Soil Science - Study Mode
[#301] Rock phosphate contains
Correct Answer
(B) 20% - 30% P 2 O 5
Explanation
Solution: Rock phosphate is also known as Phosphorite and is a non- detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite varies between 20% - 30% of phosphorus pentaoxide (P 2 O 5 ). Rock phosphate contains high amounts of phosphorus and calcium.
[#302] Coordination no. of K is
Correct Answer
(D) 12
Explanation
Solution: Coordination number is also known as ligancy, of a central atom in a molecule or crystal refers to the total number of atoms, ions or molecules bonded to the atom. The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. For molecules and polyatomic ions, the coordination number is determined by simply counting the other atoms to which it is bonded. The coordination no. of potassium is 12.
[#303] Which indices are used to quantify the effect of climate on soil formation?
Correct Answer
(D) All of the above
Explanation
Solution: Following are the indices used to quantify the effect of climate on soil formation: Thornwaite’s PE index developed a T/E index to represent thermal efficiency, Precipitation - Climate affects the formation of soil indirectly, high temperatures and rainfall increase the degree of weathering and therefore the extent of soil development. NSQ ( Niederschlag-sattigungsdefizit Quotient) is the humidity factor and is the total annual precipitation (mm) divided by the absolute saturation deficit of air.
[#304] Plasticity Index is given by
Correct Answer
(D) Atterberg
Explanation
Solution: Plasticity Index is given by Atterberg which is expressed in percent of the dry weight of the soil sample. It refers to the size of the range of the moisture content at which the soil remains plastic and it usually depends on the amount of clay present in the soil. The plasticity index is calculated as the numerical difference between the liquid limit (LL) and plastic limit (PL), PI = LL - PL
[#305] Biuret in urea applied as a foliar spray in citrus fruits should not be more than
Correct Answer
(A) 0.25%
Explanation
Solution: Urea of foliar spray should not contain biuret more than 0.25% for citrus fruits. Fertilizer-grade urea contains the impurity Biuret which is toxic to the plant, especially when applied as a leaf dressing. Thus Biuret more than the advised percentage for specific plants can damage the root of the plant and also useful bacteria and chock the capillary of the root cell, Nitrogen carrying capacity will be reduced.