BSEH Secondary Agriculture cheat sheet

Cropping intensity = (total cropped area ÷ net sown area) × 100; a value above 100 indicates more than one crop per year on the same land.

Crop rotation with a legume fixes atmospheric N via Rhizobium symbiosis, typically adding 20–60 kg N/ha to the following cereal crop.

Seed rate depends on test weight and germination: adjust by dividing the recommended rate by the germination fraction expressed as a decimal.

Intercropping advantage is measured by Land Equivalent Ratio (LER) = sum of (intercrop yield ÷ sole crop yield) for each component; LER > 1 means a real yield advantage.

Kharif crops are sown with monsoon onset; Rabi crops depend on residual soil moisture and cool winter temperatures; Zaid is the short summer season between them.

Tillage operations: primary tillage breaks the hardpan (mouldboard plough), secondary tillage refines the seedbed (disc harrow, cultivator), and tillage depth should exceed the previous ploughing depth only when compaction is confirmed.

Transplanting shock is reduced by root pruning at lifting, keeping seedlings in shade, and transplanting in the cooler part of the day; rice seedlings are typically transplanted at 20–25 days old.

Water use efficiency (WUE) = marketable yield ÷ water applied (kg/m³ or kg/ha per mm); deficit irrigation at non-critical stages raises WUE without proportional yield loss.

Soil texture triangle uses percentage sand, silt and clay; the three must sum to 100, so any two fractions fix the third.

Bulk density = oven-dry soil mass ÷ total volume (g/cm³); porosity = (1 − bulk density ÷ particle density) × 100, with particle density conventionally 2.65 g/cm³.

Soil pH affects nutrient availability: below 5.5, Al and Mn toxicity plus P fixation by Fe/Al oxides; above 7.5, Fe, Zn, Mn and B become less available.

Lime requirement is driven by exchangeable acidity and target pH; lime raises pH, gypsum (CaSO₄) supplies Ca without raising pH and is used for sodic soils.

Cation exchange capacity (CEC) in cmol(+)/kg: kaolinite 3–15, illite 10–40, montmorillonite 80–150, organic matter 150–300; higher CEC means greater nutrient-holding capacity.

Base saturation = (sum of exchangeable bases ÷ CEC) × 100; values above 80% generally indicate fertile, near-neutral soils.

Soil erosion by water: sheet erosion removes a thin uniform layer, rill erosion cuts small channels, gully erosion cuts channels too deep to cross with tillage.

Essential plant nutrients: 17 elements; macro (N, P, K, Ca, Mg, S) plus C, H, O; micro (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni).

Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂; light reactions in thylakoids produce ATP and NADPH, Calvin cycle in stroma fixes CO₂ via RuBisCO.

C3 plants (wheat, rice, soybean) photorespire and have lower optimum temperatures; C4 plants (maize, sorghum, sugarcane) concentrate CO₂ via PEP carboxylase and have higher water use efficiency.

Monocot vs dicot: monocots have one cotyledon, parallel venation, scattered vascular bundles, fibrous roots; dicots have two cotyledons, net venation, ring-arranged bundles, taproot.

Floral formula notation: K = calyx, C = corolla, A = androecium, G = gynoecium; parentheses indicate fusion, a line under G indicates a superior ovary.

Plant hormones: auxin (cell elongation, apical dominance, rooting), gibberellin (stem elongation, seed germination), cytokinin (cell division, delays senescence), ABA (stomatal closure, dormancy), ethylene (ripening, abscission).

Seed germination requires water imbibition, suitable temperature and oxygen; epigeal germination lifts cotyledons above ground (bean), hypogeal keeps them below (pea, maize).

Apomixis produces seed without fertilization, giving clonal progeny; used to fix hybrid vigour in some forage and fruit species.

Photoperiodism: short-day plants flower when night length exceeds a critical dark period; long-day plants flower when night is shorter; day-neutral plants are insensitive.

Economic threshold level (ETL) is the pest density at which control measures justify their cost; the economic injury level is the density causing yield loss equal to control cost, and ETL is set slightly below it.

Integrated pest management hierarchy: cultural, mechanical, biological, then chemical control; rotate insecticide mode-of-action groups to delay resistance.

Disease triangle: disease requires a susceptible host, virulent pathogen and favourable environment simultaneously; the disease tetrahedron adds a human/time factor.

Koch's postulates: the pathogen must be isolated from a diseased host, cultured, re-inoculated to reproduce disease, and re-isolated in pure culture.

Bacterial diseases often show water-soaked lesions and ooze; fungal diseases show mycelium, spores and lesions with defined margins; viral diseases show mosaic, mottling and stunting with no lesion margins.

Herbicide selectivity is based on crop vs weed differences in absorption, translocation, metabolism or placement; 2,4-D is a synthetic auxin selective in monocots and lethal to many dicots.

Photosynthetic rate measurement uses IRGA (infrared gas analysis); transpiration rate uses porometers; stomatal conductance links both.

Post-harvest losses are reduced by lowering respiration: cool storage, controlled atmosphere (low O₂, elevated CO₂) and ethylene removal delay ripening of climacteric produce.

Gestation periods: cattle ~280 days, buffalo ~310 days, sheep ~150 days, goat ~150 days, pig ~114 days.

Dairy milk composition of cow milk: about 87% water, 3.5% fat, 3.4% protein, 4.9% lactose, 0.7% minerals; buffalo milk is higher in fat (~6–7%).

Milk fat is measured by Gerber method; solids-not-fat (SNF) is estimated from fat and specific gravity using Lactometer readings.

Colostrum is the first milk for 3–5 days after calving, rich in immunoglobulins and vitamin A; calves need it within the first hours of life for passive immunity.

Heat detection signs in cattle: standing to be mounted, mucous discharge, restlessness, frequent urination; oestrus cycle averages 21 days.

Balanced ration: maintenance plus production needs; roughage-to-concentrate ratio and protein content vary with milk yield, typically 1 kg concentrate per 2.5 kg milk above maintenance.

Poultry incubation is 21 days for chicken, 28 for duck; incubation temperature in forced-draft setter is about 37.5 °C with 55–60% relative humidity.

Artificial insemination advantages: one bull can serve many cows, reduces disease transmission risk and eliminates the need to keep bulls on the farm.

Horticultural propagation: cutting, layering, grafting, budding and tissue culture are vegetative; seed propagation is sexual and produces variability.

Grafting success depends on cambium contact between scion and rootstock, matching polarity and a compatible union; grafting is used to add vigour, disease resistance or dwarfing.

Pruning vs training: training shapes the plant framework, pruning removes growth to control size, light and fruit quality.

Vegetable classification by botany: tomato, brinjal and chilli are solanaceous fruits; onion and garlic are bulbs; potato is a tuber; carrot is a root.

Kitchen garden planning uses succession planting and intercropping to keep continuous supply; vegetables are grouped by family to avoid repeated pests.

Fruit crops: mango, banana and papaya are tropical; apple, pear and peach are temperate and need chilling hours to break dormancy.

Post-harvest handling of horticultural produce: pre-cooling, grading, packaging and cold chain reduce respiration heat and ethylene damage; banana and mango are climacteric.

Protected cultivation uses polyhouse or shade nets to control temperature, humidity and light; insect-proof nets exclude vectors and reduce pesticide use.

Farm power units: 1 hp = 0.746 kW; 1 kW = 1.34 hp; drawbar power = draft × speed, with consistent units.

Draft of a tillage implement depends on soil resistance, width and depth; specific draft is draft per unit area of soil cross-section (N/cm²).

Field capacity: theoretical field capacity = (width × speed) ÷ 10 in ha/h with width in m and speed in km/h; actual field capacity accounts for turns and downtime via field efficiency.

Field efficiency = actual field capacity ÷ theoretical field capacity × 100; typical values are 70–90% for tillage and 60–80% for harvesting.

Machine capacity for seed drill and sprayer uses calibration: seed rate check by collecting seed over a measured distance; sprayer output = nozzle flow × number of nozzles ÷ swath.

Processing equipment principles: threshing separates grain from straw by impact and rubbing; winnowing separates by aerodynamic drag; cleaning uses screens and air.

Storage structures: moisture content must be below safe limits (roughly 12–14% for cereals) to prevent mould and insect multiplication.

Ergonomics and safety: PTO shafts need guards, and tractor stability is reduced by a high centre of gravity on slopes; ROPS and seat belts prevent rollover fatalities.

Irrigation water requirement = crop evapotranspiration (ETc) minus effective rainfall; ETc = ET₀ × Kc where ET₀ is reference evapotranspiration and Kc is crop coefficient.

Soil moisture tension: field capacity is about −0.33 bar (−33 kPa), permanent wilting point about −15 bar (−1500 kPa); available water is the difference.

Irrigation scheduling: apply water when soil moisture depletion reaches the allowable depletion fraction; total available water × allowable depletion = readily available water.

Surface methods: basin, border and furrow; furrow is suited to row crops, basin to orchards and paddy.

Sprinkler and drip: drip saves water by delivering to the root zone and reducing evaporation; emitter clogging by salts and algae is the main maintenance problem.

Pump power (kW) = (Q × H × ρ × g) ÷ (1000 × efficiency), with Q in m³/s and H in m; or hp = (Q in L/s × H in m) ÷ (75 × efficiency).

Water conveyance losses in unlined channels can exceed 30–50%; lining with concrete or HDPE reduces seepage.

Drainage: surface drainage removes excess runoff, subsurface drainage lowers the water table; waterlogging reduces oxygen in the root zone and causes denitrification.

Cost concepts: fixed cost does not vary with output; variable cost does; total cost = fixed + variable; average cost = total cost ÷ output.

Gross margin = gross return − variable cost; it is used to compare enterprises when fixed costs are shared.

Benefit-cost ratio = present value of benefits ÷ present value of costs; a ratio above 1 indicates a profitable investment at the chosen discount rate.

Internal rate of return (IRR) is the discount rate at which net present value equals zero; accept a project if IRR exceeds the opportunity cost of capital.

Farm records: physical records (livestock, land, yields) and financial records (cash book, ledger, balance sheet); depreciation is a non-cash fixed cost.

Law of diminishing returns: as a variable input increases with others fixed, marginal product eventually declines; maximum output occurs where marginal product = 0.

Extension teaching methods: individual (farm visit, office call), group (demonstration, meeting) and mass (radio, poster); selection depends on audience size and complexity.

Diffusion of innovations: innovators, early adopters, early majority, late majority, laggards; adoption follows awareness, interest, evaluation, trial, adoption.

Agroforestry definition: deliberate integration of trees or shrubs with crops or livestock on the same land unit, producing ecological and economic interactions.

Common systems: agrisilviculture (trees + crops), silvopasture (trees + livestock), agrosilvopasture (all three), alley cropping, windbreaks and homegardens.

Competition for light, water and nutrients is the main disadvantage; root pruning, wider spacing and pruning reduce below-ground competition.

Nitrogen-fixing trees such as Leucaena, Gliricidia and Sesbania supply green leaf manure and fodder; pruning biomass is applied as mulch.

Windbreaks reduce wind speed and evaporation; effective height and porosity determine the protected zone, often 10–20 times tree height downwind.

Multipurpose trees provide fuelwood, fodder, fruit, timber and shade; selection depends on site, climate and farmer objectives.

Alley cropping: hedgerows of trees between crop strips; pruning provides mulch and reduces erosion, but hedgerows must be spaced to limit shade.

Carbon sequestration and soil conservation are key environmental benefits; deep roots recycle nutrients and reduce runoff.

Sustainable agriculture aims at profitability, environmental stewardship and social equity; it uses integrated nutrient, pest and water management.

Organic farming excludes synthetic fertilizers and pesticides; it relies on compost, green manure, biofertilizers and biological pest control, with certification standards.

Soil organic matter improves structure, water holding and CEC; conservation tillage and residue retention build organic matter.

Greenhouse gases from agriculture: methane from flooded paddy and ruminants, nitrous oxide from nitrogen fertilizer; mitigation includes water management and efficient N use.

Integrated nutrient management (INM) combines organic manure, biofertilizers and mineral fertilizer to match crop demand and reduce losses.

Biodiversity and ecosystem services: pollinators, natural enemies and soil organisms support crop production; monoculture reduces resilience.

Water quality: nitrate leaching and pesticide runoff contaminate groundwater and streams; buffer strips and precise application reduce risk.

Climate-smart agriculture: adaptation (drought-tolerant varieties, water harvesting) and mitigation (reduced tillage, agroforestry) together.

Lesson plan components: objectives, prior knowledge, teaching aids, introduction, presentation, recapitulation and evaluation.

Bloom's taxonomy levels: knowledge, comprehension, application, analysis, synthesis and evaluation; objectives should be stated with action verbs at the intended level.

Demonstration method is central to agriculture teaching: it shows a skill, explains the steps, and gives learners supervised practice.

Project method and supervised occupational experience link classroom learning to real farm work; evaluation uses process and product criteria.

Teaching aids for agriculture: real specimens, models, charts, field plots, videos and laboratory equipment; real objects are most effective for skill learning.

Assessment types: formative (during learning, feedback) and summative (end of unit, grading); practical examinations assess psychomotor skills.

Laboratory and field safety: risk assessment before practicals, protective equipment, and clear instructions for tools and chemicals.

Questioning technique: use open and closed questions, allow wait time, and distribute questions across the class to check understanding.