On Conversion to Agroecology by Alan Rosenberg.
If only it were as easy as writing a few pages to promote the conversion of conventionally worked land to become organically worked land then we might not be in the current situation globally.
But if that were the task to write an article on conversion what would need to be said? There are obviously certain concepts that most people would refer to in this regard and yet as many people as were writing so you would get as many opinions.
There are always two aspects to the conversion of the farm, smallholding or other. There is of course the land itself but no less important and perhaps even more importantly is the farmer him/herself. There are two entities being converted and it begins with the human being making a conscious choice to want to work organically, biologically, or perhaps even biodynamically. This impulse must always begin with the person. This is often a challenging time both inwardly and outwardly for that person ‘in conversion’. The general description of that change one is embarking on is that one is developing ones’ attitude and positioning to the phenomena, as they exist and not as normally a purely intellectual or academic approach. This perspective goes towards developing what might be described as a “dependable instinct.” This would be the mode of being of the traditional ‘old world’ farmer. This farmer is someone who is in touch with him/herself and who is equally in touch with his or her natural environment. He/she is someone who is working in harmony with nature and is sensitive to things like the weather, the positioning of the moon and planets, the seasons, natural rhythms and orders and even subtleties like soil moisture content. By developing this dependable instinct, the farmer is empowered to make decisions for the farm that are dependable in their outcomes. Outcomes such as knowing when to plant, when to cultivate, when to make interventions and when to irrigate are all to be decided on with dependable instinct born out of experience and sensitivity. One has to learn to re-trust oneself and not your local agent or cooperative who has usually been advising you what to do, when, so that he maximised the sale of inputs to you. Here experience is the great teacher but too reading, networking and other peoples experiences can help be a part of the learning curve. This advocating for developing this dependable instinct is not a referral to be going back to the past but rather a mode of being that is very realistic for the agricultural future.
When it comes to the conversion of the farm the fundamental difference is that now one is feeding the soil and not the plant directly. During the conversion period the object will be to try and increase the soils organic matter content as far as is both practically possible in conjunction with what is economically viable. Ideally one would want to achieve and organic matter content somewhere towards 4%. Though this organic matter fraction of the soil is the smallest, (the mineral content is usually 45%, air and water 25% each) it is the most influential in its effect on production and for both soil health and crop health.
The approach to Organic agriculture is no less commercial in its approach than so called ‘conventional’ agriculture. With modern man’s scientific approach to all matters, it is no less an issue to the organically thinking person than it is to the conventional farmer. There is an objective science applicable to both agricultural approaches – the Individual sets the tone -, the method of agriculture is impartial to itself.
The concept of ‘good husbandry’ underpins all forms of agriculture and is necessary to all approaches. Care, planning, commitment, openness to new ideas, inspirations and technologies, good ‘common sense’, cooperating with nature, not imposing on fragile systems, working with the natural rhythms and routines, staying within the life sphere when fertilising, are some of the other qualities that contribute to organic success.
Perhaps people will only accept that there is science in alternative agriculture when they realise it is the same science as that of conventional agriculture – only the focus differs. It is not a question of one or the other. It is a question of finding a balance so that the science of the objective phenomena, as they exist, are acknowledged, understood and are worked with.
The ‘Life’ aspects of the approach to agriculture in general are becoming more and more important in contributing to our decision-making on policy. Organic / biological Agriculture is based deeply in the sphere of the living. The greater the understanding of living processes, the more easily one sees the connections between things. The organic grower is concerned with maintaining, understanding and working with these connections both practically and scientifically. And an understanding of the natural kingdoms is fundamental to this. All of nature is divided into four kingdoms being the mineral or physical kingdom, the plant kingdom, the animal kingdom and the kingdom of man. So when we say we need to stay in the sphere of the living we in fact have to use elements from the plant and animal kingdoms. The mineral/physical kingdom is not representative of life and therefore should not be the primary kingdom used to create fertility as is currently the conventional practice of today. The organic matter content of a soil is fundamentally critical to the living processes that happen within the soil. These biological, chemical and mineral processes do not function independently but rather interdependently and co-dependently. Nothing in nature happens in isolation.
In this sphere of the living we are often unaware the miniscule in nature, the world of the micro organisms. These microscopic creatures are as plentiful as they are small and are said to be present by the millions in a teaspoon of healthy soil. Their contribution is often overlooked or toned down. Through a lack of knowledge about these organisms and the tremendous role they play, we often neglect to include their influence in the whole. Micro organisms are present everywhere, and their involvement in the processes taking place in the natural world occurs continuously. We often neglect to give credit to the role of these micro organisms. We often forget that we live in this world as guests of green plants that tap sunlight and produce oxygen. We often neglect farm families who convert plants into products for our consumption. Though this seems so simple a fact it is actually a complex issue that needs the highest order of priority.
What are the soil processes that conversion to organics draws our attention to? They are the typical soil processes involved in all agriculture. They are described as decomposition, humification and mineralization. The life in the soil and its’ activity is influenced by soil moisture and temperature, the mineral/physical nature of the soil, the chemical nature as well as the biological status of the soil. The effects of climate are apparent.
As organic matter in the soil decomposes, two substances are left which are not totally broken-down. The first of these is derived from the original plant material i.e. lignin, resins and oils. The second type of substance is a by-product of microbial activity that was once part of the microorganism tissue. These two substances form the framework for the formation of humus. This humus is quite resistant to further breakdown and thus forms a reserve of nitrogen and other plant nutrients that go towards the feeding of the plant. Humus is defined as a complex, and rather resistant mixture of brown, amorphous, colloidal substances modified from their original tissues or synthesized by various soil organisms. Humus can absorb water equal to 90% of its weight whereas clay can absorb only 20%. Besides holding plant nutrients in a readily available form (contrary to Baron Justus von Liebigs’ research of 1850), humus also contains N, P, and S in organic forms. Humus in the soil is not only a product of decay but also a product of synthesis. Organic growers are interested in soil process and are less focused on mineral materials.
Carbon is the basis of humus formation in the soil and serves as a link between life processes and the mineral earth. Carbon could be said to be the building block for life as it is found in all things that were / are living. With large applications of Nitrogen into the soil, without the corresponding addition of carbonatious material, microbial activity is stimulated, which in turn acts upon the stable carbon compounds. Eventually a decline of humus can result. The relationship between the carbon and nitrogen is known as the carbon: nitrogen ratio (C: N ratio) and is used as a guide to organic matter stability.
Numerous studies have reported higher microbial populations and activity in organic than conventional managed soils, in rotation than monoculture crops and under a ley than wheat crops (Dick, 1992; Sivapalan et al., 1993; Elmholt, 1996; Gunapala and Scow, 1998; Stockdale et al.,2000). Increased active fungal population, fungal diversity, species richness of Fusarium and non-parasitic nematodes occurred in organic than conventional management. These are all driven by higher soil organic matter levels in organic systems (Stockdale et al., 2000). Soil enzymes are predominantly of microbial origin and are related to microbial abundance and activity. Several studies have also shown that soil enzyme activities are higher in crop rotations than mono-cultured crops (Dick, 1984).
The soil is the environment of many plant activities. Plants are anchored in it, water and nutrients are absorbed from it, vast stores of food are accumulated in underground plant parts, and it is in the soil where much vegetative propagation occurs. Of the two environments in which plants grow, the soil is much the more complex. This is true whether air and soil are each considered from the physical, chemical, or biological viewpoint. The soil not only affects the development and activities of roots directly, but also, by modifying the functioning of roots, it affects the growth and yield of aboveground parts. Next to the living organisms which it supports, soil is perhaps the most complex, the most interesting, and the most wonderful thing in nature. It is not mere dirt. It is a vast chemical and physical laboratory where reactions of the greatest economic importance are constantly occurring, where various physical forces interplay while tending towards equilibrium. It is the home of countless billions of micro organisms–bacteria, fungi, and protozoa–which throng its dark passageways. Earthworms, insects, and numerous burrowing animals delve into it for food and shelter. It consists of a complex, highly organized mixture of disintegrated and decomposed rocks (minerals), humus and micro organisms (organic matter) water and dissolved substances as well as air.
Through the above we come to recognize the need to understand the process of decomposition, mineralization and humification in our willingness to go through conversion. These natural processes bringing decomposed organic matter into the soil life processes and lifts the dead mineral nature of the soil into the sphere of the living. We have seen that the biochemical changes, which in total comprise humification, are complex because both degrading (breaking down) and synthetic (building up) processes occur concurrently or simultaneously.
The minerals released through decomposition need to be ‘trapped’ or ‘held’ in the soil so as not to be lost by leaching and/or oxidation. They can be held onto the clay fraction of the soil itself or by adding montmorillonite (bentonite) clay (or similar) to the composting process. The soils organic matter acts as a supply for the essential elements required by the next generation of plants and organisms. Release of these elements or mineralization depends on the decomposition rate and the demand made by the heterogeneous population of soil organisms. This group of organisms in the biosphere vary in size, form, their contribution to the processes and include both macro and micro organisms. Final humification takes place when decomposing matter not only leads to the release of mineral elements but also the synthesis of complex new organic compounds which are more resistant to further microbial decomposition and can then join the stable fraction of the soil. These are the soil building organic compounds leading to an improvement of soil structure, a symptom of a healthy, fertile soil.
The following questions naturally arise: What should be the content of organic matter in a soil? Should the present level be raised or merely maintained economically? These are questions of decided significance in determining policies in soil management.
The farmer attempting to accumulate as much organic matter as possible in the soil is not the correct answer. Organic matter functions mainly as it is decomposed, decayed or destroyed in its’ original form. Its’ value lies in its dynamic nature. A soil is more productive as more organic matter is regularly decomposed and its’ simpler constituents made usable during the growing season. Its’ mere presence in the soil is of value during certain stages of decay, when it influences soil structure and water relations and when it functions in holding and supplying plant food in readily available forms much more effectively than does any mineral fraction of the soil. The objective should be to have a steady supply of organic matter undergoing these processes for the benefit of growing crop. There is an ever increasing need to see the soil in terms of the dynamic contribution it has on the plants which are growing in it. The use of mineral fertilizers can negate this dynamics of the soil as we have seen from the advocating of hydroponics where the need for soil has been taken to the extreme of not being needed.
The level of organic matter content to be maintained is not the same for all regions. It varies according to climate, topography and other environmental influences.
There is a direct relationship between the health of the soil and the health of the plants growing in the soil. The more fertile the soil is the less the attack and severity of attack by the organisms associated with losses. Like any healthy body, the soil too can help to build up a resistance in plants against attack. The attack by a harmful or disease organism would be indicative that the soil itself and not so much the plant, is not healthy. The healthier the soil is the healthier are the plants that grow in it. The primary approach to disease and insect control is to address soil fertility. Bare in mind that the plant is never separate from the whole environment in which it is growing, and the plants’ form, and ability to flourish or not is a symptom of this environment.
Francis Chaboussou, the French biologist and researcher at the Agricultural Research Institute in Bordeaux, France has over many years of observation, both in the field as well as in the laboratory, found out how the resistance or the vulnerability of plants to pest attacks is determined by how balanced the metabolism of the plant is. He formulated his Theory of Trophobiosis (translated as “nutrition biology”). He demonstrated and proved Trophobiosis through the results of his practical experiments. Chaboussou discuses Trophobiosis in his book ‘Plant health and how it is affected’ the detrimental influence of synthetic fertilisers and plant protection agents’.
The theory of Trophobiosis says: “A pest starves on a healthy plant”. For the pest to thrive on a host plant there has to be an oversupply of water-soluble nutrients in the fluids of the plant. It is not possible for the pests to feed directly off foreign proteins because they do not possess any proteolytic enzymes (protein splitting enzymes). They have to find in the sap of the plant sufficient amino acids. There also have to be sugars present instead of the water insoluble carbohydrates as well as the necessary minerals. Then they can build up their own species specific proteins used to multiply themselves quickly – but only as long as the unnaturally high content of amino acids, sugars, and minerals do not decline.
When the plant is growing actively, we will find an intensive metabolism in the cell fluids. The amino acids, the sugars and minerals will be utilised in the build-up of new proteins at the same rate as they get manufactured. The cell fluid therefore is fairly poor in excess of these substances. These are certainly not enough for the pest. It starves or it may just survive but can’t multiply. In most instances a pest will not visit a plant in such a state; the plant is not attractive, not ‘tasty’ to the pest.
Any observant conventional farmer has observed that the more he uses agro chemicals the more problems with pests and diseases appear. Prior to the massive use of agrochemicals beginning in the 1950’s, mites were hardly a problem and disease produced by bacteria and viruses was an exception. Chaboussou has shown that agrochemicals even when they are so-called contact poisons always enter into the plant and influence the plants’ metabolism. Even with minimal amounts the effect can lead to delicate inhibitions in proteosynthesis and consequently leads to a congestion of amino acids in the plant. So the use of herbicides, fungicides or acaricides (poisons against spider mites) can lead to the occurrence of pests, can trigger insect attacks and /or other diseases.
Destruction of the life of the soil through humus reduction and the use of poisons applied often leads to the plant suffering from a shortage of trace elements, even if those elements are present in the soil. A good example is the lack of iron in vineyards. Often there is enough iron in the soil but the compaction of the soil through heavy machinery and / or the disappearance of the soil life obstruct the taking up of iron by the plant. A lack of trace elements also leads to a disturbed building up of proteins.
What contributes to an excessive production of amino acids in the cell fluid? When we apply massive amounts of nitrogenous fertilisers (artificial / mineral or even raw chicken manure) then we basically force the plant to an overproduction of amino acids. There are such quantities of amino acids available that the proteosynthetic process cannot handle them. Thus we create congestion within the cell. One does not necessarily see this congestion in the plant. A plant can look completely normal and only through analysis of the cell fluid will one detect a blockage, congestion, and an excess of amino acids.
The findings of Chaboussou are tremendously important. They refute / disprove the basic assumptions of the chemical plant protection / agrochemical industry.
We must learn in our steps to conversion to work in such a way that our plants receive a balanced nutrition, through fertile soils, and then we will not get disturbances in their metabolism, thus minimising the incidence of pests and disease. This becomes possible in a living, healthy soil whose basis is its organic matter content.
The consequences of feeding the soil are:
• Soil fertility is increased.
• Plant quality is increased.
• Soil health increases.
• Resistance to disease and pest attack is increased.
• The soil is less prone to erosion.
• Cultivation becomes easier.
• Water infiltration and water retention increases.
• Future generations inherit viable land.
• Soil structure / drainage improves.
The practical managerial steps to conversion are based on the understanding of the all the different aspects of the soil and these will differ from farm to farm. The process to conversion will take some time and one must expect that it might take between two and five years. There are no quick fixes though the benefits to applications of organic matter are almost immediately visible in the effect it has.
The organic matter added to soil can be applied through
• Ploughing under plant residues
• The application of composts
• The incorporation of green manures
• Practicing crop rotations
• Using ley crops as part of the long term rotation plan