What You Should Know About Fertilizer Numbers

27-3-3,6-12-0,8-8-8,4-3-3; fertilizer numbers are becoming more and more confusing as an increasing array of chemicals, designed to solve every agricultural problem, flood the market. What do these numbers mean and what should they mean to the farmer or gardener seeking to increase yield while reducing the use of traditional agricultural chemicals?


First, the numbers expressed on the label of a fertilizer are called the product's grade.


The numbers refer to the amount of nitrogen, phosphorus and potassium (known as NPK) contained in the product.  For example, 8-8-8 signifies that the fertilizer contains 8% nitrogen (N), 8% phosphorus (P), 8% potassium (K) by weight. More simply, 100 pounds of an 8-8-8 fertilizer would contain 8 pounds each of nitrogen, phosphorus and potassium.


AGGRAND Natural Fertilizer, like chemical-free products, is considered a "low analysis" fertilizer. Its guaranteed analysis provides that it contains 4% nitrogen (N), 3% phosphorus (P), and 3% potassium (K). AGGRAND Natural Fertilizer's analysis is based on the fact that it contains absolutely no chemicals normally added to boost the NPK level of a product. Does this mean that AGGRAND Natural Fertilizer is less effective than a chemical fertilizer whose NPK designation is greater than AGGRAND'S? Not at all! In fact, testing has demonstrated that AGGRAND Natural Fertilizer is even more effective than the chemical fertilizers it has been tested against!


Foliar Feeding With AGGRAND

Foliar feeding with AGGRAND is up to 20 times more efficient than applying amendments to the soil. The keys to optimizing the results when using AGGRAND products is to apply them when plants need the extra nutrients, use a biodegradable vegetable oil surfactant (spreader-sticker) to maximize adhesion to the leaf surface, and adjust the pH of the fertilizer solution to maximize uptake and plant use efficiency. Apply them in the early morning or late evening and do not apply before or after rainfall or irrigation. Plants need extra nutrients during transplanting, early growth and development, pre- bloom, early bloom, and fruit formation. Foliar applications are effective in situations where a soil chemistry imbalance, cold soils, or low soil fertility limit the root uptake of nutrients. Most plants respond to foliar applications when they are timed to coincide with seedling emergences (3-6" in height after 2 to 4 true leaves have formed), 2-3 weeks before first bloom (legumes such as snap beans or soybeans), first bloom (tomatoes, cucumbers, melons), runnering (cucumbers, melons) cluster formation (tomatoes), and fruit fill (tomatoes, melons, cucumbers).


When AGGRAND 4-3-3 and 0-0-8 fertilizers are applied before drought, frost, insect attack, or the onset of disease-susceptible stages, the effects of the stress will be reduced or eliminated. . Some growers apply AGGRAND fertilizers on a calendar-based approach every so many weeks up to 8 times per season. Apply these fertilizers according to recommendation rates every 3-4 weeks. A 1-4% dilution rate (1.25-5 oz. AGGRAND per gallon of water) is sufficient for foliar applications. Use more concentrated fertilizer concentrations on heavy feeders and low fertility soils. Never exceed 4% because the foliage could get damaged. On sandy soils reduce the rate by ~ to 1/3 and apply every 2-3 weeks (reduce by 1/3 and apply every 2 weeks for heavy feeders on sandy soil). If you choose to apply AGGRAND products every week split the application rate in half (1 % dilution rate). AGGRAND 4-3-3 and AGGRAND 0-12-0 products can also be applied to promote flowering, fruit, and seed formation. Apply these products when the plants have reached the phase (size, age, and time of year) when flowering is possible.


To increase adhesion of the spray to the leaf surface, add a spreader-sticker to the spray tank. A biodegradable vegetable oil based product that is non-toxic is recommended. Mix according to the directions (1.5-2.0% dilution rate)(2-3 oz./gal.) is usually recommended.


Converting To An Organic Or More Sustainable Cropping System

Converting to an organic fertility program will increase the productivity and quality of any cropping system in the long run. The length of time it takes to convert to a more sustainable system (one that reduces the number of non-renewable inputs) depends on the degree of degradation of the biological ecosystem, which is impacted by:  

  -  The addition of toxic substances to the system.

  -  The continuous mono cropping in the absence of a viable crop rotation plan.

  -  The lack of attention to soil chemical imbalance (i.e. base saturation percentage out of balance).

  -  Soil compaction from the overuse of heavy machinery on the fields.

  -  Practices that reduce the presence of organic matter in the top 6" of soil.


Each one of these factors needs to be addressed in some fashion, but it takes at least three years in most cases to see meaningful results when converting to a more sustainable system. It takes time to detoxify the soil and open up the soil pores so that the soil microbes will multiply and begin to release nutrients, as crops need them.


Many inputs used in modem agriculture are toxic to soil microbes, beneficial insects, and soil invertebrates such as earthworms that cycle nutrients and make them readily available to plants. Each grain of healthy soil (about a thimbleful) contains several billion microbes including bacteria, fungi, actinomycetes, and algae. Fungi are the primary invaders. They break down residue left in the highly aerobic surface layer to a point where bacteria and actinomycetes can continue the process in the top 2-6" of soil. The final result is humus, which provides highly available nutrients to plants. Microbes produce their weight in humus everyday. Some bacteria and algae also fix free nitrogen from the air, which contains 78% nitrogen. In a healthy acre of soil these microbes fix 100 lbs. per acre of nitrogen into plant available forms each growing season. In addition, earthworms produce 700 lbs of casting in one acre of healthy soil each day. Beneficial insects digest other insects, nematodes, and residue producing even more plant food.


In the attempt to create a clean seedbed farmers often run over the field five or six times in a growing season. Admittedly, a fine seedbed is required when planting a fine-seeded crop such as alfalfa or mixed hay crops, but these crops are only planted every four years or more. Compaction becomes problematic when crops are planted each year on the same ground using traditional tillage methods (moldboard plowing, disking, dragging, etc.) with heavy modem equipment. An example of this situation is the farmer that plants vegetable row crops on the same ground each year under contract. In this situation the farmer feels the pressure to get the crop planted by a certain date to get optimum yields and meet contractual harvest dates, so he or she disks and plows the field in the fall to incorporate the crop residue so the field will dry out faster in the spring. When spring comes the fall plowing has brought new weed seeds to the surface creating a healthy blanket of weeds, which must be disked in or field-cultivated before final seedbed preparation. Then the field must be run over with the disk twice more before planting (if the weather cooperates). In the effort to make a clean, fine seedbed, the repeated trips over the field compact the soil and break down the soil aggregates. The result is reduction in pore space creating the same soil condition as too much magnesium. Root growth and microbial activity are inhibited and oxygen and nutrient availability are reduced.


The same practices that cause soil compaction also reduce microbial activity in the plow layer. The moldboard plow turns over the soil placing the organic material underneath the more aerobic topsoil, which inhibits microbial breakdown of the residue into humus. The first microbes to break down the residue are fungi. Fungi are able to funnel nitrogen out of the soil into the crop residue through their mycelium. The combination of a carbon source (crop residue) readily available oxygen (in the loose crop residue) and nitrogen from the soil provide the elements that are necessary for prolific fungal growth. Crop residue must remain in the top 4" of soil for this process to be effective. An example of this situation is the presence of old com stalk residue from a crop harvested two or three years before that is still present six or eight inches below the soil surface because it was plowed under. Fungi are ineffective at this depth and the bacterial microbes while present at this depth act very slowly to break down the residue because of the lack of oxygen. Under these conditions it takes up to several years for crop residue to break down. The nutrients such as nitrogen and potassium, which are released as the residue breaks down, are leached into the groundwater instead of becoming available to the roots which proliferate in the top 4-6" of soil.


It becomes very apparent that converting to a more sustainable system does not come quickly or easily. When considering all of these mitigating factors conversion can be implemented on part of the farm on a trial basis to reduce risk factors and enable the farmer to ease into the new system without undue hardship. The first step is to gather Cl3 much information as possible about sustainable practices and soil fertility as it relates to natural soil biology. The second step is to go out and visit as many as possible where and 0% in the third year. The soil life (through the release of nutrients as excrement and rupture of cell membranes upon death) supplies some of the nutrient need, but iit supplies others through the synergistic compounds that release unavailable nutrients by stimulating soil chemistry and others through the stimulation of soil biological activity. On the average soil that is not too burned out by chemicals or too compacted, apply 10% of the remaining fertilizer need (focusing on the need for the rest of the N requirement because N is often the limiting factor in sweet com production). by AGGRAND. It takes 120 lbs. of AGGRAND 4-3-3 Natural Organic Fertilize (about 12 gallons) to meet this need.


In the second and third year of conversion process it is a good idea to apply the same amount of AGGRAND fertilizer to the crop to give the soil ecosystem a chance to develop. After that a reduction of 10-20% of the AGGRAND fertilizer per year may be possible depending on the other sustainable methods that have been employed. The minimum application rate for AGGRAND is one gallon per acre per year for crops such as hay and small grains and three gallons per acre per year for vegetable crops and citrus (rates may be reduced even further by using low volume sprayers).


The addition of 1 gallon of AGGRAND 0-12-0 Natural Liquid Bonemeal per acre banded at planting stimulates early growth and development of many crops including sweet com because microbial release of phosphate is minimal in cool, wet soil. The addition of 1-2 pints of AGGRAND 0-0-8 Natural Kelp and Sulfate of Potash per acre banded at planting, aids in the development of strong stems and roots on sandy and organic soils (soils with low potassium saturation). Positive responses to AGGRAND fertilizers are also obtained with foliar applications when the crop is 4-6" tall. The stimulation of early growth and establishment of high value vegetable crops is what often makes these crops profitable. The second window for foliar applications is during the pre-bloom stage and the last window is after fruit set up to 3 weeks before final harvest. During the pre-bloom stage 1-3 gallons of AGGRAND 4-3-3 are applied. Some crops may respond to the addition of 1-2 gallons of AGGRAND 0-12-0 and/or 1-2 pints of 0-0-8 per acre to the tank mix at pre-bloom. During the fruit fill pre-harvest stage the application of 1-3 gallons of AGGRAND 4-3-3 or 1-2 pints of AGGRAND 0-0-8 Natural Kelp and Sulfate of Potash lengthens the harvest period and increases the fruit shelf-life. The rates and combinations vary according to soil fertility, crop type, and developmental stage.


The third method to put into practice is the addition of organic matter to the soil, which offsets the need for application of high amounts of AGGRAND in the first couple of years. Cover crops, manure, compost, and crop residue from previous crops can supply a large portion of the nutrient requirements for many crops. If alfalfa is the previous crop in the sweet com example, the initial application of AGGRAND 4-3-3 Natural Fertilizer


Numerous beneficial effects become apparent as the conversion process proceeds:

  -  Heavier soils become looser and more friable as stable aggregates form.

  -  Lighter soils become stickier and less porous.

  -  Earthworms begin to proliferate (an indicator of a balanced soil ecosystem).

  -  Crops are less susceptible to insect and disease attack.

  -  Seed weights, seed protein, BRIX (tissue sugar levels), and forage protein levels Increase.

  -  Livestock become healthier (higher milk production, faster weight gains, lower vet bills).

  -  Crops are more drought, heat, and cold tolerant.

  -  Crops are darker green in color, mature earlier, and recover more quickly from stress.

  -  Crops exhibit increased nutrient and water use efficiency.

  -  Costs of production decrease.


Converting to a more sustainable or organic system produces many noticeable short-term benefits. However, the long-term benefits often determine the real success of this system:

  -  Reduction or elimination of environmental impacts.

  -  Viable crop production in years when other farms are experiencing crop failures.

  -  Buildup of topsoil.


Satisfaction of knowing that you are becoming less dependent on the industrial complex and more dependent on your own thinking used in conjunction with nature's ability to provide.


Ralph C. Kennedy Agronomist