Agronomy Module 5

Weed Science

1. Weeds reduce crop yield by 10–50% if uncontrolled.
2. Echinochloa crus-galli is a major weed of rice.
3. Parthenium hysterophorus is a highly invasive noxious weed.
4. Pre-emergence herbicides act before weed emergence.
5. Post-emergence herbicides act after weeds emerge.
6. Allelopathic crops suppress weed growth naturally.
7. Integrated Weed Management combines cultural, mechanical, and chemical methods.
8. Mulching reduces weed growth and soil moisture loss.
9. Manual weeding is labour-intensive but eco-friendly.
10. Herbicide doses must be applied correctly to avoid crop injury.

Fertilizer & Nutrient Management

1. Nitrogen promotes vegetative growth.
2. Phosphorus promotes root growth, flowering, and early maturity.
3. Potassium improves stress tolerance, disease resistance, and quality.
4. Sulfur deficiency causes yellowing of young leaves.
5. Zinc deficiency causes stunted growth and chlorosis.
6. Boron deficiency affects flower and fruit development.
7. Organic manures improve soil structure, microbial activity, and fertility.
8. Biofertilizers like Rhizobium fix atmospheric nitrogen.
9. Fertigation applies fertilizer with irrigation for better efficiency.
10. Split application of nitrogen reduces leaching and increases yield.

Seed Technology & Crop Stand

1. Certified seeds ensure high germination and disease-free crops.
2. Hybrid seeds produce higher yield due to heterosis.
3. Seed treatment prevents seed-borne diseases and pests.
4. Seed rate depends on crop, spacing, and seed size.
5. Seed dormancy can be broken by scarification, stratification, or soaking.
6. Proper plant spacing improves light interception, nutrient use, and yield.
7. Seed replacement after 3–4 years maintains viability and vigour.
8. Uniform crop stand improves mechanization efficiency and yield.
9. High-quality seed ensures uniform germination and plant population.
10. Storage at low moisture and proper temperature reduces seed deterioration.

Crop Physiology & Growth Stages

1. Photosynthesis occurs mainly in green leaves.
2. Respiration provides energy for growth and metabolism.
3. Transpiration helps in cooling and nutrient transport.
4. Vegetative growth precedes reproductive growth in crops.
5. Flowering is influenced by photoperiod and temperature.
6. Tuberization in potato is controlled by temperature and day length.
7. Vernalization induces flowering in winter cereals.
8. Lodging in cereals occurs due to excess nitrogen and wind.
9. Water stress reduces leaf expansion, flowering, and yield.
10. Harvest index = Economic yield ÷ Biological yield.

Irrigation & Water Management

1. Critical stages for irrigation are flowering, fruit set, and grain filling.
2. Drip irrigation delivers water directly to root zone.
3. Sprinkler irrigation mimics rainfall for uniform water distribution.
4. Flood irrigation is inefficient but common in rice cultivation.
5. Mulching conserves soil moisture and moderates soil temperature.
6. Excess irrigation leads to waterlogging and nutrient loss.
7. Deficit irrigation is applied in drought-tolerant crops to save water.
8. Basin irrigation is used in orchards.
9. Furrow irrigation is suitable for row crops like maize and sugarcane.
10. Water management improves yield stability and quality.

Cereal Varieties

1. High-yielding rice varieties include IR64, Swarna, and MTU 1010.
2. Wheat varieties include HD2967, PBW343, and Sonalika.
3. Maize hybrids include HQPM1, Vivek QPM9, and Ganga-5.
4. Sorghum varieties include CSV 15, CSV 21.
5. Pearl millet varieties include HHB67, HHB 117.

Pulse Varieties

1. Pigeon pea varieties: Asha, Maruti, BDN-2.
2. Chickpea varieties: JG-11, Pusa 256, KAK-2.
3. Lentil varieties: PL-639, Pusa Masoor-1.
4. Green gram varieties: PDM-54, Samrat.
5. Black gram varieties: Pant U-19, PU-31.

Oilseed Varieties

1. Mustard: Varuna, Pusa Bold.
2. Sunflower: Morden, KBSH-44.
3. Groundnut: TMV-2, JL-24.
4. Soybean: JS-335, NRC-37.
5. Sesame: T-6, RT-46.

Sugar & Fiber Crop Varieties

1. Sugarcane: Co 86032, Co 0238.
2. Cotton: Bollgard Bt cotton varieties like RCH 2 Bt, Bikaneri Narma.
3. Jute: JRO-524, JRO-8432.
4. Coir fiber comes from coconut husk.
5. Cotton fiber quality depends on length, strength, and micronaire.