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Content of Page »Vol.3,No.1«

I Forward from the Editor

by: Sahle Tesfai


Dear friends, here we are.

After the successful implementation of the NECOFA -Uganda Workshop.

The anxiously awaited NECOFA Nigeria first Country Workshop has been also successfully concluded between the 20th and 21st December.2000, in Gateway Hotel, Abeokuta Nigeria.

The Programme of the events was indeed very colourful and well organised from the NECOFA Nigeria-Group.

The Workshop on Ecofarming (Ecologically and Socially Land Management) was declared open by the deputy Governor, Ogun State Alhaji Sefiu Adegbenga Kaka and addressed by Hon. Commissioner for Agriculture and Natural Resources Engr. Sina Adegbenro.

Prof. T.O. Oseni Mr. E.O. Ogunbe welcomed the honourable Participants.

Different topics on Ecofarming has been forwarded, comprehensively discussed and visions outlined.


On this occasion I congratulate NECOFA NIGERIA in my name, the Advisory Body and all NECOFA country groups in general for conducting this marvellous event, to what I proudly can call it "THE FIRST NIGERIAN ECOFARMING WORKSHOP OF ITS KIND". Good job Mr. Edward Ogumbe/Prof. T.O.Oseni.

Keep on and again congratulation!!


The proceedings of the Workshop with its very interesting topics are wonderfully elaborated. It was in fact our intention to give to this event a priority of editorial arrangements for a special issue, but due to its large contents in pages was not possible in today's NECOFA-NEWSLETTER.


We also had to give a special consideration to the letter of our Advisory Body member Mr. Roland Bunch and his presented, well researched Topic " A New Understanding of How to Maintain Soil Fertility in the Tropics".

Due to its large content we couldn't issue the full version of the topic. In the next issue of the NECOFA-Newsletter will be considered the rest of the topic.


Please be informed that all topics, Workshops, Seminars proceedings, individual contribution of research topics, articles are to be find in the Homepage of NECOFA.

Everybody is invited to look and do research on the different already available topics and also to the new topics of Ecofarming which are being added from time to time.


Last but not least the new NECOFA co-operative Organisation; - The International Centre North South Dialogue "ICNSD" will be a toolbox for cooperative information distribution and management.

The Centre is designed to facilitate the dissemination and exchange of scientific and technological information in the fields of Ecofarming, Rural Development, Knowledge Management and Science&Technology for the provision of solutions to developmental problems and the promotion of sustainable joint venture networks, dialogue in pursuit of Development and Poverty Alleviation.


II Reports from the First Ecofarming Workshop of NECOFA-Nigeria

Newspaper report of the Nigerian 'Daily Monitor'

Tuesday , January 9, 2001

D-Gov frowns at low performance of Agric Institutes

OGUN State Deputy Governor, Aihaji Adegbenga Kaka has expressed disappointment over the country` s inability to produce food abundance for her citizens despite the huge amount being spent on Agriculture by the government.


Alhaji Kaka expressed the view in Abeokuta, Ogun State while speaking at the opening ceremony of the 1st Country workshop on Ecofarming which was organised by network Network for Ecofarming in Africa (NECOFA).

The Deputy governor was particularly disturbed that the various programs and projects which were established in the country by past government such as Agricultural Research Institutes which were to ensure seed varieties have not lived up to expectation.

Alhaji Adegbenga Kaka who mentioned the River Basin Development authorities as programmes embarked upon by the Federal Government in his worlds explained that "though governments investments is high, research result are yet to be translated in to sustainable increased food production in the country".

Although the Deputy Governor agreed that some of the projects were yet to be completed, he however wondered why those that have been completed did not effectively justify the level of investment on them.


"Farmers, situation and conditions were not totally put into consideration. This made most of the research results irrelevant to Farmers" he continued.

Alhaji Adegbenga Kaka enumerated some problems pose a great obstacle to achieving self sufficiency in food production in Nigeria.

The Deputy Governor advised participant at the workshop, at the end of the seminar, to sensitise the farmers toward embracing the use of ecofarming as a way of preserving their soil and other attendant ills that may occur as a result of the consumption of fertilizer induced crops.

Speaking on the occasion, representative of NECOFA Nigeria, Mr. E. O. Ogungbe stressed the need for the deeply involvement of policy maker for the success of ecologically, economically and socially viable and sustainable farming system in the country.

The Network for Ecofarming in Africa(NECOFA)'s objective is to ensure the effective implementation of Ecofarming practices, to facilitate exchange of information and achievement in Ecofarming research and Extension at national and international levels.



III Integrating NECOFA into the existing National Agricultural System 1/

by I. O. Vaughan 2/

1/ Invited paper presented at the First Country Ecofarming Workshop held at Gateway Hotel, Abeokuta, from December 20 - 21, 2000.

2/ Dr. I. O. Vaughan is Director of Planning, Monitoring and Evaluation of Ogun State Agricultural Development Programme (OGADEP) PMB 2122, Abeokuta.



The relevance of ecofarming in Nigeria is indebatable. Ecofarming considers the economic viability, technical feasibility, social acceptability and environmental friendliness of farming. These features confirm its superiority over conventional farming. The different pursuits of Ecofarming (including mixed cropping, multiple cropping, mixed farming e.t.c.) also confer the sustainability characteristic of this desirable system. Incontestably, therefore, this system of farming should be promoted by all. From all indications, there should be no stumbling blocks with regard to promoting it in Nigeria and other developing countries since Ecofarming does not subscribe to the use of external inputs which small-farmers do not have the funds to purchase in order to apply on their farms (for crops or livestock or fish ponds). In essence (everything being equal) small-folders that feed the nation will be more disposed to adopt ecofarming - based technologies since they reduce both ecological and social risks.


However, since a system of Agricultural Research and Extension is already in place in Nigeria, it will be expedient to evolve an integration process of ecofarming into this system. Such an effort will reduce possible conflicts and allow for a synchronized co-ordination and focus.


This paper will, therefore, attempt to propose a process for integrating ecofarming into the existing National Agricultural System. The paper is structured as follows: the next section highlights the objectives of the body (NECOFA) expected to promote Ecofarming, gives a synopsis of the National Agricultural System, presents the list of stockholders in Ecofarming and assigns responsibility and linkages for these stakeholders, proposes a research and extension process for NECOFA and finally presents some recommendations to enhance the performance of NECOFA.


Objectives of NECOFA

The Network for Ecofarming in Africa (NECOFA) was founded by seven African countries - Cameroun, Ethiopia, Ghana, Kenya, Nigeria, Tanzania and Uganda to promote ecofarming in Africa. The specific objectives of NECOFA are to:

  1. coordinate ecofarming activities in Africa;
  2. ensure effective implementation of ecofarming practices;
  3. facilitate exchange of information and achievements in ecofarming research and extension at the National and International level;
  4. solicit internal and external resources for ecofarming development in Africa;
  5. promote small-scale projects on ecofarming at the grassroot level;
  6. publish a quarterly newsletter, "NECOFA NEWS";
  7. train farmers, extension agents, staff of NGOs, policy makers, teachers and researchers on the concept of ecofarming; and
  8. create commitment among members to implement ecofarming programme at grassroot level.

From all indicators, these objectives are clear, monitorable and can be evaluated. The recommendation at this stage is that the Nigerian Chapter of NECOFA should be expeditiously formed and officers elected. This should have a national outlook. The letter head of this chapter with the list of the officials should thereafter be used for all communication. Second, NECOFA (Nigeria) should on an annual basis set targets based on these objectives. The setting of targets will foster monitoring and evaluation of the Network's performance. Third, to quickly attainment a national status and configuration, productive and energetic representative Agriculturists should be identified in the five geo-ecological zones of the country - South West, South East, North West, North East and the Middle Belt - as coordinators and animateurs.


Nigerian Agricultural System

Agriculture is on the concurrent legislative list. Therefore, the development of agriculture is in the hands of all - government, non-government, individuals etc. However, there is a structure for the coordination of the sector. The apex is the Federal Ministry of Agriculture (and its Departments - e.g. Federal Department of Agriculture (FDA), Federal Department of Fisheries (FDF), Federal Department of Livestock (FDL) etc.). The National Agricultural Research Institutes' (NARIS) activities are supervised by FDA. These NARIS generate agricultural technologies through their R&D processes. Over the years, each NRI had generated a number of conventional technologies relating to its mandate. Examples in crop include rates, method and time of application of herbicide, fertilizer, insecticide, fungicide etc. Agricultural Development Programme (ADP) of each State of the Federation is the sole agricultural extension agency. These currently use the T&V system of extension in disseminating the technologies after a formal participatory on-farm adaptive trial which is recommendation-domain specific.

A number of equally important Agencies of Government and Non-Governmental Organizations (NGOs) also participate in the scheme of things towards agricultural development in the country. Projects Coordinating Unit (PCU) for instance, coordinates all ADPs' activities. Also, Universities of Agriculture chip in their quota in their tripodal mandate of training, research and extension.

Despite the conventional research efforts, yield gaps remain in crops. These can also be extended to other subsectors of agriculture. Table I presents yield gaps in major crops. These gaps also exist in other farm enterprises - livestock etc.


The yield gaps presented in Table I can only by filled or reduced with the adoption of improved agronomic practices by the farmers.

To effectively do this, majority of the farmers require agricultural credits. It is cheering to note that more institutions (including NGOs) are now engaged in granting credits to farmers. The activities of some of these institutions must be reviewed to make them more relevant to smallholders who produce over 80% of the food we eat. One NGO is indirectly collecting over 40% interest per annum from the farmers (by paying 35 on 1,000 per month).


Application of improved external technologies by resource-poor farmers is highly low as alluded to above. Therefore, adoption levels of such technologies is poor. Table II shows the levels of adoption of major hi-grade technologies by small farmers in Ogun State.


It must be pointed out that conventional inputs (inorganic fertilizer, herbicides etc.) have been instrumental to the improvements in yields of these crops. Once the use of these inputs is de-emphasised and discouraged among farmers through the introduction of ecofarming, then potential yield levels will automatically drop. The implication, therefore, is that ecofarming scientists will have to work harder, effectively and expeditiously to evolve appropriate technologies to raise the crop yields again. Great challenges are hence, before agronomists, breeders, soil scientists and extensioners in order to actualize this objective.


Top of Page



 Potenzial yield (mt/ha)

 Actual yield (mt/ha)

 Yield gap (mt/ha)







- Open pollinated

 - Hybrid

- Upland

 - Lowland







It is necessary to note the essential characteristics of a technology that will support its adoption.

These are:

  1. it must be simple and easy to understand;
  2. technology and cognate inputs must be readily available and accessible;
  3. its price must be affordable;
  4. it should be socially compatible;
  5. it must be technically feasible;
  6. it must be economically viable;
  7. it must be divisible to allow for trialability; and
  8. it must be farmer's farming system oriented and relevant.

The low adoption levels of external technologies are explained by their contradictions to above characteristics. To promote adoption, therefore, a technology must score high on these features. Most of the technologies (e.g herbicides, insecticides etc) are not affordable price-wise. Many are not economically viable as well etc.


Table II shows that low-cost and economically viable ecofarming-based improved varieties of maize cassava, rice etc and plant population which was technically feasible are better adopted by farmers rather than herbicides and insecticides.


These further put credence on the need for ecofarming the technologies of which are cheap, available and environment-friendly. The demand-driven attribute of ecofarming technologies further supports its usefulness.


Stakeholders of Ecofarming

The citizenry of the country is the first group of stakeholders of ecofarming because their health is taken into consideration in the choice of production inputs while increased aggregate output is also ascertained. Farmers that operate in a resource-constrained, organically complete and ecologically vulnerable environment are major stakeholders of ecofarming. Ecofarming helps in reducing or alleviating their vulnerability. The adoption of appropriate technologies emanating from ecofarming R&E will lead to increased productivity, production and incomes of the farmers. Farmers must cooperate with scientists at all fronts - research especially on indegeneous knowledge.

Other stakeholders are NARLS, ADPs, PCU, NGOs, Universities of Agriculture etc. The attainment of the goals of these Agencies is dependent on their output and their usefulness to farmers in ecofarming-related activities.


Research and Extension process for NECOFA

As an NGOs, NECOFA (Nigeria) should contact the appropriate Government Organ to comprehensively formalize its existence. With this done, its integration into the National Agricultural System, especially Research and Extension will be fostered.


NECOFA (Nigeria) should introduce the Network to the Federal Ministry of Agriculture (MOA) through FDA etc. With the understanding of the MOA, NECOFA (Nigeria) should identify a link person in each Research Institute. The contact scientist will support NECOFA on the following:

  1. communication to NECOFA (HQ) on ecofarming related meetings in the Institute, relevant reports etc.
  2. proposing a date for Ecofarming Workshop;
  3. identification for NECOFA sponsorship;
  4. coordination of ecofarming activities in the institute;
  5. promoting exchange of information with other institutes on ecofarming;
  6. training of farmers in conjunction with the ADPs in ecofarming;
  7. participating at ADP's MTRM; and
  8. promoting overall commitment of colleagues and farmers in ecofarming.

MTRM coordinator of the Institutes are recommeded. These contact scientists must produce an Annual Report for NECOFA which will be nationally synthesized.


A similar arrangement is proposed for the Universities of Agriculture (UOA). However, at the UOA's level, students should also be educated on ecofarming. In fact, an attempt should be made by NECOFA to sensitize Deans of Faculties/Colleges of Agriculture in the Universities to include Ecofarming as a first or second year course in their Universities' curricula.


At the ADP level, too, a contact Technical/Extension staff with some Ecofarming zeal should be identified by NECOFA to:

  1. sensitize the overall REFILS in the ADP towards ecofarming;
  2. train colleagues on concepts of ecofarming;
  3. collaborate in the evaluation of ecofarming technology(s);
  4. encourage farmers in the adoption of ecofarming technologies; and
  5. participate in MTRMS

The Zonal NECOFA offices should, respectively, coordinate the REFILS activities and report to the Headquarters. The HQ should be able to:

  1. view of sifting out follow-on issues;
  2. assess and approve study proposals/projects;
  3. solicit for internal and external support;
  4. keep the register of national members;
  5. compile the list and addresses of all NARIS, ADPs, PCU (and Zonal Offices), NAFDAD, other NGOs etc.;
  6. produce appropriate MOAs and MOUs for Agencies to be collaborated with or scientists to benefit from its funds;
  7. effectively sensitize and mobilize the Zonal MTRM coordinators of ADPs;
  8. equip the HQ and Zonal Offices; and
  9. produce the code/rules and regulations for members on NECOFA's expectations.

A number of activities are listed here for NECOFA (Nigeria). All of them cannot be achieved at one go. They could be phased out. The members in each Zone will have to also elect officers when the need arises.


Recommendation for ecofarming research process and focus

Ecofarming will thrive best if tailored towards improving the farming system which is the complex arrangement of soils, water sources, crops, livestock, labour and other resources and characteristics within an environmental setting that the farm family manages in accordance with its preferences, capabilities and available technologies. Farmers manage the households resources involved in the production of crops, livestock, and non-agricultural commodities (e.g. handicrafts), and may also earn income off the farm (Shaner, Philipp and Schmehl, 1982). NECOFA research activities should also be:


NECOFA bulletins should emphasize these features of the research types sponsored or favoured by it. Moreover, the target/area specificity, problem and opportunity identification, timing and other critical research factors must be stressed for effective and sustainable ecofarming research.



An attempt has been made in this paper to propose the integration of NECOFA to the existing National Agricultural System. A lot of formalization and sensitization is necessary. Creating awareness must be rightly carried out. While this is being done grey areas will be further touched and made whiter. Moreover, more ecofarming disciples would be won over. At the end of it all the whole REFILS will be the better for it.



Shaner, W. W., Philipp P.F. and Schmehl N.R (1982) Farming Systems Research and Development: Guidelines for Developing Countries, Westview Press, Boulder, Colorado pg. Vaughan, I. O. (1997)



Letter from Roland Bunch

Dear Friends,

For nearly 20 years we have been working with green manure/cover crops and other ways of achieving higher productivity from tropical soils. Gradually, it has become more and more obvious to us that in situation after situation, the conventional explanation of what was happening in tropical soils and how best to get good levels of productivity from them, just did not correlate with what we were observing all around us. Finally, this last year, I got hold of and read Ana Primavesi's earth-shaking book, The Ecological Management of Soils. There was the explanation of so many phenomena we hadn't been able to understand previously.


Normally, I would just have recommended that book to everyone I knew, but it has only been published in Portuguese and Spanish. Thus, I have decided to write a paper, presenting a few of Ana's more basic ideas and their application to the developing world in general.


It represents, I believe, a new paradigm, that can help us understand much more accurately what is happening when we use a more ecological approach to soil management.

I hope you find it worthwhile. I would certainly be grateful for any suggestions or corrections, or even additional evidence, that any of you would be willing to send this way. I'm sure there is a tremendous lot more to learn about all of this.


Sincerely, Roland Bunch


Remark from the editors: The complete english paper will be published online on this website at: (Activities -> Publications) as well as in the NECOFA Newsletter in three parts, starting with this publication.


IV Nutrient Quantity or Nutrient Access ?

by Roland Bunch



If we are to achieve or maintain high levels of agricultural productivity in the tropics, it is crucial that we properly understand the relationship between nutrients in the soil and crop productivity. This understanding is especially important if we wish to achieve such productivity at the lowest possible costs, both economic and ecological. The thesis of this paper is that the conventional view of the relationship between soil nutrients and crop productivity in the tropics is leading to both damaging agricultural policies and inefficient and damaging farm-level practices. Of prime importance to small-scale farmers worldwide is that this conventional concept results in the consistent recommendation of the use of huge quantities of chemical fertilizers that are biologically unnecessary, economically extravagant and ecologically damaging. The ecological damage caused by chemical fertilizer in its own right is perhaps not that great. Nevertheless, if we include its indirect impact caused by the fact that most small-scale farmers reduce their use of organic matter (o.m.) once they start using chemical fertilizers, the indirect ecological damage brought about by chemical fertilizers in developing world agriculture and ecology is nothing short of breath-taking.


The present paper cannot delve deeply into soil chemistry and biology. For a much more in-depth analysis of the chemical and biological issues described herein, the best book at present (unfortunately available only in Spanish and Portuguese) is Ana Primavesi's The Ecological Management of the Soil (Primavesi).


Nevertheless, the present paper will describe, in general, a new conception of the fertility of tropical soils, and then, again very generally, ways in which that theory can be put into practice.

It should also be mentioned that much of the theory described in this paper was originally developed by Drs. Artur and Ana Primavesi. Furthermore, the Primavesis' theories have been widely validated by hundreds of thousands of small farmers in southern Brazil with the technical support of people such as Valdemar Hercilio (Salgado) de Freitas, Claudino Monegat and Ademir Calegari. Those of us trying to improve small farmers' productivity owe a deep debt of gratitude to these people.



Soil fertility is not an easy concept to define, (Cresser) but for the purposes of this paper, we will use the definition of soil fertility presented in Anthony Young's book Agroforestry for Soil Conservation: "soil fertility...is the capacity of soil to support the growth of plants, on a sustained basis, under given conditions of climate and other relevant properties of land." We choose this definition, rather than the much more limited one that takes into account only the soil content of available nutrients, because we agree with Young that the latter definition "leads to a myopic view of soil management, to the neglect of physical and biological properties." (Young)



The traditional concept of soil fertility basically maintains that fertility is largely a reflection of the overall quantities or concentration of nutrients in the soil. That is, plant nutrition is to be maximized primarily by ensuring that all the essential nutrients are present in the soil in significant concentrations. Therefore, if a farmer applies sufficiently large amounts of primarily chemical fertilizer, uses the right balance of NPK, and the soil has an acceptable pH and sufficiently high cation exchange capacity (CEC) to hold those nutrients in place, the farmer will have efficiently achieved good soil fertility.


The basic idea is that the soil operates like a bank: add more nutrients repeatedly, over a long period of time, and these nutrients will gradually build up, like a savings account, increasing the soil's fertility and therefore crop productivity. Although there are, of course, other factors that must be taken into account, primarily physical and chemical processes like leaching, soil pH, the soil's CEC and nutrient fixation, the basic idea is that the soil acts more or less like a static recipient of nutrients. Thus, the vast majority of the effort and experimentation of these traditional theorists have had to do with overall nutrient levels and their physical movement, mineralization and leaching within the soil profile. For the purposes of this paper, this idea of soil fertility will be called the Nutrient Quantity Concept.


The priorities of the adherents of this Concept are seen very clearly in the books they write on the subject of soil properties and management. A typical textbook, based on the Nutrient Quantity Concept--even one dealing with tropical soils-- dedicates three chapters (73 pages) to NPK, while not dedicating even a single chapter to either organic matter (o.m.) or soil biology. (Committee on Tropical Soils) Even a book published as recently as 1997 on soil fertility in Africa dedicates two long chapters (82 pages) to NP, and only a fraction of one chapter (8 pages) to specifically organic inputs. (Buresh) Other factors are mentioned in these publications, but chemical sources and quantities of NPK dominate heavily the entire discussion.


A common conclusion drawn from this conception by its proponents as late as 1997 is that in Africa "mineral fertilizers should be at the core of strategies to restore soil fertility and raise crop production." (Quiñones) Another major proponent of this conception wrote in 1994: "Some people say that Africa's food problems can be solved without the application of chemical fertilizers. They're dreaming." (Borlaug) The Financial Times goes on to write that the same author said that, "Sub-Saharan Africa had the lowest use of fertilizer in the world and soil nutrients were so low that other efforts to raise crop productivity would not be successful until fertility was improved." (Borlaug) By "fertility" being "improved," he is referring specifically to the application of chemical fertilizers.


First, allow me to include a short explanation for the benefit of the layman. Crops are capable of absorbing some nutrients that exist in the soil at levels of less than 0.2 parts per million, while other nutrients are often difficult to absorb at 100 times that concentration. (Ahn) Thus there is, in fact, little relationship between a plant's physical ability to absorb a nutrient and the nutrient's concentration in the soil. Also, plants do not absorb the various nutrients primarily according to the levels present in the soils, but rather in accordance with the plants' own needs, and in ratios between the nutrients that are relatively stable for each species or variety of plant, regardless of the supply of the nutrient in the soil. Thus, the Nutrient Quantity Concept is really saying that, other conditions being adequate, the growth or productivity of any plant will depend largely on the quantity and availability of the nutrient in the soil that is proportionately least adequate in relation to the total amount of that nutrient necessary for the plant to achieve maximum growth, and that in practice maximum crop growth should be achieved by having large enough reserves of these nutrients in the soil so that adequate quantities of them will exist in available forms. (Cresser)




Theoretical Inadequacies of the Concept


First, the Nutrient Quantity Concept, in its simplified, "banking" form, is very unrepresentative of what actually happens in the soil. Far more important for productivity than the total quantity of any single nutrient or group of nutrients is the chemical form in which it occurs, the depth in the soil at which it occurs, the kinds and numbers of macro and microorganisms that exist, the presence of soil compaction layers, and the equilibrium that exists between the nutrients, the pH of the soil, its moisture content, its organic matter content, its macro and microorganisms, its texture and structure, etc. Furthermore, these factors constantly impact on each other, creating a very complex and constantly changing environment within the soil, or, more accurately, a constantly changing complex of varying microenvironments within the soil. These factors may make it possible for a plant, in a particular time frame, to access a majority of the total store of a given nutrient in the soil, or much less than 1 % of the total store of that same nutrient.


In other words, the same nutrient that is in the same total concentration within two different soils may well be fifty to one hundred times more available to a plant in one of those soils than in the other. Obviously, the total amount of a nutrient in the soil is nowhere near as important in terms of the soil's fertility as is the availability of that nutrient to the plants growing on it.


Of course, the body of literature and scientific conclusions that have grown up around the Nutrient Quantity Concept, if taken in its total complexity, admits as much. The data of soil science, as a whole, take into account fairly well the fact that all the above-mentioned factors can affect fertility (although soil science could certainly be a good deal more aware of certain of these factors, especially the biological ones). In fact, quite surprisingly, the science built up around the Nutrient Quantity Concept in no way contradicts the very different conception of what is required to achieve soil fertility that will be described below.


Where the advocates of the Nutrient Quantity Concept of soil fertility have apparently gone wrong is in the conclusions they have made about soil fertility, based almost entirely upon only a certain, specific selection of these scientific findings. That is, the experiments, although heavily lop-sided in the dominance of their preoccupation with chemical fertilizers, do not necessarily support the Nutrient Quantity Concept any more than they support the concept presented below. What has apparently happened is that one particular fact has come to totally dominate people's thinking about soil nutrients. This is the fact that, in a uniform soil environment, the larger the total quantities of a nutrient that exist in a given soil, the larger will be the quantity of that nutrient that is in available forms. Even though there is ample proof that in a non-uniform soil, and in countless specific cases, this relationship does not exist at all, many conventional soil scientists continue to see this relationship as the most important single logical basis to soil fertility management. (See, for example, Cresser) To cite an extreme but very common example, even when the availability to plants of soil phosphorus is known to be as many as fifty times greater in an organic environment than in an infertile acid soil environment, the Nutrient Quantity Concept still leads virtually all conventional soil scientists to recommend applying additional chemical phosphorus to the acid soil rather than finding or creating an organic microenvironment within that soil in which to apply a much smaller dose of (organic or inorganic) phosphorus.


Thus, in a very few words, the Nutrient Quantity Concept does not differ from the concept to be presented below, in its scientific, experimental undergirding.


Rather, the difference lies in the somewhat arbitrary decision to emphasize the relationship between total nutrient quantity and the quantity of nutrients available to growing crops, even though scientific evidence shows that this relationship is in most cases tenuous, at best, especially in the case of small farmers in the tropics.

A second major error of the Nutrient Quantity Concept is that it seems to presuppose that these nutrients are being more stable in the soil than their own research shows they actually are, especially where the CEC of the soil is quite low and/or erosion is occurring. The idea of building up nutrients in the soil would seem to presuppose that those nutrients will remain there over, say, twenty years or so. Yet virtually all of the N, much of the K, and even small amounts of the P applied as chemical fertilizers today, will not be there twenty years from now, even if no plants were using them. And on low CEC soils and erodible hillsides, the loss of even P can be considerable. In short, the farmers' "money" is constantly leaking out of the "bank". And, sadly, the more money there is in the bank, the more will leak out.


This assumption of the persistence of nutrients in the soil seems to be assumed, also, when conventional scientists criticize those who propose using large amounts of o.m. for maintaining soil fertility. Nutrient Quantity proponents worry at considerable length that organic inputs cannot maintain soil nutrient levels over the long term, and that they do not produce as much long-lasting humus as often as we all would like. (Buresh) They seem to forget that chemical fertilizers do not maintain the levels of most micronutrients, either. Of more importance economically, chemical fertilizers, as used by small farmers, do not maintain soil pH. (And even if farmers could, theoretically, avoid acidifying their soils with chemical fertilizers, the costs of liming or using the more expensive alkaline fertilizers is seldom included in economic analyses of the costs of chemical fertilizer use.) Of course, because of the leaking from the bank, chemical fertilizers, even when used in recommended quantities, may not achieve the long-term levels of total nutrients desired.


Thus, organic amendments are little different from chemical fertilizers in not being able to increase soil nutrient quantities dramatically over time in the tropics, especially under small farmer conditions. This is not to say we should give up on striving toward at least soil nutrient maintenance over the long run, but rather to say that the use of chemical fertilizers exclusively, in the case of small farmer agriculture, will very likely achieve no more long-term improvement in nutrient quantities than will the use of o.m. exclusively. Just as most small farmers often, but not always, lack the o.m. to increase stores of P, for instance, they also usually lack the cash (and often the profitability of chemical fertilizers on their depleted lands far from markets) to buy sufficient chemical fertilizer.


Furthermore, neither this paper nor most of those people who use low input agriculture oppose all use of chemical fertilizers. The replacement of some chemical elements in the soil (mostly P), under certain conditions, and in moderate amounts, is, for us, perfectly acceptable, if not desirable.


The third error of the Nutrient Quantity Concept is that its proponents have largely avoided taking into account the tremendous impact in tropical soils of such factors as their macro and microbiology, o.m. content, microenvironments and compaction layers.



Inadequacies in Practice

Based on these theoretical considerations, most conventional soil scientists have come to a series of extremely far-reaching conclusions. Among these, they have concluded that the best, most efficient way of improving the soil fertility of the developing world's resource-poor farmers is to apply tremendous quantities of NPK along with, perhaps, a small supplement of o.m. They have concluded that "low external input" technologies must inevitably lead to "low output" results. They have therefore further concluded that "ecological agriculture" is inevitably unproductive and has virtually no future. And finally, they have concluded that soils with very low CEC's, like those of most of West Africa, have very little potential for decent crop productivity. None of these conclusions is based on the scientific understanding we have of soils in its totality. And concrete evidence from tens of thousands of farms around the world, as well as from many scientific experiments, provides considerable evidence that not one of these conclusions is, in fact, accurate.


Thus, the Nutrient Quantity Concept is failing us. It is failing to lead us to proper conclusions about agricultural priorities. It is failing to predict what will happen if we apply a whole range of agricultural technologies that are now being tried in the tropics, and it is failing to help us understand a series of both natural and agricultural phenomena that we are observing. Above all, it is failing to lead us to promising new technologies that can provide tremendous benefits at low cost to poorer farmers within the tropics.


Let's look a little more closely at these failings. One of the main negative impacts of the traditional Nutrient Quantity Concept in tropical environments is that it has caused many scientists to dismiss ecological agriculture out of hand. It has become almost a mantra of some of these scientists that "low input agriculture is low output agriculture." After all, according to the Nutrient Quantity Concept way of thinking, if not much is put into the bank account, not much can be withdrawn. Thus a whole series of promising technologies for increasing agricultural productivity-mostly those which are included in approaches referred to as ecological agriculture or agroecology--have been largely ignored by the dominant members of the scientific community, (Anonymous; Pretty and Hine) to the tremendous detriment of farmers in the tropics. In fact, millions of small-scale farmers in developing countries, representing well over 3 % of the total, have adopted ecological agriculture practices in just the last ten years, (Pretty and Hine) yet these practices are largely ignored by conventional soil scientists.


Another major negative impact of the application of this Concept is the claim that because many tropical soils have very low CEC's, they will never be able to produce large harvests. Because such soils cannot hold very many nutrients over a crop's entire life-span, it is said they will never be able to support maximum output.


This conception of the dynamics of soil fertility has caused huge areas of the tropics to be written off as "low-potential" areas, where significant investments in agricultural development are therefore not advisable. (Mosher) As a result, hundreds of millions of people have been condemned to a not-so-benign neglect and perpetually low productivity. Since these people often were already among the poorest of the poor, this mistaken policy has aggravated already serious problems of economic injustice and downright hunger. And all because of a theory of soil fertility that is questionable at best.


Another factor that becomes extremely important for those of us who focus our work on the poorer farmers of the tropics is that the Nutrient Quantity Concept leads almost inevitably to an excessively high use of chemical fertilizers. The cost of chemical fertilizer very frequently represents the largest single cash cost of resource-poor farmers in the tropics. Yet experience in nation after nation has shown that for a much lower total expense, farmers can achieve the same or even higher yields. Furthermore, as the years go by, the use of most chemical fertilizers mine the soil of micronutrients, acidify the soil even more, and help to erode away, burn out, or simply fail to replace the soil's o.m. In time, these factors all work together to reduce the response that chemical fertilizers achieve in terms of productivity, to the point that, in many cases, there remains no net economic advantage to their use whatsoever.


Furthermore, the recent staggering increase in petroleum prices (from $ 12.00 a barrel to somewhere between $ 19.00 and $ 32.00 a barrel) is going to result in major increases in the real farm gate cost of fertilizers, both because of increased costs of production and increased transport costs. Thus, tens of millions of small-scale farmers for whom chemical fertilizer is presently economically advantageous will find that in the future that advantage will have largely or totally disappeared. Thus, it is extremely important that we all learn as much as we can about the technological possibilities that will still allow farmers to increase and maintain their productivity without depending so heavily on increasingly expensive chemical fertilizers.

An additional major problem of the traditional Nutrient Quantity Concept is that increasing observation, especially of ecological or low external input agriculture, is showing that the Concept's predictive abilities are seriously lacking. Crop productivity, in most such cases, is not basically, or even approximately, a factor of the overall amount of nutrients in the soil, or of the CEC of the soil. Very high levels of productivity are being achieved on soils that, according to the traditional Concept, could never produce such yields, and with applications of nutrients that are anywhere from one-half to one-tenth the quantities the Nutrient Quantity Concept would indicate are necessary. Recent scientific experiments with o.m. and fertilizer use in Africa, where scientists cannot explain with conventional theories the yields that were achieved, are typical. (Palm)

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