Soil Science - Study Mode
[#171] Triple super phosphate contains
Correct Answer
(A) 40 - 48% P 2 O 5
Explanation
Solution: Triple super phosphate contains about 40 - 48% soluble monocalcium phosphate [(H 2 PO 4 ) 2 • H 2 O] . when it dissolves in water, its phosphorus is negatively charged (-1). TSP fertilizers are preferred as starter fertilizers for low soils. It can be used for all plants that are grown in soils with low or moderate phosphorus availability. When phosphorus is applied less than required or applied phosphorus has low efficiency due to soil conditions.
[#172] The oxygen percentage in the soil air is
Correct Answer
(B) 20.6
Explanation
Solution: Soil gases are the gases found in the air space between soil components. The spaces between the solid soil particles, if they do not contain water, are filled with air. The primary soil gases are nitrogen, carbon dioxide and oxygen. Oxygen is critical because it allows for respiration for both plant roots and soil organisms. The percentage of oxygen in the soil air is about 20.6.
[#173] Nutrient uptake by crops is fastest during
Correct Answer
(C) Active growth
Explanation
Solution: Nutrient uptake is the amount of each nutrient required for the crop to complete its life cycle at a given yield level. The rate of nutrient uptake is independent of the rate of water uptake, but the concentrations of nutrients at root surfaces depend strongly on soil water content. Nutrient uptake by crops is fastest during Active growth.
[#174] Nitrosomonas and Nitrobacter cause nitrification are an obligate
Correct Answer
(A) Autotrophic bacteria
Explanation
Solution: Nitrosomonas and Nitrobacter are chemoautotrophic organisms found in soil and water and are responsible for the oxidation of ammonium to nitrite by Nitrosomonas and nitrite to nitrate in the presence of Nitrobacter. These are obligate autotrophs that can obtain energy only by the oxidation of inorganic substrates and that cannot assimilate simple organic substrates, such as acetate, in the same way as carbon dioxide.
[#175] In tree crops fertiliser is not added near the trunk because of
Correct Answer
(A) less roots there
Explanation
Solution: In tree crops, fertilizer is not added near the trunk because of the presence of fewer roots in that area. When it comes to fertilizing trees arborists often recommend deep root fertilization. Deep root fertilization is a specialized application method used to help restore trees that are struggling or showing signs of decline, it also improves soil aeration.