Class 8 Science Chapter 1: Crop Production and Management (फसल उत्पादन एवं प्रबंध)
Curated under the guidance of Mrs. Neel Kamal Chouhan (Principal, BDRKA) and Mr. Surendra Singh Chouhan. Designed for middle-school scholars across CBSE, RBSE, and State Boards adopting NCERT.
1. What is a Crop? (फसल क्या है?)
When plants of the same kind are cultivated at one place on a large scale for food, clothing, or commercial use, it is called a Crop (फसल).
Classification of Indian Crops by Season:
| Parameter | Kharif Crops (खरीफ फसल) | Rabi Crops (रबी फसल) |
|---|---|---|
| Sowing Period | Sown during rainy season (June to September). | Sown during winter season (October to March). |
| Monsoon Dependence | Requires substantial water and warm, humid conditions. | Requires cold weather and moderate water during growth. |
| Key Examples | Paddy (धान), Maize (मक्का), Soybean, Groundnut (मूंगफली), Cotton (कपास). | Wheat (गेहूँ), Gram (चना), Pea (मटर), Mustard (सरसों), Linseed (अलसी). |
(Note: Zaid crops such as watermelon, muskmelon, and cucumber are grown in summer months between March and June).
2. Basic Practices of Crop Production (कृषि पद्धतियाँ)
Cultivation of crops involves seven sequential steps:
-
Preparation of Soil (मिट्टी तैयार करना):
- Tilling or ploughing turns the soil and loosens it, allowing roots to penetrate deep and breathe easily.
- Loosened soil promotes the growth of earthworms and beneficial microbes that add humus.
- Traditional implements: Wooden plough, Hoe; Modern implement: Tractor-driven Cultivator (saves labour and time).
-
Sowing (बुआई):
- Selection of clean, healthy seeds of good variety. Damaged seeds become hollow and float on water!
- Implements: Traditional funnel tool or modern Seed Drill (sows seeds uniformly at proper distance and depth, and covers them with soil to protect from birds).
-
Adding Manure and Fertilizers (खाद एवं उर्वरक मिलाना):
- Continuous cultivation depletes the soil of essential plant nutrients (Nitrogen, Phosphorus, Potassium - NPK).
Comparison: Manure vs. Fertilizer
| Manure (खाद) | Fertilizer (उर्वरक) |
|---|---|
| Natural organic substance formed by decomposition of plant and animal waste. | Man-made inorganic chemical salt produced in factories. |
| Prepared in fields or compost pits. | Manufactured in industrial fertilizer plants. |
| Adds abundant humus to the soil, enhancing water retention and soil texture. | Does not add any humus to the soil. |
| Relatively less rich in specific plant nutrients like N, P, K. | Very rich in plant nutrients (Urea, Ammonium sulphate, Super phosphate, Potash, NPK). |
| Environment-friendly, long-term soil health protector. | Excessive use leads to soil salinity and water pollution. |
3. Irrigation (सिंचाई)
The supply of water to crops at regular intervals is called irrigation.
Modern Water-Saving Irrigation Methods:
-
Sprinkler System (छिड़काव तंत्र):
- Perpendicular pipes with rotating nozzles at top, connected to the main pipeline.
- Water escapes through rotating nozzles, sprinkling on the crop like artificial rain.
- Ideal for uneven sandy terrain (common in Rajasthan and arid belts).
-
Drip Irrigation System (ड्रिप तंत्र):
- Water falls drop by drop directly near the plant roots through narrow emitters.
- Zero water wastage! Highly recommended for fruit orchards, gardens, and regions with acute water scarcity.
4. Protection from Weeds (खरपतवार से सुरक्षा)
Undesirable wild plants that grow naturally alongside crops are called weeds (e.g., Amaranthus/Chaulai, Chenopodium/Bathua, Parthenium/Gajar ghas).
- They compete with crops for sunlight, space, water, and nutrients.
- Removal methods:
- Physical weeding: Khurpi, harrowing.
- Chemical control: Spraying weedicides like 2,4-D (diluted in water).
5. Harvesting and Storage (कटाई एवं भंडारण)
- Harvesting: Cutting the crop after it matures (usually 3 to 4 months). Done manually using a sickle or mechanically using a Harvester / Combine.
- Threshing & Winnowing: Separating grain seeds from chaff.
- Storage:
- Grains must be dried in the sun to reduce moisture content below 14% to prevent attack by fungi, insects, and bacteria.
- Large-scale storage is done in Silos and Granaries (FCI Godowns) with chemical pest treatments.
- Farmers use dried neem leaves for domestic grain storage.
6. NCERT Exercise Focus Questions
Q: Why should seeds be sown at appropriate depths and distances?
Answer:
- Correct depth protects seeds from being eaten by birds while ensuring sufficient soil moisture for germination.
- Appropriate distance prevents overcrowding, ensuring every seedling receives adequate sunlight, water, and soil nutrients.
Academic notes verified by Mrs. Neel Kamal Chouhan, Principal BDRKA. 100% Free NCERT Learning Commons.
