Soil Science

The soil of our country is rich in clay particles and has a neutral to slightly alkaline reaction.
The soil is rich in bases, lime and calcium.
Almost 95% of Indian soil type is low or medium in Phosphorus. Approx. 49.3% of districts and Union territories are low in available P, 48.8% are medium and only 1.9% are high.

2 : 1 : 1 type of clay mineral contains an extra sheet of Brucite as compared to the 2 : 1 type of clay minerals.
Brucite is the mineral form of magnesium hydroxide and is a common alteration product of periclase in marble. It adopts a layered Cdl₂– like structure with hydrogen bonds between the layers.

Soil puddling is the process of working saturated or near saturated soil into soft structureless mud. In simple words, it can be called tillage in rice while flooded.
The main objective of puddling in paddy plantations is to create an impermeable layer in the soil, which is the first requirement of submerged plantations in paddy. It reduces the percolation rates of water by churning clay particles and making them close many soil pores.

There are overall 17 essential nutrients required by the plants for proper growth and development. Out of them, 10 are macronutrients that are required in large amounts whereas 7 are micronutrients that are required in traces.
Boron, Zinc, Manganese, Copper, Molybdenum, iron and chlorine are micronutrients.

Green manures are the crops specifically produced to be incorporated into the soil while still green. The main aim is to add organic matter to the soil for its benefit. Green manuring is mostly used with legume crops to add nutrients to the soil, especially in organic farming.
Phosphatic fertilizers enhance the manuring properties of green manures.

Triple super phosphate contains about 40 – 48% soluble monocalcium phosphate [(H₂PO₄)₂ • H₂O]. when it dissolves in water, its phosphorus is negatively charged (-1).
TSP fertilizers are preferred as starter fertilizers for low soils. It can be used for all plants that are grown in soils with low or moderate phosphorus availability. When phosphorus is applied less than required or applied phosphorus has low efficiency due to soil conditions.

Soil gases are the gases found in the air space between soil components. The spaces between the solid soil particles, if they do not contain water, are filled with air. The primary soil gases are nitrogen, carbon dioxide and oxygen. Oxygen is critical because it allows for respiration for both plant roots and soil organisms. The percentage of oxygen in the soil air is about 20.6.

Nutrient uptake is the amount of each nutrient required for the crop to complete its life cycle at a given yield level. The rate of nutrient uptake is independent of the rate of water uptake, but the concentrations of nutrients at root surfaces depend strongly on soil water content.
Nutrient uptake by crops is fastest during Active growth.

Nitrosomonas and Nitrobacter are chemoautotrophic organisms found in soil and water and are responsible for the oxidation of ammonium to nitrite by Nitrosomonas and nitrite to nitrate in the presence of Nitrobacter.
These are obligate autotrophs that can obtain energy only by the oxidation of inorganic substrates and that cannot assimilate simple organic substrates, such as acetate, in the same way as carbon dioxide.

In tree crops, fertilizer is not added near the trunk because of the presence of fewer roots in that area. When it comes to fertilizing trees arborists often recommend deep root fertilization. Deep root fertilization is a specialized application method used to help restore trees that are struggling or showing signs of decline, it also improves soil aeration.