Our Ecosystems : Soil

A farm, a rain forest or a residential colony..what is the similarity between these three? Well, the answer is that none of these familiar scenes could exist without soil. We simply can not survive without it. Soil is not just ‘what crops grow in’ as we know or not just ‘what full of bacteria’ as we see in soap advertisements; but it is much more besides. The reality is it plays an important role in producing our food, clothing and shelter we need. It also provides a base for our industries and many of our leisure activities. In spite of this dependence, we often treat the soil as if it were an inexhaustible resource which we do not need to care for! We take it for granted!!

Nowadays, most people are more aware of environmental issues. Acid rain, air pollution, global warming, conserving endangered plants and animals, to name but a few, have all received a great deal of attention in recent years. Yet why do we rarely consider that the soil beneath our feet may be affected by an equally diverse range of problems? To many people, soil is just ‘dirt’, something that is used for growing plants in the back garden, or that farmers use for producing crops. But there is far more to soil than this. Without soil, life as we know it simply would not be able to exist. Without a range of soils we would not be able to enjoy so many different habitats, plants and animals, nor would we be able to put the soil to the number of uses that we do to benefit society.

Soil is a vital part of the natural environment. It is just as important as plants, animals, rocks, landforms, lakes and rivers! How?

It harbors all of the plant species and provides a habitat for a wide range of organisms. It controls the flow of water and chemical substances between the atmosphere and the Earth, and acts as both a source and store for gases (like oxygen and carbon dioxide) in the atmosphere. Soils not only reflect natural processes but also record human activities both at present and in the past. It is therefore part of our cultural heritage.

Soil, together with the plant and animal life it supports, its position in the landscape and the climate it experiences, form an amazingly intricate natural system - more powerful and complex than any machine that man has created. Soil may look still and lifeless, but this impression couldn’t be further from the truth. It is constantly changing and developing through time. Soil is always responding to changes in environmental factors, along with the influences of man and land use. Some changes in the soil will be of short duration and reversible, others will be a permanent feature of soil development.

A difficulty with soils being underneath us is that we cannot really see when things are going wrong, as we can when plants and animals disappear or die.

But why we need to know all this?
Soil can look after itself, can’t it?

There is a tendency of humans to assume that everything is ‘all right’. But, in many parts of the world, misuse of the soil has brought about a whole list of major environmental disasters. In both the past and at present, this neglect has led to catastrophic consequences. The effect of drought on over-farmed land is a familiar example, but there is good evidence that the collapse of several ancient civilizations were influenced at least in part by mismanagement of the soil.

Whilst the situation around us is not like this, there are still several issues of concern. Soil erosion, pollution, acidification, loss of fertility and loss of organic matter all occur in different parts of the country. These problems result either directly or indirectly from using inappropriate management techniques on particular soils.

It should be evident that when we talk about nature conservation and environmental protection the well-being of soils must also be a major consideration.

Soil is essential for many of mankind’s activities. Yet it is a part of our environment which is frequently taken for granted. We only start to take notice when it becomes damaged in some way, for example by pollution or erosion.

Even then, the damage to the soil itself is not always the main issue. Instead, it is the follow-on effects on other parts of the environment that receive much of the attention. We must understand that the rate of soil development is extremely slow. It has taken hundreds, thousands and, in some environments, millions of years to produce the range of soils that exist today. The soil is not an unlimited resource to be lost or damaged by poor management as just a few years of inappropriate use can, in some instances, seriously harm a soil which has developed over centuries.

Soils are also home to an amazingly large number of different organisms. In fact, scientists believe that there are probably more individual species living below ground than above the surface. We have as yet only identified a fraction of them. Worms, beetles, caterpillars, ants and larger animals like rodents are all obvious soil creatures. However, just one teaspoon of soil will also contain up to several million protozoa (probably the simplest form of animal life), bacteria, algae and nematodes. Many of these species are vital to the proper functioning of soils.

The life sustaining ability of soil is best understood by appreciating the complex cycles of decay and erosion. Its natural formation occurs in a series of layers starting at the surface but gradating down to the deepest bedrock. The surface layer is where active decomposition begins. Exposure to atmospheric elements, surface warmth and moisture helps to break organic matter into loose mulch like material. At the microscopic level, this layer is teeming with a diversity of bacterial, fungal and algal life forms. In combination with larger organisms like beetles and worms they provide the additional recycling activity to enable minerals and nutrients to be retrieved from the decaying organic matter and returned to the soil. Another family of soil based micro-organisms are involved in relationships that enable plants to absorb nitrogen from their roots.

Ideally the layer directly beneath the surface will be humus rich topsoil. The quality of this topsoil will depend on the amount of organic material available near the surface and the activity of the recycling organisms. So if there is enough of organic matter and organisms, the soil there must be healthy and fertile.

But what do we actually do near our house..?

We don’t want the fallen leaves near our residence. So we either burn the leaves or do not allow the plants to grow there. Burning the garden leaves not only pollute the air & remove the moisture from soil, but it disrupt the soil biology also. We also want our surrounding to be clean and free of dirt. So we cover the soil with garden tiles.  And then, as per our eco-friendly gesture (???), we have no other option but to plant in pots or containers, & to buy the fertile soil from nurseries. If one really want to see how ‘eco-friendly’ this act is, then he/she should visit the site from which the nursery soil comes. The more effective, worthy, easy and cheaper way will be to protect & impregnate the soil we have..!

How?

One of the ways to achive this is by planting native trees on the ground soil and not in the garden pots. Composting and Mulching (the application of organic or inorganic material such as plant debris, compost, etc.) help to slow down the surface run-off, improves the soil moisture, reduces evaporation losses and improves soil fertility.

A coastal rainforest provides almost ideal conditions for the creation of richly fertile topsoil. With increased temperatures and humidity an abundance of organic material reaching the ground begins to decompose almost immediately. It is then broken down by organisms which thrive under the conditions. The entire process is accelerated resulting in a generous layer of finely blended topsoil.

From the perspective of the organic grower, good soil structures need to be protected. This can be achieved by minimizing digging, replacing disrupted layers in their correct order when necessary and renewing surface layers by providing a supply of organic material such as compost and manure. The addition of organic material will improve the water and nutrient holding ability of the soil.

Our future depends on the soil beneath us. In some countries, particularly like United States and Netherlands, soils are believed to be worthy of conservation. Both of these countries have specific legislation to protect soils and the Dutch express this by saying that we should regard ourselves as “guests in our environment, not masters of it”. Soils are far more important to human and environmental well-being than we often give them credit for. Just because they are out of sight, they should not be out of mind!