Soil Science MCQ Question and Answer | Agriculture MCQ Question

Dry ice is a solid form of carbon dioxide. It is commonly used for temporary refrigeration as carbon dioxide does not have a liquid state at atmospheric pressure and sublimates directly from the solid-state to the gas state. It is primarily used as a cooling agent.
Dry ice sublimes at -78°C (194.7 K) at the earth's atmospheric pressure.

The fertilizer control order came in the year 1957.
The Fertilizer Control Order, 1957 was issued under Section 3 of ECA, 1955 to regulate manufacture, trade and distribution of Fertilizers in the country.
The main aim of the fertilizer control Order is to ensure adequate availability of the right quality of fertilizers at the right time and right price to farmers, the fertilizer was declared an essential commodity and fertilizer control order (FCO). It also works to regulate, trade, price, quality and distribution of fertilizers in the country.

At present 49% of Indian soils are potentially deficient in diethylene-triamine pentaacetate (DTPA) extractable Zinc.
Zinc is one of the eight essential micronutrients. It is needed by plants in small amounts, yet crucial to plant development. In plants, zinc is a key constituent of many enzymes and proteins. It plays an important role in a wide range of processes, such as growth hormone production and internode elongation.

Stem melanosis, a disease of spring wheat and was first reported in 1965. The diseased plants are characterized by bleached empty heads and by blackening of the rachis, peduncle and stem immediately beneath the nodes.
This disease in wheat is caused by Pseudomonas cichorii grown on soil because of the deficiency of copper.

Zinc sulphate is the most commonly used zinc fertilizer worldwide.
It is a micronutrient fertilizer and it usually contains 33% zinc and 15% of Sulphur. It is available in both crystalline monohydrate and heptahydrate forms.
It helps to prevent low yields, spotted leaves and stunted growth. It can also be used as a natural fungicide.

Boron is injurious to plants when irrigation water contains more than 3 ppm concentration of boron.
When the concentration of boron in irrigation water is above the maximum level it causes havoc on the yield of the crop. There is various plant crop sensitive to boron. although boron is an essential nutrient for the plants it is required in small amounts.
Boron toxicity can cause conspicuous necrotic lesions in the interveinal areas of older leaves, leading to premature senescence and shredding of the leaves.

A polar covalent bond is seen in HCl between hydrogen and chlorine.
Hydrogen chloride (HCl) is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a covalent bond. It is formed by the sharing of an electron pair between the two atoms. The chlorine atom is much more electronegative than the hydrogen atom, which makes this bond polar.

Nitrobacteria are obligate aerobes. It plays an important role in the nitrogen cycle by oxidizing nitrite (NO₃^-) into nitrate and ultimately nitrogen in the soil.

Ammonifying bacteria convert ammonia into atmospheric nitrogen.

Denitrifying bacteria results in the conversion of nitrates in the soil to free atmospheric nitrogen.

Rhizobium species are a group of bacteria that helps in fixing atmospheric nitrogen in plants.