AGRON – 111 : Fundamentals of Agronomy 4 (3+1)
Plant ideotypes
- Definition: A biological model expected to perform or behave in a particular manner within a defined environment, yielding higher quality or quantity of grain, oil, or other products when developed as a cultivar.
- Ideotype term given by Donald in 1968
- A crop ideotype is a plant model.
Features of Crop Ideotype
- Consists of morphological and physiological traits for enhanced yield.
- Ideal plant traits vary for irrigated and rainfed cultivation.
- Model plants discussed in crops like wheat, rice, maize, barley, cotton, and bean.
Specific Crop Ideotypes
Wheat
- Coined by: Donald (1968)
- Main Features:
- Short, strong stem (lodging resistance)
- Erect leaves (better light distribution, high photosynthesis)
- Few, small leaves (reduced water loss)
- Larger ear (more grains per ear)
- Presence of awns (contributes to photosynthesis)
- Single culm (initially proposed but later doubted)
Rice
- Introduced by: Jennings (1964)
- Main Features:
- Semi-dwarf stature
- High tillering capacity
- Short, erect, thick, and highly angled leaves
- Emphasis on both morphological and physiological traits in recent models.
Maize
- Proposed by: Mock and Pearce (1975)
- Main Features:
- Low tillers
- Large cobs
- Angled leaves (good light interception)
- High yields achieved with closer spacing.
Barley
- Reviewed by: Rasmusson (1987)
- Main Features:
- Short stature
- Long awns
- High harvest index
- High biomass
Cotton
- Proposed by: Singh et al. (1974)
- Main Features:
- Short stature (90-120 cm)
- Compact, sympodial plant habit (pyramidal shape)
- Determinate fruiting habit (unimodal distribution of bolls)
- Short duration (150-165 days)
- High fertilizer responsiveness
- High inter-plant competitive ability
- Resistance to insect pests and diseases
- High physiological efficiency
- Rainfed Conditions:
- Proposed by: Singh and Narayana (1993)
- Main Features:
- Earliness (150-165 days)
- Few, small, thick leaves
- Compact, short stature
- Indeterminate habit
- Sparse hairiness
- Medium to large boll size
- Synchronous bolling
- High nutrient response
- Resistance to insects and diseases
Crop rotation and its principles
Definition: It is a process of growing different crops in succession on a piece of land in a specific period of time, with an objective to get maximum profit from least investment without impairing the soil fertility.
Principles of Crop Rotation
- Adaptability:
- Should fit the existing soil, climatic, and economic conditions.
- Land Utilization:
- Sequence of cropping should ensure proper land use, maintain yields, and minimize soil erosion.
- Soil Improvement:
- Include crops that improve soil organic matter (OM).
- Nitrogen Supply:
- Incorporate legumes to maintain soil nitrogen levels.
- Livestock Support:
- Provide roughage and pasturage for farm livestock.
- Pest and Disease Control:
- Help control weeds, plant diseases, and insect pests.
- Profitable Crops:
- Ensure the inclusion of the most profitable cash crops suitable for the area.
- Economic Production:
- Arrange crops to optimize production and labor utilization, alternating between exhaustive crops (e.g., potato, sugarcane) and less exhaustive crops (e.g., oilseeds, pulses).
- Root Systems:
- Follow crops with tap roots with those having fibrous root systems for balanced nutrient uptake and reduced root competition.
- Problem and Demand-Based Selection:
- Choose crops based on local needs, soil conditions, and climatic suitability.
- Alternate erosion-promoting and erosion-resisting crops on slopes.
- Use drought-tolerant crops (e.g., Jowar, Bajra) in dryland areas and water-tolerant crops (e.g., Paddy, Jute) in flood-prone areas.
- Match crops to the farmer’s financial conditions and environmental factors.
- Avoid successive planting of crops from the same family to prevent pest and disease issues.
- Ensure the rotation provides maximum employment, efficient use of machinery, and timely agricultural operations.
Adaptation and Distribution of Crops
Adaptation of Crops:
- Definition: The ability of crops to grow and produce yield under specific environmental conditions.
- Factors Influencing Adaptation:
- Climate: Temperature, rainfall, humidity, and light.
- Soil: Type, fertility, pH, and moisture content.
- Biotic Factors: Pests, diseases, and competing vegetation.
- Agronomic Practices: Irrigation, fertilization, and crop rotation.
Key Adaptation Strategies:
- Drought Tolerance:
- Crops like Jowar, Bajra, and certain legumes are adapted to dry conditions through deep root systems and efficient water usage.
- Flood Tolerance:
- Crops such as Paddy and Jute thrive in waterlogged or flood-prone areas.
- Temperature Adaptation:
- Warm-season crops (e.g., maize, soybeans) grow well in higher temperatures.
- Cool-season crops (e.g., wheat, barley) prefer cooler growing conditions.
- Soil Adaptation:
- Some crops are suited to specific soil types, such as sandy soils for groundnuts and loamy soils for wheat.
- Pest and Disease Resistance:
- Breeding and selecting crop varieties with natural resistance to local pests and diseases.
Distribution of Crops:
- Definition: The geographical spread of crop cultivation based on environmental and socio-economic factors.
- Factors Influencing Distribution:
- Climate Zones:
- Tropical: Crops like sugarcane, bananas, and coffee.
- Temperate: Crops like wheat, barley, and potatoes.
- Arid: Crops like sorghum and millet.
- Soil Types:
- Rich alluvial soils support rice and wheat.
- Sandy soils are suitable for root vegetables and groundnuts.
- Topography:
- Plains are ideal for extensive cereal cultivation.
- Hills and slopes support tea, coffee, and vineyards.
- Water Availability:
- Irrigated regions grow water-intensive crops like rice and cotton.
- Rainfed areas favor drought-resistant crops.
- Economic Factors:
- Market demand influences the cultivation of cash crops like cotton, coffee, and tobacco.
- Subsistence farming areas grow staple foods like maize, wheat, and rice.
- Climate Zones:
Examples of Crop Distribution:
- Wheat:
- Grown in temperate regions with moderate rainfall.
- Major producers: USA, Canada, Russia, India, and Australia.
- Rice:
- Prefers warm, humid climates with plenty of water.
- Major producers: China, India, Indonesia, Bangladesh, and Vietnam.
- Maize:
- Thrives in warm regions with well-distributed rainfall.
- Major producers: USA, China, Brazil, Mexico, and India.
- Soybeans:
- Grown in warm, temperate climates with adequate rainfall.
- Major producers: USA, Brazil, Argentina, China, and India.
Crop Management Technologies in Problematic Areas
Problematic Areas:
- Drought-Prone Areas
- Saline and Alkaline Soils
- Flood-Prone Areas
- Acidic Soils
- Hilly and Erosion-Prone Areas
Technologies and Strategies
1. Drought-Prone Areas
Technologies:
- Drought-Resistant Crop Varieties: Use crops like sorghum, millets, pulses, and drought-tolerant varieties of maize and wheat.
- Efficient Irrigation Systems: Drip and sprinkler irrigation to minimize water use.
- Mulching: Using organic or plastic mulches to reduce soil moisture loss.
- Soil Moisture Conservation: Techniques like contour farming, terracing, and conservation tillage.
- Water Harvesting: Construction of check dams, farm ponds, and rainwater harvesting systems.
Strategies:
- Crop Rotation: Incorporating legumes to improve soil fertility and moisture retention.
- Intercropping: Planting two or more crops together to maximize resource use and reduce risk.
- Timely Sowing: Adjusting planting dates to match rainfall patterns.
2. Saline and Alkaline Soils
Technologies:
- Salt-Tolerant Varieties: Cultivating salt-tolerant crops such as barley, sugar beet, and certain varieties of rice and wheat.
- Soil Amendments: Adding gypsum or organic matter to improve soil structure and reduce salinity.
- Leaching: Flushing out salts with excess irrigation water.
- Drainage Systems: Installing proper drainage to prevent salt accumulation.
Strategies:
- Green Manuring: Incorporating green manure crops to improve soil organic matter and structure.
- Crop Rotation: Rotating salt-sensitive crops with salt-tolerant crops to manage soil salinity.
- Mulching: Using organic mulch to improve soil moisture and reduce evaporation.
3. Flood-Prone Areas
Technologies:
- Flood-Tolerant Varieties: Growing crops like paddy, taro, and water-tolerant varieties of maize and soybean.
- Raised Bed Farming: Elevating crop beds to reduce waterlogging.
- Drainage Systems: Creating efficient drainage channels to remove excess water.
- Floating Agriculture: Using floating rafts for cultivation in inundated areas.
Strategies:
- Early Warning Systems: Implementing systems to anticipate and prepare for floods.
- Diversified Cropping: Planting a mix of crops to reduce the risk of total crop failure.
- Post-Flood Recovery: Quick replanting of short-duration crops after floodwaters recede.
4. Acidic Soils
Technologies:
- Lime Application: Adding lime to neutralize soil acidity.
- Acid-Tolerant Varieties: Growing crops like barley, oats, and acid-tolerant varieties of maize and wheat.
- Soil Testing: Regular soil testing to monitor pH and nutrient levels.
Strategies:
- Organic Matter Addition: Incorporating compost and manure to buffer soil acidity.
- Crop Rotation: Using legumes to improve soil health and reduce acidity.
- Proper Fertilization: Avoiding excessive use of acid-forming fertilizers.
5. Hilly and Erosion-Prone Areas
Technologies:
- Contour Farming: Planting along the natural contours of the land to reduce soil erosion.
- Terracing: Creating stepped levels on slopes to reduce runoff and erosion.
- Agroforestry: Integrating trees and shrubs into agricultural landscapes to stabilize soil.
- Cover Cropping: Planting cover crops to protect soil from erosion.
Strategies:
- Vegetative Barriers: Using grasses or shrubs as barriers to slow down water flow and reduce erosion.
- Gully Plugging: Constructing check dams and other structures to prevent gully formation.
- Sustainable Grazing: Managing livestock to prevent overgrazing and soil degradation.
UNIT 8 – Harvesting and threshing of crops, principles of storage.
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