Soil Science - Study Mode
[#251] Legumes fails to develop nodule if pH is less than
Correct Answer
(B) 5
Explanation
Solution: Legumes are the plants that form roots nodules in association with the rhizobium bacteria. The free-living soil bacteria grows near the roots of the legumes and is unable to fix nitrogen in a free condition. The formation of nodules is more sensitive to soil acidity than other aspects of plants. Legumes fail to develop nodules if pH is less than 5.
[#252] Insoluble factor of Organic Matter is
Correct Answer
(A) Humin
Explanation
Solution: Soil organic matter is the organic component of soil, consisting of three primary parts including small fresh plant residues and small living soil organisms, decomposing (active) organic matter and stable organic matter (humus). Humin is the insoluble component of soil organic matter. It is a carbon-based macromolecular substance. Humins make up about 50% of the organic matter in the soil.
[#253] Muck soil containing . . . . . . . . organic matter.
Correct Answer
(A) 20 - 50%
Explanation
Solution: Muck is sapric soil that is naturally waterlogged or artificially drained. These soils are deep, dark coloured, and friable. Muck soil is used for growing specialty crops such as onion, carrots, celery and potatoes. Muck soil contains about 20 - 50% organic matter. Muck farming on drained swamps is an important part of agriculture.
[#254] What is the connotation of 'Fol' formative?
Correct Answer
(B) Mass of leaves
Explanation
Solution: The connotation of ‘Fol’ (Folia, leaf) formative is the Mass of leaves . This is one of the types of Sub order out of 47 sub-order of the soils, the sub-order indicates genetic homogeneity. Climatic environment, vegetation and wetness help in determining the genetic processes.
[#255] The value of Von Bemmelen factor is
Correct Answer
(A) 1.724
Explanation
Solution: The “Von Bemmelen factor” is based on the assumption that organic matter contains 58% of organic carbon. The literature indicates that the proportion of organic C in soil organic matter for a range of soils is highly variable. The value of the Von Bemmelen factor is 1.724.