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CBSE Class 9 Science, Improvement in Food Resources: Chapter notes (Part-I)

Nov 28, 2017 17:29 IST
    CBSE Class 9, Improvement in Food Resources: Notes
    CBSE Class 9, Improvement in Food Resources: Notes

    This article brings you the CBSE Class 9 Science notes on chapter 15 ‘Improvement in Food Resources’ (Part-I). These chapter notes are prepared by the subject experts and cover every important topic from the chapter. At the end of the notes you can try the questions asked from the discussed set of topics. These questions will help you to track your preparation level and get a hold on the subject.

    CBSE Class 9 Science Syllabus 2017-2018

    Main topics covered in this part of CBSE Class 9 Science, Improvement in Food Resources: Chapter Notes, are:

    • Sources of Food
    • Food Revolutions in India
    • Crop Seasons in India
    • Improvement in Crop Yield
    • Manure & Fertilizers
    • Irrigation

    Key notes for Chapter- Improvement in Food Resources, are:

    Introduction

    All living organisms essentially require the food to stay alive.

    Food provides energy to perform various life activities and is required for growth, development and body repair.

    Sources of Food:

    1. Food from agriculture: Cereals, pulses, vegetables, fruits, nuts, oilseeds, condiments and spices

    2. Food from animal husbandry: Dairly products like milk, curd, butter; meat, egg, fish and other sea products.

    Food Revolutions in India

    With the increase in population, there needed a sufficient increase in food production, so as to meet the food related demands of growing population. This led to the rise of the following food revolutions in India:

    1. Green Revolution: Introduced to increase the food grain production.

    2. White Revolution: Introduced to increase production of milk.

    3. Blue Revolution: Introduced to enhance fish production.

    4. Yellow Revolution:  Introduced to increase oil production.

    Crop Season
    Different crops require different climatic conditions like temperature, moisture and photoperiods to grow well and complete their life cycle.
    Two main corp seasons are:
    1. Kharif Season:

    • Summer season from the month of June to October, i.e., during rainy season.
    • Crops grown in this season require more water.
    • Examples of Kharif season crops are: Paddy, soyabean, pigeon pea, maize, black gram, green gram and rice are kharif season crops.

    2. Rabi Season:

    • Winter season from the month of November toApril.
    • Crops grown in this season require less water.
    • Examples of Rabi season crops are: Wheat, gram, peas, mustard and linseed are rabi season crops.

    Improvement in Crop Yield
    Main approaches implemented to enhance the crop yield are as following:

    1. Crop variety improvement

    2. Crop production management

    3. Nutrient management

    1. Crop Variety Improvement

    This involves the introduction of improved varities to obtain better food qualities.

    It is mainly done to achieve the following targets:

    • Higher yield of crops by adopting technologies like cross-breeding and hybridization.
    • Improved quality of products.
    • Biotic resistance like diseases and insects.
    • Abiotic resistance like drought, salinity, heat, cold, etc.
    • Decreased maturity duration as short duration crops require less costing and more rounds of crop.
    • Wider Adaptability so that the crops growing in different environmental conditions, will help in setting high production.
    • Desired agronomic traits like height, branching, leaves, etc, will result in an increased production.

    2. Crop Production Improvement
    It involves different practices carried out by farmer to achieve higher standards of crop production.

    Main practices involved here are stated below:

    (i) Nutrient Management
    (ii) Irrigation
    (iii) Cropping Patterns
    (i) Nutrient Management
    Like other organisms, plants also require some elements for their growth. These elements are called Nutrients.

    There are sixteen nutrients which are essential for plants. These nutrients are divided into following two categories:

    • Macronutrients: The essential elements, which are utilized by plants relatively in large quantities, are called macronutrients.
    • Micronutrients: The essential elements, which are used by plants in small quantities, are called micronutrients.

    These nutrients are supplied to plants by air, water and soil.

    Sources

    Nutrients

    Air

    Carbon. oxygen,

    Water

    Hydrogen, oxygen

    Soil

    1. Macronutrients: nitrogen, phosphorus, potassium, calcium, magnesium, sulphur.
    2. Micronutrients: iron, manganese,  boron, zinc, copper, molybdenum, chlorine

    Manure & Fertilizer
    To meet the requirement of plant nutrients and essential organic matter in the soil, manures and fertilizers are added to the soil.

    Manure

    • It is a kind of natural fertilizer formed from decomposition of animal excreta and plant waste.
    • It mainly contains organic matter and some nutrients in small amount.
    • It helps in improving the soil structure by increasing the water holding capacity soil.

    Types of manures:

    Based on the kind of biological waste material used, the manures are classified as:

    (i) Farmyard manure (FYM): It is the decomposed mixture of cattle excreta (dung) and urine along with litter and leftover organic matter such as roughage or fodder. The waste materials are collected daily from the cattle shed and stored in a pit for decomposition by the microorganisms (bacteria and fungi etc.). FYM contains nitrogen, phosphorous and potassium.

    (ii) Compost: It is a mixture of decomposed organic matter derived from garbage, sewage, vegetable waste etc. the mixture is decomposed in pits and the process is known as composting.

    (iii) Vermicompost: The degradation of organic waste through the consumption by the earthworms is called vermicomposting. Earthworms used in vermicomposting are Dichogaster bolani and Drawida willisi.

    (iv) Green manure: It is prepared by cultivating fast growing green manure crops like Sunhemp, Horse gram, Guar, Cow pea before sowing of seeds. The fast growing crop is then ploughed back under the soil. Green manure enriches the soil with nitrogen, phosphorous as well as organic matter and provides protection against erosion and leaching.

    Fertilizers

    • Fertilizers are chemicals manufactured in factories and are highly rich in nutrients like nitrogen, phosphorus and potassium.
    • They provide large amount of nutrients and thus ensure better growth of plants.
    • Excessive use of fertilizers for a long period of time can damage soil fertility.

    Irrigation

    The process of supplying water to crop plants through human efforts by means of canal, wells, reservoirs, tube-wells etc., is known as irrigation.

    Most agriculture in India is dependent on timely monsoons and sufficient rainfall spread through most of the growing season. However, the extra water required by crops is met through irrigation.

    Sources of Irrigation

    Some most commonly used sources of irrigation are the following:

    (i) Wells: These are of two types: Dug wells where water is collected from from water bearing strata through bullock-operated devices or by pumps and Tube wells where water is collected from underground through diesel or electricity run pumps.

    (ii) Canal system: water from the main river or reservoir is carried by canal into the field which is divided into branch canals having further distributaries to irrigate fields.

    (iii) River lift system: In this system, water is directly drawn from the river for supplementing irrigation. It is used where insufficient flow from canals occur

    (iv) Rainwater harvesting: Rainwater is collected and recycled into ground by digging canals.

    (v) Watershed management: Small check dams are built up in watershed areas to increase percolation of water into ground, reduce flow of rainwater to prevent soil erosion.

    Try the following questions:

    Q1. Define the Kharif crop and give two examples 

    Q2. What are the desirable agronomic characteristics for crop improvement?       

    Q3. List examples of Macro-nutrients for plants?

    Q4. Differentiate between compost and vermicompost?

    Q5. Name the programmes executed in India to increase food production

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