Crop

When plants of the same kind are grown and cultivated at one place on a large scale, it is called a crop.

CROP SEASONS:

India is a vast country. The climatic conditions like temperature, humidity and rainfall vary from one region to another. Different types of crops require different climatic conditions like:

• Temperature
• Photoperiod (duration of light)
• Completion of life cycle

DEPENDING UPON THE GROWING SEASON:

There are two groups of crops:

IMPROVEMENT IN CROP YIELD

• Crop Production Management
• Variety improvement of crop through genetic manipulation.

CROP PRODUCTION MANAGEMENT:

In order to improve and manage our crop production system, we have to focus on cheaper and farmer friendly approaches. As there is direct co-relationship between the higher yields and input applications.

Successful crop production depends upon:

• Understanding how crops develop and grow.
• How various factors affect the growth and development of crops.
• How each factor can be modified and managed.

Approaches for crop production includes:

• Nutrient management
• Irrigation
• Mixed cropping
• Inter cropping
• Crop rotation

Nutrient management: Plant nutrients are the mineral elements needed by the plants for their growth, development and maintenance. Plants absorb a large number of elements from soil, besides water and air, only 16 elements are essential nutrients for plant, out of 40 elements present in plant ash. They are carbon, iron, hydrogen, manganese, oxygen, boron, nitrogen, zinc, phosphorus, copper, potassium, molybdenum, magnesium, chlorine, sulphur, calcium.

Sources of plant nutrients:

• Air: Carbon, oxygen
• Water: Hydrogen (These 3 constitute 94-99.5 % of total plant tissue)
• Soil: Nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, boron, zinc, copper, molybdenum and chlorine (0.5 to 6 %)

CHARACTERISTICS OF AN ESSENTIAL PLANT NUTRIENT:

• In the absence of such elements, the plant is not able to complete its life cycle.
• Such elements must have a direct influence on the plant nutrition and metabolism.
• The requirement of such element must be specific and cannot be replaced by another element.
• Deficiency of such elements can be corrected or prevented only by supplying that nutrient.

CLASSIFICATION OF PLANT NUTRIENTS:

On the basis of quantity required, 13 mineral nutrients obtained from soil needed for plant growth have been grouped into two categories. (Besides these, carbon, oxygen and hydrogen are called framework elements.)

MACRONUTRIENTS:

Essential elements which are utilized by the plants in relatively large quantities are called macronutrients or major nutrients. Macronutrients include Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and Sulphur. Among them Nitrogen, Phosphorus and Potassium are required in more amount thus they are called primary elements.

MICRONUTRIENTS:

These elements are needed by plants in a very small quantity (or traces) and are called micronutrients or minor nutrients. For example Iron, Manganese, Boron, Zinc, Copper, Molybdenum and Chlorine, Though micronutrients are needed in small quantities as compared to macronutrients but both are equally important and essential for the growth, development and maintenance of plants.

AGRICULTURAL PRACTICES AND IMPLEMENTS:

Soil Preparation: The preparation of soil is the first step before growing a crop. One of the most important tasks in agriculture is to turn the soil and loosen it. This allows the roots to penetrate deep into the soil. The loose soil allows the roots to breathe easily even when they go deep into the soil. Various processes are included under preparation of soil these are as follows

• Ploughing or Tilling: The process of loosening and turning of the soil is called tilling or ploughing. This is done by using a plough. Ploughs are made of wood or iron. The ploughed field may have big pieces of soil called crumbs.

Significance:

• This practice loosens the soil.
• The soil is overturned and properly aerated.
• This allows the roots to penetrate deeper, easily.

Levelling: Implement used - Leveller made of wood or iron. It is a flat 1.8 - 2 m long wooden plank with a log to put weight on it.

Significance:

• This practice smoothens the soil surface.

Agricultural Implements: Agricultural practices are done with the help of various tools. The main tools used for this purpose are the plough, hoe and cultivator.

• Plough: This being used since ancient times for tilling the soil, adding fertilizers to the crop, removing the weeds, scraping of soil. It is made of wood /iron and is drawn by a pair of bulls or other animals (horse / camels etc.). It contains a strong triangular iron strip called ploughshare. The main part of the plough is a long log of wood which is called a plough shaft. There is a handle at one end of the shaft. The other end is attached to a beam which is placed on the bull's necks. One pair of bulls and a man can easily operate the plough.

• Hoe: It is a simple tool which is used for removing weeds and for loosening the soil. It has a long rod of wood or iron. A strong, broad and bent plate of iron is fixed to one of its ends and works like a blade. It is pulled by animals
• Cultivator: Ploughing is done by tractor driven cultivator. The use of cultivator saves labour and time.

Sowing: Sowing is the most important part of crop production. Before sowing, good quality seeds are selected. Good quality seeds should be clean, healthy and good variety.

• Selection of seeds: Good quality seeds are heavier than damaged seeds. Damaged seeds become hollow and are thus lighter. So they become float on water. Seeds should be high yielding varieties, free from insects and pests.
• Implements: Broadcaster and seed drill: Broadcasting is the random sowing of seeds manually. In seed drill method seeds are sowed uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. This prevents damage caused by birds. Sowing by using a seed drill saves time and labour.
• Transplantation: The process in which seeds are sown in nurseries and are transferred to the main field e.g. Paddy.

The uncultivated fields are known as fallow.

Precautions during sowing:

• Spacing should be proper between seed.
• Seeds should be treated with fungicides before sowing.
• Depth should be proper.

Manures and Fertilizers:

• Manure: A manure is a mixture of various decomposed organic substances like dead leaves, city garbage, agricultural wastes, animal dung, crop residue etc. through the action of microbes. Manure increases the fertility and productivity of crops, as it contains plenty of organic compounds and almost all the essential elements required by the plants.

Types of Manure

Advantages of manures:

The organic manure is considered better than fertilizers. This is because

• it low cost
• it increases organic matter in soil.
• it reduces soil erosion.
• it enhances the water holding capacity of the soil.
• it increases the number of friendly microbes.
• it makes the soil porous due to which exchange of gases becomes easy.
• it improve the texture of the soil.

Disadvantages of manures:

• Manures are bulky and not easy to be absorbed.
• They have low amount of nutrients.

Fertilizers: These are commercially manufactured inorganic salts or an organic compound containing one or more essential plant nutrients like Nitrogen, Phosphorus or Potassium which are used for increasing soil fertility. Fertilizers usually contain higher amount of nutrients than manures hence required in small quantities.

Fertilizers (Only urea is an organic compound)

Advantages of fertilizers:

• They are nutrient specific.
• Required in small quantities.
• They are water soluble so can be applied and absorbed by the plants easily.

Disadvantages of fertilizers:

• They cause water pollution.
• Fertilizers can change the chemical composition of soil.
• They can cause eutrophication in near by water bodies.

DIFFERENCES BETWEEN MANURES AND FERTILIZER

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