Improvements in Food Resources

Tutormate > CBSE Syllabus-Class 9th Biology > Improvements in Food Resources

04 Types of Crops

  • Kharif crops: These crops are grown during the rainy season ie from June to October.
  • Rabi crops: These crops are grown from November to April. Rabi crops are also called winter crops.


  • Crop production management refers to crop improvement for higher yield through genetic manipulation and crop protection management is three scientific approaches to obtain high crop yield
  • It has the following three components:
    • Nutrient Management
    • Irrigation
    • Cropping pattern.


Nutrient management means controlling the selection, timing and amount of nutrient supply to the crops. Air supplies carbon and oxygen to plants. Water supplies hydrogen and oxygen to plants. Plants get their remaining 13 nutrients from the soil.

Types of Essential Nutrients

  • Macronutrients (Macroelements) – The essential elements which are present in plants in easily detectable quantities are called macronutrients or macroelements. There are six macronutrients in plants. They are nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.
  • Micronutrients (Microelements) – The essential elements which are present in plants in small quantities are called micronutrients or microelements. There are seven  micronutrients viz. iron, manganese, boron, zinc, copper, molybdenum and chlorine.


Manures are natural fertilizers that are bulk sources of organic matters that supply nutrients in small quantities but organic matter in large quantities


Manures affect the soil in following three ways:

  • They enrich the soil with nutrients– Manures tend to replenish the general deficiency of nutrients in the soil. As manures contain fewer nutrients, they need to be used in large quantities.
  • They add organic matter (called humus) to the soil -Manures restore the soil texture, for better retention of water and aeration of soil. For eg, organic matter present in the manures increases the water holding capacity in sandy soils and drainage in clayey soil. They also prevent water logging in clay soils.
  • Provide food for soil organisms- The organic matter present in manures provide food for the soil organisms, (decomposers such as bacteria, fungi, etc) which in turn, helps in providing nutrients to plants.


  • Manures are bulky and possess low nutrient content.
  • These nutrients are released slowly and so are unable to fulfill the high and rapid demand of nutrients required by improved high-yielding hybrid varieties of crops.
  • They are inconvenient to handle, store and transport.
  • Manures are not nutrient specific.


  • Farmyard manure (FYM) – This type of manure is a decomposed mixture of cattle excreta or dung and urine along with litter and the leftover organic matter such as roughage or fodder.
  • Compost- Compost is prepared by decomposing farm waste, vegetable waste, and domestic and sewage waste in pits by the process of composting.
  • Green manure – The practice of green manuring includes growing, mulching by ploughing and mixing of green crops with soil, to improve physical structure and soil fertility.


Fertilizers provide plant, nutrients, commercially manufactured using chemicals. Fertilizers supply Nitrogen, Phosphorus and Potassium (NPK)


Manure Fertilizer
Manure is a natural substance which is obtained by decomposing animal waste such as dung (gobar) of cattle and buffaloes and plant residues. Fertilizer is a human made substance which is an inorganic salt or an organic compound.
It contains small amounts of essential plant nutrients such as nitrogen, phosphorus and potassium.

It is very rich in plant nutrients such as nitrogen, phosphorus and potassium.

It adds a great amount of organic matter in the form of humus in the soil.  It does not add any humus to the soil.
As manure is not soluble in water, nutrients present in the manure are absorbed slowly by the crop plants. Nutrients exist locked inside the organic compounds of humus. Being soluble in water, a fertilizer is readily absorbed by the crop plants.
Manure is not nutrient specific and it tends to remove the general deficiency from the soil. A fertilizer is nutrient specific and can specifically provide nutrients such as nitrogen, phosphorus and potassium to the soil according to the need.
Manure is voluminous and bulky. And so it is inconvenient to store, transport, handle and apply it to the crop. A fertilizer is compact and concentrated and so it is easy to store, transport and apply to the crop.
Manure is cheap and is prepared in rural homes or fields. A fertilizer is costly and is prepared in factories.

Start your learning Journey !

Get SMS link to download the app