BIO(Agricultural Production)

                   Agricultural Production

                 

        How to increase the food

production?

        We know that the cultivated land is very limited. If we make use of plenty of land for cultivation some forests may be destroyed. This leads to environmental problems. So we need to think of another

solution. Observe the following solutions.

1. Increasing the area of cultivated land.

2. Increasing production in the existing

land.

3. Developing high yielding varieties.

4. Crop rotation

5. Cultivating Mixed crops.

6. Cultivating short term crops like Rabi.

       Which of the above option do you think

is more meaningful?

You have already learnt about long term

and short term crops or Kharif and Rabi

crops in your classes. Short term varieties

produce grains more than long term

varieties.

Alternating of crops preserve the soil

fertility. Mixed crop system helps the

farmers to produce variety of crops as well

as increase in the production.

To get high yield 3 types of methods

are being used.

1. Developing high yielding varieties.

2. Using high yield management methods.

(Crop production management)

3. Crop protection management.

Improving high yielding crop varieties:

Observe the size and colour of maize in your kitchen. (if not, ask your mother why she doesnot purchase maize as a food material) Some seeds are small with yellow colour and some are large with white colour. The white coloured large ones are hybrid variety. They give high yield. Refer annexure for more information.

   

High yielding crop management methods:

(A) Irrigation:

An experiment was conducted to find out how irrigation affected the production of a crop. In the experiment, crops were grown in two fields. One field was irrigated while the other wasn’t. The same amount of nutrients, like nitrogen, was applied to both the fields.

What does a plant do with water?

We learned in the chapter ‘Nutrition in

plants’  that a plant absorbs water 

from the soil. What does it do with this

water? We know that the plant combines

water and carbon dioxide with the help of

sunlight to produce carbohydrates. Starch

is one such carbohydrate. Different types

of sugars and cellulose are also

carbohydrates. A chemical analysis will

show that 100 grams of water reacts with

260 grams of carbon dioxide to form 180

grams of carbohydrates.

But the plant roots do not use all the

water they absorb to produce

carbohydrates. Actually, most of this water evaporates into the air.

  Activity:

Take a polythene bag. Cover the bag on

leaves and tie it. Keep it 4-5 hours. You

observe it. What did you find in the

polythene bag? Where did they come from?

Do this experiment during day time and

night time separately. Note the differences

in your note book

If you tie a plastic bag over a leaf, you

will be able to see how much water a plant

releases into the air. It is estimated that a

plant uses only 0.1 percent of the water it

absorbs to form carbohydrate.

Water evaporates through these stomata.

We know that more water evaporates when

the weather is hot. In such a situation, the

stomata begin to close. This lessens the

amount of water that evaporates from the

leaves

We learned in the chapter ‘Nutrition in

Plants’ of that plants absorb

carbon dioxide. The carbon dioxide also

enters the leaves through the stomata.

When the weather is hot and the stomata

close, what effect would this have on

the absorption of carbon dioxide by the

plant?

What effect would a change in the

amount of carbon dioxide absorbed

have on the growth of the plant?

If the plant does not get water at this

time, what effect would this have on its

growth? Discuss in your class and find

out reasons.

Plants cannot absorb nutrients directly

from soil. Only the nutrient that dissolves

in water is absorbed by the roots of the

plant. We discussed about transportation of

substances in the chapter, “Transportation

of material across the cell membrane” and

in the chapter “Plant Cell”. Try to think of

how xylem and phloem are useful in

transportation.

Water is essential for Agriculture.

What are the main water sources in your

village for agriculture? How farmers

utilize them?

Paddy require more quantity of water.

Can you give such examples?

Cultivation of paddy, wheat and sugar cane

are suitable where places have rich water

resources. If we cultivate such crops by

irrigating them with water from wells and

bore wells what will happen?

Most of the farmers of our state

cultivate crops like paddy, sugar cane

irrespective of proper availability of water,

only because of supporting price and

marketing facility. So farmers invest more

on irrigation of water, electricity bills,

pesticides and fertilizers. Agriculture

Officers advise to cultivate dry land crops

(Aruthadi Pantalu) in less water areas and

follow different water management

practices.

Make a list of crops which require

less amount of water.

Drip irrigation is a good practice in

agriculture to prevent water wastage. In drip

irrigation, water is supplied through small

pipes. These pipes have small holes through

which water passes drop by drop.

 Soil Nutrients:

Nutrients present in the soil are

consumed by plants and are replenished or

returned to the soil in many different ways.

In nature the continuous process of death

and decay add nutrients to the soil and the

process is too slow to be commercially

useful. Rotating crops, adding organic

manure or chemical fertilizers etc. are man

made processes.

Crop rotation:

Usually, farmers do not grow only one

crop in a field. Different crops are grown

in different seasons. It has been seen that

cereal crops take a lot of nutrients from

the soil. Legumes are different. While they

do take nutrients from the soil, they also

provide some nutrients to it. Growing

leguminous crops result in an increase in

the quantity of nitrogenous salts in the soil.

Thus to grow a leguminous crop between

cereal crops is beneficial either by

crop rotation or by mixed cropping.

Nitrogen, Phosphorus and Potassium

are the important nutrients.

To avoid nutrient deficiency in the soil, farmers cultivate alternate crops. A farmer cultivated sugar cane in his land for the last five years. Another farmer cultivated sugarcane in the first year and soya bean in the second year and sugarcane in third year. In which case do you think has the land lost most of its nutrients? Crop rotation is the process in which one crop is followed by another crop on an

agricultural field. Some best combinations for crop rotation are given below. After cultivation of paddy, pulses/ groundnut has to be grown, followed by paddy again for cycle to continue. After cultivation of tobacco, mirchi has to be grown for the cycle to go on.

After cultivation of redgram, maize/ paddy has to be grown for the cycle to go on.

What is the benefit of crop rotation?

When cereals are cultivated more

nutrients are utilized. If legumes are grown

in the soil, less nutrients are utilized. Not

only this, they synthesize some nutrients

into the soil. Do you find any crop rotation

methods in your village? What are they?

Ask your village elders and collect the

information about it.

Cultivating mixed crops:

Have you ever seen two types of crops

in the same field?

Which crops are grown in this way?

What are the uses of cultivating mixed

crops?

Discuss in groups and display your

writings in your classroom.

If more than one crop is cultivated in

the same field then it is called mixed crop.

Because of mixed crop cultivation, the soil

becomes fertile. The nutrients which are

used by one crop will be regained by

cultivating another crop.

Which crops can be cultivated as mixed

crops? Observe the following...

Soya grown along with Pea

Pea grown along with Green gram

Corn grown along with Black gram

Groundnut grown along with Sunflower

Groundnut grown along with Red gram

Sorghum grown along with Pea.

         Haldi Plantation

                    Red Gram

      

 

      Peanuts and groundnuts

Is betel a mixed crop?

How can you justify your answer?
Can you name some leguminous crops?
Leguminous crops usually have many small
nodules on their roots. Several different
kinds of bacteria live in these nodules.
These bacteria absorb nitrogen from the air
and convert it into a form that can be used
by the plant. You will learn more about
nitrogen fixation in Bio-Geo-chemical
cycles.
Ask your teacher about names of the
nitrogen fixing bacteria.
You could uproot a Soya bean plant or
a Bengal gram plant to see the nodules on
their roots.

Root nodules in legume plants:

The microorganisms in the nodules use

some of the nitrogen for their own purpose.

Some nitrogen is used by the leguminous

plant itself. But after the crop is harvested,

the roots remain in the soil. So the soil gets

some nitrogen in this way.

Experiments have shown that a

leguminous crop gives about 50 kg to 150

kg of nitrogen per hectare. The crop grown

after the leguminous crop can take

advantage of the availability of more

nitrogen in the soil.

Nowadays a bacterial culture is also

available. This is mixed with the seeds.

When the seeds are sown, the plants are able

to produce more nodules on their roots.

Apart from this, there are various kinds

of blue-green algae that add nitrogen to the

soil. Blue-green algae culture is also

available. It is applied in rice fields.

So if a leguminous crop is rotated with

a cereal crop, the leguminous crop

replenishes, to some extent, the nitrogen

taken from the soil by the cereal crop. But

Potassium, Phosphorus and other nutrient

elements cannot be replenished in this way.

Organic manure:

Do you ever saw a herd of goats in a

vacant field? Why shepherds make

arrangements to stay their goats and sheeps

in the field.

The organic (natural) manure is

produced by decaying the plant and animal

wastes! The manure produced from

decomposed plant and animal products has

more organic material. This gives good

nutrients to the soil. It makes the soil

fertile. Because of humus, the natural

manure, water holding capacity of soil is

increases.

Natural organic manures are generally

divided into two types. One is Concentrated

organic manures and the other is Macro

organic manure.

Groundnut, Gingelly, Castor, Coconut,

Neem, Jatropa seed powders are the

examples of Concentrated organic

manures. These are also used as fodder for

cattle and poultry.

Animal excreta, compost, deep litter

are the examples of Macro organic manure.

Nutrients are rich in the concentrated

organic manures than in macro organic

manure.

         Green Manure

Soil testing:

How do farmers know what type of

crop needs to be cultivated? What types

of crops are suitable for the soil in their

fields? Farmers, who are experienced, are

able to make out from the colour and

texture of the soil.

You had also studied about the same in

your earlier class. Ask a farmer to find

out about crops that can be grown in

different types of soil.

Nowadays, Agricultural officer and the

Soil Testing Technologist are available in

every area. They observe the field and

suggest what to do.

Have you ever heard about Soil Testing Centre?

At these centers the soil technologist collect soil samples from fields and tests the fertility levels of soil. They give us knowledge about the soil. The testing centers are situated in division and district levels. If you send the sample of soil from your field, they send you a report after testing it.

Organic farming:

By using chemical fertilizers, we can

get high yield for only 20 to 30 years. After

that soil becomes reluctant to plant growth.

These chemicals damage soil fertility. If

the soil health is proper, then only the soil

responds to fertilizers. Otherwise, usage

of fertilizers become mere waste.

Long term high yielding capacity of

soil (soil productivity) depends on both

availability of nutrients in the soil (soil

fertility) and suitable physical, chemical

and biological characters of soil (soil

health).