UPMSP Class 12 Vocational Crop Science cheat sheet

Crop = any plant grown by humans for economic or subsistence use; agronomy deals with field crops, horticulture with garden crops (fruits, vegetables, flowers, plantation crops).

Botanical classification: family → genus → species → variety; e.g. wheat Triticum aestivum (Poaceae), rice Oryza sativa (Poaceae), chickpea Cicer arietinum (Fabaceae).

Agronomic classification by use: cereals (wheat, rice, maize), pulses (gram, pea, lentil), oilseeds (mustard, groundnut, sesame), fibre (cotton, jute), sugar (sugarcane, sugarbeet), fodder, tuber and root crops.

Seasonal classification: kharif (sown with monsoon, June–July; rice, maize, cotton, groundnut), rabi (winter, October–November; wheat, mustard, gram), zaid (summer; moong, watermelon).

Life cycle: annual (wheat, rice) completes in one season; biennial (sugarbeet, onion) needs two years; perennial (sugarcane, banana) persists over years.

Photosynthetic groups: C3 crops (wheat, rice, pulses) have lower photosynthetic efficiency; C4 crops (maize, sorghum, sugarcane) have higher efficiency, lower photorespiration and better drought tolerance.

Cropping intensity = (gross cropped area ÷ net sown area) × 100; multiple cropping and relay cropping raise intensity, while sole cropping keeps it near 100.

Crop rotation rule: alternate deep-rooted with shallow-rooted crops, and legume with cereal, to restore nitrogen and break pest cycles; avoid same-family crops in succession.

Soil profile horizons: O (organic), A (topsoil, humus-rich), E (eluviation), B (illuviation, clay/iron accumulation), C (weathered parent material), R (bedrock).

Soil texture classes by particle size (ISSS): sand 0.02–2 mm, silt 0.002–0.02 mm, clay <0.002 mm; a soil with these in balance is loam, generally best for crops.

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

Field capacity is water held at about −1/3 bar (0.33 atm); permanent wilting point at −15 bar; available water = field capacity − wilting point.

Soil pH classes: strongly acid <5.5, moderately acid 5.5–6.5, neutral 6.5–7.5, alkaline >7.5; most field crops grow best at pH 6.0–7.5.

Cation exchange capacity (CEC) measures cmol(+) charge per kg soil; high-clay and high-humus soils have high CEC and buffer nutrient supply better than sandy soils.

Soil erosion control: contour ploughing, terracing, strip cropping, bunding and mulching reduce sheet and rill erosion; wind erosion is checked by shelterbelts and stubble mulching.

Saline soils have high soluble salts and EC >4 dS/m with pH usually below 8.5; alkali (sodic) soils have high exchangeable sodium (ESP >15) and pH often above 8.5.

Essential elements: 17 total - C, H, O from air/water; macronutrients N, P, K, Ca, Mg, S; micronutrients Fe, Mn, Zn, Cu, B, Mo, Cl, Ni.

Law of the minimum (Liebig): yield is limited by the nutrient in shortest supply; other nutrients added beyond that do not increase yield.

N is central to chlorophyll and protein; deficiency shows as general yellowing (chlorosis) of older leaves first because N is mobile in the plant.

P promotes root development and early maturity; deficiency causes purple or reddish discolouration of leaves and stunted growth, especially in cold soils.

K regulates water balance and enzyme activity; deficiency shows marginal leaf scorch and weak stems; K is also called the 'quality nutrient'.

Urea contains 46% N, DAP 18% N and 46% P2O5, single superphosphate 16% P2O5, muriate of potash 60% K2O; fertiliser grade is expressed as N–P2O5–K2O.

Fertiliser dose rule: apply full P and K and half N at sowing, remaining N as top dressing at active growth; split N reduces leaching and volatilisation loss.

Biological nitrogen fixation by Rhizobium in legume root nodules; Azotobacter and Azospirillum are free-living/associative fixers; blue-green algae fix N in flooded rice fields.

Seed germination requires water, oxygen and suitable temperature; some seeds also need light (lettuce) or darkness, and hard seeds need scarification.

Germination percentage = (number of normal seedlings ÷ total seeds sown) × 100, tested on specified substrate (paper or sand) under controlled temperature.

Seed viability is the capacity to germinate; seed vigour is the potential for rapid, uniform emergence under field stress, tested by accelerated ageing or electrical conductivity.

Seed dormancy is a resting state; causes include hard seed coat (impermeable), immature embryo, or chemical inhibitors; broken by scarification, stratification or gibberellic acid.

Seed treatment: fungicide (e.g. carbendazim or thiram) before sowing; Rhizobium culture for legumes; hot-water or acid treatment for loose smut of wheat.

Seed moisture content is measured by oven-drying at 130 °C for 1 hour or 105 °C for 24 hours; safe storage moisture for cereals is about 10–12%.

Seed certification classes in India: breeder seed → foundation seed → registered seed → certified seed; certified seed carries the certification tag with lot and germination details.

Seed rate depends on test weight and germination; lower germination or larger seed size means a higher seed rate, and 1000-grain weight is used to calculate it.

Seed quality components: genetic purity, physical purity, germination percentage, moisture content, seed health (free from disease) and vigour.

Genetic purity is maintained by isolation distance between varieties of the same crop to prevent cross-pollination; distances differ for self- and cross-pollinated crops.

Roguing is removal of off-type, diseased and volunteer plants from the seed field; it is done at vegetative, flowering and maturity stages.

Minimum field standards for certified seed vary by crop; typical certified seed requires genetic purity near 99% and germination above 80% for cereals.

Seed lot sampling uses a trier or probe to draw a composite sample; the submitted sample must represent the whole lot and be sealed and labelled.

Physical purity analysis separates pure seed, other crop seed, weed seed and inert matter; purity (%) = pure seed weight ÷ total sample weight × 100.

Seed testing methods: tetrazolium test for quick viability, standard germination test for germination percentage, and moisture meter for storage safety.

Seed storage: cool, dry conditions; seed bag labels show lot number, germination date, purity and inert matter; carry-over seed must be retested before sale.

Wheat: rabi crop, sown October–November, seed rate about 100 kg/ha for timely sowing, row spacing 20–22.5 cm; irrigate at crown root initiation (about 20–25 days after sowing).

Rice: transplanted paddy needs about 5 cm standing water; nursery of 20–25 days, transplanting 2–3 seedlings per hill, spacing 20 × 10 cm or 20 × 15 cm.

Maize: kharif or rabi, seed rate about 20 kg/ha, spacing 60 × 20 cm; detasselling in seed production and control of fall armyworm are key operations.

Pulses (gram, pea, lentil, moong) are legumes that fix nitrogen; they need inoculation with Rhizobium and are sensitive to waterlogging and excess nitrogen.

Gram (chickpea): rabi pulse, seed rate about 75–100 kg/ha, spacing 30 × 10 cm; pod borer (Helicoverpa) is the major insect pest.

Oilseeds: mustard seed rate about 5–6 kg/ha, groundnut about 100–120 kg kernels/ha; groundnut needs calcium at pegging and gypsum application.

Crop geometry: plant population per hectare = 10,000 ÷ (row spacing in m × plant spacing in m); closer spacing raises population but may reduce per-plant yield.

Critical growth stages for irrigation: crown root initiation in wheat, flowering in pulses and oilseeds, tasselling in maize; stress at these stages cuts yield sharply.

Sugarcane: planted in spring (February–March) or autumn; setts with 2–3 buds used as planting material, about 75,000–80,000 buds/ha; earthing up and trash mulching are standard.

Cotton: kharif fibre crop; seed rate about 15–20 kg/ha for desi and 3–5 kg/ha for hybrid; bollworm and whitefly are major pests; picking begins about 150–180 days after sowing.

Jute: fibre from stem bark, sown March–April, harvested at early pod stage for best fibre quality; retting in water separates fibre from woody core.

Horticultural crops are grouped as fruits, vegetables, flowers, plantation crops, spices and medicinal/aromatic plants; vegetables are mostly short-duration annuals.

Vegetable nursery: raised beds, sowing depth 1–2 cm, transplanting when seedlings have 4–6 true leaves; hardening before transplanting improves survival.

Banana is propagated by suckers or tissue-cultured plantlets; it is a perennial herb with a pseudostem, and bunch weight depends on number of hands and fingers.

Mango: grafted plants (approach or veneer grafting) bear in 3–5 years; flowering is induced by cool, dry weather and the crop is harvested in summer.

Protected cultivation: polyhouse and shade-net control temperature, humidity and light; drip with fertigation is standard for high-value horticultural crops.

Water requirement of a crop = evapotranspiration (ET) over the season; irrigation requirement = water requirement − effective rainfall − soil moisture contribution.

Irrigation water quality is judged by EC, SAR and residual sodium carbonate (RSC); high RSC water needs gypsum amendment before use.

Duty of water = area irrigated (ha) per unit discharge (cumec) over the crop season; delta = total depth of water (cm) required over the base period.

Duty (ha/cumec) = 8.64 × base period (days) ÷ delta (m); this links canal discharge, crop season and irrigation depth.

Surface methods: flooding, furrow, border strip and basin; sprinkler suits undulating land and light soils; drip saves water and suits wide-row and horticultural crops.

Drip irrigation applies water at the root zone with 30–50% water saving; emitters are rated in litres per hour and lines are spaced by crop row distance.

Dryland agriculture: crops grown on stored rainfall; practices include contour bunding, compartmental bunding, mulching, deep ploughing once in 3 years and moisture conservation.

Dryland moisture-saving measures: summer ploughing, ridge and furrow sowing, intercropping with drought-tolerant crops, and use of short-duration varieties to escape terminal drought.

Weed classification: grasses (narrow leaf), sedges (triangular stem, e.g. Cyperus), and broadleaf weeds; Phalaris minor in wheat and Echinochloa in rice are key grassy weeds.

Critical period of crop–weed competition is generally the first 30–45 days after sowing; weeds removed in this period prevent most yield loss.

Weed control methods: mechanical (hoeing, weeding), cultural (crop rotation, stale seedbed), biological (bioagents), and chemical (herbicides).

Herbicide classification by mode: selective vs non-selective; pre-emergence (applied before weed emergence) vs post-emergence; contact vs systemic.

Herbicide selectivity and resistance: continuous use of the same herbicide selects resistant weed biotypes; rotate herbicide groups and integrate mechanical control.

Insect pest types: chewing (caterpillars, beetles), sucking (aphids, jassids, whitefly), borers (stem borer, pod borer) and storage pests (weevils, grain moth).

Integrated pest management (IPM): monitoring and economic threshold level, resistant varieties, cultural and biological control, and need-based pesticide use as a last resort.

Plant disease triangle: susceptible host + virulent pathogen + favourable environment; control by resistant varieties, seed treatment, crop rotation, and fungicide only when needed.

Nematodes: root-knot nematode (Meloidogyne) causes galls on roots; management uses crop rotation with non-hosts, organic amendments, and nematicides such as carbofuran.

Tillage implements: mouldboard plough for deep inversion, disc plough for primary tillage, cultivator and harrow for secondary tillage, and leveller for field levelling.

Sowing implements: seed drill for line sowing, seed-cum-fertiliser drill for simultaneous placement, dibbler for spot sowing; row spacing is set by the metering mechanism.

Sprayers: knapsack sprayer is common for small holdings; flat fan nozzle for herbicide, hollow cone for insecticide; calibrate before use to apply the correct dose.

Harvesting and threshing: combine harvester performs cutting, threshing and winnowing; threshing floor and power thresher are used for small farms.

Post-harvest losses arise from moisture, heat, insects, rodents and handling damage; grain must be dried to safe moisture (about 10–12% for cereals) before storage.

Storage structures: mud bin, metal bin, and bag storage; fumigation with phosphine tablets and airtight storage reduce insect infestation.

Cleaning and grading: winnowing removes chaff, sieving removes foreign matter, and grading by size or density improves market price.

Value addition: milling of paddy to rice, dal milling of pulses, and oil extraction from oilseeds; by-products (bran, oilcake, husk) have economic value.

Farm management decisions are based on marginal analysis: apply an input until marginal value product equals marginal factor cost; beyond that, returns fall.

Gross income = yield × price; net income = gross income − total cost; farm profit depends on both yield and price, not yield alone.

Cost concepts: fixed costs (land rent, machinery depreciation) do not vary with output; variable costs (seed, fertiliser, labour, irrigation) vary with the crop season.

Benefit–cost ratio = gross returns ÷ total cost; a ratio above 1 indicates a profitable enterprise, and it is used to compare crop options.

Farm records: physical records (area, inputs, yields) and financial records (receipts, payments, inventory); records support credit, insurance and planning decisions.

Marketing channels move produce from farmer to consumer through middlemen; a shorter channel generally gives the farmer a larger share of the consumer rupee.

Market functions: assembling, grading, storage, transport, processing and financing; price is influenced by supply, demand, quality and timing of sale.

Agricultural price support and minimum support price (MSP) protect farmers against price crashes; cooperative marketing societies help small farmers bargain better.

Field layout: measure plot with tape, mark rows with a rope and pegs, and record plot size, row spacing and plant spacing before sowing.

Plant population per plot = plot area ÷ (row spacing × plant spacing); record actual plant count and compare with the target to assess establishment.

Seed germination practical: count normal seedlings after the specified test period, and calculate germination (%) and note abnormal seedlings and dead seeds separately.

Soil sampling practical: take samples from 0–15 cm depth at several spots in a zig-zag pattern, mix them, quarter to about 500 g, and label with field, depth and date.

Plant protection record: note pest or disease, stage of crop, intensity, control measure applied, dose, date and result; this supports IPM decisions.

Project record format: title, objective, materials, procedure, observations in tabular form, calculations, results and conclusion; maintain a field diary with dated entries.

Yield calculation: yield (q/ha) = plot yield (kg) × 10,000 ÷ plot area (m²); convert to quintals per hectare and compare with the crop's average yield.

Field demonstration: prepare a layout sketch, list inputs and costs, record operations and dates, and compare demonstration plot yield with the farmer's practice plot.