Q10.What is not correct about plain It is very fertile O Flat land O High productivity O Formed by black soil O
Answers
Answer: Flat land
Explanation: The plains are flat land regions which are suitable for agriculture
Answer:Alluvial soil is found in the valleys of the Terai region and in the middle hill valleys around Kathmandu and Pokhara. The valleys lie between the Siwalik and Mahabharat hills which widen out in places to form flat fertile valleys called Dun valleys. New alluvial soil with more sand and silt than clay is being deposited in the flood plain areas along the river courses. Alluvial soil is also found in the higher areas above the flood plain covering a greater part of the Terai. The nutrient content of new alluvial soil is fair to medium depending on how long it has been cultivated. Conversely, the nutrient content of old alluvial soils is very low.
Explanation:
The morphological, physical, chemical, and mineralogical properties of alluvial soils depend greatly on the characteristics of the alluvial parent material in which the soils formed, especially when the soils are young. As alluvial soils develop with time, the other soil-forming factors influence the resulting soil properties.
Recent Alluvial Soils
Recent alluvial soils are often highly stratified, containing layers of alluvium that were deposited successively and/or in fining-upward sequences (Figure 2b). Soils on active floodplains receive deposits of new alluvium with each flooding episode. The amount of alluvium deposited during each event will vary. Small amounts of material deposited on the soil can be barely perceptible and incorporated into the underlying surface horizon rapidly, the rate of which depends on the climate and biota. Larger amounts of new alluvium can completely bury underlying soils.
Because of periodic disturbance by flooding, soils on recent floodplains often develop only A or O horizons, resulting from the near-surface deposition and decomposition of plant material. Subsequent deposition of new alluvium and reinitiation of landform stability and soil formation results in soils containing one or more buried A or O horizons.
Recent alluvial soils typically can have somewhat elevated concentrations of organic carbon at depth. New alluvium is often derived from the eroded A or O horizons of upland and/or upstream soils. In addition, soils with buried A or O horizons clearly demonstrate an irregular decrease in organic carbon with increasing depth