1. Crop Production 1. Crop Production

Agriculture

Unit 1: Food

Introduction

We are largely dependent upon plants and animals for our daily food requirements. Most of our food products like cereals, pulses, vegetables, fruits and spices are obtained from plants. Other food products such as milk, eggs and meat derived from animals are also indirectly obtained from plants as these animals depend on the plants for their food. The science of growing crops and raising animals in order to obtain food and other products useful to man is called agriculture. In this chapter, we will learn how crops are raised and the different practices of food production in detail.

The branch of science which deals with methods of food production is known as agriculture. The methods of food production used to grow new and better varieties of crops, rear animals and birds, like cows, hens, etc., well so that they give more milk and better quality eggs are called agricultural practices.

Do You Know?The word ‘agriculture’ comes from the Latin words ager meaning ‘field’ and colere meaning ‘cultivate’. Agriculture started centuries ago in around 10000 BC from a region, which is now a desert.

Different types of plants have different requirements. Paddy requires a lot of water while cactus needs very little water. Apples thrive in the cold climate while grains and cereals grow well in specially prepared fields in the plains. When plants are cultivated on a large-scale, their requirements are taken into consideration to increase their productivity. The plants of same kind grown at one place on a large-scale are collectively referred to as crop. There are many types of crops. Table 1.1 lists some common crop plants.

Table 1.1 Some common crop plants

Type Examplescereals paddy, wheatfibre crop, jute, cottonpulses gram, peas, beansoil seeds mustard, groundnut, sunflowerroot crop sweet potatotuber crops potato, tapiocasugar crops sugar cane, beetrootplantation crops coffee, tea, rubbermedicinal crops basil, (tulsi) aloe vera

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A crop may grow well in a particular season, depending upon the temperature, humidity and rainfall. Based on the seasons, the crops are categorised into the following two types.

Kharif cropsThese crops are grown in the rainy season between June and October. The kharif crops are dependent upon the south-western monsoon. A few examples of kharif crops are paddy, cotton, soybean, groundnut and maize.

Rabi cropsThese crops are grown in the winter season between October and March, and are not dependent upon the monsoon. A few examples of rabi crops are wheat and legumes like clover, pea, gram, mustard and linseed.

A field needs to be managed properly to yield good crops. Crops are grown in soil or in water. What we obtain from the crops is called produce. Certain conditions are very important to increase the quantity as well as the quality of the crops. Some of these conditions are the kind of soil, quality of seeds, water availability, implements and agricultural practices, and protection from weeds, pests and pathogens. All these factors collectively determine crop productivity.

Agricultural products can be divided into the following groups as given in Table 1.2.

Table 1.2 Various categories of food items

Category Examplesmillets sorghum (jowar), finger millet (ragi), pearl millet (bajra)

pulses arhar (tur), black gram (urad), green gram (moong), Bengal gram (channa)

beans peas, soybean, cowpea, lentil

oilseeds mustard, groundnut, soybean, sunflower, linseed, castor, cotton seed

root crops carrot, turnip, sweet potato

tuber crops potato, tapioca, ginger, turmeric

sugar crops sugar cane, beet root

plantation crops coffee, tea, rubber, coconut

HorticultureDid you observe that something is missing from the list of food items which we eat every day? What is it that we have not listed here in table? Yes, we have neither included vegetables nor fruits in this list. Vegetables and fruits are essential items of our diet and their growth and production are studied under a branch of agriculture called horticulture.

Horticulture is derived from two Latin words hortus which means ‘garden’ and colere which means ‘cultivate’. Horticulturists carry out research to find new ways by which better varieties of fruits and vegetables can be grown in large quantities.

Activity 1

Collect a few crop plants growing near your house or make a visit to agricultural fields to collect a few plants. Dry them. Prepare a scrapbook. Find out their common name and scientific name and label the plants.

Fig. 1.1 Horticulture

Category Examples

vegetables tomato, cabbage, spinach

fruits banana, grapes, apple, mango

ornamental plants croton, cactus, Bougainvillea

flowers rose, jasmine, sunflower






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Formative Assessment

1. Define agriculture. What do you understand by agricultural practices?2. Give any two examples of crops and oilseeds.3. Differentiate between agriculture and horticulture.4. Categorise the following crops on the basis of the season they grow in. peas, gram, groundnut, cotton, mustard, cucumber, linseed5. Define crop and produce.

Steps to Improve Agricultural Produce Agriculture involves systematic use of some basic practices called agricultural practices that fulfil the needs of the plants grown in a field. Some of the agricultural practices that help to produce a good crop yield are listed below.1. The crop fields should be open so that sunlight and air are abundantly available.2. The fields should be protected from animals and trespassers.3. The soil should be loosened and ploughed before sowing. This allows easy penetration of roots to hold

the plants firmly as well as helps the roots to breathe.4. The right amount of water should be available for the proper growth of plants.5. The soil should contain sufficient nutrients for the healthy growth of the plants.6. Unwanted plants, such as weeds, should be uprooted from the soil. These weeds compete with the main

crops for nutrients and deprive them of their nourishment.To increase the food production, we can sow good quality seeds and improve the methods of sowing. We

can make the soil richer and even use better techniques for harvesting the crops. Some of the agricultural practices developed by the scientists are explained here.

Preparation of Soil The soil acts as a medium for the germination of seeds and the growth of crops. It provides water and minerals to the plants. The growth of plants depends upon the fertility of soil. Also, different kinds of plants require different kinds of soil. Therefore, it becomes necessary to prepare the soil before growing a crop. This is an important practice which helps to enrich the soil and make it more fertile and aerated. It involves addition of manure followed by turning, loosening and levelling the soil, using agricultural implements like hoe, plough or mechanical farm implements. The preparation of soil involves loosening and turning of soil. The process of loosening and turning the soil is called tilling or ploughing. Some of the main tools used for ploughing are discussed here.

require different kinds of soil. Therefore, it becomes necessary to

Fig. 1.2 Ploughing of soil






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Plough The soil is tilled with the help of plough. Plough is a tool made up of iron or wood. The use of plough has several benefits.1. It improves the air circulation within the soil, allowing the roots to breathe easily. 2. The loosened soil allows the roots to penetrate easily. 3. It enhances the water retaining capacity

of the soil.4. The earthworms and microbes present

in the soil are farmer’s friends as they aid in further turning and loosening of the soil, and also increases its fertility. The loosened soil also helps their survival.

5. Turning of soil uproots the undesirable plants, i.e. weeds growing in the field. Weeds can also be removed with the help of a harrow.Plough has been in use since ancient times for tilling, removing weeds and scraping the soil. It can be

drawn by a pair of bulls or other animals. It consists of a triangular iron strip called ploughshare. There is a long shaft of wood called plough shaft which has a handle at one end. The other end of the shaft is attached to a beam which is placed on the bulls’ necks.

HoeIt is a simple tool used for removing weeds and loosening or breaking the lumps of soil. It has a long rod made up of wood or iron. A broad bent plate of iron is fixed to one of its ends and works like a blade.

TractorLarge fields are ploughed with the help of tractors. Tractors are motor vehicles with heavy tread tyres. These are used to pull farm machinery. This saves labor as well as time. Ploughing of dry soil results in the formation of large soil crumbs. These are further broken down by a soil plank.

The tilled or ploughed land is then levelled with the help of a wooden or iron leveller. This prevents the erosion of soil by wind or water. Sometimes, manure is added to the soil before tilling. This helps in the proper mixing of manure with soil. Once the soil is tilled and levelled, it is ready for sowing the seeds.

Sowing

Selection of seedsSowing is the process of putting seeds in the soil. Before sowing, the selection of seeds is very important. The seeds should always be healthy and of good quality. Diseased and low quality seeds reduce crop productivity

Fig. 1.4 Harrow

Fig. 1.5 Hoe

Fig. 1.6 A tractor in a field

Fig. 1.3 Small plough






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in terms of both quantity and quality. Also, if infested seeds are sown in the crop fields, pests may emerge out of these seeds which may infest the crops and damage them completely.

Seed treatmentSeeds can easily be attacked by microorganisms. The crops that grow out of diseased seeds will also be unhealthy. So farmers treat these seeds by dipping them in certain chemicals. These chemicals do not allow the microorganisms to attack the seeds and damage them. Such chemicals are called fungicides. Once the seeds are treated, they can be sown.

Preparing the seed bed and care of the seedlingsOnce the seeds are selected, they are sown in the fields. There are different ways of sowing the seeds. These can be sown manually or by using seed drills.

Also, a few seeds like sorghum (bajra) and maize are sprayed in the field, instead of being put in the soil. This process is known as broadcasting.

Sowing by traditional tools like seed drills is the easiest method.A seed drill is a long metal tube with a funnel at the top. It is tied

to the back of the plough. As the plough makes the furrows in the soil, the drill releases the seeds into the furrows and sows them. The seeds sown with drills are always in rows.

While sowing of seeds, few precautions should be taken.1. Seeds should be planted at a proper depth in the soil. If seeds are planted deep, they may not germinate

due to non-availability of moisture as well as air. The seeds, if planted on the surface, may get eaten up by the birds.

2. Seeds must be sown leaving appropriate distance between them. This is important to avoid overcrowding of crop plants. Otherwise, the plants will not get sufficient sunlight, nutrients and water from the soil.The seeds for certain crop plants like paddy

and some of the vegetables, such as tomato and onions, are first sown in a nursery bed.

When they grow to a certain age they are transferred and planted in the main field.

Fig. 1.7 Some seeds

Fig. 1.8 Seed drill

Activity 3

Take three containers and mark them as A, B and C. Put some oil in each container. Take thirty green gram seeds and put ten seeds in each container. Sow container A at a depth of 5 cm, B at10 cm and C at 15 cm. Water them for a few days and observe. What do you observe? The number of seeds that germinate in each container is different.

Take about two handfuls of wheat grains stored for more than 10 months. Put them in a beaker containing water and wait for 5 minutes. What do you observe and why? Some seeds float while others settle down at the bottom. A few seeds are hollow and light because they are infested or eaten by pests. As a result, they float on the surface of water. The healthy seeds are heavy and sink at the bottom.

Take about two handfuls of wheat grains stored for more than 10 months. Put

Activity 2






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These small plants are called seedlings. From these, healthy and disease-free seedlings are selected and transplanted in the field manually. Transplantation enables us to select the better seedlings. It also promotes deeper penetration of roots, which helps to increase the crop productivity.


1. What is tilling?2. Why are earthworms called farmers’ friends?3. What are the advantages of seed treatment before sowing?4. Define transplantation.5. What is the use of a seed drill?

Manuring You have already studied that plants require certain nutrients that are essential for their growth. These nutrients are obtained from the soil. Every crop utilises certain specific nutrients for its growth. Therefore, continuous growth of the same crop in a field makes the soil deficient in certain nutrients. Crops need nutrients like phosphorus, calcium, nitrogen, etc., for their growth and pick up these nutrients from the soil. Fertilisers provide nutrients to the soil and help obtain a better crop yield. Depending on the type of soil and the crop to be grown, we use different fertilisers. The process of adding fertilisers to the soil is called manuring.

Chemical fertilisersA chemical fertiliser is usually rich in a specific mineral content. Most fertilisers contain nitrogen (nitrogenous fertiliser) and are given in two or three doses. Other fertilisers are phosphatic and complex fertilisers. Some fertilisers are added to the soil before transplanting. An example of the most commonly used fertiliser is NPK. The letter N stands for nitrogen, P for phosphate and K for potassium.

ManureManure is an organic substance obtained from plant or animal wastes, such as cow dung, urine, plant parts vegetable or fruit peels, night soil and similar other organic wastes. These wastes are dumped at open places and allowed to decompose. The decomposition is helped by organisms like bacteria and fungi. The decomposed matter is used as manure. Manure is the traditional natural fertiliser used by the farmers. It is considered better than the chemical fertilisers. Food crops grown by using manures are safer than the crops grown with the help of excessive use of chemical fertilisers.

While chemical fertilisers are manufactured from chemicals in factories, manure is made from organic substances and contains nutrients in small quantities. Some of the commonly used manures are given below.

Fig. 1.9 Manual transplantation of seedlingsin an agricultural field






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1. Farmyard manure, a mixture of decomposed cattle dung (excreta) and urine, left over fodder (cattle feed) and litter (bedding provided to cattle in the farm).

2. Compost is manure made from vegetable and animal refuse collected from domestic waste, straw, weeds, etc., dumped in a deep pit to decompose.

3. Vermicompost is the compost broken down by earthworms. The following table gives some of the basic differences between chemical fertiliser and manure.

Table1.3 Differences between chemical fertiliser and manure

Chemical fertiliser Manure1. It is an inorganic chemical compound. 1. It is a natural substance formed by the decomposition

of animal and plant wastes.

2. It is prepared artificially. 2. It is prepared naturally in the fields.

3. It is poor in organic nutrients. 3. It is rich in organic matter.

4. It is rich in inorganic nutrients like nitrogen, phosphorus and potassium.

4. It is comparatively less rich in inorganic nutrients.

Natural Methods

Besides the supply of nutrients artificially, there are certain natural methods as well that help in regaining the lost nutrients in the soil.

Field fallowingYou must have heard that the wheat crop is planted during the month of November and harvested in March and April. The rice crop is planted in June-July and harvested in October and November. The land lies fallow (or free) in between these two cereal crops. This helps in replenishing the lost nutrients naturally, because during this free time, dead plants, animals and other organic matter get collected on the field. This collected matter gets decomposed by the microbes, thereby returning the nutrients to the soil.

Crop rotationSome farmers may use the land for sowing a leguminous crop in between the two seasons. A leguminous crop does not take as long as wheat or rice to grow. So, by the time the farmer has to plant the cereal crops (rice, wheat, etc.) the leguminous crop grown is ready to be harvested. Leguminous crops include pea, beans, grams and pulses. They harbour nitrogen fixing bacteria in nodules of their roots. These bacteria convert free nitrogen from atmosphere into usable forms. Thus, after the leguminous crop is harvested, the soil is left fertile for other crops. The process of growing a different crop preferably a leguminous crop in between raising of two similar crops is called rotation of crops.

Crop rotation has a lot of benefits. Firstly, the land gets utilised. Secondly, the soil is not continuously depleted of a particular nutrient. This way the next crop gives a better yield.

Do You Know?Farming that utilises organic manure is known as organic farming. Organic farming is the form of agriculture that uses techniques like crop rotation, green manure, compost, biological pest control, and mechanical cultivation, etc., to maintain soil productivity and control pests, excluding or strictly limiting the use of synthetic fertilisers and pesticides.

Visit a nearby agricultural farm or vegetable garden. Observe and note down the agricultural practices being undertaken there. Make a report on the practices being undertaken to ensure that the plants have a healthy growth and yield a good crop.

Visit a nearby agricultural farm or vegetable garden.

Activity 4






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Multiple croppingGrowing two or more crops together in the same field is called multiple cropping. The crops are chosen such that the products and waste materials from one crop help in the growth of the other. In fact, multiple cropping is the best solution for a country with food problem, because same piece of land is used to grow different kinds of crops.


1. Why do we need to replenish nutrients in the soil?2. What is multiple cropping?3. Define organic farming.4. Why do we plant leguminous plants in the fallow land?5. Name two tools for weeding.

Irrigation Plants need water for their growth and preparation of food. It is necessary to supply water to plants in the fields periodically, which is known as irrigation. Irrigation is necessary for proper development of plants. Irrigation is essential during the seedling, flowering and grain filling stages of the crop.

The major source of water in the fields is rainfall. Since the time and amount of rainfall fluctuates, farmers depend on the alternate sources of irrigation. These sources are rivers, water reservoirs, lakes, ponds, wells and tube wells. Water from these sources is either pumped by using electric or diesel pumps or distributed via irrigation canals.

Some of the modern irrigation methods are discussed below.

Sprinkler systemThis method is useful in water-scarce areas such as deserts, and where there is less or uneven rainfall. It consists of a main pipe, to which many pipes are attached in a series. These perpendicular pipes have nozzles at right angles.

Water is flown through the top of the main pipe with the help of a pump. The water enters into the attached pipes and comes out in the form of sprinkles through the nozzles. It sprinkles water on the crop like rain.

Drip SystemThis technique is used for watering fruit plants, gardens and trees. The drip system consists of a water pump attached to the main pipe, which further has lateral pipes attached to it. These lateral pipes have small nozzles which are located just near the roots of the plant. When water flows through the system, it falls drop by drop at the position of the roots. This is useful in areas where there is shortage of water.

Harvesting The process of cutting and gathering of crops from the fields after the crops have matured is called harvesting of crops.

Fig. 1.10 Sprinkler system of irrigation






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Harvesting can be done by the following methods.

Manual harvestingFarmers use sickles to harvest their crops, especially, wheat, maize and paddy. Fruits and vegetables are plucked manually by the farmers. The tractor-driven machines called harvesters are also used for harvesting wheat and paddy.

Threshing and winnowingOnce the crop is harvested, the grains are separated from the crop by a process called threshing.

The crops are spread on the ground. Generally, certain animals like camels, oxen and buffaloes are used to trample over them. This separates the grains from the chaff or husk. In large farms, a machine, called thresher, is used for separating the grains. It has big rollers under which crops are passed, resulting in the separation of grains.

Sometimes, both harvesting and threshing are done simultaneously by using a motorised machine known as combine. However, in case of wheat, the use of a combine is not preferred, as it produces less amount of fodder than the amount produced by other methods.

The grains separated by threshing are further separated from the chaff by winnowing. This can be done with the help of wind. In this process, the mixture is tossed or dropped on the ground from a height. The chaff, being lighter, is blown away by the wind to some distance while the heavier grains fall straight on the ground because of gravity.

The stem of the crops is cut into pieces and fed to cattle along with the chaff. This food for the cattle is known as fodder.

Protection of Crops in the Field As crops grow in the field, they have to be protected such that they produce a healthy yield. The weeds growing along with crops have to be removed and growing crops have to be saved from the attack of pests especially insects.

Weed controlObserve the potted plants in your school or in the garden of your house carefully. You may find some other plants growing along with the desired plant. These unwanted plants are called weeds. There is a variety of weeds that grow with different plants. They vary from place to place and from season to season. A few examples are Parthemum (carrot or congress grass), Amaranthus, Chenopodium, grass and wild oat.

Weeds are undesirable plants, and they spread very fast. These undesirable plants compete with the main crop for sunshine, water and space in the field. Weeds must be removed as they use up the nutrients in the soil and thereby make them unavailable for the crop. The process of removing weeds from a field is called weeding. Farmers adopt many ways to remove weeds and control their growth. Some of these are given here.

Fig. 1.11 Manual harvesting

Fig. 1.12 ThreshingFig. 1.12 Threshing

Fig. 1.13 Winnowing






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Manual removal: The weeds can be removed manually by pulling or cutting them close to the ground from time to time. This is done with the help of a trowel (khurpi) or a harrow. Weeding should be done carefully as it may damage the crop plants or even uproot them. The removed weeds get decomposed and mix with the soil. Before sowing or transplanting seedlings, weeds are removed by hand or with the help of a plough or harrow. If some of these weeds start growing again during the crop growth, they must be removed.

Use of natural herbicides or bioherbicides: A chemical substance that destroys the weeds is known as a herbicide. Nowadays, herbicides based on natural biological agents known as natural herbicide or bioherbicides are being used. These are derived from specific plants and are not harmful to organisms including human beings.

Control of plant diseases and pestsA lot of plants die due to some diseases and pests which attack and damage them. Generally, plant diseases are caused by fungi, bacteria, and viruses. These diseases are transmitted either through the seed itself (seed-borne) or by air (air-borne) or soil (soil-borne). Rust of wheat and Blast of rice are two common fungal diseases in plants. To control plant diseases and pests, we can spray fungicides and pesticides on the crops or on the soil.

Preservation and Storage of Agricultural Products

Once harvested, food grains have to be safely stored. They have to be saved from being attacked and eaten up by rodents, birds or insects. Also, they have to be protected from spoilage due to improper temperature and moisture in the storage place or due to the growth of fungi. Some of the methods used to prevent loss and spoilage of agricultural products are given below.Drying: The grains are dried in the Sun or by blowing hot air on them.Maintaining storage containers: Gunny bags or tanks or earthen pots are used for storage.Chemical treatment: Spraying or fumigation (insecticide solution converted into fumes) of godowns and containers with insecticides and fungicides is done before storage of grains.

Use of improved storage structures: Structures which are airtight, rat proof, moisture proof and can maintain a steady temperature are now used for storage.

Green Revolution A general improvement in the crop yield and food production occurred in our country between 1960 and 1980. It was a turning point in Indian agriculture. This is commonly referred to as the golden era of agriculture or the green revolution. As a result of the green revolution, we have become self-sufficient in food. In fact, we are able to have surplus crop to stock and use in natural calamities like drought and floods. Famine in

Fig. 1.14 Manual removal of weeds

Make a visit to cold storage or godown where grains are stored. Find out the following: 1. the types of grain stored2. the conditions of storage, i.e. storage temperature, etc.3. the various procedures followed to protect grains from pests4. the methods of transportation and distribution, etcPrepare a report on it and submit to your teacher.

Make a visit to cold storage or godown where grains are stored.

Activity 5






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