Samacheer Kalvi Class 8 Science Unit 21 Crop Production and Management Solutions
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Unit 21 Crop Production and Management Exercise Questions Solutions :
(I) Choose the best answer :
(1) The process of placing seeds in the soil is called as
(a) Ploughing
(b) Sowing
(c) Crop production
(d) Crop rotation.
Answer :
Correct Option → (b)
The process of placing seeds in the soil is called as Sowing.
(2) Organism that control insects and pests of plant corps is
(a) Bio – pesticides
(b) Bio – fertilizers
(c) Earthworms
(d) Neem leaves
Answer :
Correct Option → (a)
Organism that control insects and pests of plant corps is Bio-pesticides.
(3) The method in which water flows over the soil surface and allow it to infiltrate is
(a) Irrigation
(b) Surface irrigation
(c) Springler irrigation
(d) Drip irrigation
Answer :
Correct Option → (a)
The method in which water flows over the soil surface and allow it to infiltrate is Irrigation.
(4) Effective microorganism preparation is not used in
(a) seed treatment
(b) foliar spray
(c) soil treatment
(d) bio-predators
Answer :
Correct Option → (a)
Effective microorganism preparation is not used in seed treatment.
(5) Which of the following is not present in panchagvya
(a) Cow dung
(b) Cow’s urine
(c) Curd
(d) Sugar
Answer :
Correct Option → (d)
Sugar is not present in Panchagvya.
(II) Fill in the blanks
(1) The process of actively growing seedling from one place and planting in the main field for further growth is called __
(2) __ is a plant growing in a place where it is not wanted.
(3) The chemicals used for killing the weeds or inhibiting their growth are called as __
(4) __ seeds transfer their unique characteristics to the descents.
(5) __ centers serve as the ultimate link between ICAR and farmers.
(6) Several popular high yielding varieties of major crops have been developed by __
Answer :
(1) → Transplanting
(2) → Weed
(3) → Herbicides
(4) → Heirloom seeds
(5) → Krishi Vigyon Kendra
(6) → Hybridization
(IV) Answer briefly
(1) Define ploughing.
Answer :
Ploughing is the process of loosening and turning of the soil up and down to facilitate the availability of nutrients in the root zone of the cultivating crop.
(3) What is foliar spray?
Answer :
Foliar spray is a technique of feeding plants by applying liquid fertilizer directly their leaves. In this plants are able to absorb essential elements through the stomata in their leaves. Foliar spraying is useful to the development of plant leaves, flowers and fruit. It is generally done in the late evening or early morning.
(4) Give a brief account on Krishi Vigyan Kendra.
Answer :
Krishi Vigyan Kendra :
It is a frame science cenetre. These centres serves as the ultimate link between ICAR and farmers. The first KVK was established in 1974 at Pondicherry. KVK can be formed under a variety if host institutions, including agriculture universities state departments, ICAR institutes and other educational institution.
There are some responsibilities of KVK such as to provide advisory service to the farmers about weather and market pricing through radio and mobile phones. Also focused on crops and cultivation methods. It also facilities rapport between the institution and the local community.
(5) What is bio-indicator? How does it help human beings?
Answer :
Bio-indicator :
A bio-indicator is any species or group of species whose function or status travels the qualitative status of the environment. Biological indicators are used to changes in earths living systems especially changes caused by the activities of an expanding human population.
Bio indicators of soil health give us information about soil structure, development, nutrient storage and biological activities. For example – lichen .
(6) What do you mean by weeding?
Answer :
The removals of weeds are called weeding. Weeding is an important process because weeds complete with the crop plants for the nutrients, sunlight ,water ,space and other resources. And it results low yield. Therefore removal of weeds are important for the production of crops.
(7) What is crop rotation?
Answer :
Crop rotation : Crop rotation is the planting a series of different crops in the same field following defined order. Mono cropping and mixed cropping are the two methods for crop rotation.
- Mono cropping is the repeated planting of the same crop in the same field year after year.
- Mixed cropping is the cultivation of two or more than two crops simultaneously on the same land without any pattern.
- Advantages of this both type of crop rotation is like positive effects on succeeding crops in the rotation, leading to grater production over all.
(V) Answer in detail
(1) Explain the agricultural practices.
Answer :
Agriculture practices are have three main categories for growth :
(a) Kharif crops : the crops which are in the rainy season are called kharif crops. For eg- paddy, maize.
(b) Rabi crops : the crops grown in winter season are called rabi crops. Foe eg- wheat, pea, mustered.
(c) Zaid crops : the crops which are grown in summer season are called zaid crops. For eg- watermelon, cucumber
For this crops there are various types of cultivation practices or activities is present like ploughing, sowing ,supplying fertilizers, harvesting and seed storage all are the different methods for cultivation of agricultural crops.
(2) Give a detailed account on irrigation.
Answer :
The supply of water to crops at regular intervals is called irrigation. The time and frequency of irrigation varies from crop to crop and season to season. The various sources used for irrigation like wells, tube wells, ponds, lakes, rivers, dams and canal.
Irrigation can be carried out by two different ways Traditional methods and modern methods
• Traditional methods :
In this method irrigation is done by manually. in this method farmer pulls out water from wells or canals by himself or using cattle and carries to framing fields. Pump are used commonly for lifting water from various sources. This is very cheap method but it leads to heavy water loss.
• Modern methods – irrigation have two types :
(a) Sprinkle system : in this method sprinkles water over the crop and helps in an even distribution of water. This method is much advisable in areas facing water scarcity water is sprinkled through the fine nozzles of pipes.
(b) Drip system : in this method water is released drop by drop exactly at the root zone using hose or pipe.
(3) What is weed? Explain the different methods of weed control.
Answer :
In the agriculture field many other undesirable plants may grow naturally along with the main crops these undesirable plants are called weeds. The processes of removing weeds are known as weeding. There are some methods to control weeds as following –
(a) Mechanical methods : it is the most common method in which weeds are destroyed physically. Hand pulling or weeding with the help of weeding hoe is the oldest and most efficient method for controlling weeds.
(b) Tillage method : it is the one of the practical methods of destroying weeds of all categories. Weeds are buried in the soil and also exposed to sun heat by deep ploughing.
(c) Crop rotation : in this method proper rotation of crops is followed for controlling crop associated and parasitic weeds.
(d) Chemical methods : it is very effective in certain cases and have great scope in weed control. The chemicals are used to killed the weeds or inhabiting their growth. The herbicides are used as chemical for killing the weeds.
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