Soil Science - Study Mode
[#546] Phosphorus is drilled in upland crops to
Correct Answer
(A) Put it near roots
Explanation
Solution: Phosphorus is drilled in upland crops to put it near roots. Phosphorus is important in cell division and the development of new tissue. Adding phosphorus to soil low in available phosphorus promotes root growth and winter hardiness, stimulates tillering and often hastens maturity.
[#547] Which mineral substance placed at number 10 in Mohs scale
Correct Answer
(D) Diamond
Explanation
Solution: Diamond is the mineral substance placed at number 10 on Mohs scale. The Mohs hardness scale was developed in 1822 by Frederich Mohs. This scale is a chart of the relative hardness of the various mineral (1-softest to 10-hardest). Diamonds also show a variation in hardness (the octahedral faces are harder than the cube faces). Mohs hardness is a measure of the relative hardness and resistance to scratching between minerals.
[#548] Approximate specific gravity of H 2 SO 4 (AR grade) is
Correct Answer
(D) 1.84
Explanation
Solution: The term specific gravity refers to the ratio of the density of a solid or liquid to the density of water at 4 degrees Celsius. The term can also refer to the ratio of the density of a gas to the density of dry air at standard temperature and pressure. The approximate specific gravity of Sulphuric acid (AR grade) is 1.84.
[#549] The most widely used source of nitrogen in agriculture in India is
Correct Answer
(A) Urea
Explanation
Solution: The most widely used source of nitrogen in agriculture in India is Urea. Urea is a source of nitrogen, an essential nutrient crucial for crop growth and development. Urea is the most important nitrogenous fertilizer in the country because of its high Nitrogen content i.e. 46%.
[#550] If the contents of exchangeable ions (cmol kg -1 ) determined in soil are Na + = 5, K + = 5, Ca 2+ = 10, Mg 2+ = 2, H + = 1, Al +3 = 1, Cl - = 1.6 and HCO - 3 =0.4, the CEC of soil is
Correct Answer
(C) 24 cmol (P + ) kg -1
Explanation
Solution: CEC is cation exchange capacity is a measure of the soil’s ability to hold positively charged ions. If the contents of exchangeable ions (cmol kg -1 ) determined in soil are Na + = 5 K + = 5 Ca 2+ = 10 Mg 2+ = 2 H + = 1 Al +3 = 1 Cl - = 1.6 HCO - 3 = 0.4 Summing up all the values of positive ions, we get the value of CEC of soil i.e. 24 cmol (P + ) kg -1