Crop Production and Management
Every plate of food you have ever eaten began as a decision someone made in a field: which seed to sow, when to water it, how to feed the soil, and how to keep the harvest safe. Ten thousand years ago people were nomadic, wandering in search of wild fruit and hunted meat, until someone noticed that a dropped seed grows into a plant that makes more seeds, and agriculture was born. Feeding over a billion people in India today depends on that same simple trick, at an enormous, organised scale. This chapter walks through that scale-up as a chain of practical steps, in the order a farmer performs them: choosing the right season, preparing the soil, selecting and sowing good seed, feeding the soil, irrigating it, keeping weeds away, cutting and threshing the ripened crop, and storing the grain safely. Along the way you will meet the tools that make each step possible — plough, seed drill, sprinkler, sickle, combine — and the science behind them: why loosened soil helps roots breathe, why legumes secretly enrich the soil with nitrogen, and why drying grain before storage is not optional. None of this is exotic science. It is biology and chemistry you already know — germination, decomposition, evaporation — applied to growing enough food for a nation. By the end you should be able to look at any farm, real or in an exam diagram, and name what stage of crop production is happening and why it matters.
- A crop is the same kind of plant cultivated at one place on a large scale; India has two seasons — kharif (rainy, June-September: paddy, maize, soyabean, groundnut, cotton) and rabi (winter, October-March: wheat, gram, pea, mustard, linseed).
- Crop production follows seven practices in order: soil preparation, sowing, manuring/fertilising, irrigation, weeding, harvesting, storage.
- Tilling or ploughing loosens soil so roots can breathe and nutrient-rich soil returns to the top; tools include the plough, hoe and cultivator.
- Seeds are tested by the float test (damaged hollow seeds float) and sown with a funnel tool or a seed drill, which places seed at uniform depth and spacing.
- Manure is natural, humus-rich but nutrient-modest; fertiliser is factory-made, nutrient-concentrated (urea, NPK) but adds no humus.
- Crop rotation with legumes, whose root nodules host nitrogen-fixing Rhizobium, restores soil nitrogen naturally.
- Irrigation ranges from traditional labour-driven methods (moat, chain pump, dhekli, rahat) to modern sprinkler and drip systems that use far less water.
- Weeds compete with crops for water, nutrients, space and light; removed by manual weeding or chemical weedicides sprayed before flowering.
- Harvesting cuts the crop, threshing separates grain from chaff, winnowing completes it, and grain is sun-dried before storage in bins, silos or granaries.
- Key idea: crop production is a seven-step managed cycle — prepare soil, sow selected seed, feed the soil, irrigate on schedule, control weeds, harvest and thresh, and dry and store safely — repeated every kharif and rabi season to feed a growing population.
Growing enough food for a large population means deliberately managing, in the right season and the right order, seven linked practices — soil preparation, sowing, manuring, irrigation, weeding, harvesting and storage — each one protecting or restoring what the crop needs to turn a seed into a safely stored grain.
What this chapter covers
The chapter opens by defining a crop and splitting India's growing season into kharif and rabi patterns, since almost every later idea depends on which season a crop belongs to. It then walks the seven basic agricultural practices in order: preparing the soil, sowing, adding manure and fertilisers (with crop rotation as a natural alternative), irrigation, protecting from weeds, harvesting, and storage. A short closing section notes that food also comes from animals, reared under animal husbandry. Read the sections in order — each practice protects the gains of the one before it.
The core ideas
Kharif and rabi: the two great growing seasons
Before people learned to cultivate land, they were nomadic, wandering in search of food, until around 10,000 BCE they learned to grow rice, wheat and other food crops, and agriculture began. A crop is the same kind of plant grown at one place on a large scale; a field entirely sown with wheat is a wheat crop. India's climate varies across regions, but two broad seasonal patterns cover most crops.
Kharif crops are sown in the rainy season, roughly June to September: paddy, maize, soyabean, groundnut and cotton, plants needing plenty of water while establishing. Rabi crops are sown in the cooler winter season, October to March: wheat, gram, pea, mustard and linseed. Pulses and vegetables are additionally grown in many places during the short summer window between the two. Paddy cannot simply be sown in winter, because it needs standing water that winter rainfall cannot supply — a temperature and water requirement, not a calendar preference.
Preparing the soil: tilling, ploughing and levelling
The first step before growing any crop is preparing the soil — turning and loosening it, called tilling or ploughing. Loosened soil lets roots penetrate deep and breathe, and helps earthworms and soil microbes thrive, adding humus. Only the top few centimetres of soil support plant growth well, so turning it brings buried, nutrient-rich soil back up to where roots can use it. Ploughing is done with a plough, traditionally a wooden implement pulled by bulls, with a long ploughshaft, a handle at one end, and a strong triangular iron ploughshare cutting the earth at the other. A hoe is a simpler tool with a bent iron blade for weeding and loosening soil, while a tractor-drawn cultivator now does the same job faster with far less labour. After ploughing, large soil clumps called crumbs are broken up, and the field is levelled, which helps sowing and irrigation.
Sowing: choosing and placing the right seed
Before sowing, farmers select good quality, healthy, high-yielding seed. A simple float test separates good seed from damaged: a handful stirred into water is left to settle, and damaged, hollow seeds float while healthy seeds sink. Sowing must place seeds at an appropriate depth and distance, since crowded plants compete for sunlight, nutrients and water. The traditional sowing tool is funnel-shaped, with sharp-ended pipes piercing the soil to drop seeds in as it is dragged along. The modern seed drill, pulled by a tractor, sows seed uniformly at set depth and distance and covers it automatically, saving labour while protecting seed from birds. Some crops, like paddy, are first grown as nursery seedlings and transplanted once big enough.
Feeding the soil: manure, fertilisers and crop rotation
Soil supplies the mineral nutrients a crop needs, and continuous cultivation steadily depletes those nutrients, leading to weak plants unless the farmer replenishes them — a process called manuring. Manure is a natural organic substance made by decomposing plant and animal waste in pits, prepared right in the fields. Fertilisers, by contrast, are inorganic salts manufactured in factories and very rich in specific nutrients — urea, ammonium sulphate, super phosphate, and NPK (nitrogen, phosphorus, potassium). The two are not interchangeable. Manure adds a great deal of humus, improving water-holding capacity, porosity, texture and friendly microbes, but is relatively low in concentrated nutrients. Fertiliser adds no humus but delivers a much higher, targeted dose of nutrients, driving large yield increases — at the cost that excess use makes soil less fertile and pollutes water. A sustainable field usually needs manure and, periodically, a fallow period or crop rotation — alternating a heavy feeder like wheat with a legume such as gram, pea or moong. Legume roots carry nodules hosting Rhizobium bacteria, which fix nitrogen from the air into the soil, so rotation naturally restores nitrogen and cuts dependence on chemical fertiliser. A harvest is finally measured against how much land it came from, using one relation applied throughout this chapter's numericals:
where: yield per acre is the field's reported average productivity, converted to everyday units through 1 quintal kg and 1 tonne kg quintals. The two derivations below trace this arithmetic, alongside the nitrogen pathway that keeps yield-per-acre from falling.
Irrigation: water at the right time, in the right amount
Plants are roughly ninety per cent water by content: seeds need it to germinate, it carries dissolved nutrients through the plant, and it protects the crop from frost and hot air. The regular supply of water to a crop is called irrigation, and its timing and frequency change with crop, soil and season — summer needs more frequent watering because evaporation speeds up in the heat. Sources include wells, tubewells, ponds, lakes, rivers, dams and canals. Traditional methods of lifting water — the moat (pulley system), chain pump, dhekli, and rahat (lever system) — rely on animal or human labour, cheap but inefficient. Modern methods use far less water for the same result. In the sprinkler system, water is pushed under pressure through pipes with rotating nozzles, spraying like artificial rain, suiting uneven land and scarce-water regions. In the drip system, water falls drop by drop directly at each plant's root through narrow tubes, wasting almost nothing — best for fruit trees, gardens and water-scarce regions. How much a modern method saves is expressed as a percentage of the older requirement:
where: both water-used figures are measured for the same field over the same period, so the fraction isolates exactly what the modern method avoided wasting.
Protecting the crop from weeds
Undesirable plants growing alongside a crop, competing for water, nutrients, space and light, are called weeds; some even interfere with harvesting or are poisonous. Removing weeds is called weeding, best done before weeds flower and produce seed. Tilling before sowing already uproots many weeds; manual weeding uses a hand tool called a khurpi. Chemical weedicides, such as 2,4-D, are diluted with water and sprayed to kill weeds without harming the crop; since handling them can affect health, farmers cover their nose and mouth while spraying.
Harvesting, threshing and storage
Harvesting is the cutting of a mature crop, which for most cereal crops takes three to four months to reach; done manually with a sickle or, at scale, by a harvester. Separating the harvested grain from stalks and husks is called threshing; a combine performs both harvesting and threshing in one pass. Small farmers often separate grain from the lighter chaff by winnowing, letting wind carry the chaff away while grain falls straight down. Freshly harvested grain has too much moisture to store safely — stored wet, it can be attacked by insects, bacteria and fungi. So grain is dried in the sun before storage. At home, dried neem leaves keep pests away; at scale, grain is stored in jute bags, metal bins, silos or granaries, with chemical treatments protecting big storage godowns against pests and microorganisms.
Food from animals: animal husbandry
Just as crop production feeds us with plant food, many people depend on food from animals — milk from cows, buffaloes, goats and camels, and, for many in coastal areas, fish, also a source of vitamin D via cod liver oil. When animals reared at home or on farms are given proper food, shelter and care at scale, this is called animal husbandry — the same logic as crop production, deliberate managed care replacing chance.
The goal here is to trace, step by step, how a field that has been growing wheat continuously and losing nitrogen every season can get that nitrogen back without a bag of factory fertiliser, using nothing but a rotated legume crop and a bacterium the plant already carries in its own roots. This matters because nitrogen is the nutrient a plant needs in the largest amount for healthy growth, and the atmosphere is nearly eighty per cent nitrogen gas, sitting uselessly above every field unless something can convert it into a form roots can absorb.
Step 1. The air above every field is about seventy eight per cent nitrogen gas, but ordinary crop plants, including wheat, cannot absorb nitrogen in this gaseous form; their roots can only take up nitrogen already combined into compounds such as nitrates, dissolved in soil water. Continuous cultivation of a nitrogen-hungry crop draws down the soil's nitrate stock season after season, and without replenishment the soil becomes progressively poorer.
Step 2. Bring in the legume. Leguminous plants — gram, pea, moong and similar crops — carry small swellings called nodules on their roots, home to Rhizobium bacteria, in a mutually beneficial partnership with the plant. The bacteria, using enzymes the plant alone does not have, fix atmospheric nitrogen gas — convert it chemically into compounds the plant's cells, and later the soil, can use.
Step 3. Follow the nitrogen into the soil. Nitrogen compounds accumulate around the legume's root nodules as it grows. When the crop is harvested and its roots and stubble are ploughed back in, or decay in place, that fixed nitrogen releases into the surrounding soil, raising its nitrate content for whatever is planted next.
Step 4. Close the loop with crop rotation. A farmer who grows wheat one rabi season and a legume the next is deliberately exploiting this pathway: the legume season restores the nitrogen wheat used up, so the next wheat crop finds richer soil than if wheat had been grown twice running — the practice farmers in northern India traditionally followed, and why crop rotation, alongside manure, is one of the two natural alternatives to chemical fertiliser.
Go deeper · Derivation B · 1 minFrom per-acre yield to total farm produce — the arithmetic of a harvest
The goal of this derivation is to turn the kind of number a real farmer actually reports — a yield quoted per acre, in quintals — into the total quantity of grain that farm produced, and then into kilograms and tonnes, using nothing beyond multiplication and unit conversion, the relation introduced in the core ideas above.
Step 1. Fix the units. Total produce (quintals) equals yield per acre multiplied by number of acres. One quintal is 100 kilograms, and one tonne is 1000 kilograms, the same as 10 quintals.
Step 2. Apply it to the gram crop. Take the midpoint of the reported range, ten quintals per acre, on a farm of six acres. Total produce equals ten multiplied by six, giving sixty quintals of gram.
Step 3. Convert into kilograms and tonnes. Sixty quintals times 100 kilograms per quintal gives 6000 kilograms; dividing by 1000 gives 6 tonnes.
Step 4. Repeat for wheat. The midpoint yield of twenty two and a half quintals per acre on eight acres gives 180 quintals, equal to 18,000 kilograms, equal to 18 tonnes. The reported range for each crop is not sloppiness — real yield varies with soil quality, rainfall and how well the earlier practices were carried out.
Worked examples
Board level - total gram harvest from a field, in quintals and kilograms
A farmer's gram field covers 4 acres, yielding 10 quintals of gram per acre, in line with the chapter's reported range. Find the total gram harvested, in quintals and kilograms.
Step 1. Apply the yield-area relation: total produce equals yield per acre multiplied by acres, so 10 multiplied by 4.
Step 2. Multiply: 10 times 4 gives 40 quintals of gram from the whole field.
Step 3. Convert to kilograms using 1 quintal = 100 kg: 40 times 100 gives 4000 kilograms. Answer: the field yields 40 quintals, which is 4000 kilograms, of gram.
Board level - water saved by switching a field to drip irrigation
A one acre vegetable field needs 12,000 litres of water per day under flood irrigation. Switching to drip irrigation cuts the daily requirement by 70 per cent. Find the water used per day with drip irrigation, and the water saved.
Step 1. Find 70 per cent of the flood figure, the fraction drip irrigation saves: 0.70 times 12,000 equals 8400 litres saved per day.
Step 2. Find the water actually used: 12,000 minus 8400 equals 3600 litres per day.
Step 3. Sanity-check: drip irrigation delivers water exactly where the root needs it, so a large saving fits the mechanism. Answer: drip irrigation uses 3600 litres per day, saving 8400 litres per day.
Higher-order thinking (HOTS / olympiad-style) - explaining and quantifying a six-year yield gap between two fields
Two adjacent one-acre wheat fields, A and B, receive identical seed, rainfall and sunlight every rabi season. Field A has grown wheat continuously for six years, unmanured and never fallow. Field B was rotated every alternate season with a legume fodder crop and manured at the start of each wheat cycle. After six years, A yields 14 quintals per acre and B yields 22. Explain the difference, and state by what percentage A's yield falls short of B's.
Step 1. Diagnose Field A. Growing wheat season after season with no manure and no fallow period steadily removes nutrients, especially nitrogen, without replacing them, so the soil becomes progressively poorer.
Step 2. Diagnose Field B, using both mechanisms the chapter names. Manure added each cycle restores humus and water-holding capacity; the alternating legume hosts Rhizobium that fix atmospheric nitrogen, leaving the soil richer in nitrate — the pathway traced in the first derivation above.
Step 3. Quantify the gap. The difference is 22 minus 14 equals 8 quintals per acre; as a shortfall of A relative to B, 8 divided by 22, multiplied by 100, is approximately 36.4 per cent. Answer: Field A's soil was depleted of nitrogen by continuous unmanured cultivation, while Field B's manuring and legume rotation restored humus and nitrogen every cycle; Field A's yield is about 36.4 per cent lower than Field B's. Timing note: about three minutes. The reasoning half — manure's physical role versus the legume-Rhizobium nitrogen role — is worth more than the arithmetic; computing 8 quintals without explaining both mechanisms loses the marks that matter most here.
Common traps
- Mixing up kharif and rabi: kharif is rainy season (June-September), rabi is winter (October-March) — the names refer to sowing season, and paddy cannot simply move to dry rabi.
- Treating manure and fertiliser as the same thing: manure is natural and humus-rich; fertiliser is factory-made and humus-free but concentrated.
- Assuming more fertiliser automatically means more yield: excess use makes soil less fertile over time and pollutes water.
- Confusing threshing with winnowing: threshing separates grain from stalk and husk; winnowing later blows away chaff with moving air.
- Underestimating weeds: they actively compete for water, nutrients, space and light, so weeding timing matters.
- Forgetting the quintal-kilogram-tonne chain: 1 quintal = 100 kg, 1 tonne = 10 quintals.
- Assuming irrigation needs are fixed: timing and frequency change with crop, soil and season.
You should be able to…
- Define a crop, and classify it as kharif or rabi from its sowing season.
- Explain why tilling before sowing helps root growth and nutrient availability.
- Describe the float test and explain why damaged seeds float.
- Explain the difference between manure and fertiliser, including humus content and origin.
- Explain how crop rotation with a legume restores soil nitrogen, naming Rhizobium and nodules.
- Compare traditional and modern irrigation, and explain why drip and sprinkler save water.
- Explain why weeding is necessary and how it differs from weedicide use.
- Distinguish harvesting, threshing and winnowing as three separate steps.
- Explain why grain must be dried before storage, and name two storage structures.
- Convert between quintals, kilograms and tonnes, and apply the yield times area relation.
Ask the tutor: if you would like to work through more numericals on yield and irrigation savings, or want the nitrogen-fixation pathway explained again with a diagram, just ask.
Why do farmers sometimes leave a field fallow instead of just adding more fertiliser every season?
Leaving a field fallow, uncultivated for a season, lets the soil naturally recover structure and nutrient balance without any input, breaking the cycle of nutrients being drawn down every season. Fertiliser replaces specific nutrients quickly, but it does not rebuild humus, texture or friendly microbes the way rest, manure or legume rotation can, and heavy continuous fertiliser use can itself make soil less fertile and pollute water. A fallow season is a low-cost, no-input way of letting the soil's own processes catch up.
I always mix up manure and fertiliser. What is the one difference I should remember?
Anchor it to origin and humus: manure is natural, made by decomposing plant and animal waste in the fields, and adds a lot of humus; fertiliser is an inorganic salt made in a factory, and adds no humus at all. Once you remember manure equals natural plus humus and fertiliser equals factory-made plus no humus, the rest follows — manure improves soil structure gently, while fertiliser delivers a fast, concentrated dose of specific nutrients like nitrogen or potassium.
If irrigation can supply as much water as I want, why can't I just grow paddy in winter by watering it a lot myself?
Rabi season brings cooler temperatures and less natural rainfall, and paddy's whole life cycle, including germination, is suited to the warmer, wetter kharif conditions, not just a large volume of water on demand. Growing paddy in winter would also mean supplying artificially, every day, all the water the monsoon otherwise provides free, on top of unsuitable temperatures. This is why kharif and rabi are fixed seasonal categories, not flexible watering choices.
Weeding already removes weeds by hand, so why do farmers also need weedicides?
Manual weeding works well but is slow across a large field, and weeds that are missed or regrow can still flower and seed before the next round reaches them. Weedicides like 2,4-D can be sprayed over a large area quickly, killing weeds without harming the crop, timed before the weeds flower and seed. Farmers often use both: tilling and manual weeding as first defence, weedicides for faster, wider coverage — though handlers should protect their nose and mouth, since the chemicals can affect health.