A 2016 study looked to quantify the economic and environmental implications of reduced intensity tillage practices when crop mixes are optimised for profit (gross margin).
Six tillage systems were compared:
Reduced till and the bottom line
- Conventional (CT)
- Rotational ploughing (RP)
- Deep reduced tillage (DRT)
- Shallow reduced tillage with medium disc harrow (SRT1)
- Shallow reduced tillage with spring-tine harrow (SRT2)
- Zero tillage (ZT)
By reducing the intensity of tillage it was found that farmers could increase gross margins and net energy whilst reducing their green house gas (GHG) emissions.
| RP | DRT | SRT1 | SRT2 | ZT | |
|---|---|---|---|---|---|
| Gross margin (£ farm−1) | +14% | +23% | +23% | +24% | +35% |
| Net energy (GJ farm−1) | +2% | +8% | +8% | +8% | +9% |
| GHG emissions (kg CO2-eq farm−1) | -5% | -9% | -9% | -11% | -11% |
Table 1: Gross margins, net energy and GHG emissions for each tillage system in comparison to conventional tillage
The study found:
- Gross margins were higher for reduced till systems.
- All reduced till systems had similar gross margins.
- Higher net margins for reduced till systems reflected the reduced labour, machinery and fuel costs.
- Time and labour requirements of conventional tillage were higher as a result of the slow work rate of the power harrow. The time and labour requirement often exceeds the farms resources meaning work is contracted out increasing costs.
- To spread out the workload and limit contractor costs in the conventional tillage system, a less valuable crop mix was untilised. Reduced till systems require less cultivation, as more resources are available a more valuable crop mix could be grown.
- Although reduced tillage frees up resources, reduced tillage restricts the use of root crops. Therefore flexibility of crop choice is reduced.
- Two sets of machinery are required for rotational tillage systems so machinery costs are similar to that of conventional tillage systems. However, machinery use is reduced.
- SRT1 requires a smaller tractor than DRT, but as the work rate is lower gross margins remain similar.
- Gross margins remained higher in reduced till systems compared to conventional systems when additional herbicides were required for black grass control.
| RP | DRT | SRT1 | SRT2 | ZT | |
|---|---|---|---|---|---|
| GM (£ ha−1) | +14% | +23% | +24% | +23% | +25% |
| Fuel use (L farm−1) | -23% | -47% | -47% | -54% | -58% |
| Contractors’ fees (£ farm−1) | -74% | -78% | -78% | -78% | -78% |
| Machinery costs (£ farm−1) | -3% | -7% | -24% | -27% | -30% |
| Machinery costs (£ ha−1) | -3% | -6% | -24% | -27% | -30% |
| Fuel costs (£ farm−1) | -23% | -47% | -47% | -54% | -58% |
| Fuel costs (£ ha−1) | -22% | -47% | -47% | -53% | -58% |
| Labour costs (£ farm−1) | -14% | -39% | -40% | -31% | -45% |
| Labour costs (£ ha−1) | -14% | -39% | -41% | -32% | -46% |
| Net margins (£ farm−1) | +23% | +39% | +51% | +56% | +59% |
| Net margins (£ ha−1) | +22% | +39% | +51% | +56% | +59% |
Table 2: Fuel, labour, machinery, and contractor costs and the resultant net margins for each tillage system in comparison to conventional tillage when crop mix is optimised for gross margins.
Uptake
Although yields are reduced, a zero till system can absorb reduction in yield of 14.2% before the gross margin falls below that of a conventional till system. A rotational till system can sustain a yield reduction of 8.1%. This ultimately means that more land will be required to produce yields required to maintain total food production. The benefits of zero till over shallow reduced till are minimal.
- Cost savings are the main consideration for uptake in Northern Europe.
- 30-40% of arable land in England is under reduced till cultivation, most in the from of mixed tillage systems.
- Rotational ploughing is common as some benefits are achieved whilst minimising risk.
Barriers to uptake
- Change in machinery requirements (capital and learning costs)
- Benefits are uncertain
- Farm size – smaller farms are less likely to be able to cover costs associated with changing system.
- Crop rotation
- Climate
- Soil type
- Difficulties with increased weed burden
- Yield penalties
Reference
Townsend, T.J., Ramsden, S.J. and Wilson, P., 2016. Analysing reduced tillage practices within a bio-economic modelling framework. Agricultural systems, 146, pp.91-102.