Soils, Nutrients and Fertilizers Part I I Handouts: Home Garden Soil Testing and Fertilizer Guidelines MontGuide Nutrients 17 elements essential for plant growth Oxygen Carbon Hydrogen Nitrogen Phosphorus Potassium Magnesium Calcium Sulfur Iron Boron Chlorine Manganese Zinc Copper Molybdenum Nickel Carbon, Hydrogen, and Oxygen A dried plant is 94% Carbon, Hydrogen, and Oxygen Why don t we ever hear about adding these nutrients ti t to the soil? CO 2 H 2 O 1
Nitrogen (N) Favors vegetative growth such as leaves and shoots Good sources: High N Fertilizers Blood Meal* Fish Meal* Cottonseed Meal* * = organic source Nitrogen Deficiencies Deficiency : Chlorosis (insufficient chlorophyll) in older plant tissue (Shows up in older leaves) Phosphorus (P) Promotes good seed and fruit ripening, maturation, energy storage/transfer Good Sources: Superphosphate Diamonium Phosphate Bone Meal* Rock Phosphate* * = organic source 2
Phosphorus Deficiencies Deficiency: Older leaves first turn dark green with red/purple between veins. Reduction in growth, poor fruit size and yield. Potassium (K) Stomatal regulation (gas exchange), new tissue growth, root and stem development, hardiness, fruit flavor and fruit color Good Sources: Potassium Chloride Potash* Seaweed Meal* Cow Manure* * = organic source How about Manure? Make sure that the manure is fully composted and contains no residual herbicides! 3
Potassium Deficiency Deficiency: Mottled chlorosis in older leaves How about wood ash? Not recommended for gardens Raises the ph High in salts No more than a 5 gallon bucket full per 1000 sq.ft. Watch the ph levels! Iron Deficiency The soil may have plenty of iron, but due to high soil ph the plants can t absorb it. 4
Iron Deficiency Interveinal Chlorosis Highly susceptible plants include raspberry, Amur maple, crabapple, mountain ash, and roses Be sure you have a real problem and not a pseudodeficiency by virtue of insufficient or excess irrigation Correction of Iron Deficiency Soil acidification. Can you do it? Difficult in highly buffered soils Acidifying liquid fertilizers will not help Applications of iron Iron Oxide (ferrous oxide) Fast acting; rapidly dissipates; some leaf discoloration rust stains on concrete Chelated Iron Foliar expensive; must be applied often Fast acting; rapidly dissipates; more expensive than ferrous sulfate Bone meal or blood meal are also sources of iron Plant Deficiencies Healthy leaves Shine with a dark green color when adequately fed Phosphorus Deficiency Leaves with reddish purple, particularly on young gplants Potassium Deficiency Drying along the tips and edges of the lowest leaves Nitrogen Deficiency Yellowing that starts at the tip and moves along the middle of the leaf 5
http://landresources.montana.edu/nm/default.htm Ultimately, how do you know if you have a nutrient deficiency? Soil test to determine if fertilizer is needed Keep in mind that some garden soils can actually have TOO MUCH fertility; look kfor toxicities You will only know if you have a deficiency or toxicity by testing! Use a tulip bulb planter Soil testing Collect soil from upper 6 inches in about 10 locations Mix and send to lab See MT200705AG Home Garden Soil Testing and Fertilizer Guidelines for details and laboratory addresses 6
Which Lab to Pick? Make sure that the lab: Makes recommendations Makes the recommendations in lbs. per 1000 sq.ft. rather than in acres The lab s turnaround time Fertilizer Sources Organic? Inorganic? 7
Inorganic vs. Organic Fertilizers Organic Bulkier ( ) Nutrient content low ( ) Nutrient content difficult to quantify ( ) Slow release (+) Usually supplies organic matter (+) Inorganic vs. Organic Fertilizers Amount of organic manure needed to add 2 lbs of actual nitrogen/1000ft 2 of garden Manure (dry) N (%)* P (%)* K(%)* Per 1000ft 2 Chicken 2 to 4.5 4.6 to 6.0 1.2 to 2.4 62 Steer 1 to 2.5 0.9 to 1.6 2.4 to 3.6 115 Dairy 0.6 to 2.1 0.7 to 1.1 2.4 to 3.6 150 Pig 0.5 to 1.0 0.3 to 0.7 0.1 to 2.0 133 Horse 0.3 to 0.6 0.1 to 0.2 0.3 to 1.0 225 * Analysis is approximate Inorganic vs. Organic Fertilizers Inorganic No carbon ( ) Easy to store (+) Higher analysis (+) Custom formulated (+) Easy to use (+) Liquid and solid (+) Environmental and health concerns? ( ) 8
Applying Fertilizers Timing Preplant Postplant Method Banding Broadcasting Sidedressing or Topdressing How much should you fertilize your garden, flower bed, turfgrass? First: Do a soil test and interpret results Second: Assess the plant s growth. Not all plants need additional nutrients Third: Figure amount of NPK N P K % Potassium oxide K 2 O % Phosphoric acid P 2 O 5 % Nitrogen N 9
Actual Nitrogen Nitrogen is the most limiting nutrient. Therefore, most calculations are based on % nitrogen Don t worry about the P and K at this time, unless deficient A 100 pound bag of 10 10 10 contains 10 pounds of actual N (10% of 100 = 10) (0.10 x 100 = 10) A 25 pound bag of ammonium sulfate (21 0 0) contains 5.25 pounds of actual N (21% of 25 = 5.25) (0.21 x 25 = 5.25) A 50 pound bag of sheep manure (2 1 2) contains 1.0 pound of actual N (2% of 50 = 1.0) (0.02 x 50 = 1) Finding the right amount of fertilizer from a recommendation Recommended Amount/N Fraction MSU Extension recommends 1 lb. of actual N per 1000 sq.ft. of lawn. You have 5 10 10 fertilizer. How much fertilizer should you apply per 1000 sq.ft.? 1 lb. /.05 = 20 lbs (how much N you need to apply divided by the fraction content) Conclusion: You will need 20 lbs of a 5 10 10 fertilizer to apply 1 lb. of actual N per 1000 sq.ft. Calculating Fertilizer Applications Recommendations call for applying 2 lbs of actual N per 1000 sq. ft. You have a 5000 sq. ft. lawn. How much 12 6 5 should you use? First: 2 lbs 0.12 = 16.67 (So, 16.67 lbs will supply 2 lb. of actual N / 1000 sq. ft) Second: You have 5000 sq. ft., so 16.67 x 5 = 83 lbs. of 12 6 5 will provide 2 lbs of actual N per 5000 sq. ft. 10
Common Soil Amendments are they needed? Amendment Purpose Fact Coarse Sand Improve aeration/drainage Can cause concrete-like affect in soil with heavy clay Sulfur Increase acidity Will only change slightly and is short lived Limestone Increase alkalinity Will only change slightly and is short lived Gypsum Decreases sodic conditions Takes too long and are short lived, leaches iron Peat Moss, Compost, Composted Manure Increase water and nutrient-holding capacity Great amendment. Watch for herbicide residual When Should You Amend? When your soil needs it Fall is the best time to add amendments if you can find them. Finding a good reputable source is very important Watch for herbicide residual in manure and compost. Summary Soil texture, structure, and CEC affect soil fertility Bacteria and fungi do a lot of the work in making nutrients available Do not work soil when it is wet It is not recommended to try to change the soil ph 11
Summary There are 17 elements essential for plant growth 4 of those (N, P, K and sometimes Fe ) have highest chance of impacting your plants By recognizing nutrient deficiency symptoms, and/or soil testing, you can fertilize to optimize plant growth Apply amendments in the autumn after the growing season has ended Make sure that your amendments come from a reputable source Make sure that manure is fully composted End 12