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Class 9 biology Improvement in food Resources notes




These are the CBSE class 9 biology notes on chapter Improvement in food resources Topics covered in this page are

Crop production

Crops are plants grown on longer area for food or other use. Branch of agriculture connected with rearing and management of crop plant is called agronomy.

Successful crop production depends upon understanding of how crops develop and grow, how various factors affect the growth and development of crops and how each factor can be modified or managed.

Types of crops

Example

Source

Cereal crops

Wheat, rice, maize, barley, oats etc.

carbohydrates

Pulses

Gram, green pea, pigeon pea etc.

proteins

Oilseeds crops

Soyabean, groundnut, mustard etc.

Oils, fats and fatty acids

Fruits and vegetable crops

Orange, apple, mango, cabbage, potato, brinjal etc.

Vitamins, minerals, proteins, roughage, carbohydrate  and fats

Spices

Chilly, turmeric, black pepper etc

Used for enhancing palatability of food

Fodder crops

Oat, berseem

Green fodder to the cattle

Crop Seasons:

Various crops require different climatic conditions, temperature and photoperiod for their growth and completing their life cycle. In northern India, there are following two distinct season crops:

Kharif season crops (summer season crops):

These crops are grown in rainy seasons, i.e., Kharif season from the month of June to October. For example, paddy, soyabean, arhar, maize, cotton and moong are kharif season crops.

Rabi season crops (winter crops):

These crops are grown in winter season, i.e., rabi season from November to April. For example, wheat, gram, peas, mustard and sugarcane are rabi season crops.

Improvement in Yields or Increase in food production

Following three scientific approaches are adopted in India to obtain high yield s from our agriculture farms:

  1. Crop variety improvement
  2. Crop production management
  3. Nutrient management

Crop variety improvement:

 Varietal improvement means combining desirable characteristics in one and multiplying it. Plant breeders select plant varieties with desired character and cross them. The developed offsprings combine the qualities of both plants. These varieties are multiplied and supplied to farmers.

Need for higher crop yield

  • Continuous increase in human and animal population has created a demand to increase food and fodder production.
  • Increased standard of living, health consciousness and competition in market demand quality products.
  • To develop disease-resistance varieties.
  • To develop superior varieties in terms of quantity and quality of yield.

The objectives of crop improvement may differ from crop o crop. Crop variety improvement is done for the following factors:

Higher yield: Higher yield of crops can be brought about by developing High Yielding Varieties (HYV) by cross-breeding and hybridization.

Improved quality: Quality consideration of crop products varies from crop to crop, e.g., baking quality in wheat, protein quality in pulses etc.

Biotic and abiotic resistance: Under different situations crop suffers due to biotic stresses (such as diseases, insects) and abiotic stresses (such as drought, salinity, heat, cold). If we develop crop varieties which are resistant to these stresses, then we can improve significantly the crop production.

Changes in maturity duration: In some of the short duration crops, early maturing varieties can make the crop fit into double and multiple cropping system.

Desirable agronomic traits: If we develop those varieties of crops which contain desired agronomic traits then it will help in setting higher production.

Wider adaptability: If we develop those varieties of crops which have wider adaptability, then it will help in stabilizing the crop production under different environmental conditions.

Easy to acclimatize: The varieties should have the ability to adapt themselves to new climatic conditions.

Crop production management:

  • India is an agriculture based country. Three fourth of the population engaged in agriculture.
  • In India, as in many other agriculture based countries, farming ranges from small to very large farms. Different farmers thus have more or less land, money and access to information and technologies. There is a correlation between higher inputs and yields.
  • In other words, farmer’s purchasing capacity for inputs decides the cropping system and production practices. These include ‘no cost’ production, ‘low cost’ production and ‘high cost’ production practices.

Nutrient management:

Like other living organisms, plants also require inorganic elements for building their structure and maintaining their metabolic process. These inorganic elements are called nutrient. There are sixteen nutrients which are essential for plants. Nutrients are supplied to plants by air, water and soil.

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.

Source

Nutrients

Type

Air

Carbon (C), Oxygen (O)

Macronutrient

Water

Hydrogen (H)

Macronutrient

Soil

Nitrogen (N), Phosphorous (P), Potassium (K), Calcium (C), Magnesium (Mg), Sulphur (S)

Macronutrient

Iron (Fe), Maganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Chlorine (Cl)

Micronutrient

Deficiency of these nutrients affects physiological processes in plants including reproduction, growth and susceptibility to diseases.



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