Class Notes NCERT Solutions for CBSE Students
Question: What are the different ways / methods of hybridisation?
Answer: Hybridisation can be
- Inter-varietal – between different varieties of crops
- Inter-specific – between two species of same genus
- Inter-generic – between two different genera
Question: What are the main characters required in a crop during its improvement practices?
Answer: The useful characters that are required in a crop during its improvement:
- Disease resistance
- Response to fertiliser
- Product quality and
- High yield.
Question: State the difference between macro-nutrients and micro-nutrients.
Answer:
Macro-nutrients
Micro-nutrients
These are required by crops in larger quantity.
These are required by crops in very small quantity.
Six macro-nutrients are: Nitrogen, Phosphorus, potassium, Calcium, Magnesium and Sulphur.
Seven micro-nutrients are: Iron, Manganese, Boron, Zinc, Copper, Molybdenum and Chlorine.
Question: How do deficiency of nutrients affect the crop?
Answer: Deficiency of any nutrient affects physiological processes in plants including reproduction, growth and susceptibility to diseases.
Question: State the difference between manure and fertilizer.
Answer:
Manure
Fertiliser
It consists of organic matter.
It consists of inorganic matter.
Prepared from animal excreta and plant waste.
It is prepared commercially from chemicals.
Its use causes no pollution.
It causes pollution in soil and water.
Question: What are the harmful effects of fertiliser? .
Answer: It causes soil and water pollution. Continuous use can also destroy soil fertility.
Question: What is organic farming?
Answer: It is the farming in which no chemical fertilisers, pesticides or herbicides are used. But uses all organic matter for its growth like manure, neem leaves as pesticides and for grain storage.
Question: State the preventive and control measures used before grains are stored.
Answer:
- Cleaning of the grains
- Proper drying of the produce in sunlight, there should be no moisture.
- Fumigation of produce using chemicals that kills pest.
