Tag: biology

Questions Related to biology

Which of the following is not true for fertilisers?

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. They increase the yield.

  2. Their excessive use disturbs the balance of nutrients in soil.

  3. They are generally used in small quantity.

  4. They are environment friendly.

Show answer
Correct Option: D
Explanation:
The by-products of fertilizer industries are pesticides and some chemical fertilizers. They are non-biodegradable, so they get accumulated at each trophic level. These mix up with soil and water. From there, these pesticides are absorbed by the growing plants along with water and minerals.
When herbivores eat these, these poisonous chemicals pass into their bodies through the food chain. When carnivores eat herbivores, these pesticides transfer to their bodies. Man being omnivore, eats both plants and herbivores and these gets accumulators into their body.
Thus, pesticides enter the food chain at the producer level and in the process of transfer of food through food chains, these harmful chemicals get concentrated at each trophic level. This is called bio magnification.
Therefore, the correct answer is option D.

Which of the following statement is not true for organic manure?

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. It enhances water holding capacity of soil

  2. It has a balance of all plant nutrients

  3. It provides humus to soil

  4. None of these

Show answer
Correct Option: D
Explanation:

  • Manure is an organic substance produced by the decomposition of plant and animal wastes in the presence of the microorganism. 
  • Organic manure contains a few nutrients. It enhances the water holding capacity of soil. 
  • This makes more water available to plants. It has a balance of all plant nutrients. It provides humus (organic matter ) to soil. 

Therefore, option D is correct.  

In compositing, solid waste is converted into;

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Ashes

  2. Manure

  3. Clinkers

  4. Fumes

Show answer
Correct Option: B

A few gram seeds were placed in each of the three pots A, B and C containing soil. The soil in Pot A is mixed some green twigs and leaves. The soil in pot B is mixed with old cow dung while soil of pot C is mixed with urea. Pots are watered regularly. Which of the following will be observed after 10 days?

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Lot of growth in A

  2. Not much growth in B

  3. Lot of growth in B but very little growth in C

  4. Very little growth in A but lot of growth in B and C

Show answer
Correct Option: D
Explanation:

Manure is an organic substance produced by the decomposition of plant and animal wastes in the presence of microorganism and used as fertilizers. Thus, the fresh manure contains decomposing bacteria along with active digestive enzymes. These enzymes contribute to the faster heating of the manure which accelerates the decomposition of organic materials by the soil microorganisms. The end result of better decomposition of organic material is faster nutrient release to the plant. When urea is placed on the surface of the soil, a chemical reaction takes place that changes the urea to ammonium bicarbonate. Urea should be mixed in with the soil for maximum effectiveness. For plants that love acidic soils, urea is one of the top fertilizers for acidifying soils. Hence, seeds will grow most in pots B and C.

Which of the following rotation of crops will reduce dependence on the use of chemical fertilizers?

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Rice and Chilli

  2. Wheat and Potato

  3. Potato and Rice

  4. Gram and Rice

Show answer
Correct Option: D
Explanation:

Crop rotation helps the farmers to maintain the fertility of the fields by growing alternate crops. A particular crop with one type of nutrient sown in one season restricts the cultivator to sow the other crop with another type of nutrient  in the next season, which is most beneficial for the field e.g., gram is nitrogen rich crop and rice is sugar rich crop, so, their alternate cropping can give different nutrients to the field and thus, reduces the use of chemical fertilizers.

Fairly good yield of rice can be had over a number of years without adding any nitrogenous manures because

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. They require very minute quantities of nitrogen.

  2. Their roots have nitrogen-fixing bacterial associated with them.

  3. There are nitrogen-fixing algae in the rice fields.

  4. Rice plant do not require any nitrogen.

Show answer
Correct Option: C
Explanation:

The rice paddy field contains the Azolla weeds with the nitrogen-fixing cyanobacteria which can help in the conversion of the atmospheric nitrogen to nitrates. This nitrate can be used for the growth of the plants without the introduction of nitrogenous manures externally. These organisms help increase the yield of the rice plants. 

Thus, the correct answer is option C. 

Consider the following microbes

A. Azotobacter
B. Azolla
C. Mycorrhiza
D. Nostoc

The aforementioned microbes are

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Manure yielding biofertilizers 

  2. Converters of atmospheric nitrogen into ammonia

  3. Capable of improving the elements phosphorus, potassium, zinc etc., in soil

  4. The source of nitrogenous fertilizer

Show answer
Correct Option: A
Explanation:

  • Azotobacter, Azolla, Mycorrhiza, and Nostoc are manure yielding biofertilizers. Biofertilizers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilizers are bacteria, fungi, and cyanobacteria.
  • Azotobacter is bacteria that can fix atmospheric nitrogen while free-living in the soil, thus enriching the nitrogen content of the soil.
  • Azolla is a water fern. It lives in a symbiotic relationship with a cyanobacteria Anabaena azollae which fixes nitrogen. It is used as an excellent fertilizer in the rice field.
  • Mycorrhiza is a symbiotic relationship of fungi with roots of higher plants. The fungal symbiont absorbs phosphorus from soil and passes it to plants. Plants having such associations show resistance to root borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development.
  • Nostoc is a cyanobacterium. It can fix atmospheric nitrogen. It also adds organic matter to the soil and increases its fertility. 

Different types manures are

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Farmyard, compost and green

  2. Green and farmyard

  3. Green and compost

  4. Farmyard and compost

Show answer
Correct Option: A
Explanation:

Manure is an organic substance produced by the decomposition of plant and animal wastes in the presence of microorganism and used as fertilizers. Farmyard manure, compost and green manure are the most important and widely used bulky organic manures. Farmyard manure is the decomposed mixture of excreta of farm animals along with litter and leftover material from fodder fed to the cattle. Green manure and compost are the decomposed substance of crop. It is helpful in maintaining soil form, aeration and hydration. 

The distribution of fertilizers by aircraft is widely practised in______________ 

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. England

  2. France

  3. Germany

  4. New Zealand

Show answer
Correct Option: D
Explanation:
  • Aerial application, or crop dusting, involves spraying crops with crop protection products from an agricultural aircraft. Agricultural aircraft are highly specialized and used for the application of agricultural materials.
  •  It was used by John Chaytor in 1906 to spread seed over a swamped valley floor in Wairoa, New Zealand. Therefore, the correct answer is option D.

Ignition of manure is possible if__________________

biology improvement in food resources manure manures and fertilisers role of organic manures in soil management

  1. Stored in a very large pile

  2. Stored in small piles

  3. Stored near fodder

  4. All of the above

Show answer
Correct Option: A
Explanation:

Manure is an organic substance produced by the decomposition of plant and animal wastes in the presence of microorganism and used as fertilizers. Thus, the fresh manure contains decomposing bacteria along with active digestive enzymes. These enzymes contribute to the faster heating of the manure which accelerates the decomposition of organic materials by the soil microorganisms. Manure generates heat as it decomposes, and it is possible for manure to ignite spontaneously if stored in a very large pile. 

Therefore, the correct answer is option A.