Soil Science - Study Mode
[#736] Who suggested that the principal nourishment of plant was water
Correct Answer
(C) Francis Bacon
Explanation
Solution: Francis Bacon (1591 - 1624) is the scientist who suggested that the principal nourishment of plants was water. The main purpose of the soil was to keep plants erect and to protect them from heat and cold. Water helps a plant by transporting nutrients through the plant. Nutrients are drawn from the soil and used by the plant. Water carries dissolved sugar and other nutrients through the plant.
[#737] "Horse hoeing husbandry" was written by
Correct Answer
(D) None of these
Explanation
Solution: “Horse hoeing husbandry” was written by Jethro Tull . It is an essay on the principles of vegetation and tillage, designed to introduce a new method of culture, whereby the produce of land will be increased and the usual expense lessened. Together with accurate descriptions and cuts of the instruments employed in it.
[#738] During Isomorphous substitution within clay, two cations (replaceable & replacing) must have ionic radii within range of
Correct Answer
(A) 0 - 15 %
Explanation
Solution: During isomorphous substitution within the clay, two cations replaceable and replacing must have ionic radii within the range of 0 - 15%. The process of replacing one structural cation for another of similar size is known as isomorphic substitution. This replacement represents the primary source of both negative and positive charges in clay minerals.
[#739] Rocks containing more than 65% SiO 2 are
Correct Answer
(C) Acidic
Explanation
Solution: Rocks containing more than 65% SiO 2 are acidic. Rocks with more than 65% of silica are called Felsic or acidic, those with between 55 and 65 percent silica are intermediate, and those with between 45 - 55% silica are mafic (Basic) and those with less than 45% are ultramafic. Acidic magma solidifies in the crust commonly as granite and erupts as rhyolite lavas. Within an intrusion, crystals grow large within the magma chamber.
[#740] The exchangeable sodium ratio (ESR) can be calculated as
Correct Answer
(D) $${ ext{ESR}} = frac{{{ ext{Exchangeable}},{ ext{N}}{{ ext{a}}^ + }}}{{{ ext{Exchangeable}}left( {{ ext{C}}{{ ext{a}}^{2 + }} + { ext{M}}{{ ext{g}}^{2 + }}}
ight)}}$$
Explanation
Solution: The exchangeable sodium percentage measures the production of cation exchange sites occupied by sodium. The exchangeable sodium ratio (ESR) is the relative amount of the sodium ion present on the soil surface, expressed as a percentage of the total cation exchange capacity. It is calculated as: $${ ext{ESR}} = frac{{{ ext{Exchangeable}},{ ext{N}}{{ ext{a}}^ + }}}{{{ ext{Exchangeable}}left( {{ ext{C}}{{ ext{a}}^{2 + }} + { ext{M}}{{ ext{g}}^{2 + }}}
ight)}}$$