The national soil question

by Ranil Senanayake

There are some very disturbing trends in the management of the land of this nation, that cries out for action, but who will hear the cry ? It was not long ago that the organic soil of the mountains of this country, built over a period of twenty million years, was destroyed in a matter of decades.

This destruction and plunder did not go unrecorded. Fredrick Lewis in his book Sixty Four Years in CEYLON makes this observation on the destruction of the mountain forests in the Agra Patana area;

“I know of no more awe-inspiring sight, than that of a thousand acres on fire. Sheets of flame appear to leap into the air, and yell with a sort of devilish delight at their victory over the magnificent trees they are reducing into charred masses of cinder and charcoal. It is more than impressive, it is fearful, yet grand ! After the fire has completed its work, the land is covered with .black logs, lumps of charred timber, masses, and often great fragments of stones, broken by the heat that has swept over them. A deep black covers the landscape; impressive, but depressing.

It was in a burned wilderness like this, that I found my new home. It lay at the extreme end of one of the many blocks of land that had been simultaneously burned off. My path, for road it could not be then called led over hundreds of fallen and charred logs, and followed the valley of the Agra stream.......

When morning broke upon the day following the events recorded at the conclusion of the last chapter, I found myself gazing upon a scene not altogether unfamiliar to me. All around me lay hundreds of charred black logs, stumps in fantastic shapes and outlines: fallen branches, broken and distorted by fire: cinder heaps, and little rivulets of sodden ash: all indicative of the fierce, merciless fire that but a few weeks ago, had raged over a spot that so lately had been a beautiful forest land.

A strange picture

It was now a blackened wilderness, to be changed into fields of coffee, by the labour and patience of man. A strange picture; fascinating in one respect: fearful in another and yet so full of a strange mixture of possibilities was this wild heap of ruins, this uncouth mass of slaughtered giants of an inarticulate, yet eloquent world, to be transformed by , industry in the pursuit of fleeting wealth.”

The colonial exploiters, cannot claim ignorance of their deeds Dr. Strange, an agricultural expert made this observation in 1909 with respect to the clearing of the mountain forests;

“It would not have been necessary to notice here the matter of soil denudation, did it not affect irrigation and water supply. The result of stripping the soil is to make the springs on tea states dry up quickly; to diminish the fair-weather flow of streams and to increase their storm flow (whereby temporary irrigation weirs are carried away) and to choke with silt the beds of the streams and the irrigation channels led from them. It is also said to reduce the fertilising property of the water, as there is now less leaf mould in solution. Even paddy fields have been ruined by sandy deposits laid on them. When tanks lie in the course of streams thus affected, the rate of their silting-up will rapidly increase and their storage capacity will greatly diminish. Even the large rivers, such as the Kelani, have had their section diminished by soil debris, so that for this reason, as well as on account of the greater run-off produced by the clearance of the forest entailed by the establishment of estate plantations, the flood waters cannot be contained in the river channel, but are spread over the riparian land and do much damage. If such damage affected only a small area it would not, of course, matter much, but it has to be remembered that the tea and rubber estates are on the hills, and uplands, which are the principal sources of supply to rivers draining two-thirds of the Island; the effect of denudation it thus widespread.”

Question of soil

Thus forest denudation and soil erosion seem to go side by side. While we have begun to address the questions of forest and tree loss there is much to be done with the question of soil.

Soil, is one of the most important components of terrestrial ecosystems, yet its value has been overlooked by most modern approaches to land development, agriculture and forestry. To most of us soil is the stuff that holds trees up. We see it as a solid surface for us to walk, ride or construct upon. Our perception of its usefulness in our daily lives does not exceed much beyond providing a medium to grow our crops. In fact modern agriculture has discounted the value of soil in providing nutrients for plants. by enhancing the role of artificial fertilizer to the detriment of good soil management. In Sri Lanka most texts on soil only address the physical or chemical nature of soil, a view that has allowed our farmers to be pushed into reliance on ‘high input chemical agriculture’.

This high input chemical agriculture has been conclusively demonstrated to be harmful to human health, local biodiversity, sustainability of production, environmental functions, social functions and local economies.

The question that arises is ‘what are the options?’ There are many options that have been proposed, ranging from the adoption of traditional agricultural practices to developing new farming systems such as biodynamic and organic agriculture. All these approaches pay great attention to the management of soil as a primary resource. Thus a closer look at soil is warranted.

The soil ecosystem is comprised of two distinct fractions called the ‘organic (biological) fraction’ and ‘inorganic (chemical/physical) fraction’. There is a slow flow between them in the form of mineralisation and decomposition.

These fractions act as reservoirs that can be identified by their history. The organic fraction is largely the breakdown products of photosynthetic compounds and their derivatives. The inorganic fraction is largely the breakdown products of rocks.

Most soils comprise of a mix of these two fractions in various proportions. These fractions are called mineral matter and organic matter respectively. the amount of organic matter in most soils are typically low ranging from under 1% to 10%.

But it is this fraction that drives the ecosystem that lies above it. Sustainable agriculture and forestry will be an impossibility without the optimum levels of organic matter for that soil. The organic matter of soil when extracted is seen as a dark, amorphous solid mass.. On closer examination this ‘solid mass’ is seen to be comprised of millions of organisms. In fact, any one acre of farmyard soil contains as much biomass as an Elephant. It is also the biological filter that detoxifies a large proportion of the poisons that we apply to the environment we live in. It is a world as complex as, and most certainly older than, the world that lives on its surface. It lies continuous over most of the land surface of the planet It is in a very real sense the ‘living skin’ of our planet.

The world of soil is bizarre to us who live on the surface. It is opaque to light and mostly solid. Communication is by chemicals, e.g.. pheromones or physical, e.g.. vibrations. Movement is slow, the faster organisms like the worms are the giants of this world, tunneling through at a fairly rapid rate measured in centimeters per minute. More common are the fungi who move by growing through the soil at rates measured in centimeters per month, or the bacteria which have rates measured in centimeters per year.

It is a busy world, one gram of ordinary farmyard soil can contain over 1 billion individual bacteria, over 100 million individual actinomyctes and over 1 kilometer of fungal hyphpae, notwithstanding plants like algae and animals like collembolids, nematodes or worms.

Understanding soil ecosystems and how they work is important for both production and conservation goals. In production systems this information will enable the optimization of inputs and help develop more sustainable agriculture. For instance, while phosphorus is needed as an amendment on most soils to produce good crops, the source of phosphorus used can make a great difference to both productivity and profitability. Phosphorus that has been acted upon by certain soil bacteria can produce a higher volume of crop than that produced by the same amount of phosphorus added as superphosphate. At present this bacterially produced phosphorus has been observed only in certain soil ecosystems. If this can be developed commercially it has the potential to reduce fertilizer bills significantly.

Understanding soil ecosystems and how they work is important for both production and conservation goals. In production systems this information will enable the optimization of inputs and help develop more sustainable agriculture.

In 1938 Dr, William . Albrecht made the following observation for US agriculture;

“Soil organic matter is one of our most important national resources; its unwise exploitation has been devastating; and it must be given its proper rank in any conservation policy as one of the major factors affecting the levels of crop production in the future... The Nation should be made aware of the rapid rate at which the organic matter in the soil is being exhausted. Farm-management practices should be adopted that will at least maintain, and in as many cases as possible even increase, the supply of this natural resource in the soil. The maintenance of soil organic matter might well be considered a national responsibility.”

In 2006 in Sri Lanka , we still have to appreciate this fact. The colonial experience robbed us of that precious organic matter, leaving plantations that cling to the subsoil and yield only with artificial fertilizer that we have to import.

But, today a new threat has sprung up. Irresponsible land use decisions, sanctioned by the officials concerned, are rooting out the tea plants that gave some stability to the degraded mountains and replacing it with annual vegetable cultivation that bleeds away the remnant bits and poisons our water sources..