Irrigation schedule based upon pan evaporation for various growth stages of Thompson Seedless vines raised on Dogridge rootstock using saline irrigation water**
| Growth Stage | Expected duration (days after pruning) | Water requirement (litres/day/hectare per mm of evaporation) | Month of operation | Expected monthly Pan evaporation (mm) in different grape growing regions | Approximate water (litres /hectare/ day) |
|---|---|---|---|---|---|
| Foundation pruning | |||||
| Shoot growth | 1-30 | 4200 | April-May | 8-12 | 33,600-50,400 |
| Shoot growth | 31-40 | 4200 | April-May | 8-12 | 33,600-50,400 |
| Fruit bud differentiation | 41-60 | 1400 | May-June | 8-10 | 11,200-14,000 |
| Cane maturity and Fruit bud development* | 61-120 | 1400 | June-August | 0-6 | 0-8,400 |
| 121 days - fruit pruning* | 121 - | 1400 | August- Fruit pruning | 0-6 | 0-8,400 |
| Fruit pruning | |||||
| Shoot growth | 1-40 | 4200 | October- November | 6-8 | 25,200-33,600 |
| Bloom to Shatter | 41-55 | 1400 | November- December | 4-6 | 5,600-8,400 |
| Berry growth and development | 56-70 | 4200 | December - January | 3-6 | 12,600-25,200 |
| Berry growth and development | 71-105 | 4200 | December - January | 3-6 | 12,600-25,200 |
| Ripening to Harvest | 106- harvest | January - March | December - January | 8-10 | 33,600-42,000 |
| Rest period | Harvest to Foundation pruning (20 days) | - | March-April | 8-10 | - |
*The above growth stages generally coincide with rainy season and no irrigation may be required in heavy soils.
** The schedule has been worked based on experiment carried out in heavy and calcareous soils using saline irrigation water (EC ranging from 1.7-1.8 dS/m).
Note:
- Depending on water quality, the amount of water needed may change. Irrigation should not be applied after the soil has reached field capacity after rain.
- Irrigation requirement will be less by 20% compared to above given schedule if low salinity water (EC less than 1.0 dS/m) is used.
- By application of organic mulch (3¢¢ thick layer of Bagasse and covering the 3 feet wide vine root zone strip) @ 10 t per acre or plastic mulch in combination with spraying of Anti-stress (permitted biodegradable acrylic polymer) @ 4-6 ml/ L at 30, 60 and 90 days after foundation pruning and 30 and 60 days after fruit pruning, the irrigation water quantity could be reduced by 25%. Mulching also reduces weed incidence.
- The irrigation water requirement can be reduced by 25 % in the existing surface drip irrigated system by applying irrigation directly in the root zone at 9 inches depth in heavy soils and at 4 inches depth in light soil. Any hollow pipe of 2.5 inches diameter open on both sides (PVC pipes, earthen pipes, discarded plastic bottles) with holes on lower side and microtubes can be used for delivering irrigation water in the root zone in heavy soils. This irrigation technique also reduces weed incidence.
- This experiment was conducted in a row to row and vine to vine spacing of 10¢ × 6¢. Irrigation schedule can be suitably applied up to a row to row and vine to vine spacing of 8¢ × 5¢.
- The nutrient quantity given are guidelines for distributing the NPK doses at different growth stages and may change based on the site and climatic conditions.
- One kg P=2.29 kg P2O5 and one kg K=1.21 kg K2O.
- Under normal climatic conditions generally, it takes 10-12 days for sprouting.
- The nutrient applications should necessarily take into account soil, petiole and water testing report.
- Contribution of nutrients from other sources like composts, FYM, green manuring irrigation water, etc. should also be taken into consideration for adjusting the nutrient dose. All the manures and fertilizers, irrigation water and other inputs should be tested for presence of heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Tl) before use.
By: Dr. A.K. Upadhyay and Dr. J. Sharma