16 October 1999

Trialled and tested

Its a hassle, yes, but running your own farm trials is the best way of making sure inputs pay their way. Gilly Johnson meets someone who does just that.

WHENEVER Lincoln-shire grower Robert Pask sits down and goes through the farm accounts, he asks the $64,000 question: could we be doing this job any better?

But unlike other producers in his position, Mr Pask has the answer to hand. Thats thanks to extensive field-scale trials, run by him, at Heydour Lodge Farm, near Grantham. He can see, at a glance, the solution to all those niggling "what if" problems: what if I had used less/more fertiliser? What if I had stayed with cheap sprays rather than spent out on strobs? What if I had lowered the seed rate and drilled early?

Knowing the answer makes the extra effort and hassle of running 20 large, field-scale plots worthwhile. And last years results contradict some widely held beliefs…

But first, details of the experimental set-up. The trials are not replicated small plots. Theyre the sort preferred by practical growers – tramline widths, and 300m long – which give realistic farm yields although statisticians might quibble at the scientific validity of the results. But yields were weighed accurately to Mr Pasks satisfaction, using a load cell on the trailer as well as combine weighing. Hes convinced the figures stand up to scrutiny.

The natural field variation, which follows changing soil type, was taken out of the equation by drilling across the variable soil. That way all the blocks had a mix of soils – though the field is mainly a thin limestone brash, typical of the Lincolnshire heath.

Spotting Mr Pasks enthusiasm, fertiliser company Hydro Agri and agchem supplier Zeneca quickly came on board. Thanks to their help, different fertiliser and spray regimes were overlaid on these seed rate blocks. "With hindsight, we made life just a little too complicated," says Mr Pask. "It made it more difficult to tease out general trends from all the figures because there were too many layers within. This year were simplifying things somewhat."

Seed rates

His main question last autumn was on seed rates. Mr Pask is keen to follow the new thinking and drill super-early with less seed – but only if its of real benefit, rather than being a short-lived fad. So splitting a field into four blocks, he drilled wheat variety Drake at four different seed rates (table 1). Low rate early drilling (3 Sept) was compared against conventional seed rate at a more normal date – 29 Sept.

The gap between best and worst yield was a whopping 1.2t/ha (10cwt/acre), illustrating just how sensitive crop performance is to seed rate and timing. Clearly, worst strategy was to use conventional seed rate and drilling date, which proves that Mr Pask is right to change tack. But within that early drilled slot, the seed rate must be right.

Top yield, which adds an extra £100/ha or so to the profitability, was from the higher rate: 250 seeds/sq m. "I was surprised," says Mr Pask. "I thought we could have done better with the 100 seeds plot, but I think we didnt put on enough nitrogen on the lower seed rate plots."


That brings us to the next question – which wasnt completely answered by the trials. Nitrogen dose rates were based around the use of the hand-held N-Tester, and the N-Sensor, a clever gizmo from Hydro Agri which can sense how much nitrogen a crop needs simply through assessing how it looks. The N-Sensor is mounted on the fertiliser spreader and instructs the machine how much to apply, on each bit of the field, while on the move.

Its not just a case of the degree of yellowness – the N-Sensor takes crop biomass into account as well. So a thin crop wont be given as much as a thick canopy. But Mr Pasks trials were used as a means of checking the calibration of this machine. So N doses and timings were chosen as those best suited to achieve this. "As a result, I dont think N dose was high enough, and the timing of the last treatment at flag leaf was too late," he says. But he has only gut feel to go by; sadly, a comparison with standard farm practice wasnt tried on the low seed rate plot. Mr Pask is looking more closely at N in this years trials.

"If only we had put on more N, and gone on earlier, Im sure we could have improved the yield from the lowest seed rate plot with 100 seeds/sq m," he says.

Standard farm practice is a 40/90/90 kg N/ha split sequence; with the N-Tester and the N-Sensor, the treatments were 40/20/74 kg N/ha for the low seed rates. The 250 seed rate plot had a higher dose of N at 40/65/68 kg N/ha – might this explain why it managed a better yield? Mr Pask hopes to have the answer by next harvest. Because of the uncertainty, the results are not given here.


Cheap and cheerful, or a strob-based programme? Heres the shock. Last year, a simple triazole fungicide sequence won hands down. Lack of disease pressure explains the results, says Mr Pask. "We should remember that in a more normal season, were likely to have been caught out with that cheap triazole programme." Dose rates in the programme which mimicked standard farm practice, number 2 in table 2, would have been trimmed on his commercial fields, he adds.

There was little to choose on yield between either the strob-based or the triazole programmes. And because the strob sprays were more expensive, the budget sequence wins out (table 2). But that was more a case of luck rather than judgement, he comments. "We had a lot of rain before harvest. The cheap and cheerful plot went off and lost colour dramatically – as did the Amistar-based programme without the earwash."

The main lesson learnt from the trials is that early drilling does pay. "These results have made us rethink. This year were aiming to go in as early as we can – on the brash land, at the end of August, beginning of September." True to his word, when he spoke to Crops at the end of September, Mr Pask was drilled up, including the stronger soils, on all bar the sugar beet fields.

Task for this season is to refine management strategies for that low seed rate, early drilling slot. Hes convinced that he can boost yield potential from a skimpy seed rate, given good establishment conditions, the right fertiliser programme, and taking soil type into account. It also means avoiding dry seedbeds where the grain might sit around and lose vigour. Watch out for more results from Pask Farms next harvest.

Seeds Tillers/ Cost Yield Drilling

no/sq m kg/ha sq m £/ha t/ha date

100 40 1332 £10.60 10.2 3 Sept

160 64 1280 £16.94 10.6 3 Sept

250 100 1680 £26.50 11 3 Sept

375 150 880 £39.75 9.7 29 Sept

Source: Pask Farms

Programme Cost £/ha Yield t/ha

1 £18 10.2

2 £44 10.4

3 £66 10.4

4 £65 10.3

5 £66 10.3

Fungicide programmes, at growth stages 32/39/59:

1: Cheap and cheerful: Opus 0.25/Opus 0.35/Folicur 0.25

2: Farm practice: Landmark 0.5/Landmark 0.4/Amistar 0.25 with Folicur 0.25

3: Amistar mix based: Amistar 0.6 with Opus 0.3/Amistar 0.8 with Opus 0.3/Folicur 0.35

4: Late Amistar based: Opus 0.5 with Bravo 1/Amistar 0.8 with Opus 0.3/Amistar 0.5

5:Two strob: Amistar 0.8 with Opus 0.3/Amistar 0.8 with Opus 0.3/no ear spray

Source: Pask Farms

&#8226 Youll be hearing more from Robert Pask in Crops in future issues, in our Farm Diary slot. Keep an eye out for regular missives from Pask Farms on how the trials are progressing, and how hes fine-tuning his business.

&#8226 Robert is also a speaker at the Crops Conference on 23 November. Come and listen to how hes cutting costs and targeting his inputs more precisely; see page 39 for registration details.