lesson-food (POST 4)

Good morning boys! 
You have learnt about autotrophic and heterotrophic nutrition in plants.
Plants get their mineral nutrients from the soil. If crops are grown year after year on the same soil, the soil will get poor in such nutrients. Nitrogen , phosphorus, potassium , magnesium ,calcium are the major nutrients .
THINK ABOUT THIS-
What happens when soil becomes poor in these nutrients?
Does it effect crop yield?
( discuss with an elder in your family)
Yes, you got it right! Soil loses its fertility and crop yield falls. 
Therefore it is important to replenish these nutrients in the soil.

LEARNING OUTCOMES OF THIS CLASS-
By the end of this lesson you will be able to-
.list ways to replenish nutrients in the soil
.distnguish between manure and fertilizer

METHODS OF REPLENISHING NUTRIENTS IN THE SOIL
1. By using manure


Recollect...
Is manure made from remains of dead plants and animals or from chemicals in factories ?
2. By using fertilizers like urea 

3. By crop rotation method - This involves sowing a cereal crop alternately to a leguminous crop.
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Usually plants require a lot of nitrogen to make proteins.
This is made possible by-
. Using nitrogenous fertilizers like urea , ammonium nitrate etc.
. Rhizobium bacteria present in the root nodules of legumenous plants helps to convert  atmospheric nitrogen into nitrates. Nitrates are soluble in water and be provide nitrogen to plants.



HOTS!
1. Do you think rhizobium bacteria and the root nodules of a pea plant have a symbiotic relationship?

HOME WORK
1. Read pages 9 and 10 of the reader.
2. Do questions A,D on page 11 in your rough notebook and in your reader when you get it.
3. Do question C on page 12 in your rough notebook and in your reader when you get it. 
With this we come to the end of lesson -1  FOOD. 


SDG ACTIVITY- life on land
Reflect.... is man over expoliting land and overusing its resources?How can this be minimized?