Soil Science MCQ Question and Answer | Agriculture MCQ Question

An anemometer is an instrument that measures wind speed and weed pressure.
It is based on the principle that the air stream will cool a heated object because the cooling rate can be determined by the airflow speed. The height of the anemometer should be placed at 10 m.

The carbon and nitrogen ratio of soil microorganisms is near 8 : 1. Soil microorganisms must acquire enough carbon and nitrogen from the environment in which they live to maintain that ratio in their bodies.
The C/N ratio of organic matter in soil is 10 : 1 approx.
The C/N ratio of rotted manure is quite higher and it is 20 : 1. Manures and legume straws will decompose in soil without net immobilization of N.
The recommended proportion of C/N in sawdust is 3 : 2, not 1000 : 1.
Saw dust contains 40% lignin and 60% cellulose, only 0.048% of nitrogen and traces of phosphorus, potassium and calcium.

Chroma in soil colour determination refers to the relative purity or strength of the spectral colour and increases with decreasing greyness. In the soil colour chart, all colours on a given card are of a constant hue, designated by a symbol in the upper right-hand corner of the card.

A blood meal is extremely rich in Nitrogen. It contains about 13 - 20% Nitrogen, 1% phosphorous and 0.6% of potassium. It is a dry, inert powder made from blood, used as a high-nitrogen organic fertilizer, non-synthetic and high protein animal feed.
A blood meal is composed of protein mostly, small amounts of fats and ash. It usually comes from cattle or hogs as a slaughterhouse by-product.

Hydraulic conductivity is a property of vascular plants, soils and rocks that describes the ease with which a fluid can move through pore spaces or fractures. It depends on the intrinsic permeability of the material, the degree of saturation and the density and viscosity of the fluid. It also depends on pore geometry, pore size and pore tortuosity.
It does not depend on No. of pores.

pF value characterizes the energy with which the soil water is held against gravity in the soil matrix. It is defined as the decadic logarithm of the amount of soil water tension in hectopascals. The higher the pF value, the drier the soil or the lower its water content.
The pF value of available water is 2.54.

Mehlich’s cunninghamella Plaque method is used to test Phosphorous.
In this method, the soil is mixed with the nutrient solution, a paste is made, spread uniformly in the well of a specially constructed clay dish, inoculated on the surface in the center of the paste, and allowed to incubate for a few days.

Stem nodulating Rhizobium species is Azo-rhizobium. It belongs to the genus of Gram-negative soil bacteria. Like root nodulating bacteria they fix nitrogen in symbiosis with plants in the genus sesbania.
Stem nodules occur at the site of adventitious root primordia located on the stems via crack entry.

Gnesis is a metamorphic rock which is having banded or laminar appearance. It has a distinct banding, which is apparent in hand specimens or on a microscopic scale. It is formed by high-temperature and high pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks.

Fe deficiency is mostly seen in crops growing on Calcareous or alkaline soils. The high soil pH is the most common cause of the iron deficiency.
The deficiency of Iron is a major nutritional disorder that causes a decrease in vegetative growth and marked yield and quality losses.