Agriculture – Maharashtra Board Class 8 Solutions for General Science (English Medium)
Besides food, plants are used for the following purposes:
- Medicinal purposes
- Energy farming
- Making yarn
The three stages of tilling of land:
- Pre-sowing stage: In this stage, the land is ploughed and harrowed.
- Sowing: This stage includes arranging the soil, sowing the seeds and planting the saplings
- Post-sowing: This stage includes thinning the crop, loosening the soil, weeding, watering, adding fertilisers and spraying pesticides.
Advantages of pre-sowing tilling activities:
- It loosens the soil.
- When the soil is ploughed deep, it gets turned up which makes the soil friable and suitable for growing crops.
- It helps in weeding.
- It exposes the germs and insects to the Sun and helps to kill them.
- Aeration of the soil takes place which enables the roots of the plants to grow deeper and stronger.
- It improves respiration in plants.
- Loose soil helps to percolate water into the soil.
- Water-holding capacity of the soil improves due to better seepage of water in loose soil.
The following activities are undertaken at the post-sowing stage of tilling:
- Thinning the crop: Some plants are pulled out to reduce their number and prevent overcrowding. This enables standing crops to get sufficient water and fertilisers.
- Loosening the soil and weeding: Loosening the soil and weeding is carried out with the help of a sickle. Loosening aerates the soil.
- Watering and adding fertilisers: Watering is done through channelling or by drip or sprinkle irrigation. Fertilisers are then added in appropriate quantities.
- Spraying pesticides: Pesticides are sprayed to prevent the plants from getting infected by fungi, insects etc. or to cure them from the diseases which they have acquired.
Differences between thinning and weeding:
|1.||Thinning involves reduction in the number of crop plants by pulling out some of these plants.||Weeding is the removal of unwanted plants in the cultivated field.|
|2.||The plants left standing get sufficient water and fertilisers and grow vigorously.||It loosens the soil around the crop and thereby aerates it.|
|3.||Thinning is the first process carried out during the post-sowing stage of farming.||Weeding is the second process carried out after thinning in the post-sowing stage of farming.|
Differences between preventive and curative measures of spraying of chemicals:
|Preventive spraying of chemicals||Curative spraying of chemicals|
|1.||Pesticides are sprayed to prevent the crop from the attack of pests such as fungi, germs or insects.||Pesticides are sprayed after the crops have been affected by pests such as fungi, germs or insects.|
|2.||Preventive measures are taken before pest infestation of crops.||Curative measures are taken after pest infestation of crops.|
|Crop||Method of sowing|
|Wheat||Scattering or poking seeds into the soil|
|Rice||Transplanting seedlings in the soil|
|Sugarcane||Making furrows in the soil|
|Pumpkin||Poking seeds into the soil|
|Jowar||Scattering or poking seeds into the soil|
|Cotton||Poking seeds into the soil|
Methods of sowing seeds:
- Scattering: Seeds are scattered over the soil.
- Transplantation: Immature seedlings are again transplanted to grow further. This transplantation is done on seed beds which are made by piling soft soil on the ground.
- Poking: Seeds are poked into the soil, one by one.
|a. Plough||3. Ploughing|
|b. Seed drill||1. Sowing|
|c. Sickle||2. Weeding|
|d. Scythe||4. Harvesting|
When the field is ploughed, the layers of the soil are turned up. This makes the soil loose. Ploughing makes the soil friable and suitable for growing crops. Stubble roots of previous crops and weeds become loosened. The type of soil and its water-holding capacity, the amount of rainfall in the region and the type of crop to be sown are also considered while ploughing the soil. To have more production of crops, the depth to which ploughing is done is then decided.
The sickle is used for weeding and loosening the soil which helps in aeration of the soil and retaining its nutrients. Crops grow vigorously after weeding. The sickle is also used during harvesting. Although the sickle is smaller in size, it is of great help to farmers for increasing agricultural produce. Therefore, it is said that the importance of a sickle cannot be judged from its small size.
Many farming implements are used continuously to carry out farm work. They are made of iron and their handles are made of wood. These implements come in contact with mud and water all the time. Therefore, they can get rusted. If these implements are kept in moist and damp places, they become useless. The wood of their handles may also get attacked by termites. The life of the implements would be shortened due to rusting and termite attacks. Therefore, it is necessary that the farming implements should be stored in dry places.
- Hybridisation is the process of crossing two different strains of organisms to produce a new organism called a hybrid.
- The hybrid strain thus obtained not only retains its own good qualities but also acquires those of another strain. Hence, the overall quality of a particular strain is enhanced.
- In foreign countries, plants of tangerine and pomelo were cross-bred and a new variety of fruit-giving tree, the tangelo, was produced.
- Efforts are made to develop strains of dwarf plants and strains with qualities such as better crop characteristics, resistance to diseases and better taste.
- Botanists and agriculturists are trying to cross more varieties and find out new and better hybrid varieties.
1. Seed drill (Tiphan)
3. Wooden board
6. Spray pump