Converting To An Organic Or More Sustainable Cropping System

by Ralph C. Kennedy, Agronomist

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:

1. The addition of toxic substances to the system.
2. The continuous monocropping the absence of a viable crop rotation plan.
3. The lack of attention to soil chemical imbalance ( i.e. base saturation percentage out of balance).
4. Soil compaction from the overuse of heavy machinery on the fields.
5. Practices that reduce the presence of organic matter in the top six inches of soil.

Each one of these factors needs to be addressed in some fashion, but it takes a 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 modern 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 inches 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. 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 food.

Beneficial nematodes eat other nematodes reducing or eliminating root damage and supplying available nutrients. This incredible army in the soil supplies most of the nutrients that are necessary for prolific crop growth if the proper substrates and environment are provided, but addition of toxics to the system inhibits their activity.

Salt-based fertilizers such as Ammonium Nitrate and Potassium Chloride inhibit the natural systems in the soil. The use of these fertilizers maximizes luxury growth of many crops (and weeds), but tissue solute levels (BRIX%) are very low and leaf cuticle are weak which makes these crops more vulnerable to insect attack. The need for insecticide and herbicide applications increases which further degrades the natural ecosystem in the soil. As the soil ecosystem degrades, niches open up for pathogenic fungi, nematodes, and other non-beneficial invaders to come and populate the soil. Then the farmer must increase the use of fungicides, nematicides, and insecticides to control damage and diseases caused by the offending invaders. One can begin to see how the use of toxic chemicals creates a never ending upward spiral in the use of chemical inputs and an equal, but opposite, downward spiral in the level of beneficial soil biological activity resulting in reduced profit margins.

Continuous monocropping of the land, especially with row crops that remove large amounts of nutrients from the soil, reduces the soil's ability to produce viable crops year after year. In addition to reduced yields, the crops become more susceptible to disease and insect attack. An example of this situation involves the depletion of nitrogen by successive corn crops without crop rotation. The farmer must add more and more nitrogen to obtain a viable crop. Insects and other pests that attack corn are able to multiply and thrive on the susceptible corn crop so the farmer must increase the use of pesticides, but the pest seem to develop resistance to the pesticides faster than the farmer raise the rate and/or try new combinations of pesticides that are supposed to provide effective control.

The lack of attention to soil chemical imbalance leads to conditions that reduce the availability of nutrients. An example of this situation involves the build up of soil magnesium levels through continued applications of dolomite lime when the soil has the tendency to become too acidic even though adequate magnesium is present. Calcium flocculates the soil (loosens the soil by forming a glue in conjunction with humus polysaccharides, and organic acids that paste together the fine clay fraction into stable soil aggregates) so the farmer sees the beneficial effects effects until the magnesium level reaches 14 to 15% (depending on which method of analysis is used). The soil then turns into a solid mass, which reduces the capability of the soil to hold oxygen and other nutrients (magnesium also becomes unavailable at this point). Crops look chlorotic, have a hard time getting established, and it takes more and more fertilizer to produce a crop.

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 modern 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 of 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 ( the loose crop residue), and nitrogen from the soil provide the elements that are necessary form prolific fungal growth. Crop residue must remain in the top 4 inches of soil for this process to be effective. An example of this situation is the presence of old corn 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 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 inches 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 as 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 these practices have been put into place to get a picture of what an actual organic and/or more sustainable system looks like. The third step is to write down some of to the practices that were the most impressive and applicable to your farm. The fourth step is to figure out how much land can be put at risk for conversion and how much funding is available on a 3 to 5 year basis to implement the plan. The fifth step is to choose what methods can be put into practice for the amount of funding available. A consultant who works in sustainable agriculture can be great benefit in pinpointing specific areas of concentration. The sixth step is to put together a specific working plan to follow. The last step is implementation of the working plan.

The choice of methods depends on the soil type; fertility levels, base saturation balance, type of crops grown, and soil tilth. Biological activity is maximized when the soil chemistry is in balance. The first method to put into practice is soil testing. The saturation percentages of the base (Cationic) elements (CA,Mg,K, and Na) and the cation exchange capacity of the soil are extremely relevant to creating the right conditions for microbial and root growth as well as nutrient uptake. Major adjustments to this balance take time; if the soil is too far out of balance it may not be economically effective depending on the potential productivity of the soil and the potential value of the crops to be grown on that soil. Major adjustments in base saturation often involve addition of lime (calcitic or dolomite), sulfate, and/or potassium sulphate.

The second method to put into practice is the addition of AGGRAND 4-3-3 Natural Fertilizer which stimulates microbial activity in the soil and supplies additional nutrients to the crop. Microbes and other soil life requires oxygen, hydrogen, carbon,nitrogen, and trace amounts of other elements to proliferate. AGGRAND 4-3-3 Natural Fertilizer contains the elements necessary for proliferation of soil life in the form of proteins, enzymes, hormones, humus substances, vitamins, sugars, and synergistic compounds. Higher application levels of AGGRAND are required early in the conversion process when chemical fertilization is eliminated in the first year. It is possible to recoup the cost of high application rates during the first two or three years when growing high value crops such as tomatoes or melons, but most situations require a gradual decline in chemical fertilizer applications while maintaining moderate levels of AGGRAND fertilizer applications.

For example, the gradual reduction scheme for sweet corn involves reducing the standard chemical fertilizer rate by 50% in the first year, 75% in the second year, and elimination in the third year. The initial AGGRAND 4-3-3 application rate focuses on the N-P-K requirement for sweet corn on a specific soil. If the fertility level of the particular soil requires the addition of 100 lbs of N, 50 lbs of P, and 20 lbs of K per acre, 50% of this requirement is supplied by the chemical fertilizer in the first year, 25% in the second year, 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 nutrients. AGGRAND directly supplies some of the nutrient need, but it supplies others through the synergistic compounds that release unavailable nutrients by stimulating soil chemistry and other 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 corn production). Ten percent of 50 lbs equal 5 lbs of N to be supplied by AGGRAND. It takes 120 lbs of AGGRAND 4-3-3 Natural Organic Fertilizer (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 are planting stimulates early growth and development of many crops, including sweet corn 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, aid in the development of strong stems and roots on sandy and organic soil (soil with low potassium saturation). Positive responses to AGGRAND fertilizers are also obtained with foliar applications when the crop is 4-6 inches 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 Natural Kelp and Sulphate of Potash lengthens the harvest period and increases the fruit shelf-life. The rate and combinations vary according to soil fertility, crop type, and developmental stage.

The third method to put into practice is the addition of organic material into 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 corn example, the initial application of AGGRAND 4-4-3 Natural Fertilizer and Chemical N to the corn crop is reduced because the alfalfa supplies as much as 100 lbs of N in the first year, 50 lbs of N in th second year, and 25 lbs of N in the third year. It also supplies appreciable amounts of other nutrients. The chemical N application is reduced to 25 lbs applied as a starter to insure rapid growth in the early stages of development during the first two years. The AGGRAND 4-3-3 applications is reduced to six gallons per year in the first three years (instead of 12 gallons) which still promotes increased proliferation of microbial activity. In this example, enough N is supplied during the first and second years by the preceding crop and chemical N. In the third year the alfalfa, crop residue, biological activity, and the AGGRAND will supply enough N for another sweet corn crop, but the alternate plan involves rotation into a small grain or back to another legume such as beans. The rotation effect, return of crop residue in addition to AGGRAND applications produces optimum yields of succeeding crops in the fourth and fifth years. The AGGRAND application rate is reduced by 10-20% each year thereafter until the minimum thresholds are reached, which will maintain crop productivity levels and soil biological activity. By the fifth year the field is rotated back to alfalfa. The alfalfa is maintained for four years or more depending on severity of climatic conditions. This 10 year crop rotation plan is much more sustainable, less costly, and produces optimum yields of successive crops throughout the rotation.

Other methods such as minimum tillage can be incorporated into this plan. The land only needs to be plowed once on the alfalfa, sweet corn, small grain, and bean rotation (before alfalfa planting). Minimum tillage for row crops and small grains involve the purchase of special “no-till” planters that are effective in planting through stubble. If the purchase of these planters if possible depending on the budgetary restraints of the plan, then the benefits of minimum tillage are realized. Special once over tillage machines are also available and provide effective seedbed preparation in one or two passes if the budget allows this purchase. Minimum tillage reduces weed competition, keeps residue near the soil surface where it can be broken down quickly by fungi and bacteria, reduces compaction, protects the soil from erosion, and minimizes leaching of nutrients into the groundwater.

Numerous beneficial effects become apparent as the conversion process proceeds:

• Heavier soils become loose 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 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.