Soil Science MCQ Question and Answer | Agriculture MCQ Question

Mohr and van Baren have recognized the five stages of soil development that are Initial Stage, Juvenile stage, Virile, Senile and final.
The senile stage of soil is most matured as in this stage, Decomposition arrives at a final stage and only the most resistant minerals have survived.

Carbon to Nitrogen Ratio is a ratio of the mass of carbon to the mass of nitrogen in a substance. Carbon and nitrogen are the most important elements required for microbial decomposition of organic matter to produce compost.
When composting is under process the C/N ratio is higher but the final C/N ratio noted is about 25:1.

Nitrification is the microbial process by which reduced nitrogen compounds are sequentially oxidized to nitrite and nitrate. The bacteria involved in the process of nitrification are very sensitive to pH. The pH should be between 7.0 - 8.0 for Nitrosomonas, and the optimum pH range for Nitrobacter is approximately 7.5 - 8.5.
Therefore as per the given options, the optimum pH for the nitrification process is 8.5.

As we know a pH level above 7 is basic and referred to as the alkalinity of any substance. Likewise, A soil having pH of 8 is also referred to as alkaline soil.
Alkaline soil is a type of soil with high amounts of calcium, sodium and magnesium. A variety of perennials, shrubs, trees and vines like lilac, daphnes and elms have adapted to tolerate higher alkaline levels.

L-value is the amount of phosphorus in the soil and in the soil solution which is exchangeable with added orthophosphate to the soil as measured by a plant growing in the system.
L-value is lowest for Arid region soil.

The primary mineral is the mineral that is formed during the original crystallization of the host igneous primary rock and includes the essential mineral used to classify the rock along with any accessory minerals.
Primary minerals can be used to analyze geochemical dispersion halos and indicator minerals. The diameter of primary minerals are having a diameter greater than 2 μm (0.002 mm), which includes silt, sand and gravel.

Calcification is the soil process in which the surface soil is supplied with calcium. Calcification of soil occurs when evapotranspiration exceeds precipitation causing the upward movement of dissolved alkaline salts from the groundwater and at the same time, the movement of rainwater causes a downward movement of the salts, and hence the net result causes the deposition of the translocated cations in the B-horizon can be labeled as B_k where B is the B horizon and K is referred to an accumulation of carbonates.

Fertilizer is the supplement added to the soil and plants to fulfill the nutrient deficiency in any plant and increase the fertility of the soil, it is usually a chemical supplement Whereas, Biofertilizers are living microbes that enhance plant nutrition by either mobilizing or increasing nutrient availability in soils.
Here, Green algae are the Biofertilizer used to increase yield and soil fertility and are mostly used in Rice fields.

Normality is any solution is the number of gram or mole equivalents of solute present in one litre of a solution.
Normality = Molarity × Basicity or Acidity of the solution.
The molecular weight of sulphuric acid is 98.079.
As 24.5 g of H₂SO₄ is added to 500 ml of water,
Hence, on calculation Molarity of the diluted Sulphuric acid solution = 0.524 M
Normality = 0.5 × 2 [(SO₄)^-2 has 2 Hydrogen ions]
                = 1 N

Crop logging is a system of monitoring the nutritional status of plants by periodic and regular sampling and analysis of soil and plant parts. The main aim is to overcome the nutritional problem while the plant is still standing and can benefit from the corrective measures.
This system was discovered by H. Clements for growing Sugarcane in Hawaii.