Soil & Water Conservation Flashcards
Green Manure?
Green undecomposed plant material used as manure. Obtained from green manure crops (insitu) or by collecting twigs, leaves etc (exsitu)
Insitu green manuring?
Plants of leguminous types are grown upon reaching flowering stage are incorporated into soil.
Why at flowering stage green manure crops are added to soil?
Low C:N ratio, largest amount of N is made available.
Examples of green manure crops?
Sunhemp, dhaincha, pilipisera, clusterbeans, sesbania rostrata.
Green manure crop that can be grown across India?
Sunhemp
Amount of N/ha on avg released by green manuring
60-80 kg
Exsitu green manuring?
Process of collecting leaves from available sources and incorporating them into soil. Also called green leaf manuring
Examples of concentrated organic manures
Guano, Blood meal, fish manure, oilcakes etc
Why r conc organic manure slow acting?
They need to broken down into ammoniacal nitrogen and nitrate nitrogen by bacterial action. Hence available for longer time.
Guano?
Accumulated excrement of birds and bats. Rich in NPK
Examples of non-edible oil cakes?
Neem, Castor, Mahua
Classify fertilizers based on number of nutrients with examples.
- Straight fertilizer - Urea, Ammonium sulphate, Kcl, K2SO4
- Complex fertilizer - Diammonium phosphate, nitrophosphates
- Mixed fertilizer
Ternary fertilizer?
Contain 3 nutrients - Ammonium Potassium Phosphate
Complete fertilizer?
Contain all 3 major nutrients - NPK - Eg: IFFCO
Low analysis & High analysis fertilizer?
Presence of major nutrients less than 25% - low analysis (Eg: SSP, Sodium Nitrate)
More than 25% - high analysis (Eg: DAP, Urea)
More than 80% fertilizers used in the country are _________ fertilizers
Nitrogenous
Types of nitrogenous fertilizer
- Ammoniacal - Ammonium Sulphate, Ammonium chloride
- Ammoniacal & Nitrate - Ammonium nitrate, Calcium ammonium nitrate, Ammonium sulphate nitrate
- Nitrate - Sodium nitrate, Calcium nitrate, Potassium nitrate
- Amide - Urea, Calcium Cynamide
Advantages of ammoniacal fertilizer include
- Soluble in water - easily available to plants
- Prevents leaching loss as ammonium ions gets absorbed in colloidal part of soil
Ammonium sulphate is used for ________ cultivation
Rice & Jute
Which are the crops affected by ammonium chloride and why?
Tobacco & Potato. Injured by chlorine
Nitrate fertilizers are acidic. (T/F)
False. They r basic
Problem with nitrate fertilizer is
Lost due to leaching because of high mobility of nitrate ions. Also easily converted into atmospheric nitrogen by denitrification.
Which fertilizer is called Chilean Salt Peter?
Sodium Nitrate
Benefit of ammoniacal & nitrate crops
Nitrate is available for rapid utilization while ammonium is gradually absorbed.
Ammonium nitrate is acidic (T/F)
True
Calcium ammonium nitrate is neutral in nature (T/F)
True
Benefits of amide fertilizers
- Readily soluble in water and easily decomposable
- Amide is converted to ammoniacal form to nitrate in soil
Neem coated Urea objectives?
- Growth of wheat & paddy
- Curb black marketeering
NUE of Urea?
30%-50%
Role of neem oil coated on Urea
Effective nitrification inhibitor avoiding loss of N
Most widely used phosphatic fertilizer in India?
Superphosphate
Why are phosphatic fertilizers placed at the root zone?
Because of their very low mobility
Chemical formula for murate of Potash?
KCl
Which potassic fertilizer is preferred for Tobacco & Potato?
Potassium Sulphate
How are utilization rate of magnesium and potassium related?
Utilization rate of magnesium reduces with increase in potassium supplies.
Foliar nutrient?
Applied on leaves than on roots
Micronutrients required by plants
Fe, Mn, Zn, Cu, Mo, B, Cl
Examples of Fe fertilizers
Ferrous Sulphate, Fe - EDTA, Fe - EDDPA
Examples of Mn fertilizers
Manganese Sulphate, Mn - DTA
Examples of Zn fertilizers
Zinc Sulphate, ZnO
Examples of Cu fertilizers
Copper Sulphate
Examples of B fertilizers
Borax, Boric Acid
Examples of Mo fertilizers
Sodium Molybdate, Ammonium Molybdate
Fertilizer ratio
N:P2O5:K2O
Conditioners?
Low grade organic materials like paddy husk, peat soils etc to reduce hygroscopicity & improve phy condition.
Neutralizers of residual activity
Materials like dolomite, limestone added to fertilizer to counteract acidity of N fertilizers
Only natural N fertiliser?
Urea
Broadcasting at sowing or planting?
Main objective to uniformly distribute fertilizer over field and mix with soil
Top dressing?
Broadcasting of fertilizers in closely planted crops, make sure nutrients are readily available.
Disadvantages of broadcasting
- Nutrients can’t be fully utilised
- Weed Growth
- Nutrients are fixed in soil
Placement?
Placement of fertilizers in a particular place with or without reference to position of seed.
Where is placement used and for which fertilizers?
Normally recommended when qty to apply is small, soil has low fertility & development of root system is poor. Used for phosphatic & potassic fertilizer.
Types of placement
- Plough sole placement
- Deep Placement
- Localised placement
3.1 Side dressing
3.2 Drilling
Plough sole placement is used in?
Dry soils upto few cms below top soil
Deep placement is used for?
Ammoniacal fertilizers especially in paddy (10-15cm). It prevents loss of nutrients by run off
Types of band placements?
- Hill Placements
- Row Placements
Hill Placements?
Fertilizer placed close to plants in bands one or both sides of the plant. Practiced in orchards
Row placements?
Fertilizer placed close to plants in rows one or both sides. Eg: Sugarcane, Potato, Maize, Cereal
Pellet application?
Used for N fertilizers in paddy field in the form of pellets 2.5 to 5 cm deep.
Methods of applying liquid fertilizer?
- Starter solution
- Foliar application
- Through irrigation water
- Injection through soil
- Aerial application
Starter solution?
Application of NPK in ratio of 1:2:1 or 1:1:2 to young plants at the time of transplanting esp vegetables. Help in rapid establishment and quick growth of seedlings
Foliar application?
Applied on foliage of plants, used mainly for micronutrients.
Fertilizer application through irrigation water is used for?
Nitrogenous fertilizer
Biofertilizer?
Preparation containing living or latent cells of microorganisms that help in increased intake of nutrients when applied to the rhizosphere
Benefits of biofertilizer?
- Sustainable
- Cost effective
- Renewable
Most efficient biofertilizer in N2 fixing?
Rhizobium (Soil habitat bacteria)
The dominant inhabitant/species of Azotobacter found in arable soils? Amount of N2 it can fix/kg of C
A.Chroococcum. 12 - 15 mg of N2/kg of C
Primary inhabitants of Azospirillum in soil
A. Lipoferum & A. Brasilense
Benefits of Azospirillum biofertilizer?
- Drought resistance
- Nitrogen fixing
- Disease resistance
- Growth promoting substance production
Biofertilizer generally used for rice cultivation?
Cyanobacteria
Azolla biofertilizer?
Free floating fern that floats on water that fixes atmospheric nitrogen in association with nitrogen fixing blue green algae. Used in wetland rice cultivation.
Species of phosphate solubilising microorganisms (PSM)
Species of Pseudomonas, Bacillus, penicillium, aspergillus.
How do PSM dissolve phosphates?
By producing organic acids & reducing pH in the vicinity.
Examples where PSM is used?
Wheat & Potato
How does AM (Arbuscular Mycorrhiza) fungi help?
Intake of nutrients like P, Zn & Sulphur through roots are mediated by these intracellular fungal symbionts.
Plant growth promoting Rhizobacteria (PGPR)
Bacteria that colonize roots/rhizosphere but are beneficial to crops.
Typers of PGPR
- Disease protection - Bioprotectants
- Growth - Biofertilizers
- Phytohormones - Biostimulants
Why are biofertilizer not used widely?
Because of varied response of crops based on the bacterial strain used
Ways of using liquid biofertilizer?
- Soil Application
- Root dipping
- Seed Coating
How to apply PSM by seed coating?
First Azotobacter, Rhizobium, Azosprillium has to be coated uniformly then PSM has to be applied.
How is PSM applied using soil application technique?
Use 200 ml PSM per acre. Mix PSM with 400 - 600 kg of Cow dung FYM, mix 50% rock phosphate also
Vermicomposting? What are the important nutrients in worm casting?
Process of conversion of organic debris into worm casting. Important nutrients - N,P,K,Ca,Mg
Vermicomposting vs Top soil
5 times more nitrogen, 7 times more Potash & 1.5 times more Calcium than in good topsoil.
Five essentials for worms?
- Bedding
- High absorbency
- Good bulking potential
- Low protein/Nitrogen content (High C:N ratio)
- Housing
Recommended rate of Vermicompost application?
15 - 20%
Which type of earthworm is most efficient and why?
African Worm - More production of vermicompost in given time & presence of younger ones in composting period.
Which earthworm is suitable for vermicomposting? Give examples
Surface dwelling earthworms only should be used.
Eg: African earthworms, Tiger/Red earthworm, Asian earthworms
What is protein poisoning/Sour crop? How is it caused?
It is a disease affecting earthworms that causes its intestine to rupture and eventual death. It is caused becos of the high acidic condition in the soil due to high protein content that is released due to action of microbes. Hence excess protein whenever added shld be neutralised by adding Ca.