Q. Define humus
Q. Draw and explain soil profile
Q. Prove with the help of an activity
that air is present in the soil
Q. A sample of soil took 40 mins to
percolate in 600 ml
ofwater .Calculate the rate of
percolation
Q. Which soil is needed to make pots
and toys?
Q Which soil is good for growing
cotton. ?
Answers
Answer:
1 ) a substance made from dead leaves and plants, that you put into the ground to help plants grow
2 ) A soil profile is a vertical section of soil like the diagram above. It allows you to examine the structure of soil. A soil profile is divided into layers called horizons. The main soil horizons are A, B, C and D. Most important for plant growth, the A and B horizons are the top two layers of the soil.
3 ) Take soil and pour water over it and within few seconds you will see few bubbles. These bubbles came due to the air spaces in the soil particles. The water filled up the spaces which were earlier filled with air. Now these air particles rise up as bubbles as air is lighter than water.
4 ) Percolation rate = amount of water / percolation rate
= 600/40
= 15
5 ) Clayey soil
Clayey soil is used to make pots, toys and statues because the clayey soil has the highest water holding capacity than loamy, sandy and silt
6 ) sandy loam soils
Cotton plants tend to do well in deep, well-drained, and highly fertile sandy loam soils with a pH between 5.5 and 7.5—cotton plants are vulnerable to the aluminum concentration often found in soils with a pH below that range.
sorry for answering late
hope it helps u
Ans1 :- Humus is dark browntopmost layer of the soil. It is rich in minerals. It increases the soil fertility and the water retaining capacity of the soil.
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Ans2 :- The soil profile is the layers of soil found when we go deeper into the ground. There are three main layers of soil – top soil, subsoil and parent rock.
Topsoil ( A – horizon) :- Top soil is the upper most layer of the soil which is made up of humus and small particles of rocks. It is dark in colour due to the presence of humus. Plants grow in this soil as humus makes this layer porous and fertile.
Sub soil (B – horizon) :- It is the layer situated below the topsoil. This layer does not have much humus and thus lighter in colour. Bits of rocks and some nutrients are the main constituents of this layer. Rain water collects in this layer.
Parent rock (C – horizon) :- Parent rock is the layer below the subsoil which consists of pieces of rocks with cracks and crevices. Below parent rock is the layer of solid rock called bedrock. Water table is formed over it.
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Ans3 :- Take take soil and pour water over it and within few seconds you will see few bubbles these bubbles came due to the air spaces in the soil particles are water filled up the spaces which were earlier filled with their now these particles rise up as bubbles as air is lighter than water.
pour pour water to soil you will notice that air comes out this is because the air which is it trying to escape from soil when you pour water to the dry soil.
pour pore water on soil and you can see the tiny air bubbles on make sunrise soil in the water you will see the air bubbles in water which confirm the presence of air in dry soil.
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Ans4 :- Given,
Time = 40 minute
Volume of water = 600 ml
Percolation rate = amount of water in ml ÷ time taken for percolation
= 600 ml ÷ 40 min = 15 ml per minute
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Ans5 :- Clayey soil is used to make pots, toys.
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Ans6 :- Black soil is best for growing cotton because it has excellent water holding capacity and aeration and good drainage as it cannot withstand excessive moisture and water logging.