Reaping the benefits of zero-till

As the industry looks to reduce crop establishment costs, an increasing number of growers are looking more closely at zero-till drilling and the benefits it may offer.

Ten years ago, Tony Reynolds made a decision – he decided to stop ploughing and cultivating and zero-till drill all his crops. And when he says zero-till he means just that and not strip-tillage or any form of min-till.

“The idea with zero-till drilling is that the ground is not disturbed,” he says. “Which, in the early years often calls for some strong discipline and not giving in to temptation to reach into the back of the barn for the plough or the power-harrow.”

Based at Bourne, Lincolnshire, Mr Reynolds farms a total of 1,200ha – 250ha at Bourne and a further 1,150ha at Melton Mowbray, Leicestershire, which is about 20 miles away. Cropping comprises winter wheat, oilseed rape and spring-sown crops such as peas, beans, linseed or oats.

Before zero-till was adopted by the farm, crop establishment was achieved using the plough and a series of cultivators with the ground annually “beaten” into submission using successive passes with cultivators pulled by fuel-guzzling high-powered tractors.

“I look back on it all now and question why we did it,” he reflects. “For centuries farming had tilled the soil using implements that needed only one or two horses to pull and, by and large, the land was maintained in a way where there was little compaction, there were ample earthworms, high levels of organic matter and the crops grew. And I don’t think we fully realised the true value of what it was we once had.”

Fully committed to the change, a sale in 2004 saw all the cultivation and drilling kit being sold and he traded in his bigger tractors for some lower horsepower models.

“All I needed was a drill, sprayer, fertiliser spreader, combine harvester and a number of lower cost, lower-powered tractors,” he says.

While the sprayer/fertiliser spreader, combine harvester and tractors posed few problems, finding the right drill has proved to be rather more challenging. While most manufacturers of any note offered what they described as a direct-drill, which could work directly into untilled stubble, trials with a series of different makes of drill proved that this was not always the case.

“Given the ability to penetrate soil, all zero-till drills will work effectively in the dry,” says Mr Reynolds. “After all those are the conditions most of them are designed to work in, if only to prevent excessive soil disturbance, moisture loss and erosion.”

Present such drills with a rain-soaked stubble field and plenty of crop residue and the vast majority of drills simply cannot cope, it seems.

“It’s like pushing the dog down the cellar for a bath,” he says. “Try as you might to prevent discs blocking up or mud building up on depth wheels, you have to finally accept that the drill is simply not going to work.”

The seeders he has tried with varying degrees of success have been a Bertini, John Deere, Weaving and a KRM. With its Great Plains’ coulter system, it was the latter that showed the most promise, although there was also praise for Weaving’s disc coulters, which he says worked well in last autumn’s good drilling conditions.

“I trialled a 3m KRM drill about four years ago in what was to be one of the most difficult and wet autumns,” he says. “It went remarkably well to the point that, while all my other drills were back in the shed, it managed to keep going.”

No great surprise then that when Great Plains acquired Simba and a 6m pneumatic drill designated the Spartan 607HD became available in the UK, Mr Reynolds became the first person to buy one.

A twin-hopper machine for seed and/or fertiliser, the 6m Spartan employs a coulter system with a single leading disc, which makes the initial cut in the soil. Two angled discs then run in this cut to create a narrow trench into which the seed is delivered. A following wheel closes the gap and the job is done.

To cope with tough conditions the weight on each leading disc can be as much as 250kg if required – the bulk of the drill’s weight is carried on two transport wheels.

“I have been impressed with the performance of the Great Plains drill and it seems to suit our ground well,” he says. “That’s not to say that it is the drill for all zero-till situations – far from it. It is for each grower to assess the performance of a drill when working on his own farm.”

tony-reynolds©TS

Not all the crops on Mr Reynolds’ farms are drilled though. The oilseed rape is broadcast by an Autocast seeder off the back of the combine’s 6.2m Shelbourne Reynolds stripper header.

“We use this header on the home farm, but use a conventional header over at Melton Mowbray where most of the straw is baled,” he says. “I think the stripper header does a good job not only as a means of harvesting the grain but by also providing cover for the rape seedlings as they emerge.”

Drive for the Autocast is activated when the header is lowered into work and its twin hoppers are used to hold seed and slug pellets – the latter applied at a third of full rate.

So, with the oilseed rape and cereals both established into zero-tilled soil and, to be fair, looking as good if not better than those which have been drilled into cultivated ground, it’s perhaps time to take a look at how a farm can be changed over to a zero-tilling regime.

Getting started

 So you want to direct-drill your farm and be done with the high cost of ploughing or min-tilling?

The vision of an autumn devoid of days spent sub-soiling and cultivating stubbles, ploughing and power-harrowing is an attractive one. And then there’s the prospect of avoiding starting each day with a queue of tractors waiting to a take a long and expensive fill from diesel tank.

Instead, there is the thought that the whole job could be done with just a gentle roll round the farm with the drill – leaving plenty of time to think of all the money that could be saved.

Unfortunately, it’s not quite like that; making a success of zero-tilling calls for as much care and attention as any other crop establishment system.

“If it’s done properly, there is no doubt there are big benefits to be gained,” says Tony Reynolds. “But there are also opportunities to make a complete hash of it and waste a lot of time and money doing it.”

The first point to note is that there needs to be a commitment made to the changeover – whether it goes as far as Mr Reynolds did when he sold all the farm’s cultivation equipment, is down to the individual to decide.

“A priority is to acquire a suitable drill – not one with tines which will sweep all the surface trash into heaps but a disc drill which can cut through it and create seed-to-soil contact. And if the straw is not being baled, the combine needs to have a good chopper and spreading unit on board.”

For a field which has the potential to produce 10t of wheat/ha, the first year yields of zero-tilling are likely to be down to between 9.25t and 8.75t, although it should be noted that different soil types react differently and at different rates. Clay soils, for example, take longer to recover than loams and it may be that sandy soils experience no yield loss at all.

It’s the soil recovering from years of being battered and pounded by heavy machinery and, understandably, it’s reasonable to expect that some soil types need longer for their soil chemistry to be corrected than others and this will be reflected in the yields they produce.

In the second year of zero-tilling, yields can be expected to fall to 8.75t to 8.5t, and in the third year to 8.5t to 8.0t.

“At this stage many growers will start questioning just what it is they are doing,” he says. “But take heart, always remember that these yield losses are likely to be covered by the saving in establishment costs.”

By the fourth and fifth years yields normally start to pick up again and, come year six it can be back to 10t/ha, with even higher yields to look forward to in future years.

To help reduce the effects of yield loss during the changeover period it is possible to increase seed and fertiliser rate to improve plant population.

Slugs 

For the first couple of years of zero-tilling, slugs are the number one pest which, left to their own devices, can decimate unprotected crops almost overnight.

Thanks to the intensive battering the soil has had over the years, there are very few natural predators left in the ground to eat them and, for the same reason, there’s little for them to eat. So they set about devouring the only food available: the seed and crops thoughtfully provided by the grower, explains Mr Reynolds.

The good news is that as zero-till continues, the number of natural predators increases – the ground beetle, for example, which is partial to slug eggs – and the level of soil organic matter begins to build up.

“There is no absolute solution to slug problems, but if the soil is healthy and there is a high population of natural predators along with alternative organic food for slugs, then there’s every chance that a workable balance can be struck,” he says.

After 10 years of zero-till, Mr Reynolds reports that the earthworm count on the farm has increased from 20/sq m to 140/sq m which, he believes has had a big impact on the slug population. Interestingly, when min-till techniques are used, the earthworm population increases only marginally when compared to conventional ploughing and cultivating.

“For so many reasons, earthworms are incredibly useful beast to have in the soil,” he says. “Not only do they contribute to slug control they also aerate and help drainage, increase the soil fibre and, as part of a whole chain of soil microorganisms, help to keep the soil in a healthy condition.”

Interesting to note that, despite the heavy rainfall earlier this year, very few of his crops appear to have suffered from an excess of water around their roots.

Dig up a trowel of soil and you’ll note its high fibre content, the passageways made by earthworms and the overall condition, which compares starkly with the numb, lifeless soils which now exist in so many arable areas of the UK.

In terms of grass weed control – blackgrass and brome, for example – Mr Reynolds believes that leaving the ground unmoved limits seed activity to the surface, leaving the greater part of the seed bank buried to naturally decompose.

“There is no doubt that, over the years, our blackgrass population has reduced significantly even down to levels in some fields where it is possible to hand rogue,” he says. “It could be that the absence of suitable pesticides to control increasingly resistant blackgrass becomes one of the major drivers towards adopting direct-drilling.”

Ten years on 

Today, 10 years after he first commenced zero-tilling, Tony Reynolds says he is a contented man. During the last decade he has seen some major changes to the way his farm performs, not only in the quality and weight of the crops it produces but also in the diversity of wildlife it now attracts.

“Leaving the fields with the stubble helps to create popular environments for all manner of birds including lapwings and partridges,” he says.

But it’s not all good news. He reports that field mice are on the increase as are self-planted ash trees and, with badger numbers on the up as well, those all-important earthworms are getting hammered too. Worst of all is the dramatic expansion in the hare population, which this year have grazed off large areas of spring beans.

“I’ve never seen so many hares,” he says. “I don’t mind the odd pair but there’s a whole drove of them – if that’s the collective term to use.

“Wildlife and crops aside for the moment, the bottom line in all this is that we manage to maintain the farm in good workable condition for the long term and we make a profit doing it.”

In terms of potash and phosphate use, the instigation of a soil fertility mapping programme and variable rate application, which aims to apply only what the crops remove, has resulted in savings of between 15t and 20t each year or, at current fertiliser costs, about £14.22/ha.

The use of nitrogen has also been reduced – by as much as 50% – due to the increased organic matter in the soil.

“With the farm now yielding very near to what I consider to be its full potential, our margins have also improved – a situation helped by a reduction in the amount of investment in front-line machinery.”

Establishment costs compare very well with any other system and it’s also worth noting that the fuel used on this 1,250 ha arable farm has reduced from 96 litres/ha in 2005 down to 43 litres/ha in 2011.

Establishment costs compared £/ha 

 Operation  Traditional  Zero-till
 Sub-soil  60 0
 Plough  55 0
 Discing  45 0
 Spring tine  23 0
 Power-harrow  4 0
 Drill  30 30
 Press  15 0
 Total  272 30

zero-till-coulters

Coulters on the Great Plains Spartan drill. Note the spring loaded opening disc which is followed by double discs through which the seed is planted.