ORGANIC FARMING IN HAWAII
It wasn’t long before the tropical rainforests were cut down, the land overrun by cattle and eventually planted out in huge plantations of sugar and pineapple. The farming practices were exploitive to the extreme, delivering huge profits into the pockets of the new landowners, who chose to exploit our fragile tropical soils with high inputs of soluble fertilizers and toxic chemicals.
When Captain Cook first “discovered” the Hawaiian Islands, he found, by most estimates, close to 1,000,000 healthy, well-fed people, who lived in harmony with their environment. The indigenous population cultivated their fields and forests in a sustainable manner, and managed their near shore environment for hundreds of years supplying all their food, fuel, fiber, and medicines, with no outside inputs. Within just a few years of Captain Cook’s historic contact, 90% of Hawaii’s population was decimated by disease…over 10,000 more Hawaiians died, when Kamehameha (with British help) subsequently ”unified” the island chain into a kingdom. As the Hawaiians had no written language, much of the oral traditions that had been passed from generation to generation, were pretty much wiped out, as the Kapu were broken. The real secrets of how the Hawaiians had developed their amazing lifestyle (i.e. fish ponds, agriculture) were literally lost forever, as most of the people of Hawaii became dependant on their colonizers for their very survival. We now know, that Hawaiians did extensive mulching with leaves (kukui) stomping them into taro patches, for example.
Though Hawaii has seen a number of different crops like papaya, banana, coffee, macadamia nuts, flowers, and herbs, etc., conventional agriculture has continued this exploitation. With the demise of the large sugar and pineapple plantations much of Hawaii’s polluted land lays fallow, land banked by its “owners” waiting for a future development windfall. It is unfortunate that Hawaii is not at this time able to produce enough clean, nutrient-dense food to feed its own population, and instead depends on imported food and products from around the world.
In response, successful sustainable farmers have come to recognize that the health of their communities is directly linked to the health of the soil. By having healthy soil we can grow healthy crops more easily and a healthy crop means greater economic returns to our farmers and of course a healthier population. Sustainable soil improving practices include cover crops, crop rotations, composting, mulching, living mulches, and natural-source fertilizers.
The varied, young soils of Hawaii are typical of the humid tropical and equatorial zones where chemical and mechanical decomposition of the parent rock (The rock from which the parent materials of soils are formed) is complete. Silica has leeched from the soil because of moisture and heat conditions and humus is deficient because of the rapidity of bacterial action in the prevailing warm temperatures. Losses of silicate clay minerals also result in damage to soil structure, making soils remarkably porous. The ancient Hawaiians were able to maintain their fields over time with sophisticated mulching techniques and fertility practices, without the use of animal products (manures). In fact, many of these “primitive” practices inspired the modern organic movement.
Although soils in the Pacific Region can create luxuriant growth of broadleaf evergreen rainforest, once exposed by clearing the forest, the soils quickly lose their fertility because excessive leeching removes plant nutrients found, in all but a thin surface layer. In times of drought these exposed soils can be further degraded, becoming extremely hard and better used as building material (bricks) than for growing crops.
Soils of Hawaii are young and weathered, and because there is little natural renewal of natural minerals, the problem of low soil fertility in the tropics is centered on demineralization (the leeching of unrenwewed silica and silicate clay minerals like the cations calcium, magnesium and potassium), and the lack of stable organic matter (humus).
Instead of solving this problem conventional farming practices strive only to fix symptoms rather than the root causes. Conventional farming systems do not recognize soil as a living medium to be nurtured for future generations, and instead concentrate solely on making short-term financial gains. This conventional strategy involved feeding the plant and not the soil, leading to the use of soluble acid-based chemical fertilizers, which quickly used up any remaining minerals, further acidifying the soil. Farmers in Hawaii also have to recognize that we must also counteract the acid rain from the Vog of our active volcanoes. The focus of conventional agriculture then fell on the low pH (high acidity) levels that had then been created in their soil. Soils to be fertile must have a pH approaching neutral, between 6.2 and 6.7.
Conventional liming was then recommended (without acknowledging the unique character of our tropical soils). In Hawaii, imported dolomite (because of its low cost) has been the ‘lime of choice’. In other parts of the Pacific, the lime is usually coral-based calcium carbonate; however these practices allow for, and in fact can require, increased use of soluble chemical fertilizers. If conventional lime is all that is available it must be used, but keep in mind that calcium, magnesium, and other cations must be kept in proper balance.
Use of these products can create long-term problems for our farmers because the recommendations are made without recognizing the importance of balancing the minerals in our soil. For example high magnesium levels relative to calcium (as in dolomite) can create the need for increased potassium, which conventionally is supplied by low cost muriate of potash (KCl) (a chemical deadly to beneficial soil bacteria). High calcium can create a boron uptake problem. A fertilizer that should be avoided is ammonium nitrate (NH3NO4), as it can turn our tropical soils into brick.
Increased use of soluble nitrogen fertilizers also creates an increase in diseases like fungus and insect problems that conventional agriculture then treats with extremely dangerous chemicals sold as ‘medicines’ to the unwary farmer. Insecticides kill all insects including many beneficial ones. Fungicides kill all fungi – good and bad. This becomes a serious problem because beneficial bacteria and fungi are critical to creating humus (stable organic matter), developing healthy soils and growing a healthy crop. Because of this loss of fertility, increased use of chemical fertilizer is then recommended, which requires more lime, creating more imbalances and around we go on the chemical treadmill.
Another problem that must be addressed in our Pacific Island Region is salt (sodium chloride) build up. This occurs from salt in the air getting into the ground, the use of manures that are high in salt such as seabird guano or steer manure, irrigating with brackish water, these problems cannot be corrected with conventional chemical soluble salt fertilizers.
In the tropics the availability of phosphates is a problem, as this nutrient is easily tied up with aluminum (as aluminum phosphate) in our acidic soils. Adding more acidified phosphates as is the conventionally practice is only an expensive short-term fix. By liming with silicates, the phosphates can be released back into the soil and made available again to your crop.
We must keep in mind that less then half of all commercial fertilizers applied to our farmland are ever utilized by our plants. The rest contaminates our ground water and fouls our coastline.
When growing food in Hawaii, in a backyard garden, on a small or large farm, it is critical to use agricultural practices that can build humus and balance minerals in the soil. Below I have listed four methods that can help to sustainably increase soil fertility.
1) Testing the soil –this requires taking a soil sample and sending it to a laboratory where a complete analysis is performed.
Tools necessary to take a soil sample include a clean shovel, and a soil sampling tube (stainless steel, chrome or a plastic pail).
Sample must be taken from 10 to 20 random locations
Samples must then be mixed and sub sampled so that one or one and a half cups are sent to the laboratory •Samples must be taken from a depth of at least 6 inches
Samples should be of no more than 40 acres
Small areas must be sampled individually if the soil is not uniform throughout the farm
Avoid different areas, end rows and areas close to roads or buildings
Remove large stones and visible organic matter
2) Amending the soil
Add finely ground basalt (or mixed rock) rock powder
Adjust pH to proper levels
Balance the minerals taking into account the percentage base saturation levels
Add compost in order to increase populations of beneficial soil organisms and humus.
Inoculate your soil with as many different types of beneficial soil fungus and bacteria that are available (including mycorrhizae, endomycorrhizae (VAM) and ectomycorrhizae)
Follow fertility recommendations for each crop, but keep in mind you are feeding the soil and the soil feeds the crop.
High levels of organic matter can solve numerous problems experienced by farmers. Adding mined humic acid is an efficient way to increase humic and fulvic acid levels.The problem of salt build up can be solved by first establishing the amount of salt in the soil by doing a soil test and then adding sulfur or gypsum (CaS04) in the proper amount and then, with water, the sodium bind to the sulfate and the salt is leeched out. It is critical to have a good idea of the extent of the problem before adding any amendment as too much sulfur in the soil can make phosphate uptake more difficult. Also we must remember that we want a ratio of 1 part magnesium to 10 parts calcium for proper organic matter cycling
Phosphate availability can be improved in our acid soils and pH adjustment should be made using silicate limes like calcium silicate. When we use carbonate limes CO2 is released into the atmosphere and this can add to “the green house effect” as only the calcium remains in the soil. Carbonate limes are only soluble up to pH 5.8 – creating wide swings of acidity during our wet /dry cycles – so use of carbonate lime can be inappropriate in a tropical sustainable agricultural system. Silicate based limes are much more soluble and penetrate the soil more efficiently. These limes also add silicates to the soil, which are sorely needed. Understand that the soil holds onto (sequesters) huge amounts of carbon (as organic matter).
3) Making Compost in the tropics
Layered hot (Bio-Dynamic) compost
This is the classic compost that utilizes a variety of microorganisms that heat a pile – killing pathogens and seeds. Usually constructed by layering different organic matter, green waste, animal manures, basalt rock dust, 3 or 4 feet high, inoculated with a compost starter that contains a wide variety of beneficial soil bacteria and fungus
Fungal “cold” compost
This is a compost method that uses fungal action (white “fire fang”) to turn high cellulose waste into soil using molasses. Green wastes of leaves and other shredded material will slowly be turned, into a wonderful compost, by being wetted BT a water, molasses mixture (1-2 tbls. molasses /1 gal water). The white fungus (mycelium) that is encouraged in this method is very beneficial for a healthy garden.
4) Cover crops, ground covers, green manure and mulching
Because of high rainfall it is imperative to protect fragile soils from the elements. If we don’t protect the soil nature will, and when nature does it on her own, she does it with fast growing, deeply rooted plants that can also be called weeds. Use of herbicides only encourages this type of growth and is not cost effective.
The true cost of herbicides
If the true environmental cost of herbicide use where calculated no one in the Hawaii would or could resort to a regular herbicide program. The true costs of regular herbicide use include contamination of ground water, loss of soil to erosion, loss of beneficial soil organisms, increased fungal, disease and insect damage, health problems associated with herbicide exposure and the development of “super weeds”. It is therefore imperative that we help nature by establishing plants that will act as companions to our primary crops.
Cover crops are plants that protect our soil and can actually build soil; they discourage the growth of unwanted weeds and are easily cut down and turned into the soil when time comes to plant a crop. Cover crops are often legumes like glycine that add nitrogen to the soil. In a vegetable garden a cover crop may be squash/pumpkin as this plant grows quite easily, discourages other plants and can easily be mulched when it is time to replant the garden. Sweet potato can be grown as a cover crop in orchards. The nice thing about using plants like sweet potato or squash/pumpkin as cover crops is the extra food they bring to the table. Grazing animals such as sheep, geese or horses can also control cover crops, with their manure adding valuable humus to our soil.
Ground covers are a bit more permanent and can be legumes or grasses that act as companions in orchards, they are chosen because they grow slowly like paspallum grass or fix nitrogen like certain species of desmodium.
Green manure is grasses and legumes grown to be cut and used elsewhere on a farm. In a perfect world one third of our farm should be devoted to growing green manure crops. They are fast growing plants that produce lots of biomass like soya/desmodium, alfalfa, sunhemp and Sudan grass.
Mulching is a wonderful method to suppress weeds in an orchard or garden around established plants. Any fine shredded green waste or compost will slow down weed growth and add humus to your plants (mulching with green compost can remove a bit of nitrogen from the root zone while it breaks down, but will give it back when break-down is complete). You can also mulch with cinders or crushed rock. Mulching will also conserve moisture so resist during dry periods unless the plants you are mulching have first been thoroughly watered.
Improving soil fertility is the key to success in sustainable agriculture. Recognizing what good soil structure (tilth) is critical for developing successful farming operations. Science has always illustrated that a healthy ecosystem of soil organisms is necessary to grow healthy crops.
Unfortunately the conventional agriculture establishment has chosen to ignore nature as a partner in the growing business, and as a consequence we have all subsidized their profitable, toxic and environmentally disastrous experiments. It is a relief to recognize that these diverse beneficial soil organisms, from earthworms to mycorrhizae, perform as unpaid biological fertilizing machines, putting the profits from their work into farmer’s pockets.
It is also heartening to realize that as one toxic chemical after another is removed from the conventional farmer’s arsenal; there are natural, low-cost alternatives that can protect our farms from erosion and droughts, insects and disease. This approach is leading to improved yields, greater economic wealth, healthier plants, a healthier population and a safe environment for future generations.
Learning from history:
Before Justis Von Liebig’s scientific explanation of the role of minerals, especially Nitrogen, Phosphorus and Potassium (NPK), in the growth of crops, European, Asian and indigenous people alike followed a form of organic agriculture.
Nomadic tribes and indigenous people worldwide have followed their animal herds that converted grass into food and fiber; in fact cattle and capital (money) were the same. There is evidence that many indigenous people worldwide in the Americas and Hawaii and Asia managed their farmland and forests in a sustainable manner that provided food, fuel fiber and medicines for countless generations.
All forms of “organic” agriculture, i.e. Permaculture, Biodynamic, “traditional” organic, “Hensal-Bread from Stones” remineralization, etc., understand the need to build organic matter to grow crops in a sustainable way. All of these practices understand that agriculture and agroforestry are life styles and that food is medicine and should be grown this way. By using polyculture and fully integrating animal (milk, meat, eggs, fiber) and plant (food, medicine, fuel and fiber) production costs can be reduced while eliminating non-point source pollution. “Organic” enthusiasts understand that our soils are a resource that must be preserved.
But the focus of the then emerging “coal-chemical” cartels in the late 1800’s, on NPK as fertilizer and the development of more and more toxic pesticides, changed the face of food production forever. Slash and burn, milpa-type agriculture, where there was seemingly unlimited land, allowed indigenous people to grow crops on exposed virgin forest land until the fertility was exhausted, and then move on to another virgin area.
If there was enough land this type of farming worked quite well (working within 40-50 year cycles that involved a progression of crops, orchards to mature forest). European Farmers had no such luxury and as farm after farm was “burned out” more and more chemical inputs were required to grow a crop.
After only a few years, Von Liebig renounced the partial implementation of his theories, which besides NPK also spoke of the importance of trace minerals. However the power of the chemical companies had become so great that his pleas were ignored. Higher and higher doses of acidic chemical fertilizers were able to grow crops even on depleted land and this exploitation made them money.
We are now reaping the bitter harvest of unsustainable farming practices. As conventional science comes up with one thing after another to solve the problems they created. They “give” us one toxic chemical after another, now contaminating our land, water, food and people, making it more and more difficult to grow our own food, we seek new answers. They give us hybrid seeds that can produce greater yields in demineralised, polluted soils yet have less color and flavor and are less nutritious. Now they promote Biotech and genetically modified crops, promising to increase yields and reduce pesticide use. According to a report by The Center for Food Safety, Genetically modified crops, actually increase pesticide use, and fail to increase yields. GMO’s also contain new proteins that threaten the health of people that consume them. There is also a potential that dangerous genes can transfer to other organisms in the open environment (horizontal gene transfer) and actually cause problems far into the future, even after open growing of GMO’s are finally banned. Hawaii unfortunately has become ground zero for the development of this criminal, dangerous, life-threatening experiment.
Sustainable farming – Why Organic?
Sustainable farming is any system of farming that promises to improve, over time, the fertility of the farmland in an economical and ecological manner by making nature a partner in the growing process. This form of farming has many faces and many styles, from Organic to Biological, from Biodynamic to Permaculture, from EM (Effective microorganisms) natural farming to IMO (Indigenous microorganisms) to Terra Preta (adding rock minerals and charcoal to the soil). As sustainable systems mature they become increasingly diverse and diversity creates stability.
Sustainable agriculture recognizes that farmers are miners of minerals, using the air, water, sunlight and plants, to produce food, fuel, fiber and medicines.
Sustainable agriculture avoids using farming techniques that result in loss of topsoil, toxic residues that lead to serious health problems, contamination of soil and groundwater and destruction of the near shore environment. (For every dollar earned by a conventional farmer there is close to $.90 damage to our environment and health (externalities), the cost of which becomes a burden to our taxpayers and literally amounts to a subsidy for conventional farmers).
Sustainable farmers have come to recognize that the introduction of genetically modified organisms into our environment and supermarkets, by conventional, university promoted agriculture represent a direct threat to our health and our environment.
Sustainable agriculture understands that we must feed the soil and then allow the soil to feed our crops. Biological farmers realize that the soil is alive with a wide variety of soil organisms. These organisms live in a complex relationship and the exchange of minerals and nutrients between plants and these microscopic organisms represent a critical link to plant health and productivity.
Farmers who practice sustainable agriculture will not exploit the fertility of their soil to make short term-profit, but strive to increase the fertility of their soil to better fulfill their long-term needs.
Sustainable farmers use an ever-developing sense of observation in recognizing pest problems, and use available biological controls that are available. We all depend on a clean and healthy food supply and a safe environment to live in. By practicing sustainable agriculture we can have both.
Successful sustainable agriculture depends on an enlightened and intelligent farming community willing to work with nature, cooperate with neighbors, use and share the latest scientific knowledge to improve the environment.
Sustainable farmers are also entrepreneurs who seek the highest value for their labor. To achieve this they must be thoughtful observers, always striving to enhance their knowledge and techniques. All farmers involved with sustainable agriculture understand that beneficial soil organisms are nature’s volunteers. By providing these workers with a safe home (a soil free of toxic chemicals with plenty of air and moisture), food (compost/organic matter), a good mineral balance, they work tirelessly, providing us with clean nutritious food, valuable fuel and fiber and important medicines. By feeding these soil microbes, they feed and protect our crops. Exactly as nature intended.
Least Toxic Pest Management for the Tropics
The Pacific Island region supports unusually high pest loads – both native and introduced – due to its diverse environments and year round growing season.
Years of monoculture, coupled with the use of chemical pesticides, have resulted in the loss of soil fertility, making it difficult to grow clean and healthy crops. This has created a problem given that the market now demands an ever-greater focus on the value of a clean environment and safe food. To meet this demand it is clear that farmers must use sustainable strategies to control pests, thus reducing the application of toxic and often dangerous chemicals.
Sustainable farming is a total system that seeks to re-establish a more natural mechanism for growing healthy crops. This system recognizes that all living things are connected, and that by working within natural cycles less effort is expended and yields are increased – less costs and more profit.
Sustainable agriculture embraces Integrated Pest Management (IPM) practices. IPM is a strategy that seeks to minimize damage to plants by careful observation and monitoring, predicting trouble before it happens, and then choosing the least toxic controls. IPM requires the farmer to study and understand the plant’s environment, and monitor closely the life in the orchard, field or garden. IPM also requires that a farmer understand the wide range of options that are at his disposal.
Weeds are plants out of place, competing with cash crops and reducing yields. Sometimes weeds can make it almost impossible to grow crops. In pastures weeds are the inedible plants animals cannot eat and so they reduce the amount of forage available for consumption. Weeds can also make it more difficult to harvest a crop. Vines and tall weeds in coffee fields and thick weeds under mac-nut trees increase picking times and some weeds use up valuable nutrients from crops and reduce available sunlight.
2) Insect Pests
Insects can cause severe damage to crops. They are most likely to attack plants that are stressed by poor fertility, drought, over-watering and other, often solvable problems. The Pacific Island Region also suffers from introduced insects that have no natural predators. Monoculture, still encouraged by some, has been found to encourage considerable damage by insects.
a) Above ground insect pests
Sucking insects are insects that cause damage by sucking fluids from plants. They usually do not move around very much and can cause damage in a number of ways. Sucking insects dramatically slow down the growth of plants, damage new and old leaves; spread viral diseases and cause fungus and bacterial diseases. These pests include aphids, scale, mealy bug, white fly larva, leafhoppers, spider mites, spittlebug, stink bug and thrips.
Chewing insects actually take bites out of our plants, and can very quickly cause serious damage to crops. These include larvae of caterpillars and moths, cut worms, rose beetles (at night), larvae of other beetles and cutworms. These insects can move around and evidence of their damage can be very clear.
Borer and miners
These insects cause damage inside leaves (leaf miner), stems (stem and vine borers) and inside fruit (larvae of fruit flies). Farmers must be observant with regard to these pests – as economic loss can be considerable. There a number of products made with a microbial source poison called spinosad, which can control a number of these pests, An Organic product called Monterey seems to be very effective.
b) Below ground insect pests
These larvae of beetles can do considerable damage to roots of host plants but it is the chewing damage by adults that is most obvious, grubs can also cause damage to grasses and turf.
These are tiny soil worms that can cause a great deal of frustration for the tropical farmer as most plants can be affected by one or more species. Symptoms of nematode damage include malformed leaves, stems and roots; dwarfed plants and wilting. Some endoparasitic (living within the root) nematodes cause the classic gall or root knot that blocks nutrient uptake and allows for infection of other disease organisms.
c) Microbial Pests
Viruses can be extremely damaging to crops such as papayas, bananas, tobacco, peppers and other fruits and vegetables grown in the Pacific region. While sucking insects spreads most viruses, some are spread by air. Viruses cause the loss of green in the leaves, reduce the sugar content of fruit and can kill off whole crops. They must therefore be taken very seriously.
Fungi can cause different diseases such as sooty mould, powdery mildew, fungal blight, root rot, damping off, anthracnose, rusts, leaf spot, fusarium wilt, Phytophthora, pythium and watery soft rot to name a few. Problem fungus’s can spread rapidly and cause considerable damage to a crop.
Bacterial diseases are usually foul smelling and can spread easily. Damage and wounds caused by insects and animals are the most common reasons for infection. High moisture also makes it easier for bacterial infections.
d) Animal Pests
Pigs, feral sheep, horses, deer, dogs, cats, mice, rats, birds, mongoose and many others can quickly cause considerable damage to a crop.
e) Toxic herbicides, insecticides and fungicides
The conventional approach of killing weeds with expensive toxic chemicals can also create problems. Herbicides can kill or injure other plants and animals besides the targeted weed. Certain herbicides can also kill beneficial soil organisms and reduce organic matter in the soil. This creates extra problems in the long term, such as loss of topsoil, increased fertilizer rates, increases in insect damage and fungal problems. The problems and costs to our society, associated with chemical herbicide use, far outweigh the financial gains made by conventional farmers and amount to a subsidy for their use.
Pesticide chemicals used by conventional agriculture are as much a part of the problem as the pests they seek to control. Use of insecticides kills both bad and the good (beneficial) insects. Beneficial insects are extremely important in controlling other insects in nature, so the spraying of a toxic chemical to eradicate a specific insect will therefore often lead to an increase in insect problems in the long-term. Similarly, fungicides kill both good and bad fungus. Beneficial funguses have been proven to be an important link in maintaining healthy fertile soil and in providing nutrition to crops.
Pesticides – counting the costs
Herbicides, insecticides, and fungicides can have a very dangerous effect on human health. Insecticides are the same class of chemicals that are used as nerve agents in chemical warfare. They are nerve toxins that can cause irreparable harm to the public, especially the young. Use of chemical pesticides also pollute the near shore environment and contaminate public drinking water. Insecticides, herbicides and fungicides can also leave toxic residues on our food and their combined effects can be extremely dangerous, leading to a plethora of acute and chronic diseases. When the costs of the above are taken into account there is no economic benefit in the use of these chemicals; they cause more economic and social harm than any possible benefit.
The mistakes that have been learnt from the inappropriate use of pesticides are today becoming tools that can be used to generate farming solutions based on safety and sustainability. By working with nature farmers are recognizing that they can both increase their returns and protect public health and the environment at the same time.
It must be understood that plants in an orchard only become weeds when they impact negatively on the growing of primary crops. Just because a plant is in an orchard shouldn’t make it the target of expensive and toxic herbicides.
Desmodium is a weed to many in Hawaii, yet to others it is excellent ground cover, fodder for grazing animals and a source of free nitrogen. It is also a good place for beneficial insects to live that will in turn protect the primary crop from disease. Many also consider blue Vervain a weed, yet it is a valued medicinal herb sold in health food stores. It is therefore quite possible that what is considered a pest may have economic value as a crop.
Weeds are an indicator of soil health – proper pH adjustment and mineral balancing can reduce the impact of weeds on a farm.
Even when weeds need to be controlled, toxic chemicals can still be avoided. There is an herbicide on the market that is made from synthesizing a chemical found in a certain soil bacteria. ‘Finale’ kills most weeds like conventional herbicides yet is said to break down to water and carbon dioxide, leaving no residues, yet there is evidence that exposure to the active ingredient in ‘finale’ can cause major health problems. Another problem with using this product is that the bare ground it leaves is the perfect place for more weeds and soil erosion and it can create a dependency if a ground cover is not established.
Planting groundcovers are the best way to reduce dependency on herbicides. Ground covers are any plant or plants that do not interfere or help with the growing of a crop. Grazing animals controls ground covers, mowing, cutting and weed-eating. The extra time spent establishing proper ground cover will eventually be much more beneficial and cost effective than the perpetual use of herbicides. Help in deciding what the best ground covers are in a specific area can come from soil conservation representatives or agricultural extension agents.
Other ground covers include cinders and ground rock. These types of material are excellent around the base of trees in an orchard or between the rows of a raised-bed garden.
Solarization and weed mats
In sunny locations, solarization is an efficient way to kill weeds and weed seeds before planting. Simply lay 2 sheets of clear plastic sheeting over the ground. The area needs to be watered thoroughly before covering in order to reach high enough temperatures to kill the weeds. It may take 1 to 2 weeks but this method is very effective. In areas without hot sun, covering with one sheet of black plastic, or even cardboard will effectively kill off the ground cover in about a month, but not all seeds. There are also weed mats that can be placed semi-permanently in an orchard or garden, but care must be taken so that weeds don’t get established on top of them (a little attention once a month is all it takes). Burning can also be a very effective method of eliminating weeds.
Sometimes, in certain plantings, weeds from wind blown seeds can cause a lot of damage. The easiest way to control this problem is using Corn Gluten which, besides being an excellent fertilizer source (9-0-0) will prevent seed germination for up to 3 months when applied at a rate of 800lb/acre. This is a great product for established lawns and orchards where you do not want any seeds to germinate, also in vegetable/herb operations where there is no direct seeding into the garden. The problem with corn gluten is that it may be derived from GMO corn, and just may not be an appropriate fertilizer anymore.
The best way to control weeds though is just not to let them get in control. This can be done with proper cultivation techniques, for example waiting to plant seeds or starts in the garden until weeds start to grow and then turning them into the soil when they are about an inch high. If this is done 2 or 3 times before planting, plants will not have as many weeds to compete with. It seems weed problems increase in the tropics as soil acidity increases. Acidity in soil increases with lack of air (compaction), standing water in the surface layer, cultivating too wet a soil, insufficient cultivation, insufficient drainage, using the wrong kinds of fertilizers (acid-chemical) that cause erosion and loss of humus.
Integrated Pest Management
Integrated Pest Management (IPM) is the principle that guides sustainable farmers as they attempt to solve the problem of insect pests. It is time to spray when evidence or damage of pests is visible, so one must be observant and recognize problems in their earliest stages. Most above ground pests can be controlled with the use of botanical sprays containing pyrethrum, rotenone or neem oil, individually or in combination. These types of sprays control insects pretty much on contact but these sprays will also kill beneficial insects, so care should be taken.
Sustainable agriculture recognizes that most insects are good, and in fact, beneficial insects can keep pest insects under control. The ability of parasitic wasps to control fruit flies is a good example of how beneficial insects can solve a pest problem. Other beneficial insects include Lady beetles, green lacewings, seraphid fly, praying mantis, and larger wasps.
Soaps and oils
Use of insecticidal soap can also control most above ground insects, especially sucking insects; yet do little damage to beneficial insects because they can move out of the way quickly.
Light oils, like paraffinic oil are also very effective at controlling insect pests. In the case of borers and leaf miners increasing growth rates and sap flows with fertilization and watering will be more beneficial than using toxic controls.
One of the more interesting controls is the use of Bt; bacteria specific to caterpillars, making them stop eating the crop and then die without impacting on any other insects. This product is effective for almost all larvae (worms) of moths and butterflies.
The gene that produces this toxin is the one that has been inserted into the commonly used gm crops of BT corn, soybeans, and cotton…there are real concerns that it is responsible in part for the dramatic die offs of certain butterflies and honeybees. There are also grave concerns that with the widespread use of these genetically manufactured crops, targeted insects will quickly develop resistance to one of the more valued pest control options for organic farmers.
There are also many fungi that are used to protect crops from a variety of pests. Specific commercial fungal strains target a wide variety of insects including aphids, thrips, beetles, and whiteflies among others. One of these products (that is OMRI certified) is Mycotrol that contains the hyphomycete fungus, Beauveria bassiana.
A bio control known as Spinosad seems very effective with a variety of ants and other insects.
Collecting the offending bugs by hand, blending them in water and spraying the mixture (bug juice) on crops can also be an effective means of control, it is especially efficient if you use scale killed by fungus. This juice will infect all the scale with disease without harming beneficial insects.
Certain sucking insects are tended to by ants that collect their “honey-dew” as food. To effectively control these insects, which can be scale or aphids on citrus or coffee and mealy bugs on palms, it may be appropriate to put a sticky barrier around the bottom of the tree to discourage re-infestation by the ants. Using baited traps (with borate baits) can be an effective way to reduce ant populations.
Light row covers
The use of light floating row covers is also an excellent way to protect your crops from insect damage. Below ground pests like Japanese and rose beetle grubs (evidence of night beetle damage on leaves and brown patches in turf) can be effectively controlled with a milky spore virus applied to the ground or turf where you think the grubs are living. Also, light applications of diatomaceous earth to leaves can discourage all chewing insects.
Many insects can be controlled using “bug lights” that attract offending insects placed over oil water mix that captures the adult insects at night. Good for moths and beetles.
Nematodes are a major problem in the tropics and are major reason farmers should never bring soil or plants possibly infected by nematodes onto their farm. If nematodes are suspected high levels of organic matter will control them. Nematode control centers on chitinase fungi and soil bacteria, which are organisms, that digest chitin (shells of insects). One form of control is the direct application of chitin (shrimp and lobster-meal are excellent forms of chitin). As the bacteria that digest chitin proliferate they kill of the nematodes. A product developed and sold specifically for that purpose is sold as ‘Chitosan’. High phosphate bat guano (composted digested insect parts) used as an inoculant can also help control these pests.
The sesame plant is also very effective at controlling nematodes. ‘Neotrol’ is the name of a product made entirely from sesame that is sold for this purpose. Neem cake added to the soil can also effectively control nematodes (Neotrol and neem cake are also good sources for plant nutrition) and solarization also controls nematodes and sterilize the soil.
Planting in a polyculture is also a good strategy to confuse insects because insects love a monoculture. It is therefore helpful to use companion planting; farmers can plant companion plants that act as a repellent like marigolds repelling the cabbage moth from laying her eggs. Plants can act as a trap allowing the grower to both witness and remedy insect problems before they get to the primary crop For example fruit flies will spend their nights on corn plants, where they can be controlled before they damage your fruit. Nasturtiums are an indicator of aphid problems and Amaranth for spider mites. It is basic common sense that by planting a cover crop that is liked more by insects a farmer will avoid major damage to the primary crop (e.g. aphids on desmodium in a citrus orchard). Nematodes can be controlled by planting nematicidal marigold, which becomes a most beneficial weed in the carrot or beet patch.
Root fungus and bacterial soil disease is best controlled by proper cultivation and by not allowing free water to develop in the garden. Diseased plants must be removed immediately as problems can be spread quickly and a different type of crop should be planted until the problem is solved.
That is why good fertile soil is the goal of sustainable agriculture. A good healthy soil, full of beneficial organisms and properly balanced can absorb four times as much water as conventional soil before it becomes water soaked. Healthy soil also drains more efficiently, reducing the threat of fungal or bacteria problems. If a problem is suspected, well-made compost full of friendly microbials will usually help correct future problems. There are also specific microbial anti-fungal preparations on the market such as “soil guard” by Trilogy corp. that are quite effective.
Healthy well-balanced soil with good drainage is really the key to controlling soil born fungus and bacteria. It has been proven that the use of soluble high nitrogen chemical fertilizer can cause fungal problems and its use must be avoided.
Sooty mould caused by the honeydew of sucking insects can only be controlled once you solve the insect problem. Powdered sulphur, micronized copper and copper sulphates are very effective products on most above ground fungal problems like anthracnose. To be really effective regular spraying following product label advice should start before a problem is seen.
Powdery mildew can be controlled quite effectively using a spray made from two tablespoons of Paraffinic oil and two tablespoons of baking soda, or potassium bicarbonate (kali-green) per gallon of water. Two applications over ten days should work quite well. A bacterial preparation (organic) made from a bacteria (b.subtilis) known, as Serenade is a very effective fix. Sulfur and copper sprays can also be effective as a control. Under proper conditions neem oil is a very natural control for a variety of fungus problems.
A virus is impossible to cure once a plant is infected. If a virus is suspected all diseased plants must be removed and buried and it is also wise to remove and bury surrounding plants. If the threat of a virus is real, the best way to keep it away is to grow healthy plants and discourage transmission using plant protectants such as polymer coatings or paraffinic oil mixed with repellents and applied regularly. These sprays should contain a high quality potassium salt of humic acid as this substance has been proven to stop the transmission of tobacco mosaic virus.
Fences, netting and traps should be used as much as possible. Poisons should be used as a last resort and applied in such a way they do not injure untargeted animals. The use of light floating row covers over just planted corn seed or other vegetables is an easy way to discourage bird and rat damage to tender seedlings.
Pesticides and herbicides kill all living things. They do not distinguish between pest organisms and beneficial organisms. By killing beneficial insects and organisms their use cripples the natural system hampering efforts to grow healthy crops. It is therefore essential to understand the importance of the polyculture and the use of short crop rotations to reduce weed, disease and pest problems.
Sustainable farmers understand that diversity builds stability and that all living creatures large and small are interconnected. Certain elements prepare the way for a healthy crop and encouraging natural cycles will lead to higher yields and less work. Sustainable farmers have learnt from the mistakes of decades of chemical farming. When it comes to developing the least toxic strategy for controlling pests, farmers must take into account the importance of thoughtful observation as opposed to thoughtless application of toxic inputs as the key to their success.