
Alfalfa has lower root density than many grasses and a deeper rooting zone.
P and K application increase root growth, enabling roots to obtain moisture and nutrients from greater volume of soil.
Slide21: P Fertilization Increases Nodulation Azcon et al., 1988 Soil P, ppm
P Response: Timing & Application Study: P Response: Timing & Application Study Mullen et al., 2000; OK Six-year study initiated to evaluate effect of P
timing and application method
Broadcast or banded P fertilizer
Frequency:
100 lb P2O5/A every year
200 lb P2O5/A every 2 years
600 lb P2O5/A in a one-time preplant application Total 6-year P rate was the same for all treatments: variables were timing and placement
Yield Response to P in Years One and Six: Yield Response to P in Years One and Six P application, lb P2O5/A and frequency Mullen et al., 2000; OK
Yield Response: Method and Timing: Yield Response: Method and Timing P Application, lb P2O5/A and frequency Cumulative Yield Response Mullen et al., 2000; OK
K fertility is important in alfalfa production: K fertility is important in alfalfa production Adequate K improves:
Plant persistence
Number of shoots per plant
Shoot yield
Deficient K reduces root starch storage
Reduces protein concentration in root
Results in poor survival and slow shoot growth
In K-deficient alfalfa, small white or yellowish spots first appear around the outer edges of older leaves : In K-deficient alfalfa, small white or yellowish spots first appear around the outer edges of older leaves
Diagnosis of Nutrient Deficiencies: Diagnosis of Nutrient Deficiencies Visual Observation
Soil Testing
Tissue Analysis
Silage: Silage
Silage: Advantages and Disadvantages: Silage: Advantages and Disadvantages Advantages
Reduced field and harvest losses compared with hay
Many crops can be used
Less chance of weather damage during harvest
Long-term storage
Flexibility in feeding programs
Mechanization of storage, harvesting, and feeding
Disadvantages
Bulky to handle and store
Equipment and storage structure needs
Losses if not stored properly
Not readily marketable off-farm
Must be fed soon after removal from silo to avoid spoilage
Harvest and storage losses with legume-grass forages: Harvest and storage losses with legume-grass forages
N fertilization considerations: N fertilization considerations With some crops high levels N fertilizer can decrease the water soluble carbohydrate level
Carbohydrates are required to make good quality silage
Therefore, high levels of N fertilization can affect fermentation and silage quality,
Especially true in cool season grasses since they are already low in carbohydrates
Corn silage is not affected as much since corn is already high in available carbohydrates.
Consider nutrient removal in silage fertilization: Consider nutrient removal in silage fertilization
Summary: Summary Balanced and appropriate fertilization of hay, silage, and pasture increases forage yield, quality, and profit potential
Inputs such as water, nutrients, and other factors are used more efficiently with adequate and balanced fertility
Fertilize and utilize…if additional forage isn’t utilized, increased profit won’t be realized