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ILEIA Newsletter 13 nº 3
ILEIA Newsletter • 13 nº 3 • October 1997
New Kekulam rice cultivation: a practical and scientific ecological approach
G.K. Upawansa
Paddy farmers in Sri Lanka face serious problems. In conventional rice
cultivation inputs are expensive and yields are low. Although new improved rice
varieties have a potential return of over three tons per acre, in reality they
often yield less than one and half tons. This production level reflects a history
of indiscriminate agro chemical application and the effects of soil erosion
caused by inappropriate land preparation techniques. This article explores a
way of mitigating the potentially disastrous consequences of this process.
After a detailed study of the problems associated with conventional rice cultivation,
the Eco-Conservation Organisation (ECO) developed the new Kekulam method of
rice growing.
'Kekulam' means the sowing of paddy seed that has not been pre-germinated and
the new approach seeks to combine farmers' experiences with concepts drawn from
modern farming such as mulching wetland rice, using weeds as crop protection
agents, and carefully avoiding normal weed control measures and agro-chemicals.
Mulch in the new Kekulam system reduces erosion to near zero and has the added
benefit of improving soil properties and reducing both the incidence of weeds
and the amount of tillage required. Farmers, supported by ECO, found that the
system was 75% cheaper, more time efficient than conventional rice cultivation
and achieved water savings of up to 50%. This helped to offset the negative
effects of climatic irregularities. In ecological terms the system leads to
a substantial improvement in fauna and flora bio-diversity. In the earliest
stages of cultivation, rice grown by the new Kekulam method requires no pest
or disease management measures and whilst yields may be 10% less than conventionally
cultivated rice in the first one or two seasons, they subsequently rise to a
similar level.
Weeds on bundsIn conventional rice cultivation, weeds are normally removed from bunds and
thrown into the fields. In Kekulam cultivation, however, weeds are left on the
bunds to harbour predators. Whilst there may be some harmful insects amongst
these predators, their numbers are relatively small and can be kept under control.
Weeds that grow on bunds are slashed and laid on the bunds when they become
taller than the rice crop itself.
Not puddling but mulchingIn Kekulam cultivation, the soil is loosened with a country plough, a mommoty
(flat-bladed hoe) or a tractor-drawn tyne cultivator. Ploughing and other forms
of soil turning are avoided. A rotovator can be used if no tyne cultivator is
available but should never be used to cultivate below a depth of five centimetres.
Kekulam cultivation requires a cloddy soil and not the fine surface usually
associated with conventional rice cultivation. If rains are expected within
a few days of sowing, mommoties are used to construct shallow drains to carry
away excess water. This is all the land preparation required.
Experience has shown that rice varieties that mature within four or more months
are the most suitable for Kekulam cultivation. Seed is broadcast on dry land
if rain has fallen or the land is wet from irrigation. Sprouted seeds are sown
broadcast. Once the field has been sown, it is covered with a mulch made either
from rice straw gathered the previous season or, if this is not available, with
green leaves, dried grass or branches and twigs. It is not necessary to apply
fertiliser if the fertility level of the land has been built up to an appropriate
level.
A manure-fertiliser-neem mixtureOnly very small amounts of nitrogen fertiliser are applied. A manure-fertiliser-neem
mixture provides the basis for soil fertility management. It can be prepared
in the following way. Powder 1-2 kg neem seeds and add them to 7 kg urea. Powder
this mixture again, mixing it well with at least 50 kg of well-rotted, fine
compost. Whenever possible, use more than 50 kg of compost. The mixture of neem
seeds, urea and compost should be gathered into a heap, covered with polythene
or sacks, and kept for no longer than 12 hours before being spread on the fields.
Preferably the mixture should be made in the morning and applied at sunset,
thus allowing the insect repellent and manuring properties of the neem seed
to be used to full advantage.
The manure-fertiliser-neem mixture should be applied 10 to 12 days after the
seedlings emerge and a second application should be made 10 days later. Before
any subsequent application is made, the crop should be observed carefully. If
there are yellow leaves indicating nitrogen deficiency, a third application
should be made fifteen days later. Normally a fourth application is only necessary
when soils are very infertile or when varieties that take longer to mature are
grown. The number of fertiliser applications needed decrease when the Kekulam
system has been in use for several seasons.
Effective micro-organisms (EM)Direct feeding to soil microbes rather than the rice itself will fix sufficient
nitrogen and make other essential nutrients available once microbes are established.
In Sri Lanka experience has shown that it is possible to bring the soil into
balance again within four to five seasons by using composts and neem seeds.
In infertile soils, the extraction of soil nitrogen by microbes decomposing
mulch and other organic matter causes seedlings to yellow in the early stages
of growth. An EM (Effective Micro-organism) solution or home-made liquid manure
(see Box) can be applied to overcome adverse effects and retarded crop growth.
It can also be applied when a thicker than normal layer of mulch is being used.
The EM solution is a combination of different beneficial and coexisting soil
micro-organisms and was developed in Japan by Professor Higa. It is currently
being used in many countries.
No weedingIn Kekulam cultivation, mulch is used to keep the weed population to a minimum
and it becomes unnecessary to remove the few weeds that do appear because these
will act as host plants to predators. The weeds of the Echinochloa species,
however, must be removed and this can be done by hand because of the small numbers
involved. There are two or three varieties of weeds - members of the grass family
- that germinate with the rice and absorb nutrients faster than the rice plant
itself. Kekulam farmers sow rice at higher densities than in conventional cultivation
in order to smother weeds. The mulch, the manure-fertiliser-neem seed mixture
and a high seed density keep weed populations at a level that favours bio-diversity
in both fauna and flora.
Home-made liquid manure
Liquid manure acts not only as a manure but also as a foliar spray, mild fungicide
and mild insecticide. It has the properties of plant-growth hormones and enhances
soil life. In addition to all these effects it appears that crops treated with
this liquid manure also develop resistance to viral diseases. As a nutrient
source the liquid manure is complete and balances macro, micro and organic compounds.
It can also be used as a catalyst to promote growth. When used regularly in
sufficient quantities no other manures are required. The use of liquid manure
is a way of maximising the utilisation of available nutrients. Crops respond
well to liquid manure even on soils poisoned and inactivated by excessive use
or agrochemicals. When applied to starved crops, the visual effect of application
is clear within 24 hours.
Preparation
To prepare the liquid manure, sheep, goat, pig or cattle dung should be mixed
with water and fresh leaves of the Gliricidia or any leguminous trees. An equivalent
to 10% of the wet weight of the dung required should be added to the mixure.
The fresh dung should be mixed with water in a tank or a barrel and the fresh
leaves dipped in the dung mixture. The leaves selected ought to be those that
dissolve when dipped. Leguminous leaves are preferred because of their high
nitrogen content.
In Sri Lanka the best species were found to be 'keppitiya' (Croton lactifer)
and 'hinguru' (Lantana camara). The mixture should be churned daily. After about
eight days a pungent odour will develop so it is better to keep the tank or
barrel well away from dwellings. The vessel should also be covered to avoid
mosquito breeding. Gas bubbles will appear as decomposition begins. After about
three weeks the manure is ready and a layer of foam appears on the surface of
the mixture.
Use
When using this manure add one volume of the concentrated liquid to 3 to 4 volumes
of water. High value crops are sprayed at a rate of about one litre per square
meter, depending on the crop and growth stage. The liquid manure can also be
applied to the soil. When paddy is being cultivated, the manure can be mixed
with the irrigation water. If the treatment is carried out weekly, excellent
results can be expected.
No pesticide applicationIn conventional agriculture, weeds, harmful insects and diseases are treated
as pests. In ecological farming and Kekulam cultivation, they are treated as
a natural resource. No chemical pesticides are used and plant-based pesticides
are only applied during the initial stages of conversion when harmful insects,
disease-causing organisms and pernicious weeds still dominate. Kekulam farmers
try to establish a balance between all organisms as quickly as possible by improving
bio-diversity and avoiding activities that might harm any form of visible or
invisible life. The proportion of harmful organisms can gradually be reduced
over time if there is a balanced natural supply of plant nutrients from organic
matter, host plants are provided for predators, and the diversity of soil microbes
is increased as a result of protective measures. Avoiding the use of excessively
nitrogenous fertiliser also helps reduce the incidence of pests and diseases.
Climate changes, variable weather and mistakes by farmers can cause an upsurge
of pests and disease. In such situations a kem (a traditional rite) which does
not damage the eco-system, is carried out. Sometimes a plant extract from neem
seed preparation or Derris scandence stems is used. Kekulam farmers, however,
never use chemical insecticide.
One might think that a Kekulam farm, surrounded by conventional, high-external-input
farms, would be vulnerable to diseases and pests. This is not the case. I have
personally observed two small beds on a conventional farm being cultivated using
Kekulam farming techniques: these beds remained free of pests and disease even
though the rest of the farm was affected.
MulchingKekulam cultivation had been practised in the past but, with the emphasis on
irrigated rice cultivation, its significance declined. The most significant
difference between the two systems is mulch and the way it is used. Mulching
allows straw to be recycled very simply. The mulch protects the soil from erosion
and improves its physical, chemical and biological properties. The effect of
mulch is something that has to be experienced: it cannot be explained. Improvements
to fertility exceed expectations probably because of the combined effect of
soil conservation, nutrient enrichment, enhancement of biological activities
and the improvement of moisture-retention capacity. Weed suppression also contributes
to yield improvement. Mulching increases the soil's moisture retention capacity
at the beginning of cultivation providing cover for seeds and helping to ensure
uniform germination.
In conventional rice cultivation intensive land preparation is an essential
factor: it keeps fields weed free and encourages a good plant stand. Perfect
levelling ensures a uniform depth of water which checks weed germination and
growth. In the Kekulam system, mulch helps keep weeds down to an optimum level,
encourages moisture retention without perfect levelling, and protects nutrients
from being leached out. The Kekulam farmer does not have to till his or her
fields so intensively and can keep manure and fertiliser use to the minimum.
Maximising water useAt the national level, using Kekulam cultivation can reduce the amount of irrigation
water required by as much as 50% - a great leap forward in improving irrigation
efficiency. At present farmers are often restricted to planting small areas
because there is not enough water in the reservoirs to allow them to cultivate
more extensively. Using the new Kekulam method it may sometimes be possible
to cultivate all the land available and still use only half the amount of water
normally required. At the moment cultivation takes place when there is sufficient
water in the reservoirs.
Quite often the season is delayed and this can lead to pest damage. These delays
can be avoided if the Kekulam method is used and water is saved. The increase
in the area available for potential cultivation can be of tremendous national
significance. A 25% extension can have the same effect as constructing reservoirs
with 25% of the capacity of those currently in use. The Kekulam method is particularly
important because often the number of suitable reservoir sites is limited and
water is always in short supply.
Lower inputs, savings in labour and reasonably high yields even with a limited
supply of water mean higher profits and demonstrate that the new Kekulam method
is not only viable but also economically sound, environmentally friendly and
gives sustainable yields. It is a valuable, alternative, cultivation method
and as such warrants further research and popularisation.
Upawansa, GK, ECO, 46, Jaya Mawatha, H.S. Watapuluwa, Kandy,
Sri Lanka
References
- Upawansa, GK, 1996. Ecological farming manual
- Upawansa, GK, 1996. Cosmovision and eco-sound practices. COMPAS report of
workshop held in Bolivia, April 1996. PO Box 64, 3830 AB Leusden, Netherlands. |