Soil Science - Study Mode
[#856] The soil organisms are most active at . . . . . . . . temperature.
Correct Answer
(A) 24° - 35°C
Explanation
Solution: The soil organisms are most active at 24° - 35°C. It is the optimum temperature range required for the better functioning of microorganisms. At very low temperatures they move to an inactive state and high temperatures may harm the structural damage to the microorganisms. Soil temperature impacts the rate of nitrification. It also influences soil moisture content, aeration and the availability of plant nutrients.
[#857] Hydromorphic soils are evolved by which process
Correct Answer
(B) Gleization
Explanation
Solution: Hydromorphic soils are characterized by the reduction of localized segregation of iron, owing to the temporary or permanent waterlogging of the soil pores which causes a lack of oxygen over a long period. Hydromorphic soils are evolved by the process of Gleization . It is a typical pedogenic regime of soil that occurs in a moist or cool and cold climate. The pedogenic regime in the soil formation process results in the development of a Glei in the lower part of the soil profile above the parent material due to poor drainage conditions and where waterlogged conditions prevail and such soils are called hydromorphic soils.
[#858] What is the porosity percentage if the particle density of soil is 2.6 and bulk density is 1.3
Correct Answer
(C) 50%
Explanation
Solution: If the particle density of soil is 2.6 and bulk density is 1.3 then the porosity percentage will be: $$eqalign{
& { ext{Soil porosity}} = left( {1 - frac{{{ ext{Bulk Density}}}}{{{ ext{Particle Density}}}}}
ight) imes 100 cr
& = left( {1 - frac{{2.6}}{{1.3}}}
ight) imes 100 cr
& = 0.5 imes 100 cr
& = 50\% cr} $$
[#859] In plants, the common symptom caused by the deficiency of K, P, Ca, and Mg is the
Correct Answer
(D) Appearance nectrotic areas in the leaves
Explanation
Solution: In plants, the common symptom caused by the deficiency of K, P, Ca and Mg is the Appearance of necrotic areas in the leaves. Necrosis is the condition in plants when plants undergo abiotic stress they initiate rapid cell death with necrotic morphology. In simple words, it is the death of the tissue in a localized affected area.
[#860] Apatite is a group of minerals which mainly contains
Correct Answer
(B) P
Explanation
Solution: Apatite is a group of minerals that mainly contains Phosphorus . It is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH - , fluoride, and chlorine ions respectively in the crystals. The formula of the admixture of the three most common end members is Ca 10 (PO 4 ) 6 (OH, F, Cl) 2 . The primary use of apatite is as a source of phosphate in the manufacture of fertilizer and industrial uses.