Soil Science MCQ Question and Answer | Agriculture MCQ Question

The soil thermal conductivity is the ratio of the magnitude of the conductive heat flux through the soil to the magnitude of the temperature gradient.
According to heat conductivity soils can be classified as : Sand > Loam > Clay > Peat.
The soil thermal conductivity of sandy soil is maximum and the lowest is for Peat soil.

To apply NPK, an NP complex has to be supplemented with Potash (Potassium-K).
NPK is a complex fertilizer consisting of Nitrogen, Phosphorus and Potassium. Each of these fundamental nutrients plays a key role in plant nutrition. Plant cells use these nutrients to grow and develop. They help root and shoot development, flower and fruit formation and assist natural pest and disease resistance.

The lime requirement is defined as the amount of agricultural limestone or other basic. Material needed to increase the pH of the soil from an unacceptability acidic condition to a value that is considered optimum for the desired use of the soil.
Estimation of the lime requirement was developed by Shoemaker et. al (1961). Of the several buffer methods for measuring lime requirement of acid soils and is the most widely adopted by soil testing laboratories.

The extractant used for available phosphorus in soils is 0.5 M NaHCO₃, (Olsen). It is the most widely used method in P extraction for Routine fertility purposes, although it was initially proposed for neutral and alkaline soils.
An extractant is a liquid used to remove a solute from a solution. Here, in Olsen method uses NaHCO₃ extractant that can remove Ca-Phosphates and phosphate absorbed on the surface of surfaces of calcium and magnesium carbonates along with Al-phosphates. Phosphorus is extracted from the soil with 0.5 M NaHCO₃ at a nearly constant pH of 8.5.

Soil testing-based doze is better because it is made for a particular field. Soil test refers to one or more of a wide variety of soil analyses conducted to estimate the plant available concentrations of plant nutrients, to determine fertilizer recommendations in agriculture.
Soil testing helps in selecting the right fertilizer and its quantity for an optimum dose of fertigation.

Soils have no diagnostic Pedogenic horizons included in soil order Entisols. Entisols are defined as soils that do not show any profile development other than an A horizon.
An entisol has no diagnostic horizons and is most basically unaltered from its parent material, which can be unconsolidated sediment or rock.
Entisols are the most abundant soil order. Occupying about 16% of the global ice-free land area.

Basic slag and Pelophos come under Citrate soluble.
Basic slag is a slag low in silica and high in base-forming oxides that are used in the basic process of steelmaking and that is subsequently useful as a fertilizer.
The alkaline Phosphorus fertilizer manufactured from rock phosphate and foundry slag contained 17 - 18% P₂O₅ and Mg and various micro-nutrients and were more effective on grassland than superphosphate.

Khaira disease of rice is a micro-nutritional deficiency characterized by the presence of dusty brown patches on leaves which ultimately undergo necrosis. This is one of the common diseases in rice which is caused by the deficiency of Zinc (Zn).
Khaira disease affects the leaf of the plant. The rate of photosynthesis decreases which ultimately causes 25 - 30% production loss.

The symbiotic association of fungal hyphae with plant roots is referred to as Mycorrhiza.
It is a mutual symbiotic association between a fungus and a plant. It refers to the role of the fungus in the plant’s rhizosphere, its root system. In this association, the fungus colonizes the host plant's root tissues, either intracellular or ectomycorrhizal fungi. Mycorrhizae play important roles in plant nutrition, soil biology and soil chemistry.

Soil fertility is reduced due to Continuous cropping.
The continuous cropping on the same piece of land causes a decline in the nutrients in the soil. The quantities of nutrients removed from the soil in harvested products exceed the quantities of nutrients being applied.