Advantages of Organic Fertilizer

Made from naturally occurring sources, therefore limited amounts of fossil fuels are used in production, potentially lowering the amount of greenhouse gas that is released into the atmosphere. Nutrients are released only when media is warm and moist, coinciding with times of greatest need in lawn care and agriculture (although this may not be an issue for greenhouse/ nursery plants, which are always kept under optimum growing conditions). The slow-release nature of most organic fertilizers may slightly decrease the runoff of nutrients into local water systems when compared to some quick-release nature of most organic fertilizers may slightly decrease the runoff of nutrients into local water systems when compared to some quick-release synthetic sources that release nutrients regardless of media conditions. It is important to note that slow-release synthetic sources may offer similar benefits. In terms of the end product, such as the quality of plant produced by a commercial greenhouse, organic fertilizers can be quite competitive with traditional synthetic sources when used over a long period of time during in-ground production, organic fertilizers may increase the quality of the soil, including an increase in the efficiency of nutrient utilization. 

FERTILIZER RATE CALCULATION

Nutrient recommendations for landscapes and gardens are expressed in pounds per 1000 square feet (figure 1; table 1). Calculate the amount of organic fertilizer needed by using the soil test nutrient recommendation, the concerntration of nutrients in the fertilizer selecte4d, and the size of the area fertilized. A simple formula used to calculate the amount of fertilizer required to meet a nutrient recommendation is:


Fertilizer needd'XLbs of Nutrient x 1Lbs fertilizer x Z Sq.f area
                    1000 Sq.ft.      Y Lb Nutrient

Where X is the nutrient recommendation from a soil test reqort in pounds/1000 sq. ft, Y is the percent of the nutrient in the fertilizer divided by 100, and Z is the square footage of the area fertilized. Garden and landscape areas are usually different than 1000 Sq.ft. Estimate the size of the area to be fertilized by pacing or using a measuring tape to determine length and width. Multiply length by width to calculate area.

Example: A gardener is using blood meal (12-2-1, Table 2) to supply 2 pounds of nitrogen per 1000 square feet. The garden area is 1400 square feet. How much 12-2-1 fertilizer is required for this situation? Answer: In the above equation, X is 2 pounds, Y is 0.12 (12% divided by 100), and Z is 1400 square feet. Entering these numbers into the equation gives an answer of 23 pounds of 12-2-1 fertilizer for the garden.

AVERAGE NUTRIENT CONCENTRATIONS AND RATES OF AVAILABLITY FOR VARIOUS ORGANIC MATERIALS

Material	% Nitrogen	% Phosphate	% Potash	Availability*	Notes**
Alfalfa Hay	2-3	0.5-1	1-2	Slow/Mod.
Bone Meal	1-6	11-30	0	Moderate	alkaline
Blood Meal	12	1-2	0-1	rapid	acidic
Cottonseed Meal	6	3	1	slow	acidic
Composts	1-3	1-2	1-2	moderate	alkaline
Feather Meal	12	0	0	moderate
Fish Meal	6-12	3-7	2-5	rapid	acidic
Grass Clippings	1-2	0-0.5	1-2	moderate
Hoof/horn Meal	12-14	1.5-2	0	moderate	alkaline
Kelp	1-1.5	0.5-1	5-10	moderate	zinc, iron
Leaves	1	0-0.5	0-0.5	slow
Legumes	2-4	0-0.5	2-3	Moderate
Manures: Cattle	2-3	0.5-1	1-2	Moderate	weed seed
Horese	1-2	0.5-1	1-2	slow	weed seed
Swine	2-3	0.5-1	1-2	rapid
Poultry	3-4	1-2	1-2	rapid
Sheep	3-4	0.5-1	2-3	moderate	weed seed
Pine Needles	0.5	0	1	slow	acidic
Sawdust	0.1	0-0.5	0-1	very slow
Sewage Sludge	2-6	1-4	0-1	moiderate	zinc, iron
Seaweed Extract	1	2	5	rapid	zinc, iron
Straw/corn Stalks	0-0.5	0-0.5	1	very slow
Wood ashes	0	1-2	3-7	rapid
Neem Cake	2-5	0-5-1	1-2	rapid	weed seed
Mustard Cake	4.8	2	1.3	rapid
Castor Cake	4-4.4	1.9	1.4	rapid
* Approximate rate of nutrient release from the material
** Special Properties or Charactristic of the materials

INTRODUCTION TO ORGANIC FERTILIZER

The organic fertilizer refers to materials used as fertilizer that occur regularly in nature, usually as a byproduct or end product of a naturally occurring process. Inorganic or synthetic fertilizers are produced artificially in  a chemical refinery. Organic fertilizers such as manure have been used in agriculture for thousands of years; ancient farmers did not understand the chemistry involved, but they did recognize the benefit of providing their crops with organic material. Only within the past 100 years have fertilizers containing essential micro and macro-nutrients been synthesized in the laboratory. Mass production of synthetic fertilizers has greatly increased crop yields and made the green industry more cost efficient. However, within the past 10-20 years negative effects of fertilizer runoff on the environment have been identified, and there is a renewed interest in organic fertilizers as an environmentally friendly alternative to artificially synthesized chemicals. What, exactly, goes into an organic fertilizer? Like any fertilizer, organic fertilizers typically provide the three major macro-nutrients required by plants: nitrogen, phosphorus, and potassium. 

COMMON COMPONENTS of ORGANIC FERTILIZER

•  Oil Cake- contains all three major macro-nutrients
• Bone Meal- slow release fertilizer high in phosphorus and calcium
• Bat Guano- contains all three major macro-nutrients
• Poultry Humus- waste products from the chicken industry contain all three macro-nutrients and are used locally in Maryland
• Fish Emulsion- High in nitrogen, phosphorus, and trace elements.
• Fish Meal- traditionally used as fertilizer prior to advent of synthetic sources, provides high nitrogen and phosphorus
• Cotton Seed Meal- high in nitrogen
• Seaweed (Kelp) Meal- high in micro-nutrients

Some fertilizers may also incorporate materials that do not derive from a living organism, but are still accepted for use in organic fertilizers. Examples include limestone, rock phosphate, and Chilean saltpeter. Organic fertilizers on the market in the India are certified through the INDOCERT, which restricts the use of the word 'organic' to certified producers. Certification may guarantee that a fertilizer on the market does not have any synthetic chemical input, but does it guarantee a benefit to the environment.

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