Soil Science

Bulk density is defined as the dry weight of soil per unit volume of soil. Bulk density is dependent on soil organic matter, soil texture, the density of soil minerals (sand, silt and clay) and their packing arrangement. The bulk density of the clay soil is 1.10 grams per cubic centimetre.

Generally, soil contains 40 – 45 % inorganic matter, 5% organic matter, 25% water and 25% air. To sustain plant life, the proper mix of air, water, minerals and organic material is required.
Normally for agriculture purposes, Loamy-textured soils with equal distribution of sand, silt and clay are considered best.
However, the clay soils have great potential and are very fertile specifically with the presence of Chlorite and Illite.

Jean Baptiste Boussingault, was a French chemist who was considered the father of the field-plot technique. This technique is used to maintain a balance sheet that showed how much of the various plant nutrient elements came from the composition of his crops during various stages of growth came from rain, soil and air, analyzed.

When Fe contents in plants fall below or equal to 50 ppm, deficiency is likely to occur in plants.
Iron helps the plant move oxygen throughout the roots, leaves and other parts of the plant, producing the green colour that shows the good health status of the plant.

Reclamation disease is the disorder that affects crops grown on reclaimed land and is caused by the deficiency of trace elements like copper.
Reclamation disease due to copper deficiency occurs in plants grown on newly reclaimed is known as Ardisols. Aridisols are CaCo₃ – containing soils of arid regions that exhibit subsurface horizon development.

IIIite is a group of closely related non-expanding clay minerals. It is a secondary mineral precipitate and its structure is a 2 : 1 sandwich of silica tetrahedron-alumina octahedron-silica tetrahedron layers. 

Aluminium toxicity is probably the important growth limiting factor in acid soils, particularly when pH is less than 5 to 5.5.
Strongly acidic soils have high concentrations of soluble aluminium. Iron and manganese may be toxic to the growth of some plants. Soil acidity ultimately limits crop production.

The two main factors responsible for the formation of soil are active and passive. The active factors are climate and organisms whereas the parent material, topography and time are the passive factors.
Parent material is the underlying geological material in which the horizons of soil are formed.

Potassium is a very important element and plays a vital role in the growth and development of plants. However, the deficiency of potassium leads to wilt on dry, sunny days and deficient plants will have a stocky appearance with short internodes.
Some indicator plants indicate the deficiency of certain nutrients like potato, banana and cotton are indicator plants for monitoring K-deficiency.

Pore space which includes air or water occupies the highest volume percent in a fine sandy loam surface soil in good condition for plant growth.
Pore space in the soil makes it more porous and good in texture, allowing roots to respire in the soil.