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In the early 1930s, the United States witnessed a significant harvest after turning a significant land area under the plough to grow wheat, etc. The harvest was a boon to the growing population and added wealth to the economy as in those times there was the direct correlation between the extent of produce, income and economic growth.
However these practices, which brought in monoculture on a large-scale, in turn exposed soil and removed natural wind breakers and were not exactly seen as liabilities. In the late ’30s however the United States witnessed dust storms and floods and some of the dust storms literally frightened people to the extent that some imagined that the end of the world had come. Mass migration from agriculture areas took place as a result of these frequent dust storms.
President Roosevelt commenting that soil as a basic asset was compelled to push for legislation and the Uniform Soil Conservation Law came into federal statute books. Though the advent of chemical fertiliser again pushed this sound advice to the background, it is becoming well accepted that healthy soil is fundamental to sustainable agriculture.
Barricading ourselves from the problem
Soil I believe we take for granted and as laymen we literally do not understand the value. We tread on it without much thought and take its presence for granted. In urbanised living, our attitude is paving our way all around so that the soil is pushed or buried beyond our sight. We exclude connectivity to external ventilation and try to adopt forceful ventilation at much higher cost simply to keep the dust away which tends to settle on all that we build and decorate and thereby unsettle our minds which aspire for dustless existence.
The issue is, we are not addressing the cause but are only barricading ourselves from the problem. Thus we observe higher particulate matter in our air and there is no way that we can air condition the external environment. With air shed contaminated with dust and particulates, we are slowly poisoning ourselves. The unhealthy air that we are exposed to in Sri Lankan urban climates is an issue that needs addressing.
As we climb on the Colombo-Kandy Road, one can see a billboard that has been placed strategically to be viewed. The billboard is informational and states the need to adhere to soil conservation and warns us that bad practices can lead to persecution. We also do have a Soil Conservation Act.
It is not quite usual for one to observe such billboards in today’s commercial world as critical display points can generate cash by allowing billboards which pamper to one’s needs and desires. However this board has survived for some time and how many of us have heeded its contents is a point to ponder, because we see many an example of bad practice.
When we want to develop a piece of land we first clear it of its contents and even remove any grass or vegetative cover and expose the brown patch which we proudly display as developed and ready for sale. It is said that this ‘brown patch view’ is important to get the attention of the buyer and that the parties who are acting in this manner are merely responding to the market demand and perceptions. One never questions whether clearing everything is a helpful activity and whether there are any long-term consequences.
The science of soil
The science of soil and its formation is fascinating and when you understand the complexity of the process you tend to really value what we take for granted. Soil is created by weathering and through a multitude of reactions.
The basis for soil is the rock formations and that is why we speak of bedrock underneath the soil phase. If there is no top soil, the rock is exposed and we can witness those too as we travel. However, from an agriculture point of view, it is the soil that we count on. Remove soil and you remove the possibility of any cultivation. That is the basis for President Roosevelt’s dictum – you destroy your soil and thereby you are destroying yourself.
It is important to understand some of the quantitative science behind soil. A rule of thumb is that it takes about 500 years to generate a one-inch thick top soil. Another way of looking at this is reactions slowly taking place over 500 years create an inch thick soil.
Now this layer of soil when exposed, and not held together by any root structure of vegetation, can get displaced fast when either wind or rain takes place. It is not too difficult to understand that the process of removal can happen almost instantaneously depending on the speed and impact of rain or wind. What the human being is doing through his or her action is destroying something which is so vital for our wellbeing and took centuries to create, in double quick time.
Be much more careful and plan well
There had been research done on our conditions. Dr. Tilak Hewawasam of Sabaragamuwa University has studied and published widely in this area. As per his research, the rule of thumb stated above is pretty conservative when considering Sri Lankan soil. His calculations and studies have revealed that it takes about 1,000 years to for a soil thickness of six to 14 mm to form – the rate of weathering front advance.
He states that the nature of our geology leads to slow rates of soil formation. This in turn means we need to be even more careful with respect to our practices. He had further demonstrated that the typical natural rates of losses without any external interventions to be 130-1,200 t per sq. km per year. The losses observed in agricultural plots on hill slopes are 7,000 tons per sq.km per year and the value is many times more than the normal. Thus his research is asking us to be much more careful and to plan well.
As the insert shows, the practice happens anywhere. Also some of the crops we have selected to grow in hill country are incapable of soil retention. Dr. Ray Wijewardene introduced and demonstrated soil conservation via his SALT (Sloping Agriculture Land Technology) methodology. The pioneer is no more, yet his SALT legacy lives on. The problem is such demonstrations have not found its way into common practice.
Bridge the divide
In tea estates it said that today the quality of soil is a huge issue. The practices that aggravate losses are the norm rather than the exception. It is also rather unfortunate that this type of important research information stay confined to publications and in our organisations sound science is not meeting or enabling sound decision making. There is a need for both parties – scientists and decision makers – to bridge the divide that exists in our society.
We do have standards for air and water. We usually do not hear about standards for soil in common parlance. Usually monitored are the air quality and water quality, etc. We do breathe and drink and as such these efforts are directly connected to our wellbeing. Though we do not monitor soil, it is food that we realise from growing in soil that nurtures us. Hence the standards for soil start with the need for the very presence of such matter.
More developed composting standards understand the relationship between compost and soil. Soil should be viewed as the living, active, dynamic material which it actually is. Our environmental standards at present do not consider soil and this is a gap that needs attention.
At present neither our practices nor our understanding demonstrate that we are true sons of our soil. We need to demonstrate a higher connection to our environment as that is the way forward. The difficulty is in not about understanding but changing our behaviour in line with understanding.
In some of these sectors there are too many pressures in making a living through quick wins and some true champions may be needed in demonstrating change. Literally a true son of the soil is needed to emerge in these areas. It is not our comments but action by the converted that will drive the necessary changes.
[The writer is Professor of Chemical and Process Engineering at the University of Moratuwa, Sri Lanka. With an initial BSc Chemical engineering Honours degree from Moratuwa, he proceeded to the University of Cambridge for his PhD. He is the Project Director of COSTI (Coordinating Secretariat for Science, Technology and Innovation), which is a newly established State entity with the mandate of coordinating and monitoring scientific affairs. He can be reached via email on [email protected].]
