Real-World Applications of PP-04 Concepts
1. Biofertilisers (Nitrogen Fixation)
| Biofertiliser | Organism | Crop | Mechanism |
|---|---|---|---|
| Rhizobium inoculant | Rhizobium sp. | Legumes (soybean, pea, chickpea) | Root nodule fixation; replaces 50-300 kg urea/ha |
| Azospirillum | Azospirillum | Wheat, maize, rice | Associative symbiosis in rhizosphere |
| Azotobacter | Azotobacter chroococcum | Any crop | Free-living aerobic soil fixation |
| BGA (Blue-Green Algae) | Anabaena/Nostoc | Paddy rice | Free-living + symbiosis with Azolla |
| Azolla | Azolla + Anabaena azollae | Paddy rice | Green manure; 20-40 kg N/ha/crop |
2. Nutrient Deficiency Management in Crops
| Deficiency | Crop | Field Symptom | Correction |
|---|---|---|---|
| Nitrogen | Wheat, maize | Yellow older leaves, stunted | Urea, ammonium nitrate |
| Iron | Citrus, sorghum | Young leaves interveinal chlorosis | foliar spray, iron chelate (EDTA) |
| Zinc | Paddy rice | "Khaira disease" — brown patches young leaves | soil application, foliar spray |
| Boron | Cauliflower, apple | Hollow stem, internal cork | Borax soil application |
| Mo | Cauliflower | Whiptail | Sodium molybdate seed treatment |
| Ca | Tomato, apple | Blossom-end rot, bitter pit (fruit) | Calcium chloride foliar spray |
3. Crop Rotation (Nitrogen Management)
Legume → Non-legume rotation exploits nitrogen fixation:
- Soybean fixes 100-300 kg N/ha/season
- Subsequent crop (wheat/maize) benefits from residual N
- Reduces chemical nitrogen fertiliser requirement by 30-50%
4. Irrigation Management and Transpiration
- Drip irrigation: Supplies water directly to root zone; reduces evaporation; maintains high soil Ψw near roots
- Night irrigation: Reduces transpirational water loss (stomata closed at night); better water use efficiency
- Windbreaks: Reduce boundary layer removal by wind, decrease transpiration by 20-30%