ICSE Class 8 Biology Oxford Chapter 08 Food Production 2

Food Production and Management II

Learning Outcomes

Agriculture: cash and food crops; rabi and kharif crops; annuals, biennials, perennials

Different types of soil

Agricultural practices

Crop protection

Modern hybrid seeds

Crop rotation and organic farming

Observe pictures (a) to (c) carefully. Where do you think the products shown in these pictures are obtained from? All three products shown in these pictures are obtained from plants. Plants grown on a large scale, for human or animal consumption, are termed crops. The science and art of farming or cultivating the soil, producing crops, and raising livestock that sustains humans is termed agriculture.

In this chapter, we will discuss different types of crops. We will also examine different types of soil and discuss which is most suitable for crops. We will also discuss different agricultural practices in detail.

Types of Crops

Crops can be divided into groups based on different criteria.

Based on the life span Crops can be classified as annuals, biennials, and perennials on the basis of their life spans.

Annuals

These are soft-bodied seasonal plants that live for only one season, lasting only for a few months in a year. While some of these live for about three months, there are others that last almost a year. Sunflower, wheat, tapioca, and pea are examples of annuals.

Biennials

These are also soft-bodied plants, but they complete their life cycle in two years. During the first year they grow their vegetative parts (roots, stem, and leaves) and store food in underground parts such as the root or the stem. In the second year they produce flowers, fruits, and seeds. Carrot and beetroot are examples of biennials.

Perennials

These are plants that live for several years. They grow their vegetative parts during the first year and shed their aerial shoots at the end of the flowering season. The underground stem again grows new shoots after the rains. Ginger, arrowroot, and banana are true perennials. All shrubs and trees are also perennial.

Based on the growing season

Crops can be classified as kharif crops and rabi crops based on their growing season.

Kharif crops - These crops are sown in June and harvested in October. Rice, maize, tobacco, potato, and onion are examples of kharif crops.

Rabi crops - These crops are sown in November and harvested in April. Wheat, legumes, and barley are examples of rabi crops.

Based on use

Crops can be classified as food crops and cash crops based on their use.

Food crops - These are plants that are cultivated to meet the basic food requirements and include cereals, pulses, vegetables, and fruits.

Cash crops - These plants are grown solely for commercial purposes. These include plants that essentially provide us with shelter and clothing and also include certain edible products such as spices, oil seeds, and beverages.

Orchards

An orchard is an area of land devoted to the cultivation of fruit and nut trees. The trees are planted in rows at sufficient distance from one another so that each tree gets adequate light and air. The distance depends upon the kind and size of the trees. Orchards of mango, oranges, apple, pear, peach, guava, gooseberry, plums, coconut, cashew nut, sapota, pomegranate, grapes, etc., are being established in different parts of the country, depending upon the climatic conditions needed for each tree. Once planted, the trees being perennial establish themselves vegetatively during the first few years and then yield fruits every season. Introduction of drip irrigation has been instrumental in increasing the productivity. Besides producing the much needed fruits, propagation of orchards in our country is also helpful in improving the quality of the environment as it supplements the afforestation programmes of the Government.

Agricultural Practices

Food production and management has been, and still is, the most important occupation the world over, for the simple reason that it's a basic necessity of life. The basic requirement for food production is land - an open field with good top soil and plenty of sunlight and air, protected from grazing animals, if any. Agricultural practices include soil preparation, selection of the right crop and quality seeds, irrigating the land (as and when necessary), supplying adequate nutrients (fertilizers), weeding (as and when necessary), and harvesting and storage of grains. Let us examine each of these separately.

Soil Preparation

Soil provides the medium for the growth of plants. Before we discuss how soil is prepared for cultivation, let us recall different types of soil and their suitability for plant growth. Based on the size of its particles, soil may be classified into the following three groups: sandy, clayey, and loamy.

Sandy soil has a large number of sand particles. Due to the larger size of sand particles, this type of soil allows sufficient air to reach the roots. However, for the same reason (large size of particles), it does not hold much water and is, therefore, not very good for growing crops.

Clayey soil has a large number of clay particles. Due to the small size of clay particles, it has good water-holding capacity.

However, small, tightly packed clay particles do not allow much air to reach the roots and also hinder their growth. Therefore, clayey soil is not too good for plant growth either.

Loamy soil contains relatively equal amounts of sand, silt, and clay. This type of soil is best for plant growth as it holds sufficient water and also allows sufficient air to reach the roots.

The chemical properties of soil are also important in determining its fertility. Soil with a relatively large concentration of hydrogen ions is said to be acidic, whereas that with a relatively low concentration of hydrogen ions is said to be alkaline. If the soil is acidic, the nutrients become too soluble and are leached from the soil. On the other hand, alkaline soil reduces the solubility of nutrients, making it difficult for plants to extract them. Both acidic and alkaline soils need to be treated, by adding chemicals that lower their acidity or alkalinity, to make them suitable for growing crops. Acidic soils can be treated by application of quicklime or slaked lime. Sulphur, iron sulphate, and aluminium sulphate can be used to treat alkaline soil.

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