Wheat growing on sandy alkaline soil in Punjab
I was moved to write this guidance note for farmers growing Wheat on sandy alkaline soil in Punjab after receiving contradictory and occasionally harmful advice from various expert sources. The following advice is based on evidence from respectable scientific studies and on personal experience.
Starting in September or October prepare those fields to be planted with laser levelling to minimize use of irrigation water, tilth soil to reduce weeds. Incorporate at least 40 Kg Sulphur into soil per acre in alternate years at this stage if soil pH 8.3 to 8.8 (highly alkaline). Plough farm manure or biogas slurry into soil. Phosphorus rich chicken manure has a pH of around 8 while buffalo manure is around 6.6, it is best to mix the two. 6.6 is an ideal pH for most crops while cultivated land in Punjab is alkaline with pH often higher, generally 7.8 to 8.2, this alkalinity interferes with soil nutrient availability to crops. Sandy soil crops benefit from three or four split applications of fertilizer. Micronutrients in highly alkaline soil may need administration via foliar spray to be absorbed.
Wheat sowing should commence in the second week of November. Ideal dates for planting are between 15 to 18 November for Central Punjab. For unexplained reasons this is empirically critical to obtaining good yields. I find Seed varieties Galaxy-13, Fareed-11 and Faisalabad-08 are high yielding. Avoid very old varieties that have lost their vigour.
Potassium (K) and Phosphate (P) should be broadcast prior to sowing/drilling. I broadcast only K. For P I use a dual band seeding drill which seeds 38 Kg grain per acre and which simultaneously places DAP (Starter Nitrogen and full dose Phosphate) in bands adjacent to seed rows. 85% of P thus placed in bands is available while only 15% of broadcast DAP is accessible to the growing crop. If seed is broadcast, not drilled, seed application rates are 50Kg per acre before 1st December and 60 Kg thereafter. Higher seed rates result in weeds being crowded out. Other measures for weed control include herbicides and also crop rotation with two year gaps between replanting the same crop, thus the life cycle of weeds is interrupted so that they cannot re-seed. Canola is a feasible alternative in crop rotation giving similar financial returns. If allowed to, weeds such as Canary grass (Dumbi Sitti) can reduce yield by as much as 42%.
Fertilizer recommendation: The main nutrients under discussion are NPK and also Zincand Boron whose deficiencies demonstrably lower yield. Nitrogen is the major nutrient.Around 25 kg of N (1 bag Urea) are usually required as fertilizer to produce 25 maunds or 1 tonne of wheat grain. To obtain yields greater than forty maund/acre one has to give more than 50Kg of N. Applications of P and K should reflect soil test results. N may be reduced by up to 10Kg if manure has been applied. The maximum split quantity of N should be given between days 45 to 55 of seed germination, later application will have little impact on grain yield but may increase protein content. Too early an application will be leached out in sandy soil. Zinc should ideally not be mixed with P, it may need repeated application.
Urea (46% N) 2 x 50Kg Bags = (N 46 Kg)
DAP (18%N 46%P) 1 x 50Kg Bag= (N 9 Kg, P 23 Kg)
MoP (60% K) ½ x 50Kg Bag= (K 30 Kg)
- Broadcast KCL (Muriate of Potash) 25 Kg or 1/2 bag per acre prior to seeding.
- DAP (i.e., P+ starter N) to be applied with dual band seed drill. Quantity on average, 50 Kg (that is 1 bag/ac), depending on soil test. If seed drill not being used broadcast this simultaneously with KCL above.
- Apply Urea (1/2 bag) mixed with Zinc Sulphate (3 Kg) and 10 Kg Sulphuric Acid. Drip the diluted mixture into an irrigation ditch watering the crop at 20 to 25 days after seeding. If weeds promptly start appearing, follow the irrigation around 5 days later by a broad leaf herbicide spray, and then, if needed, by Pinoxaden “Axial” spray for weed grasses. It is best to alternate weed killing sprays in alternate year crops to reduce drug resistance. Sulphuric Acid solution reduces volatilization losses of Urea and may aid absorption of nutrients more soluble in low pH.
- Second and biggest split of Urea – minimum one 50 Kg bag, given with Borax (B) at 45 days – around or before 1stJanuary.
Day 50 to 60
- In very sandy soil give a Third Urea application (1/2 bag) again in January but no later than 55th day after seeding. Later applications do not increase yield but will improve protein content of grain.
Avoid water or heat stress.
- Prolonged drought at time of maturity is harmful.
- Light drizzles and cloudiness at the time of ripening help in increasing the yield.
- Frost at time of flowering and hail storm at the time of ripening can damage the crop.
Foliar Spray for Wheat to be given on 10 January and on 10 February
Two rounds of Foliar Nutrient sprays (at tillering and at anthesis stage) are claimed to increase yield by a third. Added benefits are better protein and zinc content of grain leading to better flour for a healthier nation.
Take 100 Litre Water, Thirty Three tablets Disprin 300mg (AcetylSalicylic acid is a phytohormone that stabilizes cellular functions) and a tablespoonful of Surf as wetting agent. Eighty litres is sufficient for roughly one acre.
Dissolve the following:
Urea 3 Kg – making 3% solution
KCL 1 Kg – making 1% solution (water may need to be heated)
*Zinc Sulphate 400 Gram – making 0.4% solution
*DAP 2 Kg – making 2% solution
Boric Acid 200 Gram – making 0.2% solution
*Zinc and Phosphate should not be mixed together
Mitigation of low temperature stress
- Foliar spray of 2% calcium nitrate spray for membrane integrity
- Foliar spray of 2%DAP + 1% KCl (MOP)
- Spray of 100 ppm salicylic acid – Thirty Three Tablets of Disprin 300mg in 100 Litre water
- Split application of N and K fertilizers
- Foliar spray of 2%DAP + 1% KCl (MOP) (during the spray, sufficient moisture should be present in the soil for avoiding leaf scorching)
- Foliar spray of 0.5% zinc sulphate + 0.3 % boric acid + 0.5 % Ferrous sulphate + 1% urea
- Foliar spray of 1% Urea + 2 % MgSO4 + 0.5 % ZnSO4 (for arresting chlorophyll degradation due to high temperature stress)
- Foliar spray of 2% calcium nitrate spray for membrane integrity
- Spray of 100 ppm salicylic acid for increase stem reserve utilization and increasing Harvest Index of crops under stress
Heavy irrigations are counter productive in sandy soil because they leach nutrients. Consider investing in a spray system.