History And Principles of Soil Science

History And Principles of Soil Science

Soil Science:

The branch of science that deals with the nature, formation, classification, and ecology of soil is called Soil science. In soil science, the physical, biological, and chemical properties of soil are studied in relation with its use and management.  

What do Soil Scientist do?

1.       Soil scientists study the physical, chemical, and biological properties of soil.

2.       Also, they analyze how these properties are influenced by factors like climate, Land use, and management practices.

3.       Furthermore, they investigate that how soil, water, plants, and organisms interact with each other.

4.       Moreover, they find out the role of soil in nutrient cycling, carbon storage, and climate regulation. 

       History of Soil science as a Discipline:

History shows that two of the earliest soil scientists were Greek Theophrastus and Chinese Shengzhi. They penned down their observations ‘On the causes of Plant’ and ‘Field usage, Plowing, Irrigation, and Harvesting’ respectively. However, given the fact that most of their observations had not been passed through proper experiments, therefore they are not considered proper scientists in the light of modern science.

Then towards the end of the 16^th century, Microscope was invented (1590 A.D.) by Zacharias and Hans Janssen that changed the worldview because microorganisms that were invisible became visible in a very short span of time. This helped in discovering the soil biota and the processes that were taking place there. Scholars who brought on new information to the world in that era were Francis Bacon, Robert Boyle and Leonardo da Vinci. However, despite the fact that they carried out experiments, their results lacked accuracy owing to the religious restrictions and lack of modern tools.  

The study of soil biochemistry was started in 18^th century. The word ‘Humus’ was used by Johan Wallerius in 1753 to refer to the organic surface horizon that is related to decomposing organic matter. In the second half of 19^th century, Albrecht Thaer differentiated peat from humus. The former is formed under limited Oxygen while the latter under adequate O_2.

It was in 19^th century when soil was conceived as a living system and hence a biological science. Because prior to this soil was seen as small pieces of rock and dead and at the best soil was seen as a plant growing medium. Vasily Dokuchaev was the one who brought in this conception. He was a Russian geologist.  In Dokuchaev’s words the geographical variations in soil type could be explained in relation not only to geologic factors (Parent material), but also to climatic (climate of the area), biological (microorganisms), and topographical factors (Topography) and the time available for pedogenesis to operate. (FAO) 

Main Disciplines

Soil Science is a multidisciplinary field. It draws on principles from subjects like Geology, biology, chemistry, physics, microbiology, and engineering.

Other disciplines that fall in the sphere of Soil science are Pedology and Edaphology.

Principles of Soil Science

The principles on the basis of which Soil science operate are based on the Physical, Chemical, and Biological properties of soil. Some key principles are briefly discussed below:

1.       Soil Formation: The evolution of soils and their properties is called soil formation. There have been identified five factors that contribute to soil formation which include: Parent Material, Topography, Climate, Organisms and Time. 

2.       Soil Structure: The arrangement of soil particles into different shapes is called soil structure.

3.       Soil Texture: The relative proportion of sand, silt and clay sized particles is called soil texture. Soil with more sand particles is called sandy soil (Size of sand particle = 0.05-2mm); with more silt particles is called silty soil (Silt particle= 0.002-0.05 mm); and with more clay particles is called clayey (Clay particle= 0.002 mm).

4.       Soil Composition: It shows us that of what soil is composed. Normally, soils consist of mineral particles, organic matter, air and water. The proportions of these elements vary from soil to soil. Soil composition has a significant effect on soil fertility and water holding capacity.

5.       Soil Classification: Soils are classified based on their physical, chemical and biological properties. The classification system helps in the categorization that eventually helps in predicting that how a soil of a specific category would response to different management practices.

6.       Soil Conservation: The management strategies and farming operations that are aimed to control soil erosion is called soil conservation. This is achieved by preventing or limiting soil particle detachment that is normally caused by water or air. 

7.       Soil Fertility: The ability of soil to make available the essential nutrients to plants in order to optimize crop yield is called soil fertility. 

Importance of Studying Soil Science

The knowledge obtained from Soil science research is helpful in:

1.       Improving agricultural productivity.

2.       Management of water and soil resources.

3.       Protection of environment.

4.       Developing Sustainable land use practices.

5.       Also, Soil science play pivotal role in ensuring Food Security.

6.       Address global challenges like Climate change, Land degradation, and Biodiversity loss.