Agronomy notes for IBPS AFO,NABARD,RRB SO

Introduction To Agronomy

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1. Agriculture – Derived from the Latin word “Agronomy” and the Greek word.
2. Community development program initiated in 1952.
3. Sharbati Sonara variety obtained through the application of gamma rays to Sonara-64.
4. Jaganath (Rice) variety obtained through X-ray treatment of T-141.
5. Aruna (Castor) variety obtained through the use of thermal fast neutrons on HC-8.
6. The Intensive Area Development Programme (IADP), also known as the “Package Programme,” was established in 1960.
7. In 1875, the Indian Meteorological Department (IMD) was established in Pune.
8. The first report of the Famine Commission was issued in 1880, followed by subsequent reports in 1898 and 1901.
9. In 1903, the Imperial Agricultural Research Institute was established in Pusa, Bihar.
10. A Royal Commission on Agriculture was formed in 1928, followed by the establishment of ICAR in 1929.
11. The Indian Agricultural Research Institute (IARI) was relocated to Delhi in 1936.
12. The High-Yielding Variety Programme (HYVP) was launched in 1966, followed by the Multiple Cropping Programme (MCP) in 1967 and the National Demonstration Programme (NDP) in 1969.
13. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) was established in 1972.
14. Other international research institutes include Central Plantation Crops Research Institute in Kasargod, ICARDA in Syria, CIMMYT in Mexico, IRRI in Manila, IPRI in Peru, ICTA in Cali, Colombia, and IITA in Ibadan, Nigeria.

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Structure of atmosphere

1. Meteorology derives from the Greek word and refers to the science of the atmosphere.
2. Weather denotes the instantaneous state or condition of the atmosphere, whereas climate is the aggregate of weather conditions over an extended period.
3. The structure of the atmosphere includes the troposphere, tropopause, and stratosphere, the latter containing the ozone layer or ozonosphere where photochemical reactions occur.
4. The solid portion of the Earth is known as the lithosphere.
5. The ionosphere is the most dynamic layer in the atmosphere.
6. The uppermost part of the atmosphere is referred to as the “Magnetosphere.”
7. Altitude refers to height, latitude signifies an imaginary line horizontally connecting the east and west, and longitude denotes an imaginary line connecting the north and south poles, which is useful for calculating “Local Mean Time” (LMT).
8. Greenwich Mean Time (GMT) is calculated at the 0° longitude, while Indian Standard Time (IST) is based on 82.50°E longitude.
9. Albedo is the ratio of reflected radiation to incident radiation.
10. Infrared rays serve as a source of heat for plants.
11. Approximately 42% of incident insulation is reflected back to space, while 58% is utilized.
12. The energy we get from the sun at the edge of our atmosphere is called the “Solar Constant,” and it’s about 1.94 calories per square centimeter per minute.
13. Some plants like Maize, Soybean, and Tobacco prefer shorter days, while others like Sugarbeet, Wheat, and Barley do better with longer days. Then there are plants like Sunflower and Cotton that aren’t picky about the length of the day.
14. In places with mild weather, crops often grow better on the sunny southern slopes compared to the shaded northern ones.
15. Instruments like Pyranometers measure sunlight, while things like sunshine recorders tell us how long the light lasts. Lux meters measure how bright the light is .
16. Plants soak up certain colors of light better than others. Too much light, though, can actually harm plants by causing something called “Solarisation.”
17. Heat can move through the air without touching anything. When air moves around, it’s great at spreading heat, especially upwards.
18. Sometimes, instead of getting cooler as you go higher up, the temperature suddenly gets warmer. We call this an “Inversion.”
19. Usually, the hottest part of the day is between 1:00 and 4:00 PM, and the coldest is between 1:00 and 6:00 AM. July tends to be the hottest month, while January is usually the coldest.
20. Certain thermometers can keep track of both the highest and lowest temperatures. Others record temperatures continuously.
21. Lines on maps connect places with the same temperature. As you go higher, it usually gets cooler, and we call this the “Vertical Temperature Gradient.”
22. The wind is often caused by differences in air pressure. These differences can happen horizontally or vertically.
23. Lines on maps showing areas with the same wind speed are called “Isotechs.”
24. Trade winds are breezes in the lower part of the atmosphere. They blow from the horse latitudes towards the equator, reaching the doldrums. These winds occur in both hemispheres.
25. Antitrade winds, on the other hand, are found in the upper atmosphere. They move from the equator towards the North and South poles.
26. When trade winds shift direction or pattern, we call them “Monsoon winds.”

Sea Breeze vs. Land Breeze:

• Sea breeze happens during the day.
• It’s when cool and dense air moves from the sea to the warmer land. It’s also known as “Onshore wind.”
• Land breeze occurs at night.
• It’s when cooler air from the land moves towards the warmer sea.
• It’s also called “Offshore wind.”

Valley Breeze vs. Mountain Breeze:

• Valley breeze occurs during the day.
• It’s when air flows from the valley up towards the mountains.
• The mountain breeze happens at night.
• It’s when cooler air from the mountains descends into the valley.

Important Instruments and their use

1. Instruments used to measure Relative Humidity (RH) are known as “Psychron” or “Hygrometer.”
2. Wet and dry bulb thermometers are used to measure RH in the field.
3. Hair hygrometers are typically used indoors.
4. The Hydrologic Cycle is the constant movement of water between the atmosphere, lithosphere, and hydrosphere.
5. The evaporation rate is usually expressed in millimeters per day.
6. Under similar conditions, ocean water evaporates about 5% more slowly than freshwater.
7. Evaporation is often measured using the USWB Class A open pan evaporation method for free water surfaces.
8. Sunken screen evaporimeters are used in cropped fields to measure evaporation.

• Hygroscopic particles serve as nuclei for condensation.
• The most significant hygroscopic nuclei in the atmosphere include sea salt (NaCl) and nitric oxide.
• The dew point is the temperature at which saturation or condensation occurs.
• Dew is the formation of liquid water droplets on cooled surfaces.
• Fog consists of tiny water droplets suspended in the air near the earth’s surface and is also known as “Low Cloud.”
• A haze is a mixture of smoke and dust combined with fog.
• Frost is similar to dew, but occurs when condensation freezes below the freezing point.
• Clouds are similar to fog but occur at higher altitudes.
• There are three basic cloud forms: Cirrus (fibrous or feathery), Cumulus (heaped, resembling cauliflower), and Stratus (layers).
• If a cloud extends above its usual height, it is termed “Alto.”
• Clouds associated with precipitation are prefixed or suffixed with “Nimbus.”
• High clouds include Cirrus, Cirro cumulus (common near coastlines), and Cirro Stratus.
• Middle clouds include Alto cumulus and Alto Stratus, typically composed of water droplets.
• Low clouds include Stratus, Nimbo Stratus, and Strato cumulus.
• Clouds with vertical development are called Cumulus and Cumulonimbus.
• An obscured sky occurs when clouds are completely covered with fog and smoke.
• The Southwest monsoon typically occurs from June 7th to September 26th.
• The Northeast monsoon usually happens from September 27th to January 31st.
• The hot weather period typically lasts from February 1st to June 6th.

Precipitation in the form of liquid:-

• Rain: Droplets range from 0.5 mm to 4 mm, with rainfall exceeding 0.5 mm.
• Drizzle: Rain droplets are less than 0.5 mm, usually light rains.
• Mist: Rain droplets evaporate completely before reaching the ground.
• Glaze: Rainfall freezes on objects, forming a sheet or coating of ice.
• Rime: Formation of ice due to freezing fog.
• Snow: White crystals of frozen water falling from the sky.
• Sleet: Rain that is frozen or partly frozen.
• Hail: Pieces of ice falling from the sky.
• Isohyets: Imaginary lines connecting places that receive the same amount of rainfall.

• In coastal districts, the paddy growing season from June to November is referred to as “Sarva,” while paddy growing from October to March is called “Dalwa.”
• Areas of low pressure are termed “Depressions.”
• Tropical cyclones are extremely intense storms. In the waters of the West Indies, they’re called “Hurricanes.” In East Indian and Japanese waters, they’re termed “Typhoons,” and in the Indian Ocean, they’re known as “Cyclones.”
• Predicting the weather for the upcoming days is called “Weather forecasting.”
• A concise report on weather conditions presented in coded form is termed a “Synoptic report.”

Tillage

• Tillage involves using tools and implements to manipulate the soil, and loosening the surface crust to create favorable conditions for germination.
• Tilth refers to the physical condition of the soil concerning plant growth.
• Buck scrapers or leveling planks are used for major field leveling tasks.
• The percentage of soil volume occupied by pore space is known as “Porosity.”
• Crumb and granular structure are indicators of good soil structure.
• Bulk density is the mass per unit volume of dry soil.
• Mechanical manipulation of soil at high moisture content is called “Puddling.”
• Peddamadaka is a heavy plow used for deep plowing in black cotton soils.
• Leveling implements like the buck scraper are used to level puddled soil.
• Humus is the end product of organic matter decomposition. Green manure is best incorporated into the soil at the crop flowering stage.
• High temperatures in Indian soils make it challenging to build up high organic matter content.
• Broadcasting fertilizer when there is dew on leaves is not advisable.
• Diancha is a green manure crop used for reclaiming saline and alkaline soils.
• Drilling, and seeding behind a country plow ensures uniform plant spacing.
• The Earth rotates from west to east.
• The response of living organisms to regular changes in temperature, whether day or night, is known as “Thermoperiodism.”
• When all pores, both large and small, are filled with water, the soil is considered saturated, reaching its “Maximum Retentive Capacity.”
• Water in large pores moves downwards due to gravity, and it’s termed “Gravitational Water” or “Free Water.“
• Water in small pores moves due to capillary force and is termed “Capillary Water.” It moves more freely than free water and can travel in any direction, always towards increasing tension.
• The thin film of water around soil particles that cannot be used by plants is called “Hygroscopic Water.“
• Capillary movement is driven by both adhesive and cohesive forces.
• Water moves from saturated soil to unsaturated layers.
• Moist soils exhibit more uniform water movement compared to dry soils.
• When saturated, capillary movement is fastest in sandy soils and slowest in clay soils. However, in unsaturated conditions, capillary movement is rapid in clay soils and slow in sandy soils.
• Adhesion refers to the attraction between soil particles and water, while cohesion describes the attraction between water molecules.
• Soil moisture tension measures how tightly water is held in the soil and is expressed in atmospheres.
• Soil moisture tension does not indicate the amount of water present. To show the quantity of moisture held by soil at different tensions, “Moisture Extraction Curves” or “Soil Moisture Characteristic Curves” are developed.
• The Potential of Hydrogen (pH) is defined as the logarithm of the height in a column of water. The pH value of saturated soil is ‘0’.
• The movement of irrigation water from the surface into the soil through the soil is referred to as “Water Intake,” which is the sum of “Percolation” and “Infiltration.”
• Infiltration is the downward flow of water from the surface into the soil.
• Percolation, on the other hand, is the movement of water through the soil profile.
• The rate of percolation is determined by the permeability or hydraulic conductivity of the soil.
• Permeability is the soil’s ability to transmit air and water.
• Seepage refers to the lateral movement of water within the soil.
• Leaching is the process of removing soluble salts from the soil through the passage of water.
• Field capacity indicates the amount of water a well-drained soil can hold after excess water has drained away due to gravity.
• Available water is calculated as the difference between field capacity and permanent wilting point.
• Field capacity is often approximated as one-third of atmospheric tension in the soil.
• The permanent wilting point represents the soil moisture level at which plants can no longer meet their transpiration requirements.
• The ultimate wilting point is reached when a plant dies despite receiving additional water.
• Elevated water tables can restrict root growth and may even cause root death.
• The typical water extraction pattern involves 40% of moisture being extracted from the upper quarter of the soil, 30% from the second quarter, 20% from the third, and 10% from the fourth.
• Effective root zone depth refers to the soil depth from which a crop extracts most of the water required for evapotranspiration.
• Safflower and cotton have deep root systems.
• Soil crusting can reduce infiltration, affecting water movement into the soil.
• Certain stages in the crop growth period are particularly sensitive to soil moisture stress compared to others.
• These critical stages are referred to as “Moisture-sensitive” or “Critical periods.
• “During these critical periods, the availability of water in the soil plays a crucial role in determining crop yield and quality. Therefore, it is essential to monitor and manage soil moisture levels carefully during these critical stages to ensure optimal crop growth and productivity.
• Crop-sensitive periods to moisture stress are crucial stages in their growth cycle when the availability of water significantly affects their development and yield.

Here are the sensitive periods for various crops:

• Rice, Finger Millet: Primordia development, heading, flowering
• Sorghum: Booting, Blooming
• Maize: Tasseling, Silking
• Wheat: Crown-root initiation
• Groundnut: Peg penetration, flowering
• Sunflower: Two weeks before flowering to 2 weeks after flowering
• Safflower: From rosette to flowering
• Cotton: Flowering, boll development
• Tobacco: Tapping stage
• Potato: Tuber initiation to tuber maturity
• Onion: Bulb formation

During these periods, it’s crucial to ensure adequate soil moisture to support proper crop growth and development, as moisture stress during these stages can lead to significant yield losses.

• The period in days during which irrigation water is supplied to the crop is known as the “Base period.”
• The Godavari delta system is an irrigation project constructed during the British period.
• Consumptive use refers to the total amount of water needed for transpiration, evaporation, and metabolic activities of vegetation.
• Soil moisture can be measured using direct and indirect methods.
• Direct methods measure water content directly, while indirect methods measure water potential.
• The gravimetric method is a standard technique for measuring soil moisture.
• The spirit burning method is rapid and suitable for field applications.
• The Neutron moisture meter consists of a probe and a scaler or counter. It is not suitable for measuring moisture content very close to the soil surface.
• Tensiometers are useful in sandy soils for measuring soil moisture.
• Gypsum blocks utilize the principle of resistance change with moisture content. The resistance to the flow of electricity is proportional to the moisture content in the medium.
• Soil moisture characteristics in the laboratory can be determined using a “Pressure plate and pressure membrane apparatus.”
• Water requirement for irrigation includes consumptive use, application losses, and water needed for special operations.

IRRIGATION

• The irrigation period should not exceed the irrigation frequency.
• Duty of water refers to the relationship between irrigation water and the area of crop that fully matures with the given amount of water.
• In canal irrigation, duty is often expressed as “area per unit rate of flow” and is measured in hectares per cubic meter per second (ha/m^3/sec).
• Drainage in light soils can lead to leaching loss of nitrogen.
• Furrow irrigation is commonly used for crops like maize and cotton.
• Irrigation scheduling is based on the depletion of available soil moisture, with many crops requiring irrigation at 20% depletion at moisture-sensitive stages and 50% depletion at other stages.
• Soil moisture tension, measured using tensiometers, is used for irrigating orchards, especially in coarse-textured soils.
• Potential evapotranspiration can be estimated using the Lysimeter method.
• Visual plant symptoms can indicate irrigation needs, such as leaf color changes in cotton, groundnut, and beans, plant movement in crops like sorghum and beans, and exudation or stem cutting in cotton.
• The check basin method is used for crops like groundnut, finger millet, sorghum, and vegetables, while the basin method is used for orchards.
• The border strip method is employed for closely spaced crops like wheat, barley, and groundnut, with furrow irrigation being the most water-efficient surface method.
• Subsurface irrigation is practiced in Kerala.
• Overhead irrigation, such as sprinkler irrigation, is suitable for sandy soils, while drip irrigation involves water release from nozzles and typically has a discharge rate of 2 to 10 liters per hour.
• Water distribution efficiency assesses the uniformity of water distribution within the field.
• Project efficiency measures the overall efficiency of a project in terms of water use.
• Spiles are convenient in furrow irrigation systems.
• Waterlogging occurs when the water table rises near the surface. The “Parallel field drain system” is an effective method for surface drainage, suitable for both irrigated and rainfed areas.
• The “Parallel field drain system” is necessary for both surface and subsurface drainage.
• Drainage coefficient refers to the depth of water in centimeters to be removed within a 24-hour period from the entire drainage area.
• The random or natural drainage system is utilized for draining isolated patches of land.
• Irrigation water classification by the US Salinity Laboratory (USSL) is based on Electrical Conductivity (EC) and Sodium Absorption Ratio (SAR).
• Ragi demonstrates the highest Water Use Efficiency (WUE) among crops, while rice exhibits the lowest.
• The total amount of water used in evapotranspiration by a crop throughout its growing season is referred to as “Seasonal Consumptive Use.”
• The free energy status of pure water is considered to be “Zero.”
• In lowland rice cultivation, the major type of water loss occurs in the form of deep percolation.
• The primary objective of puddling in rice fields is to reduce weed growth.
• Every living organism is a product of both its biological heredity and its environment.
• Ley farming involves the inclusion of fodders or grasses in the cropping system. The cropping index is calculated as the number of crops grown per year multiplied by 100.
• Sequence cropping refers to growing two or more crops in sequence on the same field within a year.
• Relay cropping involves sowing the seeds of another crop before harvesting the current crop.
• Catch cropping entails growing an extra crop between two main crops due to available time.
• Multi-storeyed cropping involves growing crops of different heights simultaneously.
• Alley cropping involves growing crops in alleys formed by trees and shrubs to enhance soil fertility.
• An ideotype is a biological model expected to perform predictably within a defined environment.
• In the case of rice, the “Dee Geo Woo Gene” and in wheat, the “Norin-10” stocks are responsible for dwarfness.

IMPORTANT CROPS

Rice:

• Breeding varieties for effective photosynthesis under low light intensity is crucial.
• Varieties traditionally cultivated in the tropics are termed “Indicas” and are long in duration.
• “Japonicas” are varieties adapted to temperate zones.
• “Javanicas” are referred to as bulk rice.
• Dry nursery methods in kharif seasons often yield higher compared to wet nursery methods.
• Dapog nursery involves raising seedlings without their roots touching the soil.

Wheat:

• Wheat is rich in proteins, with gluten being a major component.
• T. dicoccum, known as Emmer wheat, is a variety of wheat.
• Traditional methods like “Kera” involve hand-dropping seeds into furrows, while “Pora” refers to implements attached to ploughs.
• The “Jointing stage” marks the emergence of the stem with distinct nodes.
• Wheat crops are highly sensitive to temperature fluctuations.

Maize (Queen of cereals – C4 Plant):

• Maize protein is primarily “Zein,” deficient in essential amino acids like Lysine and Tryptophan.
• Dent corn (Zea mays indentata) is recognized by the depression or “dent” in the seed crown.
• Flint corn is predominantly grown in India.
• Popcorn, consumed by humans, is characterized by hard starch.
• Waxy corn has a characteristic waxy appearance due to amylopectin.
• Growth stages include knee-high stage, male inflorescence (tassel), and female (cob).
• “Zing” terracing is practiced in Dehradun valley with 75% maize in rice slopes and 25% in others.

Sorghum:

• Sorghum exhibits better tolerance to high temperatures and is considered a short-day plant. It can also withstand waterlogging better than rice.
• Dhurrin (HCN) is a toxic substance found in sorghum.
• Maghi jowar is grown in Khammam, and dibbling is a common practice in drylands.
• Growth stages include the vegetative period, critical stage, and grain-filling period.
• CSH-1 is preferred for rationing, and sorghum toxicity is mitigated through techniques like indigo or wild indigo green maturing.

Ragi (Eleusine coracana – Birds foot millet):

• Ragi is a major millet and an excellent source of calcium.
• Africa is often referred to as the “Heaven of millets.”
• Different varieties like Punasa, Pedda panta, and Pyru are cultivated in various regions.
• Ragi thrives in both warm and cool temperatures, making it suitable for hilly regions.
• Sowing in stallion furrows is a common practice in Karnataka.

Fodder:-

Lucerne (Medicago sativa – Alfalfa):

• Lucerne is often called the Queen of fodder but overfeeding can lead to bloat or tympanitis.
• Dodder is a parasitic plant that grows on Lucerne.

Berseem (Trifolium alexandrinum – Egyptian clover):

• Berseem, also known as Egyptian clover, is referred to as the King of fodder crops.
• Excessive feeding can cause bloat or tympanitis.

 

Subabul (Leucaena leucocephala):

• Subabul, a perennial fodder crop, contains a toxic substance called “Mimosine.”
• Hay: It is the dried form of forage crop cut before full ripening, preserving nutrients.
• Silage: Fermented forage material preserved without air, created through ensiling.
• Haylage: Remaining forage material after haymaking, used for cattle feed.
• The dough stage is ideal for harvesting maize fodder.
• Shallow sowing depth is practiced when wheat sowing is delayed.
• Rainfed rice cultivation is common in Assam.
• Mid-season drainage in rice discourages late tiller development.
• Butyric acid gives silage a bad odor.
• New plant types have a grain-straw ratio of 1:1.
• Maharashtra is the leading producer of sorghum.
• Mineral supplements provide resistance to pests and diseases.
• Dwarf wheat varieties include Kalyanasona (double gene dwarf) and Hira (triple gene dwarf).
• Hamsa is a white-grained finger millet variety.
• Drought-resistant rice variety MTU-17 is available.
• Sodium metabisulfite is a preservative used in silage making, while lactic acid aids in preservation.

Red Gram (Pigeon Pea):

• It’s a crucial pulse crop in South India, with the PDM-1 variety being popular in Andhra Pradesh.

Green Gram (Mung Bean):

• Known scientifically as Vigna radiata.

Black Gram (Urad Dal):

• Another legume variety, scientifically termed Vigna mungo.

Bengal Gram (Chickpea):

• Scientifically known as Cicer arietinum. Its seeds are recommended to cure scurvy.
• There are two types: Desi, with small-sized seeds and a rough, colored seed coat, and Kabuli, with large-sized seeds and a white seed coat.
• The “Jyothi” variety suits all districts in the state.

Cowpea:

• Also referred to as Vigna sinensis or V. unguiculata, it can withstand heat, and heavy rains, and is highly drought-resistant.
• It serves as a cover crop and aids in soil conservation, with varieties like “Russian giant” useful for fodder.

Horse Gram:

• Scientifically known as Macrotylomia uniflorus, it’s grown as a test crop for drought tolerance.

Soybean:

• Glycine max, the best time for planting is June 1st, and intermediate varieties have been found to yield higher than determinate varieties.

Groundnut (Peanut):

• Arachis hypogaea is the scientific name. It yields the highest in Zimbabwe and prefers sandy loam soil.
• Calcium deficiency leads to “pops“, while sulfur is essential for oil quality. Moisture-sensitive stages include pegging and pod development, and it’s often intercropped with pigeon peas.

Gingelly (Sesame):

• With oil content ranging from 46-52%, it’s a significant crop. Varieties like “Madhavi” released by ANGRAU are grown in Telangana.
• White-seeded varieties have higher oil content than black-seeded ones.
• Sesame is often grown in a 5:1 ratio with red gram and is one of the oldest oilseed crops.

Castor:

• Recinus communis is the scientific name, of an important industrial oilseed crop.
• Castor oil contains a high percentage of hydroxyl fatty acid known as “Recinoleic acid” and is used for various purposes, including as a purgative and in dyeing industries.
• It’s not used as cattle feed due to its toxic properties.
• Brazil leads in production, with India ranking first in area, especially in Andhra Pradesh’s Nalgonda region.
• Varieties like Aruna have specific spacing requirements, and nipping axillary buds increases yield.

Sunflower:

• Originating from Peru or Mexico, sunflower is a short-duration crop that’s not affected by day length.
• It’s rich in linoleic acid, with Canadian varieties like “Sunrise selection” being popular.

Safflower:

• Safflower, with its high linoleic acid content of 78%, helps lower serum cholesterol due to its unsaturated fatty acids.
• The oil extracted is used in making “Roghan“, which is utilized in leather preservation and waterproof cloth production. It’s mainly grown in Maharashtra, India.

Niger:

• Niger, with an oil content of 37-43%, is chiefly produced in India, primarily in Madhya Pradesh.
• It takes about 120-130 days to mature.

Linseed (Flaxseed):

• Linseed is a dual-purpose crop grown for both oil and fiber, with oil content ranging from 33-47%.
• It’s highly susceptible to weed competition throughout its growth cycle and is primarily grown in Madhya Pradesh.

Mustard and Rapeseed:

• Major Rabi oilseed crops in India, they are also used as condiments.
• Mustard oil is used in the tanning industry for leather softening, while refined oil (Colza) is utilized in Europe.
• China is the largest producer, with India ranking second and Uttar Pradesh being the top producer domestically.
• Mustard is scientifically known as Brassica juncea, while rapeseed is Brassica campestris.

Sugarcane:

• Sugarcane is believed to have originated in India.
• Different varieties include Noble cane, Chinese cane, North India cane, and wild canes from Asia and Guinea.
• Innovative methods like “Ridge mar” help prepare fields without initial plowing, and “three budded setts” are commonly used for planting.
• In the Anakapalli region, trench planting is a prevalent method.
• Wrapping: This is when the bottom leaves of the sugarcane plant are twisted around the cane.
• Propping: Sugarcane plants are supported by bamboo sticks to prevent them from falling over.
• When the brix level recorded by a hand refractometer is 18% or higher, it indicates that the cane is mature.
• To measure the brix, a hand refractometer is used, and juice is extracted from the cane using a pouch piercer.
• “Lime sucrate” is a substance used to neutralize the juice and make colloidal particles clump together in sugarcane juice.

Sugar Beet (Beta vulgaris):

• F.C. Achard is considered the pioneer of the sugar beet industry.
• Around 40% of the world’s sugar comes from sugar beet, while 60% is derived from sugar cane.
• Sugar recovery from sugar beet is typically around 15-16%, compared to 8-10% for sugar cane.

Tobacco (Nicotiana tobacum):

• N. rustica is used for making hookah, chewing tobacco, and snuff.
• CTRI (Central Tobacco Research Institute) is located in Rajahmundry.
• “Topping” refers to the removal of the flower bud along with some top leaves of the tobacco plant.
• After topping, axillary buds grow, and their removal is known as “desuckering.”
• Pit curing is a method used for curing chewing and hookah tobacco.

Cotton:

• Gossypium hirsutum constitutes around 50% of cotton production, while G. barbadense has a negligible area of cultivation.
• G. arboreum accounts for approximately 29%, and G. herbaceum for about 21%.
• Germination temperature is around 15°C, while the initiation of floral buds requires approximately 21°C.
• Seed cotton, also known as ‘Kapas‘, undergoes topping.
• The ginning percentage represents the amount of lint obtained from seed cotton.
• Sample quality is expressed in counts, with one count equal to the number of hanks (each 840 yards long) found in one pound of yarn.
• “Neppiness” refers to a defect in yarn caused by tiny knots formed by fibers.

Mesta (Hibiscus cannabinus, H. subdariffa F: Malvaceae):

• Andhra Pradesh leads in mesta production.
• The Mesta Research Station is located in Amudalavalasa, Srikakulum.
• The ideal stage for harvesting mesta is during the flowering stage.
• Mesta contains around 16% fiber by weight in dry stalks and 40% fiber by weight in fresh stalks.

Sunhemp (Crotalaria juncea):

• The proper stage for harvesting sunhemp is during pod formation.
• A common weed often found with sunhemp is Ipomoea sp.

Agave (Agave sisalina):

• Agave serves as both a hedge and a fiber plant.
• Propagation is typically done through suckers and bulbils.
• Flowering in Agave is referred to as “poling.”

Jute (Corchorus capsularis, C. olitorius, Family: Tiliaceae):

• Retting: This is a natural process where the fibers in the bark of jute plants are loosened and separated easily from the woody stalk.
• It occurs due to the removal of substances like pectins, gums, and other mucilaginous materials.
• Retting is facilitated by water and microorganisms working together.

Additional Information:

• The USA is the largest producer of oilseeds globally.
• The variety CO–7706 of sugar cane is known for producing superior-quality jaggery.
• The burning quality of tobacco is positively influenced by the potassium (K) content in the leaf.
• The long shelf life of gingelly oil is attributed to the presence of the antioxidant “Sesemolin.”
• Sesamum plants are highly sensitive to frost.
• In groundnut cultivation, the oil content is positively correlated with temperature.
• The short fibers covering cotton seeds are known as “fuzz.”
• “Rajmah” is a pulse crop that doesn’t form root nodules.

WEED SCIENCE

Weeds:

• Definition: A weed is a plant growing where it’s not wanted.
• Burmuda grass/Star grass (Cynodon dactylon): Used as a forage grass.
• Quack grass (Agropyron repens): Helps bind the soil.
• Water hyacinth (Eichornia crassipes): Considered a weed by fishermen.
• Croton sparsiflorus: Used as green manure.
• Source of Protein: Chlorella pyrenoids.
• Weed for Crop Breeding: Saccharum spontaneum.
• Pollution Indicators: Wild mustard for NO2 gas, Chickweed for SO2.
• Medicinal Plant: Leucas aspera used for snake bites and malaria.
• Soil Reclamation: Argemone mexicana (Mexican poppy) for alkali soils.
• Prickly Weed: Wild safflower.
• Other Weeds: Canada thistle (Cirsium arvense), Bindweed (Convolvulus arvensis).
• Impact on Tea Quality: Presence of Loranthus leaves.
• Congress/Municipal/Carrot grass: Parthenium hysterophorus.
• Water lettuce: Pistia lanceolata.
• Nut grass: Cyperus rotandus.
• Regrowth Ability: Simple annuals regrow easily.
• Woody Weeds: Shrubs and undershrubs, collectively known as “Brush” weeds.
• Seasonal Weeds: Summer perennial (Sorghum halopens), Winter perennial (Cirsium arvense).
• Introduced Weeds: Anthrophytes.
• Poisonous Weed: Datura fastuosa.
• Facultative Weeds: Also called apophytes.
• Objectionable Weeds: Noxious weeds with hard-to-separate seeds.
• Terminology: Rhizomes in quack grass are sometimes called “Sobolobes”. Runners in Bermuda grass, Bulb in Wild onion and wild garlic.
• Hydrilla verticillata: Bulbils in leaf axils called “Turions”.
• Seed Adaptations: Pappus, Comole, Balloon.
• Dispersal Mechanism: Endozoochory (through animal digestion).
• Satellite Weeds: Hard to separate due to similar size and shape as grains.
• Indicator Plants: Neutrophiles.
• Other Weeds: Thatch grass (Imperata cylindrica).
• Wild oat (Avena jatva) exhibits three types of dormancy: Enforced, Innate, Induced.

Important Weed Science notes

Induced Dormancy:  Results from sudden physiological changes.
Agricultural Ecotype: Continual adoption of agricultural practices can lead to the development of adaptive ecotypes.
Summer Furrow Planting: Useful method for reducing weed problems in summer.
Flooding: Common method in crop husbandry for weed control in rice fields.
Bio-agents: Living organisms employed for pest control.
Lantana Camera Control: Achieved by Crocidosema lantana, a moth borer.
Carp Fish: Used to control aquatic weeds.
Spider Mite Control: Effective against prickly pear (*Opuntia stricta*).
Starvation Test: Safeguard against introduced bio-agents becoming pests of economic crops.
Bio-herbicides: Examples include “De-vine” for *Phytophthora palmivora* and “Collego” for *Colletotrichum gleoispories*.
Spudding: Hand pulling aided by a forked sharp blade or sickle tip.
Mowing: Cutting weeds uniformly at ground level.
Dredging and Chaining: Techniques used for aquatic weed control.
Searing: Repeatedly applying flame to destroy even deep perennial weed roots.
Selective Herbicides: When applied at higher rates, they can act as non-selective herbicides (e.g., Diuron).
Atrazine: Translocates when absorbed from soil but acts as a contact herbicide when sprayed on plant shoots.
Translocated Herbicides: Used for perennial weed control.
Pre-plant Desiccation: Application to destroy existing vegetation before planting.

• Pre-plant Incorporation: Herbicides mixed with weed-free seed beds for residual control. Example: Paraquat, Fluchoralin (especially in pulse crops).
• Pre-emergence: Atrazine, Diuron.
• Post-emergence: Paraquat and Diquat.
• Adjuvants: Also known as additives.

Surfactants / Wetting Agents / Surface Active Agents: Examples include Soap, Uphar, Tea.

Stabilizing Agents: Include emulsifiers and dispersants.

• Emulsifiers disperse emulsion concentrates into stable droplets.
• Dispersants stabilize suspensions.

Solvents / Coupling Agents / Co-solvents: For instance, 2,4-D is almost insoluble in water but can be dissolved in Polyethylene Glycol (PEG) to make it water-soluble.

• Humectants / Hygroscopic Agents: Prevent rapid drying of herbicides. Example: Glycerol.
• Stickers / Filming Agents / Deposit Builders.
• Compatibility Agents: Like “Compex,” used to mix fertilizers and pesticides.
• Activators / Synergists: For example, “Ammonium Thiocyanate” is a widely used activator of amitrole.
• Drift Control Agents.

Effects of Different Herbicides:

• Triazines: Inhibit photosynthesis by affecting photolysis in the hill reaction.
• Uracil: Strong inhibitors of photosynthesis.
• Ureas: Cause abnormal meiotic cells in root tips.
• Nitriles – Bromoxynil: Act by uncoupling oxidative and P.S. phosphorylation.
• Bipyridilium: Inhibit the reduction of NADP to NADPH.
• Eichlobenil: Induces dormancy in weed seeds.
• Organic Copper or Serical Herbicides: Inhibit “Pyruvate Dehydrogenase” activity during glycolysis.
• Carbamates: Act as mitotic poisons.
• Thiocarbamates: Inhibit shoot and root growth of grass weeds.
• Dinitroanilines: Inhibit nucleic acid synthesis.
• Phenoxy Alkanoic Acid (2,4-D, 2,4,5-T): Cause epinasty, swelling, twisting.
• Troazpes: Lead to the development of albino leaves and shoots.
• Molinate Selectivity: Influenced by differences in crown root initiation levels between Oryza sativa and Echinochloa colonum.
• Activated Charcoal: Strong absorbent of herbicides like 2,4-D.
• Intermediate Metabolism: Intermediate chemical structures are often more phytotoxic than the parent compound.
• Reverse Metabolism: Involves an enzyme of the β-oxidation process for compounds like 2,4-DB and MCPB.

Selectivity of Propanil: Found between resistant rice and susceptible Echinochloa colonum due to differences in the “aryl acylamine amidohydrolase” (AAAH) enzyme content.

2,4-D: Used for killing broad-leaved weeds in monocot crops.

• Herbicides: Various herbicides and their trade names, including:
• MCPB – Methaxone
• 2,4-D (Na salt) – Fernoxone
• Nitrofen – TOK – E-25
• Paraquat – Gramaxone
• Fluchloralin – Basalin
• Pendimethalin – Stomp
• Glyphosate – Round-up
• Butachlor – Machete
• Benthiocarb – Saturn

Effect Types:

• Additive Effect: The total effect of a combination equals the sum of the effects of the components.
• Synergistic Effect: The total effect of a combination is greater or more prolonged than the sum of the effects of the two taken independently.
• Antagonistic Effect: The total effect of a combination is smaller or lower than the sum of the effects.
• Independent Effect: The total effect of a combination equals the effect of the most active compound.
• Enhancement Effect: Response is greater in herbicides when added with adjuvant.

Miscellaneous:

• Boron reduces rapid microbial detoxification of 2,4-D.
• Alachlor and metalochlor are effective against grasses but weak against broad-leaved weeds.
• Acrolein is used for destroying submerged aquatic weeds.
• Trap crop for striga – cowpea.
• Best herbicides for rice – Anilophos.
• Common weeds like Barnyard grass, Jungle rice, Water fern, Purple nut sedge, etc., are listed.
• The discovery of a natural stimulant of striga germination from cotton roots is called “Strigol.”
• Parthenin is the main toxicant present in parthenium.
• Granular formation prerequisite for herbicides – moisture pressure.
• Sugarcane weeding starts with “Blind hoeing.”
• Various wheat varieties are mentioned, including those with single, double, and triple dwarf genes like Sonalika, Kalyanasona, Hira, and Malavika.

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