Monday, August 29, 2011

8th Science-Crop Production -Macro-Micro Nutrients-Manures-Fertilizers

Q. What are macro nutrient and micro nutrients?

Elements which are needed in large quantities for growth of the plants are called Macro Nutrients. They are Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorous, Sulphur, Potassium, Calcium, Magnesium and Iron.

Elements which are needed by the plants in very small quantities are called Micro Nutrients. They are Manganese, Copper, Molybdenum, Zinc, Boron and Chlorine.

Q. What is manure ?

Manure is an organic substance and is prepared by the decomposition of plant and animal wastes
Based on the kind of biological materials used, manure can be classified as,     i) Compost & Vermi Compost     ii) Green Manure


Compost prepared by using earth worms to speed up the process of decomposition of plant and animal
wastes is called Vermi Compost.

Leguminous plants like Sunn-hemp or Cluster Bean are grown and then mulched by ploughing them back into the soil is called Green Manure

Q. What are the differences between Manures and Fertilizers


Manures
Fertilizers
1. Manure is a natural substance obtained by the decomposition of cattle dung, human waste and plant waste.
1. Fertilizer is a mineral or chemical compound containing nutrients like Sulphur, Phosphorous, Nitrogen, etc.
2. Manures are organic substances.
2. Fertilizers are inorganic compounds
3. Manures can be prepared in fields
3. Fertilizers are manufactured in factories.
4. Manures contain all nutrients but in small quantities.
4. They contain higher quantities of one or more specific nutrients.
5. Manures add plenty of humus to soil and improve the texture of the soil.
5. Fertilizers do not result in the addition of humus to the soil.
6. Manures are not easily absorbed because they are less soluble in nature
6. . Fertilizers are soluble in water and it is easily absorbed.
7. . Manures are less soluble; they are not easily washed away from the soil and hence their effect is long lasting.
7. Fertilizers are easily washed away by water   and hence their effect is of shorter duration and require repeated application

Q. What do you know about Bio-fertilizers?

Fertilizers which are derived from living organisms are called Bio-fertilizers.The main source of bio-fertilizers are bacteria, cyanobacteria and fungi.

Bio-fertilizers are renewable and non-polluting sources of plant nutrients. They also improve the soil condition. Rhizobium and Cyanobacteria such as Anabaena and Nostoc are some common bio-fertilizers.

Q. What are are different methods of controlling of the pests?

There are different methods of controlling of the pests. The most common method of controlling pests is
the use of pesticides.

Pesticides are classified as Insecticides, Fungicides, Weedicides, Rodenticides, etc., depending upon their use.
i) Insecticides : The chemical substances which are used to kill the insects are called insecticides.
e.g. DDT (Dichloro diphenyl trichloro ethane), Malathion etc.,

ii) Fungicides : The chemicals used to kill fungi are called fungicides. e.g. Bordeaux mixture.
iii) Weedicides : The chemical substances which are used to kill the weeds are called weedicides. e.g.2-4-D. (2-4-Dichloro phenoxy acetic acid)

iv) Rodenticides : The chemicals used to kill rodents like rats, mice and squirrel are called rodenticides,
e.g. Zinc Phosphate, Arsenic etc.

Q. What is Hybridization?

Hybridization is the method of producing improved varieties by crossing two or more plants of dissimilar genotypes together. A plant variety containing as many desirable characters as possible
can be produced by hybridization.
Hybridization involves selection of parents with desirable qualities. Useful characteristics are scattered in different varieties. It is possible to bring all the characters in a single variety by Hybridization.

Hybridization can be
i) Intervarietal (cross between two different varieties)
ii) Interspecific (cross between two species of the same genus)
iii) Intergeneric (cross between different genera)


Crop Production and Management
CBSE Study Notes Crops production
CBSE Practice Paper-1
CBSE Practice Paper-2
CBSE [Solved] Practice Paper -3       

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