ENABLE

ENABLE

NEWSLETTER OF THE ASSOCIATION

FOR BETTER LAND HUSBANDRY

NUMBER 17(w), JULY 2003

Contents

Editorial Transformations

Articles ‘Fire’ in the Soil – B.A.Stewart

Productive Pastures: Benefits for the Farmer and for the Environment

- Bruno J.R.Alves, Segundo Urquiaga, Robert Boddey

‘Indian Agriculture a Big Winner from A C I A R Project’

Why Better Land Husbandry ? – Francis Shaxson

Better Land Husbandry Comes of Age – FAO / WB

The Universal Soil-Loss Equation or A Universal Soil-Gain Equation ? - Francis Shaxson

Tropical Soil Management – 4 Papers from the Workshop

- F.Shaxson - D.Powlson - H.Gunston - S.Bunning

Book Reviews

Soil and Water Conservation in Honduras : A Land Husbandry Approach – Jon Hellin

Conservation Tillage & Cropping Innovation : Constructing the New Culture of Agriculture

- C.M.Coughenor and S Chamala

Bookshelf Something New Under the Sun : An Environmental History of the Twentieth-Century World

– John McNeill

FAO’s Latest Publications and Activities Regarding Conservation Agriculture – FAO

A.B.L.H. & T.A.A. The Linkage

Misc. Bits Think-pic 5 Conservation Buffers – Are They Talking about Us?

EDITORIAL

TRANSFORMATIONS

With the venturing-forth of ABLH-Kenya as an autonomous Kenyan NGO two years ago, the original prime purpose of ABLH in UK was fulfilled, and our Association’s ‘raison d’être’ was reduced accordingly. Nevertheless, our Constitution also refers to the aim of dissemination of relevant information about land husbandry, and - despite the small membership of ABLH – it seems that this activity has been relatively successful over the years, whether via the inputs made by land husbandry aficionados in the course of various consultancy visits in different countries, speaking at meetings and Conferences, the ABLH website, and/or through the publication of ENABLE at more-or-less-regular six-monthly intervals.

As a result of all this, extracts from the final draft Executive Summary of a 2002 document by FAO, which are reprinted in this issue, indicate that Better Land Husbandry has now come of age – the subject is now ‘over the threshold’ of wide acceptance. This is also evidenced by the vast number of Web-pages under ‘Land Husbandry’ that are found today by comparison with the very small number of citations only three years ago. So it has been worth the effort!

With a slowly-diminishing membership it has not been realistic to go for ABLH’s expansion into new activities. But rather than let ABLH fade away, it was felt to be important to become affiliated with another organisation of broadly comparable interests. As a result of agreeable discussions,

ABLH has now become a Specialist Group within the significantly larger Tropical Agriculture Association in UK. This allows us not only to maintain our specific identity but also to interact in-house with others having land-based experiences of the tropics and sub-tropics, so that we can both gain and offer such information, to mutual benefit.

The TAA has already kindly enabled us to have our own place within its website - http://www.taa.org.uk . Both ENABLE-15 and ENABLE-16 (‘Struggling to Survive Poverty’) now appear there in the section ‘Published Papers’.

This issue of ENABLE may be the last in the present printed format. In future it is proposed that articles of land husbandry interest be offered to the main TAA Newsletter, and to build up the ABLH portion of the TAA website by gradually transferring relevant papers from the old ABLH website into this section, and to put any future issues of ENABLE there as well. I am very grateful to Dr A. Smith, who manages the overall TAA website, for suggesting such an arrangement. This will be relatively simple and inexpensive to operate, and will extend the range of our readers to beyond our own limited circle of faithful members.

The Editor

“Soil organic matter is an important component of soil because if affects all soil processes --- chemical, biological, and physical. Perhaps most important in semiarid regions is the effect that soil organic matter has on the infiltration of precipitation and on the water holding capacity of the soil. It is well known that as the content of soil organic matter declines that the infiltration rate decreases and the amount of plant available water that the soil can hold becomes smaller. These effects are negative in all areas, but they are particularly bad in semiarid regions because they make the lack of water even more lacking. Loss of soil organic matter also leads to increased wind and water erosion and this only exacerbates poor soil water conditions. Soil organic matter serves as a “glue” to hold soil particles together and its loss greatly accelerates the erosion hazard. Soil organic matter loss also destroys soil structure that is so important in soil water properties.

Soil organic matter decline is common in all climatic regions where agroecosystems are formed. Tillage is the main cause of soil organic matter decline and the more intensive the tillage, the higher the rate of loss. The negative effect generally increases with increasing aridity because the initial soil organic matter content is usually low and the amount of biomass produced annually to replenish the supply is limited because of the lack of water. An analogy illustrating the effect that tillage has on soil organic matter decline is the burning of logs. Once the fire starts, the flame burns high and fast but after a while, the fire dims. What do we do? We take a stoker and stir the logs. WHAM! The fire gets bigger again. Why? Because we did two things --- first, added oxygen that is required for a fire; and second, exposed new surfaces that had previously been protected by overlying logs. The flame gets bigger after stirring, but it does not get quite as high as before, and does not last as long before it begins to subside again. We repeat this process over and over until either the fire goes out, or we add more firewood. This is very similar to what happens when we till the soil. There is always a fire in the soil --- the biological activity of microorganisms. When we till the soil, we add oxygen and expose new surfaces and the fire becomes larger. And, the more intensive and the more often the tillage, the more we burn out the soil organic matter and degrade the soil.

When we burn logs, we create ashes. The same is true when we burn soil organic matter. The ashes contain N, P, K, Ca, Mg, Mn, Fe, Zn and all the other nutrients essential for plant growth. Although these ashes result in good crop production, the soil physical properties are being degraded unless we are ADDING MORE FIREWOOD to the soil. Otherwise, the ashes become depleted and the first nutrient that is usually lacking is N. We often add N fertilizer to correct this deficiency, and then we run short of P, and then K, and so on. All the while, we continue to degrade the soil physical properties and decrease the amount of biological activity. Growing legumes and adding manures are good practices to reduce these losses, but these practices are more difficult to carry out in dryland regions than in humid conditions. Therefore, soil organic matter decline is a major problem in dryland regions and one of the best ways to address this problem is to reduce tillage to the fullest extent possible by using the principles of conservation agriculture”.

¹Pers. comm. from Dr. B.A.Stewart, Distinguished Professor of Soil Science, and Director of the Dryland Agriculture Institute, West Texas A&M University, U.S.A. Reprinted with his permission.

.oOo.

THE LAND BEREFT

“If society forgets or no longer cares where it lives, then anyone with the political power and will to do so can manipulate the landscape to conform to certain social ideals or nostalgic visions. People may hardly notice that anything has happened, or assume that whatever happens – a mountain stripped of timber and eroding into its creeks - is for the common good. The more superficial a society’s knowledge of the real dimensions of the land it occupies becomes, the more vulnerable the land is to exploitation, to manipulation for long-term gain. The land, virtually powerless before political and commercial entities, finds itself finally with no defenders. It finds itself bereft of intimates with indispensable, concrete knowledge.”

Barry Lopez. About This Life. Harvill 1998. p.138.

.oOo.

“PRODUCTIVE PASTURES:

BENEFITS FOR THE FARMER AND FOR THE ENVIRONMENT

Bruno J.R.Alves, Segundo Urquiaga and Robert M.Boddey

of the EMBRAPA-Agrobiology unit.

Research shows the key to the accumulation of organic matter in the soil

Recently, research undertaken by the Nutrient-Cycling Group of Agrobiology within EMBRAPA [Brazil’s national agricultural research organisation], together with EMBRAPA-Wheat and EMBRAPA-Soya, not only confirmed the superiority of direct-planting [= ‘direct-drilling’, ‘zero-tillage’, ‘no-till’] systems in the accumulation of organic matter in the soil, but also showed that it is a process highly dependent on the availability of nitrogen in the soil. Under direct-planting, quantities of organic matter were accumulated in the soil when there was a legume for green-manuring in the crop rotation, which had the role of enriching the system with N. In these conditions, crop rotations under direct planting regimes can accumulate in the soil around 1 ton more of organic matter per year in each hectare when compared with conventional systems based on the use of [disc-] ploughs and –harrows.

Although the areas cropped with direct-planting allow a rise in the carbon content of the soil, it is pastures which present the greater potential to withdraw carbon dioxide from the atmosphere and enrich the soil with organic matter, in quantities which can approximate to levels observed in soil under native vegetation.

Productive pasture is carbon in the bank

In researches in areas of pastures in Bahia, the team from EMBRAPA-Agrobiology stressed the importance of pastures intermixed with forage legumes in the accumulation of organic matter in the soil, which can enable a rate of organic matter accumulation in the soil of between 3 and 4 tons per hectare per year. This is not to say that soil organic matter is only accumulated with the introduction of legumes. What is more important is that the pasture should be productive, because in this condition the soil is being furnished with large quantities of residues, and the nitrogen certainly will be in sufficient quantity to increase the soil organic matter. “One situation leads to another!” As an example of this, there are the results obtained from research in areas of pasture in the ‘Triángulo Mineiro’. There we encounter practically 40% additional organic matter in areas of productive pastures, which support around 3 to 4 animals of 250 kg. weight on every hectare (1.7 to 2.2 Animal Units/ha.)

Importance of integrating of ‘direct-planted’ cropping with livestock production

Unfortunately a large part of the pastures of the country are found to be degraded, caused by the lack of management and only minimal investment made in terms of replacing nutrients in the soil. It is here that the importance of crop/livestock integration is most importance. [Well-managed] cropping guarantees replacement of nutrients into the soil and, when under a direct-planting regime, avoids the loss of soil organic matter, being able even to increase its content in the soil. The residual effects left after cropping keep the pasture highly productive.

The investment made by the producer to raise and/or maintain pasture production immediately translates into money through the increased production of milk and meat. In parallel, the damage to the environment caused by utilization of the land to produce food is diminished by the increase in soil organic matter and by the maintenance of the cover [over the soil] which greatly reduces soil losses.

This also enables the process of intensification of land use to become a substitute for expansion of deforestation as the means of increasing total agricultural output.

The majority of areas of pasture in Brazil could, with application of more-appropriate management, at least double their productivity.

With the strong possibility that such agricultural systems as direct-planting will come to be included in ‘Mechanisms of Clean Development’, a new source of revenue would be guaranteed to producers whose crops and pastures promote increase of soil organic matter. This is what is called the ‘Green Cash’ which pays for environmental services provided by the farmer and is qualified as one such mechanism. It is hoped that the rules for such mechanisms will be determined at the November meeting in Milan”.

As reported in ACIAR Newsletter No. 38, ACIAR’s support of zero till agriculture and management of herbicide-resistant weeds in India is helping to deliver substantial gains in agricultural productivity, farm incomes and the sustainability of agricultural land.

Now an independent evaluation has predicted gains to India of $1.8 billion over the next 30 years from the adoption of these methods in northwest India. But the eventual gains could be much more than this as the technology spreads through other regions and neighbouring countries.

The project was designed to address a serious weed infestation problem in the rice-wheat cropping system of northwest India – a region containing 3 million hectares of cropping land and accounting for around 35% of India’s wheat production. By the early 1990s the weed Phalaris minor had developed resistance to the herbicide used to control it. There was a massive decline in wheat yields – between 30 and 80% on individual farms over an area of 1 million hectares.

New herbicides were introduced as a short-term solution. But these are expensive. Adoption was poor and the development of chemical resistance in the future a certainty. What was needed was a long-term solution that would be commercially attractive to farmers. ACIAR-funded scientists, working in conjunction with their Indian counterparts, have developed a control package centred around dealing with the phalaris through changes to farming practices, including incorporation of zero tillage cropping.

The result has been spectacular.

· big cost savings in cultivation;

· yield increases through early sowing of wheat;

· better weed control with reduced reliance on herbicides; and

· avoidance of soil degradation and yield declines through continuous cultivation.

The evaluation, undertaken by David Vincent and Derek Quirke from the Centre for International Economics, provides further evidence that the stage is now set for a second ‘Green Revolution’ in the region.”

In ENABLE no. 15, July 2002 I wrote an article entitled ‘Why Better Land Husbandry? This time I use the same set of words but place the emphasis differently.

I suspect that many people assume that what we really mean is the better management of soil, and that the word ‘land’ is an unnecessarily fuzzy way of trying to carve out a niche for ABLH.

Not so.

Land is more than just the layer of soil in which plants grow: it also has three-dimensional shape(and changes over the fourth dimension – time). Land husbandry aims to maintain its lasting usefulness for the purposes which we choose. In rural situations more specifically, it is concerned not only to sustain the capacity of its soils to provide for plant growth but also – where conditions allow – at the same time to safeguard its capacity recurrently to yield clean water seeping from the catchments into which it is shaped, and from the subsurface water which is found beneath.

Sustainability of these two capacities depends on maintaining soil porosity so that rainwater can get into, and beyond, the root-zone without avoidable loss by runoff and/or direct evaporation. Organic matter, organisms and their interactions in organic processes contribute to generating and regularly renewing water-stable aggregates on which infiltration, retention and percolation of water depend, and from which both plant production and streamflow are derived.

The previous article of the same title as this (but with its other emphasis) complements this one, and vice versa, as you will perceive.

[See also, in ENABLE #14 - February 2002, the Editorial and the article:

‘Shifting Views on Land Degradation’].

.oOo.

BETTER LAND HUSBANDRY COMES OF AGE

“Food and Agriculture Organization of the United Nations

Investment Centre Division, FAO/World Bank Cooperative Programme.

Report No: 02/041 CP-SSA. Date: 23 July 2002

THE SUB-SAHARAN AFRICA SOIL FERTILITY INITIATIVE:

A REVIEW OF PROGRESS AND LESSONS LEARNED

- FINAL DRAFT –

Extracts from the

EXECUTIVE SUMMARY

(reproduced with permission of FAO-IC-CP)

(i) A vibrant agriculture is of crucial importance to the future of Sub-Saharan Africa (SSA). Achieving this will require that the nearly 70 million smallholder farm families in the region widely adopt improved and sustainable crop, land and water husbandry practices within the next decade. . . .

(ii) During the last decades, agricultural performance in SSA has generally been poor and output has changed little since the 1970s. In countries where total crop production increased, this was mostly the result of increases in cultivated area. . . .

(iii) Many SSA smallholders face constraints in adopting viable practices to increase and use efficiently organic and mineral fertilisers. As a result, they withdraw much larger quantities of plant nutrients (N, P and K, secondary and micro-nutrients) than are being replaced, with the result that soil organic matter content and biological activity decrease, physical properties deteriorate and moisture-holding capacity goes down. In short, soils are "mined", "soil health" deteriorates, and the efficiency of fertilizer and water use decreases. SSA farmers find themselves in a "vicious cycle" of lack of knowledge and resources, declining productivity and increasing poverty.

(iv) The key objectives of the World Bank's 2002 Rural Development Strategy for SSA (reduce poverty, promote growth, protect the environment) and of the New Partnership for African Development (NEPAD), cannot be achieved if smallholders, who farm around 180 million ha of land in annual and perennial crops, do not sustainably intensify their production systems and expand cropped areas, where appropriate. Achieving this requires, as a crucial component, greatly improved crop and land husbandry. Because of the close interactions between crops and animals in many SSA farming systems, livestock production will be affected as well. . . . The "Soil Fertility Initiative" (SFI), launched in 1996 in response to concerns of SSA stakeholders. . . . had, as its original goal, the introduction and adoption of sustainable soil fertility management practices by smallholder farmers.

Achievements and Lessons Learned

(v) Consultations on the SFI between lead sponsors. Government entities and other stakeholders in about 20 SSA countries resulted in almost all countries endorsing the SFI and requesting assistance in the preparation of action plans. . . . Only limited resources were allocated to the SFI, and although it has made significant achievements, implementation has been haphazard and piecemeal, with negligible impact so far in relation to the overall magnitude of the soil fertility/productivity problem.

(vi) However, the SFI has stimulated a rich debate on sustainable soil fertility and land productivity management and in several countries, there is now a better appreciation of soil productivity problems and a clearer vision of the complex set of actions needed to effectively address soil fertility deterioration and achieve long-term productivity improvement. . . . The SFI concept itself has, during the past few years, evolved beyond a narrow approach of soil fertility enhancement largely through external inputs of mineral fertilizers and the use of leguminous crops and trees. It is also increasingly accepted that the SFI must, to be successful, concern itself - in addition to institutional and policy issues - with all those aspects of soils that affect their ability to support farming on a sustainable basis, including their physical, chemical and structural properties, biological activity and moisture holding characteristics.

(vii) The problems of low farm productivity in SSA cannot be solved through isolated solutions such as increased use of mineral fertilizers, hybrid seeds, irrigation or mechanization alone. Rather, an integrated approach, which addresses soil productivity problems as a core element of sustainable land management for agricultural production, is needed. Significant and lasting improvements will be achieved through the positive synergies resulting from the combined adoption of improved crop/plant, soil and rainwater management practices that offer both production and environmental benefits. Thus, although not yet formally endorsed, the original SFI concept has evolved towards the so-called "better land husbandry" (BLH) approach [my bold – Ed.]. To reflect this thinking well and to promote a clear message, there appears to be a case for re-naming the SFI as the "Africa Land Husbandry Improvement" or "Sustainable Land Management" Programme. . . .

The Way Forward

(xiii) During the next decade, there is an unprecedented challenge to improve soil management, enhance productivity, develop sustainable farming systems and environmental protection on a significant part of the cultivated area in SSA. From being trapped in a vicious cycle of increasing poverty, SSA smallholders can be facilitated to reach a "virtuous cycle" of improved knowledge and understanding, leading to good land husbandry practices, increased productivity and significantly improved livelihoods. This will involve an approach that incorporates the interdependency of the organic, mineral, biological and physical aspects of soil management, with organic matter and mineral fertilizers being complements rather than substitutes, while recognising the site-specificity of development options for farming systems . . .”

The Universal Soil Loss Equation has been used in many places and for many years to estimate likely losses of soil by water-erosion processes. It has widely been assumed that this provides a reasonable basis for estimating the effects of erosion on plant yields (though I believe that the philosophical - let alone the technical - justification for this is debatable – see ENABLE-15).

It is worth pointing out that

a. The principle underpinning the assumed direct soil-loss/yield-loss linkage has not been satisfactorily defined, being assumed much more often than it has been clearly demonstrated by experiment;

b. The closeness of the USLE model’s soil-loss estimations to in-field realities have in many situations not been satisfactorily cross-checked, with the result that decisions on policy and actions relating to plant production in particular, based on the model’s results alone, may be of questionable validity;

c. After decades of experimentation across the world the policies, strategies, tactics, and implementations adopted to deal with the problem of soil erosion, based on the USLE model, have not of themselves been particularly successful both in eliminating the erosion problem and simultaneously stabilising or raising average yields.

These points suggest that a radical re-appraisal of the approach to land degradation by erosion and associated declines in soil-productivity is justifiable and needed. This should be undertaken urgently, no matter how many sacred cows need to be subjected to veterinary-style examination as to their continued productivity and, where necessary, be deconsecrated and relegated to the back pasture.

A Soil-Gain Equation. Now take another look at the photo on p. 26 of ENABLE # 15 – July 2002, and then at ‘Think-Pic 2’ on p. 23 of ENABLE # 14 - February 2002 (in that order) and a different perspective becomes apparent.

If plant-favourable soil is developing from the top downwards much more than from the bottom upwards under influence of organic materials and processes, then an appropriate approach to the problem becomes that of actively enhancing the quality and depth of the soil also from the top downwards. Now DMC –‘Direct Sowing, Mulch-based systems and Conservation agriculture’ (see e.g. pp. 12-15, 23 of ENABLE # 15) come into their own.

It seems likely that more-direct linkages between soil improvement (particularly in terms of organic materials and processes, and of soil porosity)and biomass- yield of crops, grasses, shrubs and trees could be more-accurately predicted using some form of ‘Soil-Gain Equation’ than has been possible with any form of Soil-Loss Equation.

This view of the problem and of the approach to its solution is validated by the growing number and range of positive experiences by farmers, their advisors and researchers after implanting zero-tillage/DMC systems on their farms and ranches in Brazil and other countries.

The results of better land husbandry, of which this is a part, is giving rise to policies, strategies, and tactics which please both people and the environment.

It may prove complicated to determine a soil-gain:yield-gain relationship, but the philosophy and principles behind it will be more comprehensible, and the consequences in the field more positive, than they have been up till now.

‘I should like to welcome all of you this afternoon and particularly our guest speakers. We have a relatively small attendance but as we shall discuss tomorrow at the AGM we are planning to merge with the TAA to gain the advantages of a larger grouping.

‘We had hoped to have a paper from the National Soil Research Institute, the successor to the Soil Survey of England and Wales. We know that there has been quite a considerable amount of investigation on the impact of changing land use in the UK on, for example run-off, and this is obviously a topic of interest in the tropics too. Unfortunately a speaker was not available.

‘Agriculture has become substantially neglected by the donor agencies. You will recall that the DfID White Paper on “Eliminating Poverty” scarcely mentioned agriculture. The subsequent paper on agriculture did admit that the greater proportion of poverty was in rural areas and that improvements in agricultural productivity would be essential if we were to make inroads on this. That agriculture is in dire straights in many countries, particularly in Sub-Saharan Africa, is not in doubt – 35 million people needing food aid this year. Some countries like Ethiopia and Malawi have structural problems such that they cannot produce enough food, even in a good year, to tide them over the bad ones. And of course the spectre of HIV/AIDS is having an enormous impact where 90% of the energy used in agriculture is human energy. The report by Patrick Hamilton, circulated by Francis, who has been monitoring the ABLH project in Kenya, on the impact of decreasing size on land holdings on poverty, especially on the ability to pay school fees, reveals just how serious the problem is.

‘Today and tomorrow we shall hear about some of the problems of land deterioration – an insidious and not always directly obvious situation and thus the more difficult to reverse, but one with long term implications. The obvious signs are usually mentioned in passing – the estimates of the area that is being lost through erosion or salinisation but the more insidious aspect of structural deterioration is scarcely mentioned. Much attention is given to farmers’ assessment of their problems but I wonder whether farmers are aware of the more insidious aspects of land deterioration. We shall hear about some of these from our speakers and about how these are being tacked in several parts of the tropics. In welcoming you I am sure we all look forward to a series of interesting presentations and discussions.

Mr Shaxson started by saying that he wanted to be passionate about soil porosity and organic matter, both being of fundamental importance to much-needed increases in food production. He pointed out the dilemma in trying to increase crop production – it requires more water at a time when the demand for water consumption is already increasing beyond the available supply. He said that this situation is exacerbated by soil compaction and by plough and hoe layers which reduce the capacity of the soil to hold water available for plant roots. The following is a summary of his presentation in which many of the points were illustrated with copious photographs and diagrams.

Think like a root

We face two interlinked problems in the quest for higher output from the land: (a) intensified use of land generally leads to more land degradation; (b) ever more clean water is demanded, but increasing proportions of rainwater are lost as muddied runoff. Land’s productivity for plants and for water are linked to the landscape. But the hydric component of the productivity of soils – interacting with the chemical, physical and biological components – is not sufficiently highlighted. It is useful to think like a root and think like a river in order to visualise the landscape conditions needed to sustain the capacities to provide plant biomass and streamflow.

Tillage and porosity

Tillage has some adverse effects on tropical soils. Degradation of optimum porosity in the soil diminishes soil capacities for both infiltrating rainwater, retaining it at plant-available tensions; and enabling through-flow of surplus to groundwater and thence to streamflow. Tillage in tropical conditions speeds the rate of oxidation of organic matter and emission of CO₂ from soils, enabling structural collapse, as well as resulting variously in loss of useful spaces within the soil architecture due to pulverisation, compaction, interstitial sealing, and closure of biopores. Soil profiles become less retentive of water, increasingly subject to runoff and erosion, less favourable to root growth and function, even to the extent of preventing root penetration below the tilled layer. Such damage can follow from use of hand-held and mechanised equipment, and from the repeated passage of feet especially on soils in a wet state. The condition of the soil – at and below the surface – affects the partitioning of rainfall between entry into the soil and runoff, and hence the efficiency of use of scarce rainfall. Economic as well as biological consequences of such soil damage are shown to be severe. The effects of water-stress in plants on their final yields are far more quickly noticed than are those of soil loss.

Organic matter and processes

Soil-inhabiting organisms have very significant effects on the self-recuperation of the porous architectural condition of most soils, as long as they are regularly supplied with organic matter as a food source. Useful soil is formed from the top downwards by their combined effects, as long as there is sufficient moisture for their activities in transforming organic materials. Water plus organisms (including plants) plus organic matter provide a common thread linking self-recuperation of soil, its resilience in the face of shocks, the sequestration of carbon, functioning of ecosystems, health of soils, and sustaining their productivity. Problems resulting from deforestation, overgrazing and excessive cultivation are best addressed by attention to protecting and improving soil porosity, soil organic mater and soil processes rather than by often-ineffective legislation. In trying to solve land-damage it is necessary to think, not only at the macro scale, of land allocations and policies, but also at the micro scale, of soil pores and bugs.

Better land husbandry in Brazil

In Brazil the development over the past 30 years of improved agricultural systems; which involves:

· planting directly through retained crop residues;

· using cover-crops/green-manures to augment the feed for soil organisms;

· avoiding dis

Chairman’s opening remarks (Dr John Coulter)

Invited papers

Adverse effects of cultivations on tropical soils,

and successes with no-till farming (Francis Shaxson, ABLH)