CBSE CLASS 9 CHAPTER 15 NOTES

 

CHAPTER 15

CBSE SCIENCE
CLASS 9

IMPROVEMENT IN FOOD

RESOURCES

INTRODUCTION

·     All living organisms – need food – supplies proteins, carbohydrates, fats, vitamins & minerals

·     Nutrients required – for body development, growth & health

·     Both plants & animals – major source of food for us

·     Food is obtained from – agriculture & animal husbandry

INDIA’S NEED FOR FOOD

·     India – populous country – need for food – raises day-by-day

·     Necessary – to increase our production of crops & livestock

·     India already had

·     Green Revolution – increased food grain production

·     White Revolution – more yield of milk

·     These revolutions means – our natural resources – getting used more intensively

·     Hence, we need – sustainable practices – in agriculture & animal husbandry

WHAT WE NEED FOR SUSTAINABLE LIVELIHOOD?

·     Simply increasing grain production for storage is of no use

·     People should have money – to buy it – their income should be increased

·     Majority of people – depend on agriculture – for livelihood

·     Therefore, it is necessary to increase the income of people working in agriculture

·     Scientific practices – should be followed – to increase the yield in farms

·     For sustained livelihood – we should follow – mixed farming, intercropping & integrated farming practices

IMPROVEMENT IN CROP YIELD – DIFFERENT CROPS

·     CEREALS provide us carbohydrates – energy requirements

·     Example: wheat, rice, maize, millets & sorghum

·     PULSES provide us protein

·     Example: gram, pea, black gram, green gram, pigeon pea, lentil

·     OIL SEEDS provide us fats

·     Example: soya bean, ground nut, sesame, castor, mustard, linseed & sunflower

·     VEGETABLES, SPICES  & FRUITS provide vitamins & minerals – in addition to small amount of – protein, carbohydrates & fats

·     FODDER CROPS food for livestock

·     Example: berseem, oats or sudan grass

CROPS – THEIR NEEDS

·     Different crops – need different climatic conditions – temperature, photoperiods – for growth & maturation

·     Photoperiods – related to the duration of sunlight

·     Growth of plants & flowering – dependent on sunlight

·     Plants – prepare their own food – in sunlight – Photosynthesis

TYPES OF CROPS BASED ON SEASON

·     Two types of crops

·     KHARIF CROPS grown in rainy season – June to October

·     Example: Paddy, soya bean, pigeon pea, maize, cotton, green gram & black gram

·     RABI CROPS grown in winter season – November to April

·     Example:  Wheat, gram, peas, mustard & linseed

ACTIVITIES TO IMPROVE CROP YIELD – STAGES

·     Major group of activities – for improving crop yield – classified into 3 stages

·     CROP VARIETY IMPROVEMENT choice of seeds for planting

·     CROP PRODUCTION IMPROVEMENT nurturing of the crop plants

·     CROP PROTECTION MANAGEMENT protection of the growing & harvested crops from loss

·     By following these 3 stages – India has increased food grain production – by 4 times – from 1952 to 2010 – with only 25% increase in the cultivable land area

CROP VARIETY IMPROVEMENT

·     In this approach – a crop in selected – which gives good yield

·     Varieties or strains of crops selected by breeding – for various useful characteristics – disease resistance, response to fertilisers, quality & high yield

·     There are 2 ways – desirable characters can be incorporated into crops – Hybridisation & Genetic modification

·     HYBRIDISATION crossing between genetically dissimilar plants

·     3 types :

o  Intervarietal – between different varieties

o  Interspecific – between 2 different species of the same genus

o  Intergeneric – between different genera

·     GENETIC MODIFICATION in this way – crop improved by – introducing a gene of desired characteristic

·     this results in – Genetically Modified Crops – GM Crops

WHEN IS A NEW VARIETY CROP ACCEPTED?

·     A new variety crop is accepted – when they

·     Produce a high yield

·     Grow under different conditions (diverse climate)

·     Grow in different areas

·     Available to farmers

·     Should be of same variety

·     Germinate under same conditions

·     Should tolerate high soil salinity

 

FACTORS FOR WHICH CROP IMPROVEMENT IS DONE

·     Higher Yield – to increase the productivity of crop

·     Improved Quality – quality considerations vary from crop to crop

·     Baking quality in wheat, protein quality in pulses, oil quality in oil seeds & preserving quality in fruits & vegetables

·     Biotic & Abiotic resistance – Crop production – go down – due to biotic & abiotic stress

·     Biotic factors – diseases, insects & nematodes

·     Abiotic factors – drought, salinity, water logging, heat, cold & frost

·     Crop varieties resistant to these stresses can improve crop production

·     Change in Maturity Duration – Crops with shorter maturity duration – more economical to farmers – grow multiple rounds of crops

·     Wider Adaptability – improved crop – should adapt itself to different environmental conditions (different climates) – in different areas

·     Desirable Agronomic Characteristics – Tallness & profused branching – desirable characteristic – fodder; Dwarfness – cereals

·     Thus, developed variety – should have desired characteristic – & higher productivity

CROP PRODUCTION MANAGEMENT

·     India – farming ranges from – small to large farms – depending on farmers financial condition

·     Thus, production practices are at different levels 

·     No cost production,

·     Low cost production &

·     High cost production

NUTRIENT MANAGEMENT

·     Plants require – nutrients for growth – like human beings

·     Nutrients are supplied to plants – by air, water & soil

·     16 nutrients – essential for plants

·     Air – supplies carbon & oxygen

·     Water – supplies hydrogen

·     Soil – supplies other 13 nutrients

·     13 nutrients – 6 macro nutrients; 7 micro nutrients

·     Macro nutrients – required in large amount

·     Micro nutrients – required in small amount

·     Deficiency of nutrients – affects physiological processes – like growth, reproduction & susceptibility to diseases

·     To increase yield – soil can be enriched with – nutrients – form of manure & fertilizers

MANURE

·     Manure – large quantities of organic matter

·     Prepared by – decomposition of animal excreta & plant waste

·     It increases – soil fertility & improves soil structure

·     Manure – improves water holding capacity – in sandy soil

·     Manure – helps drainage of excess water – clayey soil

·     By using manure – we use biological waste material – which protects the environment from excessive usage of fertilizers

·     Using biological waste – a way of recycling farm waste

TYPES OF MANURE

·     Based on the type of biological waste – there are 2 types of manure

Compost & Vermi – compost

·     Composting – process of decomposing waste materials – animal waste, plant waste, sewage waste, straw, eradicated weeds, etc.,

·     Compost – rich in organic matter & nutrients

·     Compost – prepared by using earthworms – called Vermi-compost

Green Manure

·     Before sowing crop seeds – some plants (Sunhemp & gaur) – grown & mulched by ploughing into soil

·     They turn into green manure – adds nitrogen & phosphorus

FERTILIZERS

·     Fertilizers – commercially produced plant nutrients

·     Supply – nitrogen, phosphorus & potassium

·     They ensure – good vegetative growth & higher yield

·     Fertilizers – should be applied – at right dosage & right time

·     Precautions – to be taken – before & after application of fertilizers – for complete utilization

·     Over irrigation – may wash away the fertilizers in water bodies – before absorption by plants – may lead to water pollution

·     Continuous usage of fertilizers – may destroy soil fertility – harms micro organisms in soil

ORGANIC FARMING

·     Organic farming – farming system with minimal or no use of chemicals – like fertilizers, herbicides, pesticides, etc.,

·     In organic farming – maximum usage of organic manures, recycled farm waste, culture of BGA as biofertilizer, neem leaves & turmeric as biopesticides (in storage of grains)

·     Organic farming – follows healthy cropping system – like mixed cropping, inter-cropping & crop rotation

IRRIGATION

·     In India – most agricultural lands – rain fed – i.e., most crops depend on monsoon rainfall

·     Poor monsoons – cause crop failure

·     Several kinds of irrigation followed – depending on water resources available

·     Different water resources are

·     Wells, Canals, River lift system, Tanks

WELLS

·     There are 2 types of wells

o  Dug wells

§  Water taken from – water bearing strata

o  Tube wells

§  Water taken from – deeper strata – through pumps

 

CANALS

·     An elaborative & extensive irrigation system

·     Canals receive water from – one or more reservoirs or rivers

·     Main canal – divided into branches – to irrigate fields

 

RIVER LIFT SYSTEM

·     In areas where canal flow is insufficient – River lift system works

·     Water – directly drawn from rivers – in areas near rivers

 

 

TANKS

·     Small storage reservoirs – store the run off water

·     RAIN WATER HARVESTING

·     Rain water harvesting & water shed management – increases the water available for agriculture

·     Involves building small check dams – leads to increase in ground water levels

·     Check dams – stops rain water from flowing away – also reduces soil erosion

CROPPING PATTERNS

·     Different ways of growing crops can be used – to give maximum benefit

o  MIXED CROPPING

·     Growing 2 or more crops simultaneously – on same land – called mixed cropping

·     Example: Wheat + Gram or Wheat + Mustard or Groundnut + Sunflower

·     Reduces risk & gives yield to farmer – even if one of the crop fails

o  INTER CROPPING

·     Growing 2 or more crops simultaneously – on the same field – in a definite pattern – called inter-cropping

·     A few rows of one crop – alternate with a few rows of a second crop

·     Example: Soya bean + Maize or Finger millet + Cowpea

·     Crops – selected in such a way – that their nutrient requirements are different

·     So, there is maximum utilization of the nutrients supplied

·     Also prevents the spread of disease from one row to another

·     Both the crops gives better yields

o  CROP ROTATION

·     Growing different crops – on a piece of land – in a pre-planned succession – called crop rotation

·     Depending on the duration & availability of moisture & irrigation facilities – crops are chosen

·     If crop rotation – done properly – then 2 or more crops can be grown in a year – with goof harvests

CROP PROTECTION MANAGEMENT

·     Crops get infested by – weeds, insect pests & diseases

·     If these are not controlled at the right time – damage the crop – leads to loss

o  WEEDS

·     Unwanted plants in the field

·     Example: Xanthium, Parthenium, etc.,

·     they compete – for food, space & light

·     Weeds – take up nutrients & reduce the growth of plants

·     Removal of weeds – at an early stage – important for good harvest

o  INSECT PESTS

·     Insect pests attacks plants in 3 ways

·     They cut the root, stem & leaf

·     They suck the cell sap – various parts

·     They bore into stem & fruits

·     They affect the health & reduce the yield of the crop

o  DISEASES

·     Diseases – caused in plants – by pathogens like – bacteria, fungi & viruses

·     Pathogens transmitted through – soil, water & air

CONTROL MEASURES

·     Commonly used methods – to control weeds, pests & diseases – use of pesticides – like herbicides, insecticides & fungicides

·     These chemicals – sprayed on the crops

·     Excessive usage of these chemicals – creates problems – like environmental pollution – as they are poisonous

·     Weeds – also controlled by mechanical removal

PREVENTIVE MEASURES

·     To prevent weeds we can follow

·     Proper seed bed preparation

·     Timely sowing of crops

·     Inter cropping &

·     Crop rotation

·     To prevent crops from pests

·     Use resistant varieties of crop

·     Fields should be ploughed during summer

STORAGE OF GRAINS

·     Storage loss in agriculture product – can be very high

·     Factors responsible for loss are

·     Biotic factors – insects, rodents, fungi, mites & bacteria

·     Abiotic factors – inappropriate moisture, temperature in the place of storage, etc,

·     They lead to – degradation in quality, loss in weight, poor germinability, decolouration & poor marketability

PREVENTIVE & CONTROL MEASURES

·     Strict cleaning of grains – before storage

·     Proper drying first in sunlight & then in shade

·     Fumigation – using chemicals – that can kill pests

ANIMAL HUSBANDRY

·     Scientific management of animal livestock

·     Includes – feeding, breeding & disease control

·     Animal based farming includes – cattle, goat, sheep, poultry & fish farming

·     As population increases – demand for eggs, milk & meat – increased

·     Therefore, there is a need to improve – livestock production

CATTLE FARMING

·     Cattle farming – done for 2 purposes

·     MILK – milk producing females – called milch animals

·     DROUGHT LABOUR – animals used for farm labour (tilling, irrigation & carting) – called drought animals

·     Indian cattle – belong to 2 species

o  Bos indicus – Cows

o  Bos bubalis – Buffaloes

·     Milk production – depends on duration of lactation period – period of milk production after giving birth to a calf

·     Milk production – can be increased – by increasing lactation period

·     Foreign or Exotic breeds (Jersy or Brown Swiss) – selected for long lactation periods

·     They are cross bred – with local breeds (Red Sindhi or Sahiwal) – has resistance to diseases

·     So, offsprings – will have both the qualities

 

MEASURES TO BE TAKEN IN CATTLE FARMING

·     Animals – regularly brushed – to remove dirt & loose hair

·     Sheltered under well ventilated roofed sheds – protect them from heat, rain & cold

·     Floor – should be slopping – so that they are dry & facilitate easy cleaning

ANIMAL FEED

·     Food requirements of dairy animals – 2 types

o  Maintenance requirement – support the animal – to live a healthy life

o  Milk producing requirement – food given during lactation period

·     Animal feed includes

o  Roughage – large fibres

o  Concentrates – less fibre & large proteins & other nutrients

·     Cattle feed – should contain – all nutrients in proportionate amounts

DISEASES

·     Cattle – suffer from many diseases

·     Diseases – reduce milk production – may lead to death

·     External parasites – live on the skin – cause skin diseases

·     Internal parasites – worms – affects stomach & intestine; flukes – damage liver

·     Bacteria & viruses – cause infectious diseases

·     Vaccinations – given to prevent diseases

POULTRY FARMING

·     Poultry farming – to raise domestic fowl – for egg production & chicken meat

·     Improved poultry breeds – developed to produce

o  Layers – For eggs

o  Broilers – For meat

·     Cross breeding – between Indian & foreign breeds – done for variety improvement – develop new varieties with desirable traits

o  Indian Breed – Indigenous – Aseel

o  Foreign Breed – Exotic – Leghorn

DESIRABLE TRAITS IN CROSS BREEDING

·     Number & quality of chicks

·     Dwarf broiler parent – for commercial chick production

·     Tolerance to high temperature

·     Low maintenance requirement

·     Reduction in size of egg laying bird – with the ability to utilise more fibrous cheap diets

EGG & BROILER PRODUCTION

·     For good production of poultry birds – good management practices – important

·     Care should be taken – to avoid mortality (death)

·     Maintain temperature & hygienic conditions – in housing & poultry feed

·     Prevention & control of diseases & pests – is a must

NUTRITIONAL REQUIREMENT

·     Broilers – produced & sent to market – fro meat production

·     Housing, nutritional & environmental requirements – of broilers are different from layers

·     Broiler Chicken – fed with vitamin-rich feed – for good growth rate

·     They are also given – protein rich feed with adequate fats

·     Level of vitamin A & K – kept high in poultry feed

DISEASES

·     Poultry fowl – suffer from many diseases – caused by – virus, bacteria, fungi, parasites & from nutritional deficiencies

·     Proper cleaning, sanitation & spraying of disinfectants – prevent poultry fowl – from diseases

·     Vaccination – prevent infectious disease – reduce loss of poultry during outbreak of diseases

FISH PRODUCTION

·     Fish – cheap source of animal protein – for our food

·     Fish production includes

·     Finned true fish

·     Shell fish – prawns & molluscs

·     2 ways of obtaining fish

·     Capture fishing – from natural resources

·     Fish farming – culture fishery

·     Fishing done – both in marine & fresh water ecosystem

MARINE FISHERIES

·     Marine fish – caught using many kinds of fishing nets – from fishing boats

·     Fish yield – increased by – locating large schools of fish in sea – using satellites & echo-sounders

·     Marine fish varieties – Pomphret, mackerel, tuna, sardines & bombay duck

·     Marine fish varieties of economic value – Finned fish like mullets, bhetki & pearl spots; Shell fish – Prawns, mussels & oysters

·     Oyesters – also cultivated – for pearl

·     Demand for more fish – met by culture fisheries – practice called Mariculture

INLAND FISHERIES

·     Fresh water resources – canals, ponds, reservoirs & river

·     Brackish water – where sea water & fresh water mix

·     Brackish water resources – estuaries & lagoons

·     Capture fishing – in inland water bodies – does not give high yield

·     Fish production from inland water bodies – through aquaculture

·     Fish culture – sometimes done in combination with – Rice crop – where fishes are grown in the water – in the paddy field

COMPOSITE FISH CULTURE

·     In this system – a combination of 5 or 6 fish species – used in a single fish pond

·     Species are selected in such a way – they donot compete for food among them – they have different types of food habits

·     Example: Catlas, rohus, mrigals, common carps & grass carps – grown in composite fish culture

·     Catlas – surface feeders; Rohus – feed in middle zone of the pond; Mrigals & common carps – bottom feeders; Grass carps – feeds on weeds

·     Together these fishes – uses all the food in the pond – without competing

·     This increases yield – from pond

PROBLEMS FACED IN COMPOSITE FISH CULTURE

·     In composite fish culture – many of these fishes – breed only during monsoon season

·     Therefore, when fish seed is collected – it gets mixed with other species

·     Major problem – lack of good quality seeds

·     To overcome this problem – fishes are bred using hormonal stimulation

·     This ensures – supply of pure fish seed – in desired quantities

BEE – KEEPING

·     Bee-keeping – making honey – become an agricultural enterprise

·     Needs low investments – farmers use it as an additional income generating activity

·     In addition to honey – beehives gives wax – for medicinal preparations

·     Local varieties of bees – Apis Cerana indica (Indian bee), A.dorsata (Rock bee), & A.florae (little bee) – used for commercial honey production

·     Italian bee variety – A.mellifera – used to increase yield of honey – used for commercial honey production

·     Italian bees – have high honey collecting capacity - & sting less

·     They stay in a given beehive – for a long period – breed very well

·     Bee farms or apiaries – established for commercial honey production

·     Quality of honey – depends upon flowers available – for nectar & pollen collection