ENABLE
NEWSLETTER OF THE ASSOCIATION
FOR BETTER LAND HUSBANDRY
NUMBER 15, JULY 2002
EDITORIAL
INFORMATION
In this 15th issue
of the Newsletter you will find some thought-provoking material, which I hope
will stir discussion and provoke letters and articles for the next issue!
Both the beginning and the
end of this issue are concerned with soil formation – from the top downwards,
whether by tillage, or organic activity on organic materials, or both. Will Critchley’s Letter to
the Editor contains an extract from his PhD thesis regarding soil formation
in
At the AGM in
A translation of an article
about easy and difficult conditions for success with direct-drilling / no-till
farming / conservation agriculture in Brazil indicates that weed-control may be more difficult on old ‘tired’
land than
on that newly-opened from
formerly-undisturbed vegetation. It implies the
need for dedicated research
on realistic options in weed-control for no-till systems on land that has
been in cultivation for many years. The article mentions
the use of specific species in rotations with allelopathic
effects in suppressing weeds.
There is an article on sources
of information on better land husbandry, which provides a lead-in, rather
than any attempt to provide a comprehensive list of relevant references. Please contact me if
you would like some more detail.
I have taken the liberty of
taking an extract from a pre-1982 paper by Dr Geoff Downes
to show the source of the phrase ‘Prolonging the life of resources’,
a concept clearly allied with ‘sustainability’ and ‘husbandry’.
Notices of three useful books,
and the new website of the recent global program on Direct Sowing, Mulch-Based
systems and Conservation Agriculture, are included on the Bookshelf. If the photos are satisfactory, Part 2 of the boat-rocker of the Think-pic
2 (previous issue) precedes Think-Pic 3. If not, you will find
a different diagram at the end. Take
time to consider Richard Feynman’s thoughts on the scientific method, and
apply them to the implications of Think-pic 2 of the previous issue.
Good reading! The Editor.
.oOo.
LETTER TO THE EDITOR
TOP-DOWN SOIL FORMATION
Dear Editor,
Congratulations on the last
ENABLE (no.14) which I found most stimulating. May
I add something to the debate on soil formation / soil as a self-renewing
resource? The following piece – while not exactly
approaching the issue from the same angle as your article (pp.4-9) – arrives
at a similar conclusion: farmers are often busy forming
soil at a higher rate than we assume. In this extract
from my thesis I discuss tolerable soil loss in the context of [bench]terracing
– with especial reference to Java[1].
“How much surface erosion is essentially
benign, and at what level does it become malignant? This
is an important question, which is poorly answered. Obviously,
in the current context, we need to have some idea of whether terraces reduce
erosion to an ‘acceptable’ level. High rates of surface
erosion cause a reduction in soil productivity for various reasons including
selective removal of fine nutrient-rich particles and organic matter (leading
to the phenomenon of enrichment of sediment compared with source), reduction
in rooting depth and destruction of soil structure (Stocking, 1984). There are negative downstream impacts also in rivers,
reservoirs, irrigation schemes, and towns commanded by tropical steeplands. The focus here
will be on the on-site impact of (surface) soil erosion, as that is where
the economic damage is generally greatest (Doolette and Magrath,
1990). Soil loss tolerance levels (‘T-values’) denote
the theoretical ‘maximum level of soil erosion that will permit a high level of crop productivity to be sustained economically
and indefinitely’ (Wischmeier and Smith, 1978). What is extraordinary is that the T-value most frequently
quoted and applied as a standard (11.2 t/ha/year) is simply the general maximum
calculated for use in the USA when the T-value was first developed (Kral, 1982). It is applied,
apparently, without any consideration of its local relevance, though it has
to be said that the knowledge base for independent development of T-values
for the tropical steeplands is extremely weak.
Johnson (1987) even questions
the usefulness of T-values at all due to the ‘faulty premises’ on which they
are founded. The fundamental weakness of T-values
is that they are based on rates of pedogenesis:
the development of soil itself from parent material. This
is usually a topic of authoritative sounding, pessimistic statements. In fact little is known about this side of the ‘erosion
equation’ generally, and even less about the specific situation in tropical
soils under invasive cultivation into the soil profile, as occurs under terrace
systems. Data on the subject are scarce (Walling,
1989; Hudson, 1992) – in contrast to the plethora of
erosion data. Johnson (1987) points out that many
of the published references to soil formation are traceable to two sources
(one a ‘guess’ and the other a ‘speculative deduction’).
General global rates quoted range from as low as 0.01 mm/year (0.13
t/ha/year, assuming an average bulk density of 1.3 t/m3) to 7.7
mm/year (90 t/ha/year) in exceptional cases (Morgan, 1995). Zachar (1982) quotes a global
figure of 0.1 mm/year (1.3 t/ha/year). Walling (1989) takes the ‘frequently cited’ figure of 0.025 mm/year (0.3
t/ha/year) as a guideline. While Stocking (1994) points out that the rate of formation of topsoil ‘can easily
reach ten times the formation of the subsoil’ (5-10 t/ha/year compared with
0.5-1.0 t/ha/year), this process will, self evidently, be supply-limited in
the long run.
However there is good reason to
suspect relatively high rates of pedogenesis
in tropical steeplands. (Ahn (1993) lists the four environmental
factors that, over time (the fifth factor), define the rate of pedogenesis. These are the
parent material, climate, vegetation/soil fauna, and relief. But he adds a sixth, often ignored, factor. That is human activity.
Will Critchley, 12.4.02.
[The full citations of the
references can be provided by the Editor]
[See also:
(a) the
suggestion that organic acids from the biotic transformation of organic
materials in the upper soil layers may also contribute to soil formation
from the top downwards, on p.8 of the previous edition of ENABLE (no.14);
(b) three
diagrams at the end of an article by Shaxson (1981)
[2];
(c) Think-pic 3(on last page – if adequate photo-quality).
The Editor.
.oOo.
ARTICLES
LAND HUSBANDRY
- THE A-HA! FACTOR, AND WHAT ON EARTH
ARE WE TALKING
ABOUT?
Richard Baker
I think we are constantly
confused by the question of scale. Of course in the long run we need an overview.
We might seek to have a Government-supported philosophy with regard to land
and its significance to the welfare of the community. In the long run we need
a worldwide realisation of our relation to the
environment and our dependence on the land and its productivity. Meanwhile
though, we have to help those who are suffering severe deprivation at present.
Perhaps the best way to help
is somehow to bring about sustainable increased productivity on the individual
farm by the individual farming family. So, for the moment, let's not concern
ourselves with policies of land use, the need for roads, or waste disposal
or mining or recreation, or even what type of agriculture suits a particular
area. Most rural development programmes now are
involved with empowerment of local people and the creation of local organisations including those concerned with promotion,
packaging, processing and marketing. Important as these activities may be
to rural development, we cannot regard them as encompassed solely by the concept
of land husbandry.
Let's think rather, about
what a farming family can do for themselves on their patch. Let's set our
time scale to this year next year and the year after. A vulnerable small farm
family wants to reduce its outgoings and increase its income, i.e. with regard
to its finances. With regard to production, it wants to reduce its inputs
in relation to its output. We want to promote practices that let the soil
regenerate or recuperate. We definitely want to avoid or prevent soil degradation
- rather than have to correct degradation after it has occurred. The in-situ
degradation we want to avoid includes compaction, capping, sub-surface panning,
acidification, salinisaton, water logging and
nutrient depletion. We want to improve the soil's structure, stability, available
water capacity and porosity.
We confidently expect that
in the course of achieving the desired result, we will inevitably have increased
the organic matter content and biological activity in the soil. This does
not mean we have only to add lots of organic matter and earthworms to every
piece of land. But we should try not to treat the soil in such ways that will
reduce its organic matter content and biological activity. Maintaining biological
activity requires that we conserve and maintain soil moisture as far as possible
within useful limits. The soil should not suffer extended periods of drought
or water logging.
We want to remove, avoid or
reduce any negative factors for crop production. That is, we want to control
pests diseases and weeds, but at minimal cost. We may want to protect the
soil from rainfall impact to prevent surface capping and we may need to shelter
the crop and the soil from extremes of cold, direct sun, wind and storms.
We want to avoid nutrient deficiencies and toxicities.
If we have organic residues
available, a lot could be achieved by adding them to the soil as compost or
mulch. They should increase organic matter and most likely provide some nutrients
for the crop. We would expect them to give some soil protection and help
to suppress weeds, providing that we don't include
active weeds or weed seeds in the mulch. We would expect mulching and composting
to conserve soil moisture and in time, improve soil
structure and available water capacity. Organic matter has
other beneficial effects too, such as increasing the availability to plants
of soil potassium and phosphorus, while ameliorating
the affects of acidity and toxicities. It is also the main reservoir of available
nitrogen in the soil.
Other
specific measures to be adopted may vary from place to place. In some places
shade trees or agroforestry
may be appropriate for recycling nutrients, conserving moisture and suppressing
weeds. In other places annual or perennial cover
crops may be more suitable. Crop rotations and the use of legumes
will have an important part to play. Inorganic fertilisers
may supplement nutrients in the organic matter, so
long as the other required soil properties are not impaired. Various corrective
actions may be needed initially, such as breaking-up
an existing pan, before a sustainable system can be established.
On
the ground, in adopting the principles of better land husbandry the main objectives
remain constant, in spite of variations in details
of practice. We concerned with treating the soil itself as something that
needs to be tended and improved, rather than as something
to be used, abused, exploited or taken for granted.
Focussing upon creating conditions that encourage
continuous beneficial soil microbiological activity
may give us a guide to a potentially universal concept.
.oOo.
B.L.H.
“… always trying to sustain, improve,
increase and encourage the biological activity of the topsoil”.
Richard Baker,
in a letter, 18.04.01
.oOo.
WHY ‘BETTER LAND HUSBANDRY’
?
T.F.Shaxson
At the recent AGM, someone
asked “Why do we keep talking about better land husbandry? Surely everyone believes in good husbandry, and farmers
do the best they can”. A good comment, but still a
fair question.
As I see it, the answer lies
in the fact that plant production depends not only on the husbandry skills
of the farmers nor only on the genetic make-up of the varieties used, but
also on the environmental conditions - above- and
below-ground – where the plants are growing. The
soil itself is often significantly and negatively affected by people’s methods
of husbandry, no matter how well-intentioned, such that its condition falls
away from the apparently rich physical x hydric
x biologic x chemical condition of productivity that we would like to provide
for roots.
Loss of soil organic matter
in the first few years following the clearing and tillage
of undisturbed land is an almost universal problem, which is often
accompanied by decline of the condition of soil architecture due to loss of
porosity, by increased runoff and erosion of soil, and by loss of productivity. Eventually
the organic matter level reaches some sort of low-level equilibrium within
the farming system, often of 1% or less.
Bob Stewart has pointed out
that tilling the soil is like using a poker to stir-up a fire in your hearth. It exposes previously-sheltered organic matter to greater
flows of air in the soil, resulting in oxidation of more of the organic matter
and thus a faster rate of its decline. Therefore there
is loss of organic compounds which hold soil aggregates together and enable
the formation of divers pores, which facilitate both
the passage and retention of water in the soil, which raise the CEC of the soil with benefits to retention
and slow release of plant nutrients, and which represent
the pool of plant-captured carbon serving useful purposes in the ecosystem.
As indicated in Figure 1 (page
9), poor land husbandry following the opening of land results in its ongoing degradation. Those
people with a conscience about the condition of the land respond by undertaking
conservation work to counter the signs of falling productivity, hopefully
at least achieving some kind of ‘holding
the door closed’ against further decline. But if
the conditions of the soil around each plant (as a medium for its effective
rooting) are not optimized with respect to productivity, the hoped-for yields
of crops, pastures and forests will not be achievable.
If the ‘conservation-conscious’
farmer’s land husbandry actions are insufficient to improve (rather than
just maintain) the soil condition, then better land husbandry is needed
to improve soil conditions on a continuous basis, maximizing positive changes
(in e.g. organic matter, organic activity, porosity and soil moisture, nutrient
status, soil depth) and minimising negative changes (e.g. more rainfall
partitioned to runoff, more erosion of particles, net decline in organic
matter).
Well-managed, resilient and
productive no-till systems based on principles of conservation agriculture
are prime examples of good land husbandry, which farmers have reached by
achieving better land husbandry
than they did before.
Much of the world’s agricultural
land suffers from not-very-good husbandry at present. There’s
still plenty of scope, and need, for a lot of better land husbandry.
.oOo
B.L.H. IN NO-MAN’S LAND ?
“It
is a particularly serious handicap that the main practical requirement and
opportunity for a concentrated point of synthesis of knowledge about the environment
happens to coincide, in terms of organised studies, with the no-man’s land
between ecology, geography and landscape”.
Max Nicholson,
1971.
.
oOo.
“WHAT DISCIPLINE IS A FARMER
?”
Small farmer at
a meeting in Kakamega, 1987.
.oOo.
Figure 1: The need for better land husbandry.
WHY ONLY 14 MILLION HECTARES
[of
direct-drilling in
Fernando Penteado Cardoso.
“At present in Brazil we are
making use of about 31 million hectares for annual summer crops, being part
of the area planted twice per year which includes the ‘little harvest’ in
autumn/winter (7.5 million ha.). The area cropped
in summer has been shown to be stable in recent years, though with consistent
increases in productivity.
In the international Congress
‘Conservation Agriculture’ which took place in Spain in the month of October
2001, the world of agronomy attested to the facts that cover of the soil
with vegetation or plant residues, alongside the minimum disturbance of the
soil, constitute the most appropriate technology yet developed for a sustainable
agriculture. On this basis the Direct Drilling system
is accepted in international circles.
But why are we limited to
only 14 million hectares under direct-drilling? Why
do we have only 45% of the of the area in annual crops effectively protected
and improving, when we ought to have 100%?
Leaving aside the human aspects
of the problem, it is worth analyzing this question in the light of the former
use of the soil, subdividing this into two groups: old lands and new lands.
The ‘old’ lands, generally
‘from the forest’ and with good initial fertility, were cultivated over many
years with coffee and/or annual crops which
required soil preparation
to make possible the mechanical control of ‘forest regrowth’; or, put another way, of weeds. With
the passage of time, the characteristics of the soil have been altered, as
much by the reduction of stable organic matter (humus) as by the repeated
operations of [disc-]ploughing and [disc-]harrowing.
The porosity and permeability
have been diminished and there has been reduction in the proportion of aggregates
accompanied by increases in dispersed clays. This
dispersed clay has provoked the sealing of the soil, recompaction after soil-preparation and the formation
of a less-permeable densified layer normally called
a ‘plough-pan’. As a result, the slower infiltration
produced greater runoff over the surface and consequent erosion. On the other hand, the ‘old’ land became replete with
all sorts of weeds and their dormant seeds which persisted for years and years. At the end of a long period the lands were exhausted,
leaving a necessity for replenishing nutrients.
The ‘new’ lands, generally
of low [inherent] fertility, with the vegetation types of the cerrado [Brazilian savannas] or of
native pastures, offered good original physical characteristics, principally
in terms of permeability. Above all, they are yet free of weeds and their persistent seeds. It is clear that poverty in chemical characteristics and
their acid conditions needed correction, and required the early supply of
nutrients through liming, micro-nutrients and fertilizers.
In virgin lands the imposition
of Direct Drilling has had rapid success and does not face great problems:
there is no recompaction of the soil, and the
use of herbicides is at only moderate level. Water
infiltrates readily, there is little flooding, and no erosion, through the
joint action of permeability and of dead vegetal cover. This
early facilitation explains the rapid adoption of Direct Drilling in extensive areas of the cerrado.
In ‘tired’ lands, with degraded
physical and chemical properties and large stocks of the seeds of various
weeds, the implantation of Direct Drilling is more complex, requiring early
measures for soil recuperation. These generally
involve subsoiling, liming and the planting of
species with intense branching root-systems which restructure the soil, provoking
new aggregation and providing channels both those along roots which have
rotted away and those produced
by insects and worms which are favoured by this new environment. Such recuperative species need also to have allelopathic
action to minimize the weed problem.
In the South,
Black Oats are unsurpassed for these purposes. In
regions with dry warm winters other options are Eleusine, (a giant finger-millet) or Brachiaria brizantha
which, when well-fertilized, and growing during summer and autumn, provides
much straw, restructuring the soil and ‘holding back the forest regrowth’
in the subsequent crop. These species, to be established
for the first time in the context of Direct Drilling, will be benefited by
the recycling of nutrients earlier absorbed by the restorative vegetation.
This analysis
explains the difficulties and the resistance to Direct Drilling encountered
among farmers with ‘tired’ land in the State of Sao Paulo and even in
(Translated by T.F.Shaxson from the Portuguese
‘Porque somente 14
milhões de hectares?’ in ‘Direto no Cerrado’, the
News bulletin of APDC, Yr 7, no. 23, Jan/Feb. 2002,
p.4.)
.
oOo.
CONSERVATION
AGRICULTURE, BETTER LAND HUSBANDRY,
AND INTENSIFYING
CROP PRODUCTION
T.F.Shaxson
(based on a note written for FAO in 1999).
The basic principles of caring
for the world’s soils were incorporated in FAO’s
World Soil Charter of 1982. Since then, international
meetings and publications have reconfirmed commitments and proposed steps
to maintain and improve the protection and productivity of this basic resource
on which, with water and air, our life on earth depends.
The world’s human population
continues to expand, but this is not matched by expansion in areas of easily-usable
land from which more food and other land-based necessities might come. There is therefore a rapidly-growing need to intensify
production from lands already in use, and to achieve this in ways which are
: (a) capable of maintaining and increasing productivity,
(b) able to make more-efficient use of energy, nutrients and other inputs
per unit of output, (c) effective in husbanding water,
soil and its biotic communities, and (d) capable also
of restoring to productive health those lands already degraded in various
ways by unsuitable use and management in the past, whose decline has often
and widely been manifested by excessive runoff and erosion losses.
To date, it has proved difficult
to achieve conservation of soils’ productive potentials
using those commonly-recommended actions which, though widely demonstrated
in temperate and tropical areas, have not found favour
with either the farmers on whose lands they were implemented nor with the
soils they were supposed to protect.
However, a growing number
of experiences with no-till systems -- in conditions of both mechanised and un-mechanised
agriculture, on small and large farms in both temperate and tropical zones,
and totalling millions of hectares -- now strongly
indicate that further and significant improvements in conservation-effective
agriculture are indeed possible, and acceptable to farmers, in addressing these varied concerns.
Two key facts provide firm
grounding for expanded successes in the future:
.1 The health and
production of plants is intimately related with the health and functioning
of communities of organisms in the soil which is the four-dimensional rooting
environment (three dimensions of space and one of time).
The nutrition and management of soil organisms is essential to sustaining
and improving the productivity of soils;
.2 Keeping
the appropriate porosity of a soil at every level is a key to its healthy functioning as a medium for roots and soil
organisms, to its capacity to accept, retain and transmit water into and through
the profile, to its resilience in the face of erosive
or other damaging forces. If these architectural spaces
are lost, soil functioning is damaged, and time and biotic activity are then
needed before these robust many-sized pores have been
re-formed.
Soil functions best as a rooting
environment when appropriate dynamic balances are maintained between its
physical, biological, chemical and hydric components. Where the outflow of plant nutrients is regularly balanced
by their compensatory inflow from a combination of sources -- soil-weathering products, transformations of organic materials,
and, where necessary, complementary inputs of mineral fertilisers -- intensified cropping
may be supported on a sustainable basis. Where any
land use can continuously maintain these prime conditions, the time and space
needed to be set aside specifically for adequate soil
self-restoration may be greatly reduced, without detriment to the soil’s productive
capacity.
The encouragement of ‘Conservation
Agriculture’ derives from experiences with reduced- and zero-tillage, but
is set out as an umbrella term that connotes systems of plant production –
whether from crops, pastures, trees alone or in combination – which aim to
satisfy the above criteria on a continuing basis, achieving simultaneously
both stable production as well as effective conservation and optimum use of
water and soil components.. It anticipates synergistic
benefits which arise from combining the dynamics of improved soil productivity
processes with the latent skills and enthusiasms of farmers and their rural
families, joint prime keys to sustainability into
the future.
The term embraces systems
of crop production in which (a) plant residues – whether of the previous commercial
crop or of a cover-crop - are retained at the surface
to serve the dual purposes of providing a food source for soil organisms
at the same time as providing a permeable cover. This protects against extremes of rainfall, wind and temperature; (b) direct-seeding through the residues is used so that
soils, once brought back to excellent condition, suffer minimal disturbance
by tillage or by compaction; and (c) rotations of
crops, which include legumes for N-fixation . The
techniques which are involved minimise or avoid
soil-damaging effects – notably excessively-rapid oxidation of organic matter,
and undue loss of porosity - often associated with conventional tillage-based
crop production methods, particularly in tropical zones.
In support of this means of
intensification, conservation-specific works along the contour, whether vegetative
and/or constructed in form, should still be considered as complementary physical
back-stop insurances for protection against unavoidable runoff and erosional damage by very infrequent but severe climatic
events of water and wind.
The benefits arising from
Conservation Agriculture have caught the attention of individual farmers,
groups within rural communities, and local authorities.
They have noted greater security of agricultural production and livelihoods
in the face of unpredictable variations in climate and markets, and improved availability – in quantity and duration –
of groundwater and streamflow.
At the same time this has reduced amounts of government funds – from
local and national authorities – which have needed to be allocated for maintenance
and repairs of infrastructures such as roads and bridges, for recuperation
of flood damage, and for drought relief. A consequence
has been that greater proportions of their limited
funds can be applied to making positive improvements in other social services
and infrastruture such as facilities for health,
education and public transport.
The Conservation Agriculture
approach is already put into practice on such a scale that it is possible
to see that increased resilience of the land and soil systems have several
other positive effects:
.1
By improving land’s capabilities, it permits greater flexibility of
land use in the present while also maintaining wide options for varied land
uses in the future;
.2
By increasing security of rural livelihoods, it has also reduced the
despair-driven rate of rural-to-urban migration;
.3
Infrequent climatic events of a given severity cause considerably less
damage in such areas than they would have done under conventional tillage
systems.
.4
The need for (often ineffective) restrictive and punitive legislation
concerned with land use and management at national level becomes much less
apparent, while those laws which assist local communities in framing and formalising their own encouragements and regulations
become positively effective.
.5
It enhances local capacities to do better what they are already doing,
at the level of communities , both those of people above-ground and of soil
organisms below-ground.
6.
It prolongs the useful life of carbon within agricultural systems and
diminishes its unduly-rapid recycling back into the atmosphere as CO2;
.7
It achieves effective conservation of water and soil more by stealth
within production systems than by frontal attack independently of them.
The development of common-interest
groups around the concepts and practices of Conservation Agriculture has
already served to provide encouragement and mutual support to members as
they make the changeover. For example, they have
become action-groups for facilitating infrastruture
development – notably of roads and conservation-specific works -- which benefit many contiguous farms, in conformity with
landscape conditions; they have become very effective
in farmer-to-farmer spread of the beneficial ideas and practical technologies
which they have favoured; and
have begun to develop into significant local pressure-groups for improvements
in the policy and institutional ‘environment’ so as to
have political and legal support for their own initiatives in Conservation
Agriculture.
Accumulation of results of
farmer-favoured local actions in Conservation
Agriculture now offers the chance of producing positive impacts having global
reach and effects. Such an achievement will ultimately
derive firstly from the dynamic interactions of the soil and its organisms; secondly from the interests, skills, desires and decisions
of farmers and their families, and thirdly from the more-appropriate institutional
and political assistance and support which the wider society can provide. When these come together in profitable combination, the
essential
improvements are likely to
spread widely and rapidly through farmers’ own networks and linkages.
The framework of basic principles
and developing practices which comprise Conservation Agriculture commend
themselves to national Governments because it offers practicable ways of
reaching agronomic, social, economic and environmental objectives more rapidly,
holistically and securely than in the past.
When well managed, Conservation
Agriculture represents fine examples of good land husbandry.
.oOo.
A SEVERE RAINSTORM TEST OF
NO-TILL CORN,
(A 1:100
year storm, which fell in 7 hrs.)
|
Tillage type |
Slope
% |
Rain
mms. |
Runoff mms.. |
Sediment yield kg/ha |
|
Plowed, clean tilled, Sloping rows |
6.6 |
14.0 |
11.1 |
50,781 |
|
Plowed, clean tilled,
Contour rows |
5.8 |
14.0 |
5.8 |
7208 |
|
No-till, contour rows |
20.7 |
12.9 |
6.4 |
71 |
“No-till was helped by very good
sod residue”.
(metricated
from a note about: Harrold L.L. and Edwards, W.M. 1971. ‘A severe rainstorm
test of no-till corn’ in JSWC (
.oOo.
WHERE CAN I FIND INFORMATION
ABOUT BETTER LAND HUSBANDRY
?
T.F.Shaxson
Information about better land
husbandry – concepts, background, approaches, thoughts, research, applications,
results etc. – can be found in many places, here categorized under three
main headings: in the writings of others, in the field, in your own mind.
In writings of others:
Background concepts:
- Perceptions of, and reactions to, the land itself
- Ecological dynamics in landscapes
etc
.
Research reports
- New information
- Reviews by area, by topic. etc.
etc.
Implications
- For policies
- For programmes
etc.
In the field
Technical observations
and records
- Records of your own surveys
- Effects of interventions
etc.
Farm-families’
perceptions and reactions
- How they perceive their world
- What they may not be aware of
etc.
In your own mind
Prior influences
on your own thinking and approach
- Upbringing
- Technical training
- Subsequent experiences
Own views and
perceptions
- Ranking of different
aspects
- Convincements / own convictions
- Preferred ways of spread of your understandings
- How you perceive farmers’ world
etc.
Motivations
to help to improve land husbandry:
- Own livelihood as e.g. farmer
- Ecological conscience
- Interest/mental challenge
etc.
Questioning:
- Lateral thinking – other ways of interpreting available information?
- Do the observations really fit the ‘received wisdom’?
- What more do we need to know?
etc.
Openness to others’
views:
- Rigidity / flexibility to adapt one’s own thinking
- Personal criteria for considering others’ views
- Technical criteria by which to judge validity
etc.
One’s own view of land husbandry
may be built from information from many sources according to training, work
experience and interest. From the technical viewpoint,
the relevant headings would include an understanding of the basics of e.g.:
-
Physical geography
-
Geology
-
Soil science
-
Climatology
-.
Plant physiology
-
Biology, chemistry and physics
-
Ecology
-
Photo-interpretation
-
Topographic survey, mapping
-
Hydrology
-
Agricultural systems
-
Research methodology
-
Agricultural economics
-
Rural sociology
-
et al., as appropriate
Because the life of people
ultimately depends on the growth of plants, improving land husbandry to
make the land more-favourable for plant function is a prime requirement. In my view, there are three key factors from which all
other aspects of land husbandry depend:
.1 Water in the soil, derived from rainfall
in the hydrologic cycle, is the essential component of land fit for plants. When it is insufficiently available, or absent, plants
cannot grow nor rivers flow.
.2 Voids in the soil, which comprise its porosity,
are essential components of soil productivity, together with water. Both have been largely ignored in considerations of land
management, because within the ‘physical x chemical
x biological’ definition of soil productivity, spaces
and water are only implied, not highlighted, within the ‘physical’ component.
.3 Soil-inhabiting organisms’ actions are essential to the technical aspect of sustainability
of agricultural / forest / pasture /rangeland / wildland
systems . Without their sufficient activity the continual
formation and reformation of soil architecture – the physical soil structure
whose flip-side is the spaces of porosity – would not occur. Soils would/do become less suitable as reservoirs of plant-available
soil moisture, the moderators of the rainwater that reaches groundwater,
and less favourable as rooting-environments. Undertaking
organic-rich agricultural systems improve not only soils’ productivity and
resilience but also their capacities to be self-developing (see end-photo
in this issue – if present) and self-sustaining as to plant production.
Acceptance of these bases
of ecological reality provides the framework for one’s own mind to consider
and assess the writings of others, one’s own experiences and observations,
and the ways our individual minds work in favour of better husbandry of the land.
What goes on in one’s own
head depends not only on verifiable physical facts alone but also on non-quantifiable
perceptions, insights, understandings, preferences, feelings, motivations. ‘Hard’ science is not the only basis for our treatment
of the land and its living and non-living members. ‘Husbandry’
has no meaning without people; therefore what goes
on in our heads to determine our actions as much affects the husbandry outcome as do the ecological realities of
our surroundings.
There is a mass of literature
about soil erosion and soil conservation, though less (as yet) about land
husbandry per se. It was dissatisfaction
with the inadequate success of ‘erosion control’ to
ensure sustainable and productive land uses that provoked the thinking and
development of alternative ways of
interpreting already-available data, leading over time to the framing
of concepts and the identification of land husbandry
practices which were at the same time conservation-effective. For myself there have been two specific defining moments
when discrete bits of information crystallized into
broader understanding. One was on an afternoon in
India in 1979 when the key roles of organic processes
and materials in the soil suddenly came into focus; the
other when Dr Geoff Downes’s consultancy report
on his visit to Brazil opened my mind to the ecological nature of the processes
in landscapes, of land’s degradation
and of the most appropriate means for improvement and stabilization of its
productivity.
Relevant information
can be reached-into by following leads provided by papers
presented, and the references
they cite, at e.g. biennial
International Soil Conservation Organisation Conferences (since 19781),
and the I World Congress on Conservation Agriculture in 20012. A number of the key principles have been articulated in
a WASWC/SWCS publication ‘Land Husbandry
– a Framework for Soil and Water Conservation’ (whose title and cover-picture
belies the shift in thinking)3. Norman Hudson wrote on the subject too4.
FAO offers much information.
This
Newsletter ENABLE, of your Association for Better Land Husbandry,
also contains relevant pointers. Authors’
own publications-lists provides more leads.
All of these, and others,
provide references to other work. In all cases, it
is important to consider, compare and contrast the content, relevance and validity of each document before building
any of them into one’s own mental and physical/electronic data-bases about
land husbandry. Are their contents consistent with
your observations?
1. Emergence, development
and experience of land husbandry principles, knowledge and practices can be
perceived among the papers of the ISCO Conferences. The latest to be published
is the collection of ISCO-IX, (
2. ‘Conservation Agriculture: A Worldwide Challenge’, 2001. (eds. L.Garcia-Torres,
J.Benites, A.Martinez-Vilela).
Córdoba (
3. ‘Land Husbandry: A Framework for Soil & Water Conservation’. 1989. T.F.Shaxson, N.W.Hudson, D.W.Sanders, E.Roose, W,C, Moldenhauer. Pubd. WASWC and SWCS.
ISBN 0-935734-20-1.
4. ‘Land Husbandry’.
THE USE AND MANAGEMENT OF
RESOURCES:
A PHILOSOPHY AND CONCEPT FOR
DECISION MAKING
[WITH RESPECT TO LAND USE
CONFLICTS IN A FRAGILE REGION
– THE
SOUTHWEST OF
R.G.Downes
[Formerly Director and Permanent
Head, Ministry for Conservation,
(An extract from
his Keynote address to the
Symposium on ‘Development
of the SW Region of the State’.
Date unknown, but
before 1982)
“Conservation and the associated concepts of
environment, protection and quality of life have become
common words, but like many other words having social significance, they can mean different things to different people. For this reason, a credible philosophy of conservation
must be developed and promoted widely not only to provide a framework within
which government policy can be developed, but also to eliminate the confusion
that exists in the minds of people.
‘Environment’ is where people live, their surroundings. Consequently ‘quality of life' refers
to an adequacy of human habitat in which people might reasonably expect to
enjoy their particular way of life. But the expectations
of people vary from group to group and from place to place. Furthermore the attainment of the expectations depends
on the availability of appropriate resources.
Primitive man's environment was the natural
surroundings. His interaction with it was one of
understanding, care and concern. His survival depended
on such a relationship and his culture was directed to that end.
Modern man depends on man-made environments
in which people should be able to live in greater physical comfort and with
much more freedom from fear about their survival. But
this expectation has not been attained universally as some may have expected.
The manipulation of land and water systems
to create man-made environments has impaired or in some places even destroyed
their capability for continuing to serve man's needs. To
make use of some systems, they have been manipulated without any thought about
the hazards or whether those systems could continue to be useful under that
form of manipulation, use and management. The existing
dynamic ecological stability of the system was upset without devising suitable
means for its use and management in a way that would provide stability and
so ensure continued usefulness.
The concept of conservation has arisen from
a study of these mistakes which became more evident, more widespread and more
significant as man's ability to manipulate became greater as the result of
new and more powerful technology. Concern about these
mistakes has given rise to two possible philosophies of conservation; the first, a negative preservationist approach which condemns
almost any change in the natural systems as being harmful and undesirable; the second, a more positive concept
based on an understanding of the nature and dynamics of the interactions between
the soils, plants and animals in different kinds of systems, and their capacity
for being used safely for some of the variety of purposes
required to satisfy the needs of man. In a modern
society, the second concept is not only ecologically more correct, but it
is also the only practical means for satisfying the great variety of needs
of our community.
Conservation is really a matter of fitting
man into his environment in a way that caters for the community needs without
destroying the capability of the environment to continue to provide them. In practical terms, it is a matter of achieving the proper
use and management of the resources available to the community so as to satisfy
both the present and long term needs.
Primitive man did this
naturally: his life style and culture were adjusted for survival. Modern man needs to examine both his culture and life
style critically to determine whether it will be as successful and to modify
it if necessary.
The GAMMA project of the universities
in
The resources available to a community reside
in the land and water systems coming within its jurisdiction. To achieve
conservation, it is necessary to have a philosophy on which to base policy
and to adopt procedures for making decisions about the use and management
of those systems to provide for the needs of the community in a manner which
‘prolongs usefulness’.
The GAMMA philosophy of conservation like ours
and one under consideration in the Department of Environment,
.oOo.
BOOKSHELF
NO-TILL FARMING FOR SUSTAINABLE
RURAL DEVELOPMENT
by
Christian Pieri, Guy Evers, John Landers, Paul O’Connell and
Eugene Terry.
An Agricultural and Rural
Development Working Paper.
(In English, and Spanish,
by end of July 2002 / in French by 2003 )
“This document presents no-till
(NT) farming as an ‘entry point’ to increasing farm productivity, and to
the broader agenda of sustainable rural development and sound environmental
management.
“It provides practical answers
for decision-makers, scientists, project developers, and practitioners, who
want to adapt NT farming to their own conditions. The
document presents, in a concise format, the most recent information on salient
NT agricultural systems, including economic aspects and impacts on the environment.
“Drawing on the Brazilian
experience, the document discusses the potential adaptation of NT systems
to other countries and continents, focusing on the challenges and opportunities
to develop NT farming in tropical conditions, particularly for small-scale
farming in
“Contents:
Acknowledgements
iii
Foreword
iv
Introduction
1
Sustainable Land Management,
and No-Till Systems 5
Key Features of No-Till Farming
19
Potential for Adoption of No-Till Agricultural Systems 29
A Road Map from Conventional to No-Till Farming
43
Conclusion – No-Till Farming and Sustainable
Rural Development 57
Annex 1.
The Voice of Farmers in
References
65-71. “
(From an advance notice by
the World Bank)
In UK, World Bank publications
can be obtained through: emedia@microinfo.co.uk
Website: http://www.microinfo.co.uk
FAO promotes this form of
good land husbandry under the name ‘Conservation Agriculture’. The FAO website is: http://www.fao.org/
.oOo.
HANDBOOK FOR
THE
FIELD ASSESSMENT OF LAND DEGRADATION
by
Michael A. Stocking and Niamh Murnaghan.
“With the increasing concern
over rural livelihoods and the food security of poor communities in developing
countries, it is vital that land quality is maintained.
Yet land degradation is widespread and is lowering the productive capacity
of the land in these countries. This practical handbook
presents simple, non-technical indicators for assessing land degradation in
the field. Based on the perspective of the farmer,
the methods selected lend meaning to real farming situations, helping the
field professional to understand not only the impact of degradation but also
the benefits to be gained from reversing it.
“The handbook shows how to
calculate indicators such as those of soil loss and explains the interpretation
of results and, in particular, how combinations of different indicators
can give conclusive evidence of the severity of land degradation. The focus of the book is on understanding the farmer’s
interaction with the land, and how environmental protection, food security
and the well-being of rural land users may be assured.
“With detailed figures, photographs,
worked examples and sample forms based on assessment techniques validated
by field professionals in Africa, Asia and Latin America, this will be an
essential training manual for field-workers in NGOs and in governmental and
educational institutions. It will also be of interest
to researchers and academics in development, environment and agriculture”.
(from the back cover).
.oOo.
THE PHYSIOLOGY OF TROPICAL
CROP PRODUCTION
by
G.R.Squire
“This book provides a concise
introduction to the principles of crop physiology in the tropics, and is
based on the work of a project funded by the UK Overseas Development Administration. Its focus is to examine the ways in which the physiological
processes of tropical crops are governed by the elements of the physical environment,
chiefly solar radiation, temperature, humidity, soil water and nutrients. Emphasis is placed on describing research from studies
in the field, with examples drawn from a wide range of crops including pearl
millet, groundnut, maize, sorghum, rice, cassava,
grain legumes, oil-palm and tea. The book will provide
an excellent text for students in both developed and developing countries
who are studying tropical agronomy or plant science and who already have
a basic knowledge of plant physiology”.
(from the back cover).
.oOo.
NEW WEBSITE
FOR DIRECT SOWING,
MULCH-BASED SYSTEMS AND
CONSERVATION AGRICULTURE
The DMC Web Site
is at : http://agroecologie.cirad.fr/dmc/index.php?lang=eng&menu=somm
“The DMC (Direct Sowing,
Mulch-based systems and Conservation Agriculture) is a Global Program that
aims to strengthen the capacity of key stakeholders to develop suitable DMC
systems, and to accelerate their widespread adoption. It
is oriented to development or research-&-development projects/initiatives.
The Web Site provides information
on the background of the Program, objectives and activities. As a first step, we are preparing an inventory of DMC
initiatives. Based on the inventory, we will select
some of them that are likely to be reference for others and (with the agreement
of the institutions), case studies will be carried out. The
results will be made available through the DMC Web Site and publications,
and will also be the basis for workshops and study tours.
If you work on a development
of a r&d project of DMC, we ask you for your
collaboration, filling in the form and sending it to us.
If you know other initiatives, please send this meassage to as many people as possible. Filling in the form will not require too much of your
time, but your experience may be very useful for other colleagues.
If you have any doubts or
suggestions [and/or need a copy of the form], please do not hesitate to
contact us”:
Fatima Ribeiro,
Facilitator DMC Global Program.
ribeiro@cirad.fr
(from an e-mail to many addressees,
12.07.02).
.oOo.
TWO SORTS OF ECONOMICS
“One
must never forget that though pure economics is a matter of logic, applied
economics is a matter of informed common sense”.
R.J.Hammond, 1970, in ‘Environmental Geology’.
MISC. BITS
THE AFRICAN QUEEN
by D.Cahill
The river tide surged onward,
Inexorable and blue;
The brave ship chugged against
it,
Empowered by its screw.
People standing at the prow
Saw how it cleaved the tide,
Said “Look how we’re making
progress:
We’ll be home by even-tide”.
But a young lad sitting quietly
With his mother on the deck,
Watching trees upon the bank,
Called out: “Oh, no we won’t,
by heck !
D’you know we’re going
backwards?
The current’s stronger than
this craft”.
His mother hushed him quickly,
And their fellow passengers
laughed.
Until an older voice then
said:
“You know, the lad is right
!
We’re not only going backwards
But the Waterfall’s in sight
!”.
Now call the river ‘population
growth’,
It’s tide ‘land subdivision’,
The little ship called ‘Progress’,
It’s engine donor-driven.
Its crew may think it’s reaching
port,
With future prospects fair.
But they’re steadily going
backwards
- and the Waterfall is there
!
Now the moral of this story
is –
for which the young lad thank
–
When you’re assessing progress
FOR GOD’S SAKE WATCH THE BANK
!
ROCKING THE BOAT
Look at THINK-PIC 2 at the
back of the previous issue of ENABLE - no. 14.
This photo is a real-life
illustration of the point made: that the difference
between biomass yield before and after soil erosion (assuming all other circumstances
are the same in each of the two growing seasons) is related to the difference
in the biological x physical x hydric x chemical
conditions of the rooting environments before and after the event,
and not as directly to the amount of soil loss.
TFS
Iracemápolis-SP. TFS
ON THE SCIENTIFIC METHOD
“Well, being uncertain, the next thing is to look for evidence,
and the scientific method is to begin with trials. But
another way and a very important one that should not be neglected and that
is very vital is to put together ideas to try to enforce a logical consistency
among the various things that you know. It is a very
valuable thing to try to connect this, what you know, with that, that you know, and to try to find out if they are consistent. And the more activity in the direction of trying to put
together ideas of different directions, the better it is.
After
we look for the evidence we have to judge the evidence. There
are the usual rules about judging the evidence; it’s
not right to pick only what you like, but to take all of the evidence, to
try to maintain some objectivity about the thing – enough to keep the thing
going – not to ultimately depend on authority. Authority
may be a hint as to what the truth is, but is not the source of information. As long as it’s possible, we should disregard authority
whenever the observations disagree with it”. Richard
P.Feynman, 1964.
.oOo.
VERTICAL ‘LATERAL THINKING’
Formerly I used this photo
(original = a colour-transparency) to emphasise how shallow the topsoil is
and to stress the need for ‘soil conservation’, since soil is slow to form
only by weathering of the bedrock..
But I have also upended my
thinking about it, seeing it now also as an example of the process of soil
being formed from the top downwards by biotic processes.
This has consequences for
deciding how best to look after it.
.oOo.
CONTRIBUTIONS TO ‘ENABLE’
The Editor welcomes from readers
articles, letters, reviews comments etc. concerning land husbandry, to add
to – or dilute – the evident bias in the Newsletter !
PUBLICATION DETAILS: ”ENABLE” IS THE NEWSLETTER OF
THE ASSOCIATION FOR BETTER LAND HUSBANDRY, U.K.REGD. CHARITY 1025653. AUTHORS ARE RESPONSIBLE FOR THE VIEWS EXPRESSED IN THEIR
PAPERS WHICH ARE NOT NECESSARILY THOSE OF THE ASSOCIATION.
THE NEWSLETTER FUNCTIONS AS A FORUM FOR NEWS AND DISCUSSION OF ISSUES
RELATED TO PROMOTING BETTER LAND HUSBANDRY, AND WELCOMES CONTRIBUTIONS ESPECIALLY
FROM ABLH MEMBERS AND ALSO FROM OTHER INTERESTED PERSONS.
CONTRIBUTIONS SHOULD BE SUBMITTED – PREFERABLY BY E-MAIL, OR ON DISKETTE
IN MS-WORD FORMAT – TO THE EDITOR: FRANCIS SHAXSON,
GREENSBRIDGE, WINTERBORNE
[1] CRITCHLEY, W.R.S., 2000. ‘Groundtruthing : New Perspectives
on soil erosion and conservation in the tropics’.Ph.D
thesis.
[2] Shaxson, T.F., 1981. ‘Developing
Concepts of Land Husbandry for the Tropics’, in: Soil Conservation – Problems
and Prospects (R.P.C. Morgan, ed.).
ISBN 0-471-27882-3. 351-362.