280 likes | 425 Views
Managing Manure for Crop Production when Feeding DDGS. Kyle Jensen ISU Extension Field Specialist-Crops. Feeding DDGS Changes the Manure Nutrient Content. Crude Protein is higher Phosphorus is higher Rule of Thumb DDGS contain about 3 times the nutrient analysis of corn.
E N D
Managing Manure for Crop Production when Feeding DDGS Kyle Jensen ISU Extension Field Specialist-Crops
Feeding DDGS Changes the Manure Nutrient Content • Crude Protein is higher • Phosphorus is higher • Rule of Thumb • DDGS contain about 3 times the nutrient analysis of corn
Corn and Soybean requirements • Nitrogen • Phosphorus • Potassium • Calcium, Magnesium, Sulfur • Fe, Mn, Zn, Cu, Ni, Mo, B, Cl
How Much N do I need • Depends on the year • Favorable growing conditions • More N • Unfavorable growing conditions • Get by with less N
$2.20/bu $0.11/lb N $0.22 $0.33 $0.44 MRTN LOW HIGH Maximum Return To N and Most Profitable N Rate Range
Maximum Return To N and Most Profitable N Rate Range http://extension.agron.iastate.edu/soilfertility/nrate.aspx
How much P do I need • Look at soil sampling results • Try to stay in the optimum range • 11-20 ppm depending on subsoil amount • Crop removal • Corn –grain, silage, and/or stover • Soybeans
Current Grain P2O5 Removal • Anywhere from 80-125# P2O5 per rotation • Corn • 150 bu 56# P2O5 • 175 bu 66# P2O5 • 200 bu 75# P2O5 • Soybeans • 40 bu 32# P2O5 • 50 bu 40# P2O5 • 60 bu 48# P2O5
Long-Term Benefits From Agronomic Application of Manure To Crop Land • Improved productivity • Improved fertility • Essential plant nutrients • Adds organic matter • Stimulates biological activity • Improves physical structure • Infiltration • Stability • Water holding capacity • Bulk density
Nutrients in manure should be managed with the same care as commercial fertilizer • We have to determine: • Amount of nutrients in the manure • Availability of the nutrients to the crop • Amount of nutrients needed to optimize crop yields • That manure is being applied uniformly
Determining the Nutrient Content of Manure • Have a certified lab test the manure • Having a chemical analysis • Needs to be done from representative sample of manure • Eliminates the question of what might be the nutrient content of the manure
Plant availability of the nutrients in animal manure • Animal manure contains all the nutrients essential for plant growth. • The nutrients are present in both organic and inorganic forms. • The nutrients in inorganic form are readily available. • The nutrients in organic form must be converted into inorganic form. This conversion, mineralization, is accomplished by microorganisms that live in all soils
Availability of nitrogen in animal manure • Nitrogen is present in both organic and inorganic forms in animal manure. • The total amount of N present and the proportion of organic to inorganic N depends on animal species and how the manure is handled and stored. • Recent research suggests: • About 35% of the total N in dry cattle and dairy manure is available to plants the year of application
Nitrogen loss • The two forms of inorganic N in animal manure are ammonium (NH4+) and urea. • If manure is left on the soil’s surface, ammonium and urea will form ammonia gas and be lost to the atmosphere (volatilization). • You must make adjustments for volatilization losses of N.
Use correction factors to account for nitrogen volatilization during land application of animal manure • Correction factors to account for N volatilization during land application of animal manures. • Application Method Correction Factor • Direct injection 0.98 • Bdcst & incorp. w/in 24 hrs 0.95 • Bdcst & incorp. after 24 hrs 0.80 • Bdsct liquid, no incorp. 0.75 • Bdcst dry, no incorp. 0.70 • Irrigation, no incorp. 0.60 • Source: Iowa Department of Natural Resources
Availability of phosphorus in animal manure • P is present in both inorganic and organic forms. • If the soil test for P is “high” or “very high” consider that 100% of the P is available. • If the soil test for P is “very low,” “low,” or “optimum” consider that 60% of the total P will be available the year of application.
To determine a rate what nutrient do I use? • Manure application rates can be determined using either N, P, or K needs. • Depending on which set of regulations you fall under, and P index value. • N and P are used most frequently to determine application rates.
Example of determining a Rate You have solid manure from a beef operation that contains 12 lb N, 6 lb P2O5, and 12 lb K2O per ton. You have established that you can grow 175 bushels of corn per acre on a field in southwest Iowa. Last year’s soybean crop yielded 50 bushels/acre. N fertilizer = (175 x 1.2) - 50 lb N/acre = 210 - 50 = 160 lb N/acre Manure rate = 160 lb N/acre 2.9 lb N per ton = 55 tons/acre But did we over apply P [55 tons x 6 lb P2O5/ton = 330 lb P2O5/acre]
Example of determining a Rate (Problem) You have solid manure from a beef operation that contains 12 lb N, 6 lb P2O5, and 12 lb K2O per ton. But did we over apply P [55 tons x 6 lb P2O5/ton = 330 lb P2O5/acre] According to your P index can you apply according to N requirements or P?
Concerns with DDGS • From Table 2, “Use of Distillers Grain in Feedlot Diets” • 15% DDGS in diet increases excreted P2O5 by 20% • 25% increases excreted by 40% • 40% increase by 70% • Additional Concern regarding Application Dry manure spreaders are not calibrated often enough Dry spreaders aren’t always very uniform in application.
Manure Application: things to think about • Fall applications allow time for organic portions of the manure to mineralize. • Fall applications also allow for more potential N loss to the environment. • To conserve N that is in the manure from loss • Apply manure in the fall when the soil temperature (4” deep in the soil) is 50o F and cooling. • Applying manure to frozen soils increases the potential for environmental contamination. • N and P movement into surface water can be significant. • Apply only on relatively flat land (slopes of 4 % or less). • A little common sense will keep problems away
Feeding DDGS, How am I going to change to accommodate higher manure P • Applying manure with higher P content • Crop removal • Soil test results • Manure test results • Higher P manure if applied by P requirements: • Larger number of acres to apply • Different/Better equipment to get to these acres? (may be further away) • More acres=more time
Summary • Commercial fertilizer costs $ • $400 anhydrous 1#N is $0.24 • $340 11-52-0 1# P2O5 is $0.33 • $255 0-0-60 1# K2O is $0.21 • What your manure is worth in terms of nutrients and organic matter = increased biological activity, better soil structure, increased infiltration, increased water holding capacity, increased pH buffering capacity • Corn - Corn rotations will need more N and P than a traditional Corn - Soybean rotation • Use your resource and take credit for it