Chena Cultivation and its impact on Environment and Climate Change!

Most of the farmers in Sri Lanka remain ignorant about the impacts of climate change into their crops. However, changes in rainfall patterns, gradual changes in climate zones and many other factors, which are results of climate change, have been impacting the agricultural communities in Sri Lanka and in turn threatening the food security of the country.

Meanwhile, a number of farmers have shifted to modern methods from the traditional farming methods. Those who advocate modern farming techniques, claim that traditional chena (hena) cultivation methods have largely contributed to increased deforestation leading to global warming and threatened some of the species along with flora and fauna as seen here.

As the hunter gatherer period gradually declined humans started growing crops near to their habitats while keeping a very close connection with nature. Some of the earliest evidence of cultivation in Sri Lanka were in the form of oat (Avena sp.) and barley (Hordeum sp.) recorded at Horton plains, which dates to over seventeen thousand years. This indicated that climatic conditions in central parts of Sri Lanka, were favorable for the cultivation of oats and barley in those years. However, the conditions are vastly different at present. 

Mahāvaṃsa mentions that during reins of King Kavanthissa (BC 205- BC161), brothers of the same family had been maintaining chena to cultivate black gram (Vigna mungo). More details about this can be taken from here and here. Archived   

Chena cultivation is a form of land-based farming methods and among the oldest cultivation patterns in Sri Lanka, dating back to over 5000 years. Also known by some as slash-and-burn cultivation, some argue that this form of cultivation leads to forest destruction as it involves cutting down and burning of plants to create a nutrient-rich layer to accommodate the farming. 

Also, it is considered as a shifting method of agriculture, as Chenas don’t use the same piece of land repeatedly. Instead, after cultivating for a few seasons, farmers usually abandon that land to fallow, for its fertility to be restored naturally. During such times, farmers shift to another area to set up “Chenas”. This rotation of plots allows soil and forest to regenerate.

These farming methods were practiced extensively in the dry zone of Sri Lanka  with a close eye on nature. While rice is cultivated extensively in paddy fields, vegetables, greens, grains, and cereals were cultivated in “Chenas”

Let’s investigate different types of chena cultivation methods which have been practiced in Sri Lanka and some of the beliefs related to Chena farming. There are mainly four types of chena called, “Navadeli Hena”, “Ath Danduva Hena”, “Mukulan Hena” and “Hen Kanaththa”

“Navadeli hena” was usually carried out by clearing an untouched area, setting it on fire and cultivation immediately after. As the word ‘Navadeli’ literally translates to ‘fresh soot’, which can be found in abundance throughout the Navadeli Hena. As the cultivation area has not been utilized previously, “Navadeli hena” is a highly fertile method with a high yield of crop.

Sometimes certain rituals were also followed to select this area and large trees were avoided, ensuring the most suitable place for cultivation was selected. Instead, farmers built their cottages on the large trees overlooking the Chenas. Also, the farming communities preferred small areas for cultivation under this method, as it didn’t mean major destruction to forest and at the same time smaller crops could be easily managed.

Areas in which harmful animals used to hang out were also avoided as much as possible. Farmers used several tricks to get rid of the wild animals such as shouting and singing around the chena and knocking the ground with a big stick. The animals would pick up the vibration/sound originated from these methods and tend to stay away from the Chenas. Vibration techniques are carried out especially in the mind of reptiles like snakes who do not have eardrums but could up the vibrations through their inner ear structures, complete with cochlea. Farmers would then wait for several days for any animals to leave the area and would then set fire to the cleared land. 

Chena cultivation was carried out during specific periods of the year, mainly during ‘maha kanna’ season, usually from August to April. Keen consideration is placed on “Ak vassa”, which are seasonal rains accompanied with thundering, appearing after a drought season. This traditionally happened during early September; however, effects of climatic changes have meant that the farmers have to wait till about mid / end September for “Ak vassa”

“Navadali Hena” method used during traditional Chena Farmers meant that the current Chena would be abandoned after a while, for two or three seasons (‘kanna’) which meant that the forest began to regrow in the area. Subsequently, the land can be easily recycled due to receiving pollen, seeds, and nutrients from surrounding forest areas. 

After the plants reach around the length of an adult’s arm, the semi wilderness area gets cleared, set on fire, and prepared for cultivation again. This is called “ath danduva hena”. 

As mentioned earlier extreme care is taken in selecting the land for setting up Chenas. Areas with thick forest cover were avoided, always keeping an eye on nature, while at the same time, areas with light shrubs meant the clearance was easier.

Thorn and shrub forests which consist of small and medium size trees are called ‘mukalana’. Chena farming carried out in in these areas was called “mukalana hena”

Once the land becomes infertile after a few seasons, farmers will abandon it. At that point these Chenas were called “Henkanaththa”, and these were looked after by elder farmers, who were unable to visit other areas to look for new land to cultivate. 

Human population has increased by considerable proportions in the areas which were traditionally used for Chena farming over the last few decades in Sri Lanka.

To cater to growing demands and complex needs of the modern human, mass cultivation / modern agriculture has become dominant and food production has also increased to meet this increasing demand. This requires large land area for the cultivation and as a result destruction of forest is happening at a much larger rate at present.

The forest cover of Sri Lanka in 2019 was reported to be 16.5 percent, down from 29.7 percent in 2017, due to a variety of reasons, including that for different types of cultivation.

When forests are cut down, stored carbon is released into the air as CO2, which leads to global warming. If reforestation happens, trees can absorb emitted CO2 back again.

During chena cultivation reforestation occurs, so it will reduce emitted CO2 as compared to modern agriculture processes which do not facilitate this.

Chena cultivation done in a systematic manner, is not that much harmful to the environment and does not contribute to deforestation to a large extent, in comparison to modern farming methods, hence doesn’t contribute to global warming and climate changes as much.

Furthermore, in modern agriculture methods, one or few types of crops are selected to grow. Therefore, there is no rotation of crops in cultivation for a long period of time. Hence, the fertility of the soil will decrease considerably. 

The fix which has been implemented in many parts of the world including Sri Lanka is to use economically friendly chemical fertilizers. Even though they make some crops faster it also meant that some of the important microorganisms in the soil would get destroyed. Since, the land area would be infertile for a long period, eventually these plots become barren lands, which could not be used for farming.

Shifting of farming land in Chena farming had led to saving of more nutrients of the soil while ensuring high productivity and sustainability in agriculture. Organic concepts in the old chena farming system were truly eco friendly. However, there is the possibility of soil fertility getting exhausted in Chena farming as well.

A ploy that could be used to address the concerns of soil getting infertile would be to cultivate the land for a much shorter period, and abandon the land, leaving little time to exhaust the nutrients fully.

Crop rotation is another strategy that’s used increasingly along with traditional Chena concepts to maintain soil structure for a longer period. It means growing a series of dissimilar/different types of crops in the same area in sequential seasons. Crop rotation also mitigates the build-up of pathogens and pests that often occurs when one species is continuously cropped. It also improves soil structure and fertility by alternating deep-rooted and shallow-rooted plants. 

More details about this can be reached from here | Archived.

CLAIM: Chena farming leads to serious soil erosion.

Fact: Soil erosion could occur in the early stages of setting up Chenas, however as by using multi-seed cultivation this situation can be controlled.

Farmers used to cultivate a variety of seeds at once at a particular time at chena. Even though they cultivate different seeds at once, when plants grow, it takes a different time period. Therefore, various types of crops will be harvested by the farmers throughout the year. This method of multi seed cultivation system led to improvements in the quality of soil.

On the other hand, soil erosion can happen and the agro-forestry method in which crops are grown with trees at the same time is the solution to prevent soil erosion. More details about this can be reached from here. Archived.

Claim: Traditional methods used in chena cultivation are  ineffective.

Fact : Many of the traditional Chena cultivation methods were effective and eco friendly.  However, might not be practical in some instances, hence needs to be updated.  

Mahinda Kumara Dalupotha, ethnographer and a member of intangible cultural heritage advisory board said that our ancestors farmed for thousands of years and cured diseases. It has a long history and can be called traditional knowledge.

This traditional knowledge is equally valid today but since the ecosystem has been completely distorted these structures should be developed again. The soil should be strengthened.  The use of chemical insecticides, fungicides, and herbicides should be stopped and at the same time, pest resistant plants should be planted.

Eco system can be properly maintained using these techniques, Mahinda Dalupotha explained.  

Mahinda Dalupotha added that traditional methods to control pests used in chena plantations are not seen nowadays with people having focused on large-scale monoculture. At the same time, people believe Chena cultivation also causes serious damage to the environment. Compared with modern farming it was really an eco-friendly sustainable method, he added.

Therefore, one could conclude that traditional Chena farming techniques might not be an exact fit to the more complex lifestyle requirements at present. And while there might be some drawbacks, there are many positives which can be taken from traditional Chenas and adapted to modern cultivation to gain benefits and in turn contribute to reduce forest destruction, improve soil and reduce global warming.