AGRICULTURE
Organic agriculture
To mitigate climate change :
Dr N Yogaratnam
There is dramatic evidence that various Greenhouse Gases are
responsible for global warming and climate change. It is also clear that
the most important solution to global warming is the dramatic reduction
of fossil fuel use, and that other strategies shall not be an excuse to
continue with business as usual
The role of agriculture
A haystack set for composting |
Agriculture is a major contributor to emissions of methane (CH4),
nitrous oxide (N2O), and carbon dioxide (CO2). On a global scale,
agricultural land use in the 1990s has been responsible for
approximately 15 percent of all GHG emissions.
One third of all carbon dioxide emissions come from changes in land
use (forest clearing, shifting cultivation and intensification of
agriculture). Around two thirds of methane and most of nitrous oxide
emissions originate from agriculture.
At the same time, agriculture offers options to reduce GHG
significantly. One is to reduce emissions and, thereby, to minimise the
production of atmospheric CO2, CH4 and N2O. Agriculture shares this
emission reduction potential with industry and other sectors. The second
option consists in systematically sequestering carbon dioxide in soils
and in plant biomass. It is unique for all types of land use.
However, the potential contribution of the land use sector for
climate protection is limited. Although sinks in vegetation and soils
have a high potential to mitigate increases of CO2 in the atmosphere,
they are not sufficient to compensate for heavy inputs from fossil fuel
burning. The long-term solution lies in a reduction of the use of fossil
fuel (developing alternatives to fossil fuel and reduce energy
consumption.
Yet the contribution from the land use sector could buy time during
which alternatives to fossil fuel can take affect.
But mainstream agriculture is moving in an opposite direction;
increasing releases of GHG from the green sector have made agriculture a
producer of global warming rather than a mitigating factor.
Emission reduction
Organic Agriculture can significantly reduce carbon dioxide
emissions. As a viable alternative to shifting cultivation, it offers
permanent cropping systems with sustained productivity.
For intensive agricultural systems, it uses significantly less fossil
fuel in comparison to conventional agriculture. This is mainly due to
the following factors,
* Soil fertility is maintained mainly through farm internal inputs
(organic manures, legume production and wide crop rotations),
The composting ingredients on display ANCL file photos |
* Energy-demanding synthetic fertilizers and plant protection agents
are rejected, and,
* External animal feeds - often with thousands of transportation
miles - are limited to a low level.
As a consequence, the organic variants have in most cases a more
favourable energy balance. Nevertheless there are reasons for organic
farmers to do more to further reduce their dependency on fossil fuel and
there are reasons to pay attention to the energy use on the food
distribution system.
In avoiding methane, Organic Agriculture has an important though not
always superior impact on reduction.
Through the promotion of aerobic micro-organisms and high biological
activity in soils, the oxidation of methane can be increased. Secondly,
changes in ruminant diet can reduce methane production considerably.
However, technology research on methane reduction in paddy fields -
an important source of methane production - is still in its infancy.
Nitrous oxides are mainly due to overdoses and losses on nitrogen.
These are effectively minimized in Organic Agriculture because:
* No synthetic nitrogen fertilizer is used, which clearly limits the
total nitrogen amount and reduces emissions caused during the energy
demanding process of fertilizer synthesis.
* Agricultural production in tight nutrient cycles aims to minimize
losses.
* Animal stocking rates are limited. These are linked to the
available land area and thus excessive production and application of
animal manure is avoided.
* Dairy diets are lower in protein and higher in fibre, resulting in
lower emission values.
Using biomass as a substitute for fossil fuel represents another
emission reduction option. Organic Agriculture is well positioned in
this sector.
It has the advantage that application of inorganic N-fertilizers are
avoided, which otherwise would cause significant emissions of N2O and
use a lot of energy.
Sequestration potential
Organic Agriculture has a particular sequestration potential as it
follows the key principle of tight nutrient and energy cycles through
organic matter management in soils.
This is achieved through improved practices in cropland management
and in agroforestry.
Various long-term trials provide evidence that the regular addition
of organic materials to the soil is the only way to maintain or even
increase soil organic carbon (SOC).
The systematic development and application of organic fertilization
technologies has been the domain of Organic Agriculture for many decades
and outstanding results have been achieved so far. Key issues of
technology development have been:
* To optimise the quantity and application of organic manure. A close
integration of crop production and animal husbandry and the systematic
recycling of organic waste are basic elements.
* To improve organic waste processing techniques to obtain high
quality manure. Through composting of animal and plant residues losses
in the humification process are minimized and a higher proportion of the
solid humus fraction is achieved.
The composting process |
Long and diversified crop rotations and legume cropping are further
characteristics of Organic Agriculture that help to increase SOC.
In conventional agriculture, conservation tillage is largely promoted
as a measure to sequester carbon dioxide.
This technology combines minimum tillage with organic covers,
herbicides and often herbicide resistant GMO crops.
Both of the last two are prohibited in organic agriculture. Latest
research results revealed that gains in soil organic carbon have been
overestimated and are partly or completely offset by increased N2O
emissions.
Thus it can be concluded that minimum tillage combined with mineral
fertilizer application compares less well with Organic Agriculture if
the focus is on GHGs in general rather than considering carbon
sequestration alone. The task of Organic Agriculture will be to
integrate conservation tillage in a way that negative effects are
avoided.
Agroforesty - a management system that integrates trees in the
agricultural landscape - is another technology that is systematically
applied in Organic Agriculture. It is a feasible method to succeed
shifting cultivation systems but also to improve and add value to low
productive cropland.
Agroforestry holds the biggest potential of agricultural carbon
sequestration in tropical countries.
It is worth noting that the sequestration of carbon, i.e., an
increase of soil organic matter is also leading to more fertile soils,
better water retention capacity and reduced nutrient leakage.
A strategy for climate protection
Several the measures mentioned above are often referred to as
"recommended management practices." Any type of agriculture could use
them, but Organic Agriculture is unique in the sense that it offers a
strategy that systematically integrates most of them in a farming
system.
This strategy comprises compulsory standards superior in their impact
on climate protection. It also comprises a well functioning mechanism of
inspection and certification that guarantees compliance of the organic
principles and standards. The strictness of the system has made Organic
Agriculture accountable and a generator for innovation.
Waste into wealth
The basic requirement in organic farming is to enrich the biomass to
increase the nutrient value from 0.3 to 0.4 per cent to one to two per
cent. There are technologies now available to enrich the biomass,
including Farm Yard Manure three to four times if properly composted.
Several million tonnes of agricultural waste is available in the
country every year, but most if it is not properly used. We must convert
our 'filth into wealth' by mobilizing all the biomass in rural and urban
areas into bioenergy to supply required nutrients to our starved soil
and fuel to farmers.
Several options are available to increase the biomass to meet the
requirement of minimum plant nutrients. A portion of the cropping land
could be made available for growing green manure along with the regular
crop. This green manure can be harvested at the right time and
composted, stored and used in the following growing season.
The land lost in growing green manure would be compensated by
increased yield in the remaining area and year after year productivity
would remain the same even if it does not increase. Our social forestry
can be planned to augment our biomass requirement, in addition to the
fodder and fuel now being supplied.
Compost manure |
To make several hectares of our starved land productive, adequate
organic amendments have to be provided. This requires not only enormous
quantities of biomass but also ingenuity and techniques to enrich it to
supply the required quantity of nutrients to the crops. Even if the
present production of around 13 million tonnes of fertilizers is
increased to around 20 million tonnes by the turn of the century, it
might not be available at affordable prices to the farmers.
Unless plant nutrients are supplemented adequately with compost and /
or bio-fertilizers, sustainability of production cannot be achieved.
Therefore, adequate attention to enriching our soils with as much
organic matter as possible is unavoidable.
The thrust and focus on making the thirsty soils sustainable with the
maintenance of soil-organic matter and thus supply soil nutrients
adequately under tropical conditions, has, however, been elusive.
This must be regarded as a major problem of equal importance as that
of soil-moisture availability, and should receive top priority.
Organic carbon content of soil
It is said that most of the organic matter mineralizes four times
faster under tropical conditions than in temperate conditions and unless
supplemented in every cropping season, the organic carbon content of the
soil decreases fast. Most of our soils under the dry-farming system
contains less than 0.5 per cent organic carbon. Unless it is raised to
0.9 per cent or one per cent, productivity of the soil cannot be
optimized.
Innovations improve economy
Unless the soil is kept covered by some means after harvesting the
crop, the top-soil continues to get eroded and productivity decreases.
The questions addressed now are, what are the alternatives to prevent
the colossal loss of soil nutrients and how to improve soil-fertility
for sustainable crop production?
Several new innovations are available to the farmer, including a
change of varieties, maintenance of plant population, seed treatment,
recommended dose of fertilizer and farmyard manure , plant protection
measures, etc. In addition to these interventions, the introduction of
new implements and improved breeds of poultry, sheep, piggery and fodder
crop are known.
Our soils have been totally deprived of crop residues. The entire
crop is harvested and carried out of the field. The straw and stumps are
used as fodder and fuel, respectively. Whatever crop residues are left
are eaten by termites in most cases.
Some of the experiments carried out under dry-farming conditions have
proved the possibility of increasing productivity of the soil by
incorporating in it the entire crop residues, at least once in two or
three years, taking only the grains. This should be done at a time where
there is enough moisture in the soil, which should then be covered
completely.
Knowledge on composting
It is doubtful as to how many of our farmers know the value of proper
composting, their preservation and application at the right time and
right place. Most of our farmers make a compost pit, which is filled
every day little by little for over a period of six to nine months. When
it rains, it is filled with water, the bottom of the compost becomes
cake-like, while the top portion is not compressed well and is
semi-dried.
When applied to the fields, it is eaten away by the termites. Most of
our composts and farmyard manure have less than 0.5 percent of nitrogen.
If all the crop residues and farmyard manure are properly composted
on a flat surface with vats of four to five feet width, four to five
feet height and of convenient length, the compost can be enriched to
yield one to two per cent nitrogen and other essential micronutrients.
It has to be done in a day, keeping all the materials ready,
spreading layer after layer with crop residues and farmyard manure,
maintaining at least 60 per cent of the moisture and filling the entire
vat at one time. It produces a great deal of heat in the centre.
Therefore, at least once in a month this has to be turned over
atleast two to three times, every time adding the required moisture if
it is dried.
This process has to be continued for about four to five months. Such
compost will have all the ingredients rich enough to provide proper
nourishment to the plant.
Most of the FYM or composts taken to the field are either heaped or
spread during lean months, much before the planting time. This is a
colossal waste, as the compost or the manure loses all its utility
unless it is incorporated when there is the right type of moisture in
the soil.
The best way to use FYM or compost is in furrows at the time of
sowing. Although it is labour-intensive and time-consuming, the reward
will be more than expected.
Plantation agriculture
Organic farming is best suited under perennial plantation crops which
provide proper shade and cover to the soil, keeping the microbial
activity in the soil constant.
However, the cover of the crop itself may not be enough to maintain
the soil microbial activity. Unless there is enough organic matter,
neither would the applied fertilizer uptake the maximum, nor the
continuity of the microbial activity which is suppressed by chemical
fertilizers.
Therefore, there is a need to maintain a minimum amount of organic
matter through periodical supply. There are instances where higher
levels of production of plantation crops like tea, rubber, coffee,
cardamom and pepper have been obtained through nutrient ply from organic
sources alone.
Incidentally, there is great scope for exporting organically grown
tea, coffee, cardamom and pepper. In addition to improving our soil
productivity through organic farming, we can look forward to greater
demands for our organically grown agricultural produces.
Organic agriculture could contribute significantly to reduce GHG
releases and to sequester carbon in soils and biomass. Secondly, there
is sufficient evidence that Organic Agriculture is superior to
mainstream agriculture.
This is even more important as the capacity of organic agriculture to
contribute to the mitigation of climate change can be considered as an
ancillary benefit to its primary goal of sustainable land use.
This primary goal is achieved by gains in soil productivity,
consecutive food security, biodiversity conservation and many other
benefits.
As opposed to the focus of conservation agriculture on a single
technology, organic agriculture follows a site-specific and systematic
approach that includes a comprehensive set of integrated technologies,
because of the inspection and certification systems required in organic.
Strategy for climate protection
In order to include organic agriculture as a strategy for climate
protection, two main avenues should be persued;
1. Lobbying initiatives in both public and private sector agriculture
and plantation related agencies at national level to make organic
Agriculture as explicit part of the agencies GHG inventories; this is an
important step to ensure that organic agriculture as a strategy can
participate in a joint implement mechanism with public- private sector
partnership.
2. A broad initiative, by which organic agriculture projects in
different departments and agencies tap into and utilize financial
support from various existing carbon funds. Such an initiative can
develop suitable instruments for the assessment of carbon sequestration
and for the monitoring of project implementation. |