Pg 165-170 Flashcards
What is the primary characteristic of Class I cultivable lands?
Good cultivable lands without any limitations, suitable for intensive crop cultivation.
How do Class II lands differ from Class I?
Class II lands have some limitations like gentle slope or moderate erosion hazard, requiring moderate conservation tactics.
What are the limitations of Class III cultivable lands?
Severe limitations like steep slope, high erosion hazard, poor fertility, requiring special conservation measures.
What type of land use is best suited for Class IV lands?
Mainly suitable for pasture/hay, with very severe limitations on choice of crops.
What is the primary use of Class V lands?
Not suitable for arable farming but suitable for grazing and forestry.
How do Class VI lands compare to Class V in terms of land use?
Suitable for grazing with some limitations, unlike Class V which has no limitations for grazing.
What type of land use is best suited for Class VII lands?
Suitable for woodland and wildlife, with severe limitations on grazing/forestry.
What is the primary purpose of Class VIII lands?
Suitable for aesthetic purpose and watershed protection, not suitable for any kind of crop production.
Give an example of Class I soils.
Alluvial soils of Indo-gangetic plains.
Give an example of Class III soils.
Shallow red soils, slightly saline black soils.
Give an example of Class V soils.
Arid and rocky soils.
Give an example of Class VIII soils.
Sandy beaches, river washes etc.
What is the color code for Class I land on a land capability map?
Light green.
What type of soils are formed by the sediments brought down by the rivers?
Alluvial soils.
How much of the total land area of India is covered by alluvial soils?
About 45.6 percent.
Where are alluvial soils commonly found in India?
Great Indo-Gangetic Plain, deltas of major rivers, and along the coast.
What are the two types of alluvial soils in the Great Plain of India?
Newer or younger khadar and older bhangar soils.
Where are khadar soils typically found?
In the low areas of valley bottom which are flooded almost every year.
Where are bhangar soils typically found?
On the higher reaches about 30 metres above the flood level.
What is the zone along the Shiwalik foothills with coarse, often pebbly soils called?
Bhabar.
What is the long narrow strip of swampy lowland with silty soils to the south of the bhabar called?
Tarai.
What are alluvial soils mainly formed from?
Inceptisols and Entisols soil orders.
What is another name for alluvial soil?
Riverine soil.
What is the composition of bhangar soils?
More clayey composition and generally dark coloured.
What is the C: N ratio of normal soils?
12:1
What is the C: N ratio of Legumes?
20:1 to 30:1
What is the C: N ratio of FYM?
20-30:1
What is the C: N ratio of microorganism?
4:1 to 9:1
What is the C: N ratio of Crop straw?
100:1
What is the range of Carbon in humus and organic matter?
50 to 58%.
What is the Bemlen factor used in the calculation of organic matter?
1.724.
What is the status of nitrogen in general soil?
0.03-0.05%, that means presence of 1000 kg of N/ha.
What does soil buffering mean?
Resistance to change in soil $p^{H}$.
What is the order of cation adsorption in soil?
$Al^{+3} > Ca^{+2} > Mg^{+2} > K^{+}$.
What is the order of anion exchange in soil?
$H_2Po_4^{-2} > OH^- > SO_4^{-2} > NO_3^-$.
Which cation is less tightly held by colloids and hence easily available for plants?
$K^+$.
What type of clay mineral is rich in black soils?
Montmorillonite clay minerals.
What is the local name for black soils in Maharashtra?
Regur or black cotton soils.
What are the major crops grown on black soils?
Cotton, soyabean, wheat, jowar, linseed, Virginia tobacco, castor, sunflower and millets.
Which mineral gives the red color to red soils?
Iron.
What is the P fixation capacity of red soils?
High, due to the presence of kaolinite clay mineral.
What type of silicate clay is dominated in laterite and lateritic soils?
Kaolinite.
Under what conditions are laterite soils formed?
Heavy rainfall and high temperature with alternate wet and dry periods.
What type of soils are mainly found on hills of Kerala, Karnataka, Orissa, Assam and coastal area of Goa, Maharashtra?
Laterite and lateritic soils.
What is the main characteristic of desert soils?
Found in arid conditions with practically negligible rainfall, highly pervious and low density.
Where are desert soils mainly found in India?
Thar Desert in Rajasthan.
What type of soil is known for its high specific gravity and residual formation from basalt?
Laterite soil.
What is the primary composition of laterite soils?
Calcite depositions.
What is soil fertility?
The inherent capacity of the soil to supply plant nutrients in adequate amount in suitable proportion for the growth of plants.
What is soil productivity?
The capacity of the soil to produce in a unit area, expressed in $kg/ha$ or Rs/ha.
Can a fertile soil not be productive?
Yes, a fertile soil may or may not be productive.
Can a productive soil not be fertile?
No, a productive soil is always fertile.
What factors influence soil fertility?
Physical, chemical and biological factors of the soil.
What factors influence soil productivity?
Fertility, location, and management of inputs & environmental conditions.
Is soil fertility an inherent property of the soil?
Yes, it is an inherent property of the soil.
Is soil productivity an inherent property of the soil?
No, it is not an inherent property of the soil.
What is the relationship between soil fertility and soil productivity in terms of crop yields?
Soil productivity indicates crop yields, while soil fertility is an index of available nutrients to plants.
How is soil productivity measured?
In $kg/ha$ or Rs/ha.
What is the significance of organic matter in soil fertility?
Organic matter is the key to production & maintain of soil health.
How is the method of organic matter calculated?
By multiplying the organic carbon values by a conversion factor of 1.724.
What is humus?
A complex and rather resistant mixture of brown or dark brown amorphous and colloidal substances modified from the original tissues or synthesized by the various soil organisms.
What is another name for humus?
Ligno-protein complex.
What percentage of lignin does humus contain?
40-45%.
What percentage of protein does humus contain?
30-33%.
What is the C: N ratio of humus?
10:1.
What is the percentage of nitrogen in humus and organic matter?
About 5 to 5.5%.
What is the significance of organic matter in soil?
It is the key to production & maintain of soil health.
Is organic matter found higher in forest area or grass land?
Grass land.
By what factor is organic carbon values multiplied to calculate organic matter?
1.724 (Bemlen factor).
What is the range of C: N ratio in humus & organic matter?
9:1 to 12:1.
What is the process of resistance to change in soil $p^{H}$ known as?
Soil buffering.
Which anion is less tightly held and easily available to plants or subjected to leaching?
$NO_3^-$.
