Soil Science - Study Mode

[#136] A soil having bulk density of 1.3 and particle density of 2.65, then the percentage of pore space will be
Correct Answer

(A) 50.94%

Explanation

Solution: A soil having Bulk density = 1.3 article density = 2.65 The space between the soil particles in the pore space. The formulas for calculating the pore space percentage: $${ ext{PS}} = left( {1 - frac{{{ ext{BD}}}}{{{ ext{PD}}}}}
ight) imes 100$$ Where PS is Pore Space, BD is Bulk Density and PD is Particle Density. Putting all the values in the above formula $$eqalign{
& { ext{PS}} = left( {1 - frac{{1.3}}{{2.65}}}
ight) imes 100 cr
& = 0.5094 imes 100 cr
& = 50.94 cr} $$

[#137] Lowest category of soil classification includes
Correct Answer

(C) Series

Explanation

Solution: The lowest category of soil classification includes Series . The levels from top to bottom are Order, suborder, great group, subgroup, family and series respectively. Soil classification is a dynamic subject, from the structure of the system itself to the definitions of classes, and finally in the application in the field. Soil classification can be approached from the perspective of soil as a material and soil as a resource.

[#138] Nitrate nitrogen status in drinking water according to WHO is
Correct Answer

(A) 10mg/L

Explanation

Solution: Nitrate nitrogen status in drinking water according to WHO is 10mg/L. The term “nitrate nitrogen” is used to refer to the nitrogen present which is combined in the nitrate ion. Nitrates are essential to plant nutrients, but in excess amounts they can cause significant water quality problems, it can accelerate eutrophication and increases the risk of colon cancer. Drinking water with a nitrate level above 10 mg/L is unsafe.

[#139] Which form of mercury is fat soluble, thus most harmful for ecosystem?
Correct Answer

(C) CH 3 Hg +

Explanation

Solution: CH 3 Hg + is the fat-soluble form of mercury, thus most harmful to the ecosystem. Methyl mercury (CH 3 Hg + ) is the deadly form of mercury due to its higher membrane permeability and greater tissue fixation. It affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste and sight.

[#140] Diamine putrescine accumulates due to deficiency of
Correct Answer

(C) K

Explanation

Solution: Diamine Putrescine accumulates due to deficiency of Potassium (K) . Putrescine has the potential to be a useful biomarker to reveal potassium deficiency. It is an organic compound containing a primary aliphatic amine group. Its chemical formula is C 4 H 12 N 2 and is classified as a diamine. Putrescine is found in all organisms. It play role in stress responses in plants, both to biotic and abiotic stressors.