Agronomy - Study Mode

[#821] Which one of the following is the principle 'Nitrogen' fixing algal community of blue-green algae?
Correct Answer

(B) Anabaena

Explanation

Solution: Anabena is one of the principle "Nitrogen fixing" algal communities of blue-green algae. Anabena is found as plankton in shallow water and on moist soil with beadlike or barrel like cells and interspersed enlarged spores to provide nitrogen to plants in soluble forms.

[#822] The total volume of water on melting of ice
Correct Answer

(C) Decreases

Explanation

Solution: When ice melts, the total volume of water decreases because the density of ice is less than that of water, thus when the ice melts the volume of water will decrease.

[#823] In field capacity, the water held at a tension of
Correct Answer

(B) $$ - frac{1}{3}$$ bar

Explanation

Solution: Field capacity is the maximum limit of the water available in the soil, after the drainage of excess water. The physical definition of field capacity is the bulk water content retained in the soil at $$-$$33 kPa of the hydraulic head or suction pressure. Thus in field capacity, the water is held at a tension of $$ - frac{1}{3}$$ bar.

[#824] The insect bollworm is commonly found on
Correct Answer

(C) Cotton

Explanation

Solution: Bollworm is the common term for a moth larva that attacks the fruiting bodies of certain crops, especially cotton and it causes a huge loss in the yield. The cotton bollworm is widely controlled by biopesticides Bacillus thuringiniensis (Bt) toxin and baculovirus HaNPV.

[#825] For summer soybean, seed rate should be . . . . . . . . than that of kharif planting.
Correct Answer

(A) More

Explanation

Solution: The seed rate of soybean produced in the summer season is more than the seed rate of soybean planted in the Kharif season. It is around 100 - 120 kg/ha during summer and 70 - 75 kg/ha during Kharif season.