Maharashtra HSC Crop Science (Bifocal B4) cheat sheet

Crop science integrates agronomy, genetics, physiology, and soil science to manage field crops for yield, quality, and sustainability.

Binomial nomenclature (genus + species, e.g., Oryza sativa L.) is the standard for naming crops; the authority abbreviation follows the species.

Classification by life cycle: annual (completes life in one season, e.g., rice, wheat), biennial (two seasons, e.g., sugar beet, onion), perennial (lives multiple years, e.g., sugarcane, mango).

Classification by economic use: cereals (rice, wheat), pulses (gram, tur), oilseeds (groundnut, soybean), fibre (cotton, jute), sugar (sugarcane), tuber (potato), fodder, and plantation crops.

Botanical classification by cotyledon number: monocotyledons (grasses, cereals) vs dicotyledons (pulses, oilseeds, cotton).

Classification by season: kharif (monsoon, June–October, e.g., rice, cotton), rabi (winter, October–March, e.g., wheat, gram), and summer/zaid (March–June, e.g., summer moong, watermelon).

Classification by photosynthesis: C3 plants (wheat, rice) have photorespiration losses; C4 plants (maize, sugarcane, sorghum) have Kranz anatomy and higher water-use efficiency.

Cropping intensity (%) = (total cropped area ÷ net sown area) × 100; multiple cropping and crop rotation raise this index.

Soil texture is the relative proportion of sand (2.0–0.05 mm), silt (0.05–0.002 mm), and clay (<0.002 mm) particles; texture triangle classifies soil into loam, clay, sandy, etc.

Soil structure is the arrangement of primary particles into aggregates (granular, blocky, platy, columnar); granular structure in topsoil favours aeration and root growth.

Soil pH: <6.5 acidic, 6.5–7.5 neutral, >7.5 alkaline. Acid soils are corrected with lime; alkaline/sodic soils with gypsum.

Cation exchange capacity (CEC) is the total exchangeable cations a soil can hold, expressed in cmol(+)/kg; clay and organic matter raise CEC.

Base saturation (%) = (sum of exchangeable bases ÷ CEC) × 100; high base saturation indicates fertile, well-buffered soil.

Soil organic matter improves water-holding capacity, structure, and nutrient supply; it is the main source of soil nitrogen.

Essential soil tests: pH, electrical conductivity, organic carbon, available N, P (Olsen for neutral/alkaline, Bray for acidic), K, and micronutrients.

Soil erosion control: contour bunding, terracing, strip cropping, mulching, and cover crops reduce runoff and topsoil loss.

Essential elements: 17 total - macronutrients (N, P, K, Ca, Mg, S) and micronutrients (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni).

Liebig's law of the minimum: growth is limited by the nutrient in shortest supply relative to plant need.

Nitrogen is a component of chlorophyll, proteins, and enzymes; deficiency shows as chlorosis starting on older leaves.

Phosphorus is essential for energy transfer (ATP), root development, and seed formation; deficiency causes purplish or dark green leaves.

Potassium regulates stomatal opening, water relations, and enzyme activation; deficiency causes marginal leaf scorch and weak stems.

Micronutrient roles: Fe and Mn in chlorophyll synthesis; Zn in auxin synthesis; B in pollen germination and cell wall formation; Mo in nitrate reductase.

Critical concentration is the nutrient level below which deficiency symptoms appear; sufficiency range is the optimum tissue concentration.

Nutrient uptake forms: mass flow (mobile nutrients like N), diffusion (P, K), and root interception (Ca, Mg).

Fertilizer grade (N:P2O5:K2O) is the percentage of nitrogen, phosphorus (as P2O5), and potassium (as K2O); e.g., urea = 46-0-0, DAP = 18-46-0, MOP = 0-0-60.

Straight fertilizers supply one nutrient (urea, SSP, MOP); complex fertilizers supply two or more (DAP, NPK 10-26-26).

Urea (46% N) is the highest-analysis solid nitrogen fertilizer; it is hydrolysed to ammonium carbonate by soil urease.

Farmyard manure (FYM) is bulky organic manure with low nutrient concentration; it improves soil physical properties and organic matter.

Green manure involves growing a legume (e.g., sunnhemp, dhaincha) and ploughing it into the soil before flowering to add nitrogen.

Composting converts organic waste to humus-rich manure; the C:N ratio should be about 25–30:1 for efficient decomposition.

Biofertilizers (Rhizobium, Azotobacter, Azospirillum, PSB, mycorrhiza) are microbial inoculants that enhance nutrient availability.

Fertilizer application methods: broadcasting, band placement, drilling, fertigation, and foliar spray for quick correction of deficiency.

Seed rate is the quantity of seed sown per unit area; it depends on seed weight, germination %, and desired plant population.

Plant population per hectare = (area × 10,000) ÷ (row spacing × plant spacing) when spacings are in metres.

Tillage operations: primary tillage (ploughing) loosens soil; secondary tillage (harrowing, levelling) prepares a fine seedbed.

Seed treatment with fungicides, insecticides, and biofertilizers protects against seed-borne pathogens and improves establishment.

Intercropping grows two or more crops simultaneously in the same field; crop rotation sequences different crops to break pest cycles and maintain fertility.

Weed control in field crops combines cultural practices, mechanical weeding, and herbicides in an integrated weed management plan.

Harvesting at the correct maturity stage maximises yield and quality; delayed harvest increases shattering and storage losses.

Cropping system efficiency is measured by land equivalent ratio (LER) for intercrops; LER > 1 indicates intercropping advantage.

Irrigation water requirement = evapotranspiration (ET) − effective rainfall; ET = evaporation + transpiration.

Water use efficiency (WUE) = crop yield ÷ water applied (kg/m³); it improves with drip and deficit irrigation.

Irrigation methods: surface (flood, furrow, basin), sprinkler, and drip (trickle); drip delivers water directly to the root zone with high efficiency.

Critical irrigation stages: rice (tillering, panicle initiation, flowering), wheat (crown root initiation, jointing, flowering, milk stage), cotton (squaring, flowering, boll development).

Drip irrigation efficiency is about 90%, sprinkler about 75%, and surface flood about 40–50%; selection depends on soil, crop, and water availability.

Soil moisture measurement: gravimetric, tensiometer, and neutron probe; field capacity and permanent wilting point bound available water.

Irrigation scheduling can be based on IW/CPE ratio (irrigation water ÷ cumulative pan evaporation); a common ratio for many crops is 0.8–1.0.

Excess irrigation causes waterlogging, leaching of nutrients, and salinity; drainage and controlled scheduling prevent these losses.

Integrated Pest Management (IPM) combines cultural, mechanical, biological, and chemical methods, with chemicals used as a last resort.

Economic threshold level (ETL) is the pest population at which control measures are justified to prevent economic loss.

Major rice pests: stem borer, brown plant hopper, leaf folder; major cotton pests: bollworm, whitefly, aphid.

Major crop diseases: rice blast (Magnaporthe oryzae), wheat rust (Puccinia spp.), cotton wilt (Fusarium), and bacterial blight.

Weed classification: grasses (monocots), sedges (triangular stem), and broadleaf (dicots); examples include Echinochloa, Cyperus, and Parthenium.

Herbicide selectivity is the ability to kill weeds without harming the crop; application timing (pre-emergence vs post-emergence) is critical.

Pest surveillance and scouting guide timely intervention; disease forecasting uses weather data to predict outbreaks.

Safe pesticide use: read the label, wear protective gear, observe pre-harvest interval, and follow recommended dose and waiting period.

Primary tillage implements: mouldboard plough, disc plough, and chisel plough; secondary tillage: disc harrow, cultivator, and leveller.

Sowing implements: seed drill (line sowing), dibbler, and planter; transplanting is used for rice and vegetables.

Sprayers (knapsack, boom) apply pesticides and liquid fertilizers; calibration ensures the correct dose per unit area.

Threshers separate grain from chaff; combine harvesters perform reaping, threshing, and cleaning in one operation.

Tractor power is rated in horsepower (hp) or kilowatts (kW); 1 hp = 0.746 kW.

Field capacity of an implement = (area covered) ÷ (time taken); it determines the hourly work rate.

Maintenance of tools: sharpen blades, oil moving parts, and store implements under cover to prevent rust and wear.

Precision equipment such as seed-cum-fertilizer drills and laser levellers improves input use efficiency and uniformity.

Moisture content at harvest affects storage life; safe storage moisture is about 12–14% for cereals and lower for oilseeds.

Grain drying reduces moisture to safe levels; sun drying and mechanical dryers are common methods.

Storage losses are caused by insects, rodents, fungi, and moisture; hermetic storage and fumigation reduce losses.

Grading and cleaning remove foreign matter and immature grains, improving market value.

Cold storage extends shelf life of perishables by slowing respiration and microbial growth; optimum temperature and humidity vary by produce.

Value addition (milling, processing, packaging) increases the market price of agricultural produce.

Warehouse receipt systems and proper storage structures (metal bins, silos) reduce post-harvest losses.

Post-harvest losses in India are significant; improved handling, transport, and storage infrastructure reduce them.

Farm management involves planning, organising, and controlling farm resources to maximise profit and sustainability.

Cost of cultivation includes variable costs (seed, fertilizer, labour) and fixed costs (land rent, machinery depreciation).

Gross margin = gross income − variable costs; net profit = gross income − total costs.

Benefit-cost (B:C) ratio = gross returns ÷ total cost; a ratio above 1 indicates profitability.

Break-even point is the output level at which total revenue equals total cost (no profit, no loss).

Farm budgeting (partial, whole-farm, and cash-flow) helps in planning and decision-making.

Marketing channels and cooperative marketing improve price realisation for farmers.

Entrepreneurship in agriculture includes agri-input dealership, food processing, nursery, and agri-tourism ventures.

Soil sampling: collect from multiple points in a field, mix, quarter, and send a representative sample to the laboratory.

Soil pH and EC are measured with a pH meter and conductivity meter using a soil-water suspension (commonly 1:2.5).

Seed germination test: place seeds on moist filter paper or in sand, count normal seedlings after the specified period, and calculate germination %.

Plant population count is done using a quadrat or by counting plants in a measured row length and converting to per-hectare figures.

Pest and disease scouting uses visual counts and symptom identification; record data on standard observation sheets.

Fertilizer dose calculation: nutrient required (kg/ha) ÷ nutrient content (%) × 100 = fertilizer quantity (kg/ha).

Irrigation scheduling in the field uses tensiometers or the IW/CPE ratio to decide when to irrigate.

Record keeping and data analysis: maintain field notebooks, calculate averages, and interpret results for recommendations.

Crop science integrates agronomy, genetics, physiology, and soil science to manage field crops for yield, quality, and sustainability.

Binomial nomenclature (genus + species, e.g., Oryza sativa L.) is the standard for naming crops; the authority abbreviation follows the species.

Classification by life cycle: annual (completes life in one season, e.g., rice, wheat), biennial (two seasons, e.g., sugar beet, onion), perennial (lives multiple years, e.g., sugarcane, mango).

Classification by economic use: cereals (rice, wheat), pulses (gram, tur), oilseeds (groundnut, soybean), fibre (cotton, jute), sugar (sugarcane), tuber (potato), fodder, and plantation crops.

Botanical classification by cotyledon number: monocotyledons (grasses, cereals) vs dicotyledons (pulses, oilseeds, cotton).

Classification by season: kharif (monsoon, June–October, e.g., rice, cotton), rabi (winter, October–March, e.g., wheat, gram), and summer/zaid (March–June, e.g., summer moong, watermelon).

Classification by photosynthesis: C3 plants (wheat, rice) have photorespiration losses; C4 plants (maize, sugarcane, sorghum) have Kranz anatomy and higher water-use efficiency.

Cropping intensity (%) = (total cropped area ÷ net sown area) × 100; multiple cropping and crop rotation raise this index.

Soil texture is the relative proportion of sand (2.0–0.05 mm), silt (0.05–0.002 mm), and clay (<0.002 mm) particles; texture triangle classifies soil into loam, clay, sandy, etc.

Soil structure is the arrangement of primary particles into aggregates (granular, blocky, platy, columnar); granular structure in topsoil favours aeration and root growth.

Soil pH: <6.5 acidic, 6.5–7.5 neutral, >7.5 alkaline. Acid soils are corrected with lime; alkaline/sodic soils with gypsum.

Cation exchange capacity (CEC) is the total exchangeable cations a soil can hold, expressed in cmol(+)/kg; clay and organic matter raise CEC.

Base saturation (%) = (sum of exchangeable bases ÷ CEC) × 100; high base saturation indicates fertile, well-buffered soil.

Soil organic matter improves water-holding capacity, structure, and nutrient supply; it is the main source of soil nitrogen.

Essential soil tests: pH, electrical conductivity, organic carbon, available N, P (Olsen for neutral/alkaline, Bray for acidic), K, and micronutrients.

Soil erosion control: contour bunding, terracing, strip cropping, mulching, and cover crops reduce runoff and topsoil loss.

Essential elements: 17 total - macronutrients (N, P, K, Ca, Mg, S) and micronutrients (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni).

Liebig's law of the minimum: growth is limited by the nutrient in shortest supply relative to plant need.

Nitrogen is a component of chlorophyll, proteins, and enzymes; deficiency shows as chlorosis starting on older leaves.

Phosphorus is essential for energy transfer (ATP), root development, and seed formation; deficiency causes purplish or dark green leaves.

Potassium regulates stomatal opening, water relations, and enzyme activation; deficiency causes marginal leaf scorch and weak stems.

Micronutrient roles: Fe and Mn in chlorophyll synthesis; Zn in auxin synthesis; B in pollen germination and cell wall formation; Mo in nitrate reductase.

Critical concentration is the nutrient level below which deficiency symptoms appear; sufficiency range is the optimum tissue concentration.

Nutrient uptake forms: mass flow (mobile nutrients like N), diffusion (P, K), and root interception (Ca, Mg).

Fertilizer grade (N:P2O5:K2O) is the percentage of nitrogen, phosphorus (as P2O5), and potassium (as K2O); e.g., urea = 46-0-0, DAP = 18-46-0, MOP = 0-0-60.

Straight fertilizers supply one nutrient (urea, SSP, MOP); complex fertilizers supply two or more (DAP, NPK 10-26-26).

Urea (46% N) is the highest-analysis solid nitrogen fertilizer; it is hydrolysed to ammonium carbonate by soil urease.

Farmyard manure (FYM) is bulky organic manure with low nutrient concentration; it improves soil physical properties and organic matter.

Green manure involves growing a legume (e.g., sunnhemp, dhaincha) and ploughing it into the soil before flowering to add nitrogen.

Composting converts organic waste to humus-rich manure; the C:N ratio should be about 25–30:1 for efficient decomposition.

Biofertilizers (Rhizobium, Azotobacter, Azospirillum, PSB, mycorrhiza) are microbial inoculants that enhance nutrient availability.

Fertilizer application methods: broadcasting, band placement, drilling, fertigation, and foliar spray for quick correction of deficiency.

Seed rate is the quantity of seed sown per unit area; it depends on seed weight, germination %, and desired plant population.

Plant population per hectare = (area × 10,000) ÷ (row spacing × plant spacing) when spacings are in metres.

Tillage operations: primary tillage (ploughing) loosens soil; secondary tillage (harrowing, levelling) prepares a fine seedbed.

Seed treatment with fungicides, insecticides, and biofertilizers protects against seed-borne pathogens and improves establishment.

Intercropping grows two or more crops simultaneously in the same field; crop rotation sequences different crops to break pest cycles and maintain fertility.

Weed control in field crops combines cultural practices, mechanical weeding, and herbicides in an integrated weed management plan.

Harvesting at the correct maturity stage maximises yield and quality; delayed harvest increases shattering and storage losses.

Cropping system efficiency is measured by land equivalent ratio (LER) for intercrops; LER > 1 indicates intercropping advantage.

Irrigation water requirement = evapotranspiration (ET) − effective rainfall; ET = evaporation + transpiration.

Water use efficiency (WUE) = crop yield ÷ water applied (kg/m³); it improves with drip and deficit irrigation.

Irrigation methods: surface (flood, furrow, basin), sprinkler, and drip (trickle); drip delivers water directly to the root zone with high efficiency.

Critical irrigation stages: rice (tillering, panicle initiation, flowering), wheat (crown root initiation, jointing, flowering, milk stage), cotton (squaring, flowering, boll development).

Drip irrigation efficiency is about 90%, sprinkler about 75%, and surface flood about 40–50%; selection depends on soil, crop, and water availability.

Soil moisture measurement: gravimetric, tensiometer, and neutron probe; field capacity and permanent wilting point bound available water.

Irrigation scheduling can be based on IW/CPE ratio (irrigation water ÷ cumulative pan evaporation); a common ratio for many crops is 0.8–1.0.

Excess irrigation causes waterlogging, leaching of nutrients, and salinity; drainage and controlled scheduling prevent these losses.

Integrated Pest Management (IPM) combines cultural, mechanical, biological, and chemical methods, with chemicals used as a last resort.

Economic threshold level (ETL) is the pest population at which control measures are justified to prevent economic loss.

Major rice pests: stem borer, brown plant hopper, leaf folder; major cotton pests: bollworm, whitefly, aphid.

Major crop diseases: rice blast (Magnaporthe oryzae), wheat rust (Puccinia spp.), cotton wilt (Fusarium), and bacterial blight.

Weed classification: grasses (monocots), sedges (triangular stem), and broadleaf (dicots); examples include Echinochloa, Cyperus, and Parthenium.

Herbicide selectivity is the ability to kill weeds without harming the crop; application timing (pre-emergence vs post-emergence) is critical.

Pest surveillance and scouting guide timely intervention; disease forecasting uses weather data to predict outbreaks.

Safe pesticide use: read the label, wear protective gear, observe pre-harvest interval, and follow recommended dose and waiting period.

Primary tillage implements: mouldboard plough, disc plough, and chisel plough; secondary tillage: disc harrow, cultivator, and leveller.

Sowing implements: seed drill (line sowing), dibbler, and planter; transplanting is used for rice and vegetables.

Sprayers (knapsack, boom) apply pesticides and liquid fertilizers; calibration ensures the correct dose per unit area.

Threshers separate grain from chaff; combine harvesters perform reaping, threshing, and cleaning in one operation.

Tractor power is rated in horsepower (hp) or kilowatts (kW); 1 hp = 0.746 kW.

Field capacity of an implement = (area covered) ÷ (time taken); it determines the hourly work rate.

Maintenance of tools: sharpen blades, oil moving parts, and store implements under cover to prevent rust and wear.

Precision equipment such as seed-cum-fertilizer drills and laser levellers improves input use efficiency and uniformity.

Moisture content at harvest affects storage life; safe storage moisture is about 12–14% for cereals and lower for oilseeds.

Grain drying reduces moisture to safe levels; sun drying and mechanical dryers are common methods.

Storage losses are caused by insects, rodents, fungi, and moisture; hermetic storage and fumigation reduce losses.

Grading and cleaning remove foreign matter and immature grains, improving market value.

Cold storage extends shelf life of perishables by slowing respiration and microbial growth; optimum temperature and humidity vary by produce.

Value addition (milling, processing, packaging) increases the market price of agricultural produce.

Warehouse receipt systems and proper storage structures (metal bins, silos) reduce post-harvest losses.

Post-harvest losses in India are significant; improved handling, transport, and storage infrastructure reduce them.

Farm management involves planning, organising, and controlling farm resources to maximise profit and sustainability.

Cost of cultivation includes variable costs (seed, fertilizer, labour) and fixed costs (land rent, machinery depreciation).

Gross margin = gross income − variable costs; net profit = gross income − total costs.

Benefit-cost (B:C) ratio = gross returns ÷ total cost; a ratio above 1 indicates profitability.

Break-even point is the output level at which total revenue equals total cost (no profit, no loss).

Farm budgeting (partial, whole-farm, and cash-flow) helps in planning and decision-making.

Marketing channels and cooperative marketing improve price realisation for farmers.

Entrepreneurship in agriculture includes agri-input dealership, food processing, nursery, and agri-tourism ventures.

Soil sampling: collect from multiple points in a field, mix, quarter, and send a representative sample to the laboratory.

Soil pH and EC are measured with a pH meter and conductivity meter using a soil-water suspension (commonly 1:2.5).

Seed germination test: place seeds on moist filter paper or in sand, count normal seedlings after the specified period, and calculate germination %.

Plant population count is done using a quadrat or by counting plants in a measured row length and converting to per-hectare figures.

Pest and disease scouting uses visual counts and symptom identification; record data on standard observation sheets.

Fertilizer dose calculation: nutrient required (kg/ha) ÷ nutrient content (%) × 100 = fertilizer quantity (kg/ha).

Irrigation scheduling in the field uses tensiometers or the IW/CPE ratio to decide when to irrigate.

Record keeping and data analysis: maintain field notebooks, calculate averages, and interpret results for recommendations.