Buy a zero-till drill or hire one? Costing a 6 ha wheat sowing
Manpreet Singh has 6 ha of irrigated wheat to sow between 5 and 12 November. Custom hiring of a zero-till drill with tractor and driver is quoted at ₹1,300 per hectare, but the contractor has only one machine and cannot promise that window. Manpreet already owns a 45 HP tractor that is otherwise used for about 700 hours a year. He is considering buying a 2.0 m zero-till drill for ₹65,000. The figures he has collected: tractor ₹8,00,000, life 10 years or 12,000 hours with 10% salvage; diesel 6 L/h at ₹90/L; lubricants 30% of fuel cost; tractor repairs 6% of its cost per year; insurance and housing 2% per year; interest 10% on average investment; driver ₹500 for an 8-hour day. The drill has an 8-year life, 5% salvage, repairs 8% of cost per year, and would be used only on his own 6 ha (about 60 hours a year). Forward speed is 5 km/h with 70% field efficiency.
1. Compute the field capacity and the full cost per hectare of sowing with his own tractor and drill.
Read the worked answer
Field capacity: 2.0 m × 5 km/h = 10,000 m²/h = 1.00 ha/h theoretical; × 0.70 efficiency = 0.70 ha/h, i.e. 1.43 h/ha.
Tractor fixed cost per year: depreciation (8,00,000 × 0.90) ÷ 10 = ₹72,000; interest 10% on average investment (8,00,000 + 80,000) ÷ 2 = ₹44,000; insurance and housing 2% = ₹16,000; total ₹1,32,000 ÷ 700 h = ₹188.6/h.
Tractor variable cost per hour: fuel 6 × 90 = ₹540; lubricant 30% = ₹162; repairs 6% of 8,00,000 = ₹48,000 ÷ 700 = ₹68.6; driver ₹500 ÷ 8 = ₹62.5; total ₹833/h.
Drill fixed cost per year: depreciation (65,000 × 0.95) ÷ 8 = ₹7,718.8; interest 10% × (65,000 + 3,250) ÷ 2 = ₹3,412.5; insurance 2% = ₹1,300; repairs 8% = ₹5,200; total ₹17,631 ÷ 60 h = ₹293.9/h.
Combined: ₹833 + ₹294 = ₹1,127/h ÷ 0.70 ha/h ≈ ₹1,610 per hectare.
2. Compare that with ₹1,300 per hectare custom hiring and recommend a decision, distinguishing full from marginal cost.
Read the worked answer
Full-cost comparison: owning costs about ₹1,610/ha against ₹1,300 hired - a saving of roughly ₹310/ha, or ₹1,860 over 6 ha, in favour of hiring.
Marginal-cost comparison: if the tractor would sit idle anyway, only the extra cost caused by sowing matters: fuel ₹540 + lubricant ₹162 + repairs ₹68.6 + driver ₹62.5 + drill repairs (₹5,200 ÷ 60) ₹86.7 = ₹920/h ÷ 0.70 = about ₹1,314/ha - practically the custom rate.
So the machinery choice is almost cost-neutral. The real questions are:
- Timeliness: a one-week slip past mid-November costs far more than ₹300/ha in lost wheat yield, and the contractor cannot promise the window. That argues for owning - or for a written booking with a penalty.
- Scale: the drill's fixed cost alone is ₹17,631 a year, i.e. ₹2,939/ha on 6 ha; it falls to about ₹590/ha only at 30 ha of annual use.
Recommendation: hire for this season if the contractor will commit to the dates; buy only if he can secure roughly 10–15 ha of additional sowing work, or if the contractor fails two seasons running.
3. Which operational factor could push the real cost above this estimate, and by how much?
Read the worked answer
Field efficiency. The 70% figure assumes long, regular runs. Six hectares split into small, irregular fields means extra turns, refilling seed and fertiliser (a 2 m drill holds only enough for part of a hectare), and travel between fields.
If efficiency falls from 70% to 55%, capacity becomes 1.00 × 0.55 = 0.55 ha/h (1.8 h/ha) and the cost rises to ₹1,127 ÷ 0.55 ≈ ₹2,050/ha - about 27% higher, which reverses the comparison with ₹1,300/ha custom hiring.
Other efficiency drains worth checking before purchase:
- Sowing into soil that is too wet, or into a heavy straw load, chokes the tynes and stops the work.
- Blunt tynes and worn seed metering increase draft, fuel use and skips.
- Refilling and adjusting in the field is unpaid time that the formula ignores.
Practical step: time one real hectare - from start to finish, including filling - and compare the measured ha/h with 0.70. If it is nearer 0.55, hiring at ₹1,300/ha is the cheaper and safer option this season, whatever the depreciation arithmetic says.