Nava Kekulam Method of Paddy Cultivation <

Nava Kekulam Method of Paddy Cultivation

G.K. Upawansa
Eco Conservation Organization, Hyneford, Nawalapitiya, Sri Lanka

Dry sowing of paddy in aswedumised fields is known as kekulama in Sri Lanka. When dry sowing is done in highland under shifting cultivation it is called vee hena.

In the past for kekulama the fields were ploughed with a new country plough first to get a somewhat deeper tillage then kept for a few days and dry seeds were sown with the anticipation of rains soon. Having sown seeds again, farmers ploughed the land with an old worn out plough to cover the seeds. When the fields are wet the same operations are done but sprouted seeds are sown instead.

In some paddy tracts and under some tanks certain sections were sown to kekulama and then when the tanks were full with rains other sections were sown having done the normal wetland land preparation which includes:

  1. first ploughing;
  2. cleaning bunds;
  3. re-plastering bunds;
  4. second ploughing;
  5. puddling;
  6. leveling;
  7. preparing a shallow channel system to drain the fields; and
  8. sowing sprouted seeds.

This combination of above cultural practices apparently has being adopted for centuries with the aim of controlling weeds. Weed menace is unavoidable because of depletion of soil fertility mainly caused by soil erosion inherent to wetland paddy cultivation. In depleted soil weeds grow much more vigorously than paddy because the fertility level and other physical conditions are ideal for weeds. If and when other means of weed management are available most of the said practices can be got rid of. One of the main attempts of nava kekulama is to manage weeds with other innovations not requiring more water than for an ordinary highland crop.

Main features of nava kekulama are as follows:

  1. Not clearing and re-plastering bunds:
    1. This was intended to attract and harbor insect predators to bring about biological control of insect pests and was very successful. When weedy bunds were maintained for three to four seasons more and mere benevolent incidences appeared. Those are given below.
    2. With weedy bunds more anthills and more ants inhabit the bunds. The ants during harvest period bring weed seeds of the field to anthills thus reducing the amount of germinating weed seeds in the fields.
    3. Weedy bunds are not normally subjected to making holes by land crabs.
    4. Animals such as iguana, mongoose and rat snakes inhabit weedy places and devour rats, crabs etc preventing the damage to the crop.
    5. Leaving the bunds unattended for a few seasons causes a gradually change of the vegetation in which yams and rhizomes are disappearing. At the same time the earthworm population too get reduced. When there are no yams, rhizomes and earthworms the wild boars are not damaging the bunds.
    6. Damages to bunds due to flash floods during the cultivating season are not happening when the bunds are strong due to weeds.
    7. The fauna and flora disappeared due to continuous cultivation and cleaning of bunds reappear in the bunds.
    8. Cost of production is remarkably brought down owing to reduced labour, not using or minimal use of agrochemical including chemical fertilizer and natural crop protection.

    From the above list of benefits to farmers it is clear that keeping weedy bunds is the total crop protection measure of paddy including some of natural disasters.

  2. Minimal or zero tillage:
    1. Puddling of soil avoided in nava kekulama to prevent soil erosion, surfacing of weed seed that would not germinated if kept burried, dispersing weed seeds over entire field surface and and to keepa cloddy surface favoured by the plants. Other advantages are as follows:
    2. Main objective of minimal or zero tillage is to keep the fertile soil with its stratified nature of microbes intact so that the chemical, physical and biological properties of top few millimeters of soil is ideal for the germinating seedlings. Besides this
    3. It reduces the cost of preparatory tillage,
    4. Reduces the ware and tare of machinery,
    5. Minimizes the soil erosion,
    6. Reduces the time of operation,
    7. >Less water consumption and
    8. Also reduction of weed population.

    Observations in zero tillage shows patchy good results and expect in near future to give more details about it. Our organization conduct experiments on zero tillage in three different methods including Fukoka method modified to suit tropical conditions.

  3. Mulching the fields soon after sowing: This is the most striking innovation which has not been given any thought by thousands of scientists for many decades or even centuries.
    1. By mulching alone a yield increase of five to eight bushels or 100 to 160 Kg. per acre per season has been observed in Sri Lanka. The yield increase of the crop depends on the initial fertility level of the soil.
    2. Mulch completely check the soil erosion. It is the main factor contributing to soil fertility.
    3. Adds organic matter substantially without much effort.
    4. Enhances and increases the soil microbes and particularly the earthworm population. Earthworms not only make the soil fertile but also pulverize the soil so that it paves way for zero tillage.
    5. Improves organic matter content of the soil season after season and as a result improves the water holding capacity enabling the crop to withstand short water stresses.
    6. When a mulch applied to a thickness of about 7 to 8 cm (3 inches), complete weed control can be expected.
    7. Picking the sawn seeds by birds is prevented.
    8. Though not scientifically proved, it appears that wet straw fixes nitrogen as in the rice roots. With a material like straw with very high C/N ratio when applied as mulch, yellowing of the crop due to nitrogen starvation is expected. This condition does not occur with nava kekulama but vigorous green growth observed for about one month.

    Those who are not experienced with kekulama might wonder whether the paddy seeds would germinate and immerge through the thick mulch. There is nothing to be feared. The seeds germinate almost 100 %.

  4. Water management: In nava kekulama all attempts in water management is to keep the soil at field capacity and avoid inundated situation except at the panicle initiation stage which falls around two months before the expected harvesting. This way of water management results in an extensive root system growth.

Advantages and Potential of Nava Kekulam Method of Paddy Cultivation
Kekulama: a way of exploiting the potential of paddy seed and plant

  1. Pre-sowing germination

    A practice in certain parts of Sri Lanka is to germinate the seed paddy, dry and store for a few weeks before sawing. Research into this practice shows that the radical is protected by a layer of cells not allowing to dry as one sees. Once the sufficient moisture is available this layer ruptures and begins growing. This potential is utilized in four ways:

    1. If a water shortage occurs soon after germination the seeds remain dormant until sufficient moisture is available for growth. The dormant period can even be more than four weeks under favourable conditions. The dormant period gets added up to the normal age of the crop. For instance if age of the crop is four months and the dormant period is three weeks the crop would take three more weeks to ripe. This is an advantage because the crop can be harvested during dry period following rains. When the rains are delayed normally the rainy season get extended and harvest falls within the rainy period if age of the crop remains same.
    2. For germination it requires minimum of four days. When germinated seeds are sawn just before rains in anticipation of rains or with the rains the crop comes up four days earlier than when sawn normally. It is important under scanty rainfall conditions.
    3. When flood occurs at the time of sowing the seeds can be dried and stored till the weather is suitable for sowing.
    4. It is a reliable germination test.
  2. Primordial protection

    In some years a drought occurs when the paddy crop is around four to five weeks old. Then the shoot dries but the under ground stem and some roots with primodia intact remains hardened and dormant or hibernated condition As in the case of germinated dried seeds with rains or when there is sufficient water is available plant begins to grow. Dormant period gets added up to the age of the crop.

    I and II above brings forward a strong case to change cultural practices now adopted in order to save water and bring about a natural crop protection measure.

  3. Paddy straw mulch has a weedicide effect. Mulching the soil, soon after sowing not only manage the weeds but also check the erosion completely.
  4. It is known that there are a few spirillums in the roots of paddy plant fixing atmospheric nitrogen. Same effect is observed when the mulched straw is kept moist. In fact paddy seedlings grow vigorously for about a month without any nitrogenous fertilizer with wet mulch. This is a paradoxical situation. Normally with material of wide C/N ratio when used as mulch the crop tends to yellow due to nitrogen starvation.
  5. The most important character of the seed is the ability of the radical to immerge through a grass mulch of three inches. Though most seeds cannot germinate with a mulch of this thickness, paddy seedlings immerge out in six days as in the case of normal sowing. The importance of the mulch does not need any description as it is well known in farming.

All these potentialities are being made use of in kekulam method of rice cultivation to bring down the cost of production, enhance normal eco system and sustain yields by improving the soil fertility.

Water economy

Though the precipitation, intensity of rainfall and spread over months vary annually, in the long run annual average rainfall remains constant. Because of this factor maximum amount of water available for storage with reservoirs and tanks in Sri Lanka has a limit. There is no purpose of going beyond this storage limit as there would not be water to fill any more tanks and reservoirs. A good example is the reservoir at Lunugamvehera which hardly fills in any year with the average annual rainfall. Then further expansion of farming or extent of farming land depends on economizing water or improving water (or irrigation) efficiency. The simplest and most efficient ways of economizing water are offered by the kekulam method of paddy cultivation. They are as follows:

  1. If seeds are to be sown dry no water at all is needed. The amount of water required for land preparation under wetland condition is approximately three and half acre-feet of water or fifty percent of total water requirement of the paddy crop. Paddy field bunds are cleaned and plastered to retain water. The fields are puddle to level the field so that a uniform depth of water can be maintained in the entire field. This practice of maintaining inundated condition is adopted as a weed control measure. Due to seepage average water requirement of a paddy crop rises resulting in very low water (irrigation) efficiency.
  2. Land preparation is done either wet condition or dry condition the fields are not inundated when kekulam method is adopted as the weeds are managed by other cultural practices like mulching.
  3. Mulching the crop lowers the evaporation from surface thus increasing the irrigation interval.
  4. It has been observed that crops cultivated to kekulam method reach maturity twelve days earlier than conventionally grown crops. Reasons for this phenomenon is not clear but it can be due to non use of weedicides which retards the growth rate.
  5. Sowing pregerminated and dried seeds can shorten the maturity by another four days. Reaching maturity early is very critical because of water shortages occurring often at the end of the season. 04 and 05 together is a guarantee against crop failure due to water shortage at the end of the season.
  6. Kekulam method improves the organic matter content of the soil over time. As organic matter imbibes large quantities of water the crop can withstand a reasonably long dry period on one hand and increase the irrigation interval on the other.

Practical experience shows that nava kekulam method saves forty to sixty percent of water needed during the two seasons of a year. This indicates that the acreage under paddy cultivation in Sri Lanka can be doubled when nava kekulam method is adopted. Instead of constructing new dams and tanks to increase the extent of land under paddy, popularizing nava kekulam method among farmers will be much more cost effective and also ecologically favorable.

Ecological and environmental impact of nava kekulam:

  1. In Sri Lanka as in all Asian countries wetland paddy cultivation is the common practice. In newly cultivated fields no vegetation other than paddy plants are seen. It is complete devastation of the marshland vegetation. Along with the vegetation all animals and insects except those animals, insects and other organisms live on paddy disappear. The repercussion of this devastation is ecologically intolerable and unacceptable. The insect pest damage to the crop and subsequent insecticide application is inevitable. In nava kekulam method the bunds are not cleaned or re-plastered in order to establish the natural vegetation. Very few weeds that grow with straw mulched paddy crop too are not removed. The bunds account ten to twenty percent of the total extent of the paddy fields and retaining natural vegetation on the bunds establishes the insect pest predator balance thus avoiding the use of either chemical or organic pesticides application. Further with time plants and insects inhabited earlier but disappeared due to continuous cultivation begins reappearing. As such the easiest, an inexpensive, effortless and most effective way of rehabilitating marshland eco system in paddy fields is the adoption of nava kekulam method of paddy cultivation.
  2. When weeds, stubble and roots get submerged under the normal wetland paddy field preparation methane gas is formed and liberated to the atmosphere. As paddy is treated as a highland crop in nava kekulam no more water than field capacity is maintained methane emission to the atmosphere is eliminated or minimized to a very great extent.
  3. Non-use of pesticides and minimal or non use of chemical fertilizer prevents atmospheric pollution and ecological damages as well as ground water pollution.
  4. Minimal or zero tillage adopted in nava kekulam and mulching the land completely controls the soil erosion and enhances the soil life.

Social and economic advantages of nava kekulam

The author, G.K. Upawansa
The author, G.K. Upawansa
Dekinda, Nawalapitiya
Sri Lanka
Tel. +94 71-819-4879

  1. Reduced labour and inputs reduces the cost of production
  2. Improvement of family income due to high yields, escalate the quality of life of farm families.
  3. Poison-free and healthy food reduces health hazards on one hand improves the health of family members on the other.
  4. Many farmers in Sri Lanka commit suicide owing to indebtedness caused by borrowing for farming. As no borrowing is necessary in nava kekulam due to low labour requirement and external inputs there is no need for borrowing and therefore suicide rate should come down.
  5. Price of paddy is at the lowest at the time of harvest. Still the farmers sell their produce at a low price in order to pay up the loans. When loans are not raised with kekulam produce can be stored till the prices are good.
  6. The rituals and ceremonies involved in kekulam enhances the social integrity and morality of the society.
  7. Mind fullness about ecology and environment can be a great assert for local conservation.
  8. Incorporation of indigenous concepts and practices fosters the unity of the society and quickens the favourable social changes.
  9. Foreign exchange spent on agrochemicals can be saved.