Soil Science - Study Mode
[#751] Which one is more accurate method of determination of soil texture?
Correct Answer
(A) Pipette method
Explanation
Solution: The pipette method is a more accurate method of determination of soil texture. The pipette method consists in using a pipette to take a specific volume of a water suspension of soil. If solid particles suspended in a liquid are allowed to settle freely, then by stroke's equation, after a selected time interval, t, all the particles larger than the diameter, d, will have fallen below a level designated as M.
[#752] Which of the following is a non-silicate mineral?
Correct Answer
(B) Calcite
Explanation
Solution: Calcite is one of the non-silicate mineral. Non-silicate minerals are minerals that are not composed of silicate groups. These minerals may contain oxygen atoms but not in combination with silicon. Nonsilicate minerals are less complex than silicate minerals. Non-silicate minerals are organized into six major groups based on their chemical compositions these are carbonates, halides, native elements, oxides, sulphates and suphides.
[#753] 'Lichens' are association between
Correct Answer
(B) Fungi & Algae
Explanation
Solution: Lichens are associated between Fungi and algae. A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic association. Lichens have properties different from those of their component organisms. Lichens do not have roots that absorb water and nutrients as plants do. But like plants, they produce their nutrition by photosynthesis. when they grow on plants, they do not live like parasites, but instead, they just use the plant's surface as a substrate and in return give nutrients to plants.
[#754] Grass tetany is caused by deficiency of . . . . . . . . in forage crops
Correct Answer
(A) Mg
Explanation
Solution: Grass tetany is caused by the deficiency of Magnesium in forage crops. Grass tetany is a metabolic disease involving magnesium deficiency, it occurs in such ruminant livestock as beef cattle, dairy cattle, and sheep. It occurs usually after grazing on pastures of rapidly growing grass, especially in early spring. Low magnesium intake by grazing ruminants may occur especially with some grass species early in the growing season, due to seasonally low magnesium concentrations in forage dry matter.
[#755] An alkali soil must have pH value of
Correct Answer
(D) Above 8.5
Explanation
Solution: An alkali soil must have a pH value of above 8.5. Alkali soils are clay soils with high pH, a poor soil structure, and a low infiltration capacity. They also have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physio-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell and is difficult to settle.