Some possible strategies for sustainable climate smart agriculture

• Healing the external environment by healing our soil for water absorption

By Ranjit Seneviratne

Climate change is here to stay and it is seriously impacting the ecosystem. There are much less insects – very little if any Christmas Flies (Meru) in December, the Murunga trees not covered by caterpillars during the season and many creatures that share the planet with us are fast disappearing. In some countries there is a 70% drop in insect populations and some scientists are calling this ‘The first wave of extinction’. Who is next?

King Parakramabahu the Great of Sri Lanka, famous for his words “Let not one drop of water flow to the sea without serving the people” is also famous for constructing the largest man-made lake in the world – the Parakrama Samudraya, part of a system of Wewas ‘tanks’ (man-made lakes) that filled up during the rainy season and provided water during the dry season in the ancient rice-growing areas of the country; the plains below the central mountains, extending from the north to the south. That is why Sri Lanka came to be known as ‘The Hydraulic Civilisation’. This system of lakes also took advantage of both the South West and North East Monsoons to have two harvests and the two fruit seasons. 

There were no major waterways or canals that brought water to these tanks – most of the water just seeped through springs (ulpath). To make this possible, the rain that fell must have been completely absorbed into the soil, because the mulch and top soil acts like a sponge, so that the earth itself (the aquifers) were the main reservoir of rain water. The water, while percolating through the soil, absorbed minerals and other nutrients from clays, ‘kabuks’ (hard clays), rocks, etc. and then seeped into the ‘tanks’ and lakes too, filling them with mineral-rich water. 

There were no erosive water flows, especially down the hills that could loosen rocks and therefore there were little or no landslides. The excess water in the hills would have also bubbled out of the soil to form streams that flowed into rivers, so that the rivers too, must have been clear and mineral rich; not what they are today, a brown silt-laden chemical ‘soup’ made up of erosive surface water that removes precious top soil and worse still, collects nasty agro-chemicals in soil and chemicals in household waste and rubbish dumps from processed food, toiletries, medicines and micro-plastic dust lying on today’s hard, concrete-like soil surfaces.

This water absorption must have happened because the countryside was covered by the mulch of leaves and twigs that naturally forms to cover the soil when they fall from trees. This mulch was then converted to top soil (compost) by worms and other soil creatures – something now seen perhaps only in our forests. This is because wherever people live today, the ground is swept ‘neat and clean’ – the soil made hard and smooth – to look perhaps like the concrete courtyards of the rich. Our farmlands too are usually tilled and dug up to put in fertilisers, chemical and organic, upsetting the natural order of soil organisms and their soil healing activity.

Further, during the day, the mulch acts as an insulating blanket minimising water evaporation so that only the top layer dries out. At night the mulch absorbs moisture from the night air, leaving the soil beneath soft and moist, except during prolonged droughts when the soil beneath could dry out. Thus it can be assumed that the whole land was protected by this ‘skin’ of top soil and mulch, so that all the rain that fell would have collected in the soil and then gradually seeped into the tanks – the very Foundational Principle of the Hydraulic Civilisation.

According to a recent news item, Sri Lanka was the first country in the world to develop such a smart rain-water harvesting technology in these ancient rice-growing areas, now called the ‘Dry Zones’ of the country. Could we replicate this system initiated by our ancestors as a smart way of overcoming today’s climate change problems – floods and prolonged droughts? This writer has made his garden in Colombo (Kollupitiya) a ‘Heal the soil’ Forest Garden as above and achieved similar soil benefits, as well as harvests of forest-type fruits and vegetables.

People who did chena or forest cultivation in pre Colonial Lanka may have cleared the small areas to let in sunlight and remove any unwanted plants and weeds (which would have been easily pulled out), because they are not deep-rooted when they grow in mulch.

• King Parakramabahu the Great of Sri Lanka, famous for his words “Let not one drop of water flow to the sea without serving the people” is also famous for constructing the largest man-made lake in the world – the Parakrama Samudraya, part of a system of Wewas ‘tanks’ (man-made lakes) that filled up during the rainy season and provided water during the dry season in the ancient rice-growing areas of the country; the plains below the central mountains, extending from the north to the south. That is why Sri Lanka came to be known as ‘The Hydraulic Civilisation’. This system of lakes also took advantage of both the South West and North East Monsoons to have two harvests and the two fruit seasons
• There were no major waterways or canals that brought water to these tanks – most of the water just seeped through springs (ulpath). To make this possible, the rain that fell must have been completely absorbed into the soil, because the mulch and top soil acts like a sponge, so that the earth itself (the aquifers) were the main reservoir of rain water. The water, while percolating through the soil, absorbed minerals and other nutrients from clays, ‘kabuks’ (hard clays), rocks, etc. and then seeped into the ‘tanks’ and lakes too, filling them with mineral-rich water
•  
• There were no erosive water flows, especially down the hills that could loosen rocks and therefore there were little or no landslides. The excess water in the hills would have also bubbled out of the soil to form streams that flowed into rivers, so that the rivers too, must have been clear and mineral rich; not what they are today, a brown silt-laden chemical ‘soup’ made up of erosive surface water that removes precious top soil and worse still, collects nasty agro-chemicals in soil and chemicals in household waste and rubbish dumps from processed food, toiletries, medicines and micro-plastic dust lying on today’s hard, concrete-like soil surfaces

In addition, the present day concern over dengue mosquito breeding sites would have been much less of a problem, as water cannot collect in pools, if it is absorbed by mulch and top soil.

Unfortunately when the British Colonials came they had no clue about tropical agriculture. They just cleared the land for coffee and then tea, and all the top soil was washed away down the rivers and to the sea. (King Parakramabahu must have been in tears). Even today, soil is being washed away and so rivers are brown with soil and silt. (30% rain-water lost to the sea, recent estimate). With no top soil they were forced to use chemical agriculture inputs – fertilisers and measures to prevent weeds competing for the added fertiliser.  To prevent weeds, VP (vegetativly propergated) teas planted close together to block out sunlight was introduced and later herbicides and Glyphosate. We also justify chemicals for rice and other foods claiming it increases productivity. But if this food is making people sick (35% diabetic – Health Ministry) and thousands dying of CKDu, then obviously chemical agriculture has failed, because it is now shortening lifespan and killing us – the people (and also all other life that exists as part the ecosystem of the planet).

The only way out is to go back to what our ancient kings did, and to do this we need to build up the top soil by spreading mulch on every inch of exposed soil throughout Sri Lanka. Burning of leaves, branches and trees should be declared a crime against life and civilisation – which it obviously is, because soil is the ‘basis of all life’!

The first strategy to ensure sustainability for ‘climate smart’ agriculture is healing the soil. This strategy is basically simple – to maintain a covering of a mulch of leaves and wood chips over all existing bare, hard soil. This mulch naturally becomes top soil over time and therefore needs to be replenished from time to time – ideally maintained to a depth of four inches. There would therefore be a need to plant more trees to supply the mulch, which would also have social benefits – improving air quality by oxygenating the ambient air, providing shade and cooling the ground. 

Once the top soil is established to even a depth of a foot or so, the benefits are as discussed above. Rain water better absorbed into the soil, minimises erosive surface water run offs, and therefore potentially there will be less landslides, less silt laden water flow into rivers and therefore less flood water. More water seeping into the aquifers would ensure better quality mineral-rich water in wells, tanks and rivers, which could help reverse wildlife habitat loss and even biodiversity loss. 

This is obviously not a quick fix. But the sooner it is implemented the better, given the high temperatures and severe floods that are now occurring worldwide. In order to speed up the process, it may be necessary to import truck-mounted chipping machines (used in the USA and Australia), and deploy them in every Municipality and Pradeshiya Sabha. We could even import second-hand machines, which could be repaired and created anew locally (similar to ‘Thanthri Trailers’). The immense potential of our village youth innovators could be encouraged so that they create simple machinery that help in soil restoration.

Then any person with leaves, cut branches or trees they need to get rid of, need only to call the local body and these truck-mounted machines would reduce them to chips, load them into ‘tipper trucks’ and deliver them to farms and gardens that need them.Those of us who have started ‘Regenerative or Heal the Soil Gardening’ in Colombo, have found that this top soil ‘skin’ can be developed in less than a year. To speed up the process it is breaks down to form rich top soil, necessary to cut up the leaves and stems, especially large leaves which are unsightly and could collect water. Chipping machines to cut up leaves are available from ‘Jinasena & Co.’ and ‘Udaya Machinery’ in Kandy. 

Perhaps a simpler and cheaper leaf and small stem cutting machine could be made using a bucket or plastic bin (smaller diameter base with a wider mouth). A cover could be made with a central hole having a bearing so that a rod with kitchen-blender type cutting blades, could be inserted through the hole in the cover, and be powered using a small portable hand drilling machine. The leaves, etc. in the bin could then be cut up by moving the drill up and down.

Once the soil is re-built, it is amazing to see the birds and butterflies and all sorts of insect life that appear as if by magic. Many people who now visit these gardens are surprised at the ‘mattress-like’ feel of the mulch on the soil when they walk on it. The soil below the mulch is soft and black. It is also moist because the mulch is like a blanket which dries out in the noon day sun, but absorbs water during the night. No digging tools are needed, just a rake to spread the mulch. It has also been found by researchers that steel and iron tools should never be used in microbe and worm-laden top soil because it has a negative impact (like a fire). In fact the ancient Egyptians used copper and wood as farming tools – did they know something we don’t? 

Further, growing plants in this mulch-covered soil is amazing. Trees give more fruit. Custard apple (veli Aattha) has more than doubled its production, the local yam ‘Engili Ala’ grown in this soft soil was about three times the size of the yams grown in normal soil, as sold by farmers at the ‘Saturday Good Market’ Fair at the Race Course in Colombo. This is because the soft soil allows root vegetables like yams to grow to their full extent, unhampered by hard soil that is normally found today. 

(The writer is a marine engineer by profession. He was Project Operations Officer, FAO, Rome and one of his projects dubbed ‘Blue Revolution’ by the locals, resulting in the Government of Bangladesh winning the first Souma Award, given by FAO to a government that best developed an FAO project. His FAO Project in Eritrea was shortlisted for the Second Souma Award and two of his Project Managers won B.R. Sen Awards for excellence. He is currently a soil healing consultant who maintains his Colombo home garden as a laboratory to develop various techniques of bio diversity conservation that includes rainwater harvesting. Ranjit Seneviratne is an advisor/educator at Earth Life Water Knowledge Trails.)