agriculture Soil Science questions for competitive exams

1. Soil fertility and fertilizers’ was written by

(a) NC Brady

(b) Tisdale et al.

(c) MM Rai

(d) None

  1. Who suggested that the principal nourishment of plant was water ?

(a) Pietro de Crescenzi

(b) JB Helmont

(c) Francis Bacon

(d) Jethro Tull

  1. Who gave the statement ‘water was the sole nutrient of plants’ ?

(a) Robert Boyle

(b) John Woodward

(c) JR Glauber

(d) JB Helmont

  1. suggest that saltpeter (KNO,), and not water, was the ‘principle of vegetation’.

(a) JR Glauber

(b) Jethro Tull

(c) Johnwoodward (d) John Mayow

  1. ‘Horse hoeing husbandry’ was written by

(a) Liebig

(b) Arthur Young

(c) Baker

(d) Jethro Tull

  1. ‘Annals of Agriculture’ a book was written by

(a) Sir Humphry Davy

(b) Arthur Young

(c) JS Kanwar

(d) Robert Warrington

  1. Who is considered the father of field plot technique ?

(a) JB Boussingault

(b) Pushkarnath

(c) Ramanunjan
(d) Liebig

  1. The law of the minimum, was given by Liebig in

(a) 1842

(b) 1852

(c) 1862

(d) 1875

  1. In 1843, Agricultural Experiment Station at Rothamsted, England was started by

(a) Liebig

(b) Blackman

(c) Lawes & Gilbert

(d) Benjamin Franklin

  1. Who isolated Bacillus radicicola, the organism responsible for N fixation in 1888 ?

(a) S Winogradsky

(b) MW Beijerinck

(c) Milton Whitney

(d) JB Lawes

  1. In remote sensing, which type of radiation is utilized for photography?

(a) Violet

(b) Far red light

(c) Infra red

(d) Green light

  1. One bushel (bu) is equal to

(a) 28.35 gram

(b) 35.24 litres

(c) 101.30 atm

(d) 0.454 lb

  1. One ton is equal to (kg)

(a) 100

(b) 907

(c) 1000

(d) 2240

  1. It has been observed that soil pH increases in

(a) Summer

(b) Winter

(c) Zaid

(d) Post monsoon season

  1. The behaviour of the plant in relation to day length is termed

(a) Thermoperiodism

(b) Photoperiodism

(c) Heliotropic

(d) None of above

  1. Scab of Irish potatoes, pox of sweet potatoes, and black root rot of tobacco are favoured by

(a) Acidic conditions

(b) Highly alkaline

(c) Neutral to alkaline conditions

(d) Extremely acidic condition

  1. “Increase in yield of a crop as a result of increasing a single growth factor is proportional to the decrement from the maximum yield obtainable by increasing the particular growth factor” was described by

(a) Liebig

(b) Bray

(c) Spillman

(d) EA Mitscherlich

  1. Which one of the following is an example of positive interaction ?

(a) Lime x P

(b) Mox P

(c) P x Si

(d) Na x K 19.

  1. Bray has modified the mitscherlich equation to

(a) G = f(x, X2, X3 Xn)

(b) dy/dx = (A-y) C

(c) YA (1-10)

(d) log (A-y) log AC,b cx N

  1. The nutrient concentration range in which added nutrient will not increase yield but can increase nutrient concentration is referred as

(a) Deficient range

(b) Critical range

(c) Luxury consumption

(d) Toxic range

  1. Reduction reaction (NO, to NH,) for nitrate assimilation by enzyme nitrite reductase takes place in

(a) Protoplasm

(b) Cytoplasm

(c) Chloroplast

(d) Nucleus

  1. Which element is considered as energy currency for the plant ?

(a) N

(b) P

(c) K

(d) Mo

  1. Which element is indirectly related with drought resistance?

(a) N

(b) K

(c) P

(d) Zn

  1. The purpling along the leaf edges is the characteristic deficiency symptom of

(a) P

(b) K

(c) B

(d) Fe

  1. Which one of the following element is considered to be an in the plant? immobile element

(a) Ca

(b) Mg

(c) N

(d) P

  1. Among the families of crop plants, the sulphur requirement increases in the order of

(a) Leguminosae > Graminae > Cruciferae > Cruciferae

(b) Graminae > Leguminosae

(c) Graminae < Leguminosae < Cruciferae

(d) None of these

  1. Major form of boron absorbed by plants is

(a) B40-2

(b) HBO,

(c) BO2

(d) H₂BO3

  1. When Fe contents in plants falls below or equal to ppm, deficiency is likely to occur.

(a) 20

(b) 40

(c) 50

(d) 100

  1. Fe deficiency is mostly seen in crops growing on

(a) Calcareous or alkaline soils

(b) Salt affected soils

(c) Acidic soils

(d) Neutral soils

  1. Fe is an important component of enzymes

(a) Nitrogenase

(b) Nitrate reductase

(c) Nitrite reductase

(d) All of these

  1. Bronzing is associated with Fe levels greater than 300 ppm in the leaf blade of

(a) Wheat

(b) Rice

(c) Maize

(d) Sorghum

  1. Crinkle leaf of cotton is caused by

(a) Fe toxicity

(b) Cu toxicity

(c) Mn toxicity

(d) Zn toxicity

  1. In plants, deficiency of Zn are usually associated with concentrations of less than

(a) 6 ppm

(b) 20 ppm

(c) 50 pm

(d) 100 pm

  1. Molybdenum is a component of

(a) Urease

(b) Nitrogenase

(c) Nitrate reductase

(d) Both (b) and (c)

  1. Downey mildew of pearlmillet may be suppressed by increased soil levels of

(a) Ca

(b) Cu

(c) CI

(d) Mo

  1. Fertilizers containing Cl- ions are not suitable for

(a) Sugarcane

(b) Potato

(c) Wheat

(d) Pigeonpea

  1. Intracellular deposits of which element is known as plant opals ?

(a) Sodium

(b) Silicon

(c) Nickel

(d) Vanadium

  1. Stem melanosis disease occurs in wheat due deficiency of

(a) Mn

(b) Cu

(d) Si

(c) Zn

  1. Which element is the metal component of urease enzyme ?

(a) Silicon

(b) Sodium

(c) Molybdenum

(d) Nickel

  1. CEC of which clay mineral is highest (120-150 cmol/kg) ?

(a) Mica

(b) Vermiculite

(c) Montmorillonite

(d) Chlorite

  1. The negative charge on 2: 1 clays is

(a) pH dependent

(b) pH independent

(c) Both (a) and (b)

(d) None of these

  1. CEC values for organic soils lies in range of

(a) 3-5 meq/100 g

(b) 10 – 20 meq/100 g

(c) 20 – 100 meq/100 g

(d) 50 50 meq/100 g

  1. For most minerals, the strength of cation adsorption, or lyotropic series, is

(a) Ca2+ > A13+ > Mg2+ > K=NH > Nat

(b) Al3+ > Ca2+ > Mg2+ > K+ = NH > Na+

(c) Mg2+ > A13+ > Ca2+ > K+ = Na* > NHA

(d) Al3+ > Mg 2+ > Ca2+ > K+ = NH+ > Na

  1. Which extract is used for determination of CEC?

(a) 1N NH OAC

(b) 1N NaOHCO

(c) 1N KOAC

(d) Olsen reagent

  1. Which one of the following formula is used for calculation of base saturation?

(a) Total bases/CEC × 100

(b) Exchangebale bases/CEC x 100

(c) CEC/total bases × 100

(d) CEC/exchangeable bases × 100

  1. The anion exchange capacity (AEC) increases as soil pH

(a) Increases

(b) Decreases

(c) First increases then decreases

(d) Remain unaffected

  1. One acre of soil to a depth of 6 inch weight about
    (a) 2.25 x 106 kg

(b) 2 x 106 kg

(c) 2 x 106 Ib

(d) 2.25 x 106 lb

  1. Which plant nutrient move from soil to the roots by root interaction, mass flow and diffusion in equal proportion?

(a) Zinc

(b) Boron

(c) Sulfur

(d) Calcium

  1. Which organisms are microaerobic, free fixers or in association with grasses ?

(a) Azotobacter

(b) Azospirillum

(c) Rhizobium

(d) Frankia

  1. In which country most of the N required for crop production is obtained through N, fixation by legumes ?

(a) India

(b) USA

(c) Japan

(d) New Zealand

  1. For nitrification, the optimum pH is

(a) 6.5 1

(b) 7.5

(c) 8.5

(d) 9.5

  1. Nitrosomonas and Nitrobacter causenitrification are an obligate

(a) Autotrophic bacteria

(b) Heterotrophic bacteria

(c) Both (a) and (b)

(d) Saprophytes

  1. Maximum nitrification takes place at

(a) 10% O₂

(b) 20% O₂

(c) 30% O₂

(d) 40% O₂

  1. NH fixation takes place in

(a) Vermiculite and illite

(b) Montmorillonite and kaolinite

(c) Chlorite and kaolinite

(d) All of these

  1. Which fertilizer has risk of fire or even explosion?

(a) Aqua NH,

(b) Ammonium nitrate

(c) Potassium nitrate

(d) Ammonium chloride

  1. Biuret in urea applied as a foliar spray in citrus fruits should not be more than

(a) 0.25%

(b) 0.50%

(c) 0.75%

(d) 1.50%

  1. Which fertilizer act as a nitrification inhibitor and as a slow release N source?

(a) CDU

(b) IBDU

(c) N-serve

(d) DCD

  1. The inorganic and organic labile P fraction of soil are collectively called

(a) Intensity factor

(b) Quantity factor

(c) Capacity factor

(d) None of these

  1. At what pH, three are approximately equal amounts of H,PO, and HPO,2-?

(a) 6.5

(b) 7.0

(c) 7.2

(d) 8.5

  1. ‘Peat’ soil are generally characterized as

(a) Black, heavy and acidic

(b) Red, light and acidic soil

(c) Black, light and alkaline soil

(d) Black, heavy and neutral soil

  1. P content in DAP is

(a) 20%

(b) 36%

(c) 46%

(d) 50 %

  1. What is the porosity percentage if the particle density of soil is 2.6 and bulk density is 1.3 ?

(a) 35 %

(b) 40 %

(c) 50 %

(d) 55 %

  1. Chemical formula of single superphosphate is

(a) Ca (H,PO)

(b) CaHPO4

(c) Ca,(PO4)

(d) Ca (H,PO,).CaSO,.2H₂O

  1. Height of rise of water in a capillary tube is directly proportional to

(a) Surface tension of water

(b) Radius of capillary tube

(c) Viscosity of water

(d) As in (a) and (c) above

  1. Hill soils are generally

(a) Acidic

(b) Alkaline

(c) Neutral

(d) Saline

  1. The diagnostic surface horizons are called

(a) Genetic horizons

(b) Pedons

(c) Epipedons

(d) Endopendons

  1. Available water holding capacity is maximum in

(a) Clay loam

(b) Sandy clay loam

(c) Silty clay loam

(d) Loam

  1. Size of colloidal clay particle is less than

(a) 0.2 mm

(b) 0.02 mm

(c) 0.002 mm

(d) 0.0002 mm

  1. Soil aeration limits plants growth when per cent pores filled with water are more than

(a) 50 – 60%

(b) 60 – 70%

(c) 70 – 80%

(d) 80 – 90%

  1. Soil colour determination chroma refers to which of the following?

(a) Dominant spectral colour

(b) Lightness or darkness of the colour

(c) Purity or strength of colour

(d) None of these

  1. Chemical formula of pyrite reclaiment is

(a) FeS

(b) Cus

(c) MnS
(d) FeS2

  1. How much muriate of potash will be required to supply 50 kg K,O/ha ?

(a) 50 kg

(b) 73.3 kg

(c) 83.3 kg

(d) 125.3 kg

  1. Concentration of which element highest in soil

(a) Fe

(b) O2

(c) Al

(d) Si

  1. Which is a incorrect match in the following?

(a) Soil bulk density: Hydrometer

(b) Particle size: analysis of soil

(c) Soil moisture Picnometer retention

(d) Soil moisture estimation

  1. Specific heat is higher in

(a) Sand

(b) Silt

(c) Clay

(d) Humus

  1. Laterization is a process of accumulation in soil

(a) Iron and aluminium oxides

(b) Silica

(c) CaCO3

(d) CaSO4

  1. Podzolization is a process accumulation in soil

(a) Silica

(b) Iron and aluminium oxides

(c) CaCO3

(d) CaSO4

  1. Rocks containing more than 65% SiO2 are

(a) Neutral

(b) Alkaline

(c) Acidic

(d) Calcareous

  1. Average content of silica in soil is

(a) 24 %

(b) 27%

(c) 31%

(d) 35%

  1. Concentration of nitrogen in soil air is

(a) 70 %

(b) 74%

(c) 78%

(d) 82%

  1. Critical limit of available phosphorus in soil for wheat crop by Olsen’s method is

(a) 5 kg/ha

(b) 10 kg/ha

(c) 15 kg/ha

(d) 22.5 kg/ha

  1. Sulphur content in ammonium sulphate is

(a) 12%

(b) 20%

(c) 24 %

(d) 30 %

  1. Which one is dominating salt in alkali soil ?

(a) CaCl2

(b) MgSO4

(c) NaHCO3

(d) Na,CO,

  1. In which soil, zinc availability to crop is higher ?

(a) Acidic soil

(b) Alkaline soil

(c) Calcareous soil

(d) Waterlogged soi

  1. Which of the following is correct?

(a) P₂O × 0.44 = P

(b) P₂O, 2.29 = P

(c) P₂O, × 0.83 = P

(d) P₂O, x 1.20 = P

  1. The major organic cementing agent in soil aggregate formation is

(a) Lipids

(b) Proteins and protein derivatives

(c) Polysaccharides

(d) Organic acids

  1. The element present in the porphyrin structure of chlorophyll molecules are

(a) Magnesium

(b) Iron

(c) Nitrogen

(d) Magnesium and nitrogen

  1. Among the following, the sequence of textural classes of soil with increasing order of fineness of texture is

(a) CL, L, LS, SL, SCL

(b) L, CL, SCL, SL, LS

(c) SL, SCL, LS, L, CL

(d) LS, SL, L, SCL, CL

  1. If the contents of exchangeable ions (cmol kg-¹) determined in soil are Na* = 5, K* = 5. Ca2+ = 10, Mg2+ = 2, H* = 1, Al+3 = 1, CI 1.6 and HCO3 = 0.4, the CEC of soil is

(a) 12 cmol (P+) kg-1

(b) 22 cmol (P*) kg-1

(c) 24 cmol (P*) kg-1

(d) 26 cmol (P+) kg-1

  1. Which one of the following is a manganese containing minerals ?

(a) Magnetite

(b) Tourmaline

(c) Apatite

(d) Pyrolusite

  1. Which one of the following sets shows the correct soil order in sequence of increasing age?

(a) Entisol, mollisol, alfisol, ultisol

(b) Entisol, mollisol, ultisol, alfisol

(c) Ultisol, alfisol, mollisol, entisol

(d) Alfisol, mollisol, entisol, ultisol

  1. Humic acid isolated from soils is

(a) Aromatic with high molecular weight

(b) Aromatic with low molecular weight

(c) Aliphatic with high molecular weight

(d) Aliphatic with low molecular weight

  1. The Fe-chelate suitable for application to crops grown on calcareous soils is

(a) Fe-EDTA

(b) Fe-EDDHA

(c) Fe-DTPA

(d) Fe- HEDTA

  1. Amongst oil cakes, the highest nitrogen content is in

(a) Castor cake

(b) Neem cake

(c) Coconut cake

(d) Groundnut cake

95.Plasticity of soil can be determined by using

(a) Pycnometer

(b) Buoyoucos hydrometer

(c) Atterberg’s apparatus

(d) IRGA

  1. Soil aggregation can be estimated by using

(a) Yoder’s apparatus

(b) IRGA

(c) Cone penetrometer

(d) Atterberg’s apparatus

  1. Which one of the following values given in terms of redox-potential of soils (mv) represents a highly reduced condition of the soil?

(a) -250

(b) -100

(c) +200

(d) +600

  1. From Q/I relationship described by Beckett (1964), a high PBCK indicates that

(a) The soil has been recently limed

(b) The soil needs potassium fertilization

(c) Availability of potassium in the soil is excellent

(d) The soil needs liming

  1. Which one of the following is the correct quantity of zinc sulphate required to prepare 100 litres of 200 ppm solution for foliar spray? Quantity of zinc sulphate required (in grams).

(a) 20

(b) 100

(c) 200

(d) 2000

  1. Which plant element accounts for at least one half of the total number of ions absorbed ?

(a) N

(b) P

(c) K

(d) Ca 105.

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