Soil Science MCQ Question and Answer | Agriculture MCQ Question

Nutrient index values refer to the rating of nutrients based on their critical values and based on NI values, the soil fertility is rated as low, medium, and high. If the index value is less than 1.67, the fertility status is low, and the value is between 1.33 - 2.33. If the value is greater than 2.33, the fertility status is high.
The medium range for Nutrient index value is 1.33 - 2.33.

Fertilizers are added to increase the fertility of the soil.
Fertilizer is the material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments.
Farmers apply these fertilizers in a variety of ways, through dry or pelletized or liquid application processes, using large agricultural equipment or hand tool methods.

Onion-skin weathering or exfoliation is the process of layers of the rock being peeled off like an onion.
When rock is exposed to physical erosion, these concentric layers peel off as concentric shells much like the layers of a peeled onion.
The main reasons behind the exfoliation in rocks are Temperature variation and different mineralogical compositions of rock.

The inorganic and organic labile P fractions of soil are collectively called the Quantity factor.
Quantity intensity is a fundamental relationship that determines ion uptake about the status of ions present in the soil solution.
Labile phosphorus is more plentiful than soluble P but is still only a small fraction of total soil P. This soil P fraction typically accounts for less than 1% to less than 5% of the P in soils and is more tightly bonded than stable P.

The acidic effect of fertilizer can be corrected by Liming.
Liming is a desirable practice to overcome constraints of soil acidity for enhanced crop production. It involves the application of limestone, hydrated lime, chalk or other materials, which are rich in calcium and magnesium that can increase the soil pH through the improved base solution.

Borax and Ammonium Molybdate having 10.5 & 52% of Boron and Molybdenum Respectively.
The boron deficient soil is usually sandy, acidic and have low organic matter and is fed with borax to fulfill the boron deficiency.
Ammonium molybdate is a white to colorless or greenish-yellow, odorless powder. Molybdenum is an essential component in two enzymes that convert nitrate into nitrite and then into ammonia before it is used to synthesize amino acids within the plant.

Urine is a liquid by-product of metabolism in humans and many other animals. Urine plays an important role in the earth's nitrogen cycle. In balanced ecosystems, urine fertilizes the soil and thus helps plants to grow.
Urine has large amounts of nitrogen, phosphorus and potassium. It contains 1.0% Nitrogen.

FYM (Farmyard manure), is primarily made from cow dung, cow urine, waste grass and other dairy waste. It is rich in nutrients. It contains 0.25% of P₂O₅.

Bird guano is the desiccated droppings of seabirds and it is a highly effective fertilizer. It contains 11 - 14% of P₂O₅.

Night soil is human excreta collected from cesspools, septic tanks, etc. and removed usually at night and is a good source of fertilizer with 4.0% of P₂O₅.

Compost is a mixture of ingredients used to fertilize and improve the soil. It is commonly prepared by decomposing plant and food waste and recycling organic materials. It contains 0.51%.

The salt index of fertilizer is a measure of the salt concentration that fertilizer induces in the soil solution. Puri’s salt index accounts relationship between concentrations of sodium and calcium ions in given irrigation water.

Parker's nutrient index is a three-tier used to evaluate the fertility status of soils based on the percentage of samples in each of the three classes, that is low, medium and high.

A value concept was given by fried and Dean in 1952. The concept is when the plant is confronted with two sources of a nutrient, the plant will absorb from each of these in proportion to the respective amounts available.

DRIS is Diagnosis and recommendation irrigated system given by Beaufills. It is a widely used statistical approach for interpretation of the plant tissue analysis data and diagnosing the plant nutrient needs much earlier than the reduction of crop yield with great accuracy.

Aluminum is the metal that is most dominant in the earth's crust. It is the most abundant metal in the Earth's crust which is about 8.23% and the third most abundant of all the elements after Oxygen and silicon. It is rarely found uncombined in nature, It is usually found in minerals such as Bauxite and cryolite.