As featured in Arable Farming Magazine
Late-drilled crops performing best in no-till switch
by Arable Farming Essential Varieties Supplement July 2022 Issue
Modern wheat varieties suited to later drilling could be the best bet for growers transitioning to no-till systems, latest KWS trials work suggests.
Changing to a no-till farming system can be a daunting prospect, but there is a growing convergence of thought about the best way to tackle it.
That is according to KWS technical specialist Olivia Potter, who says that when it comes to wheat, one of the biggest considerations is varietal choice and there is now clear evidence coming through about the traits which suit no-till farming best.
Ms Potter says: “The increase in no-till is being fuelled by the growth in interest around regenerative farming, but there are a lot of benefits to be gained by more mainstream producers too.
“Get it right and there are major gains to be made in soil health, general resilience of the farming system, increased farmland biodiversity and reduced carbon emissions.
“While clear differences in varietal performance have been seen across a range of different cultivation systems over the years, it’s not been easy to put a finger on a single feature that makes one variety cope better than another in a no-till situation.
Vigour “Common sense suggests vigour would be important but it’s a very loose term, meaning different things to different people, and we’ve actually seen low vigour varieties coming out top in some situations.
“There are numerous other traits that we’ve considered could be important, such as overall tillering performance, grains per ear, ability to finish, ability to tolerate trash better and drought resistance.
Root performance “There’s also a lot of discussion around root performance in terms of length, efficiency in scavenging for water and nutrients, plus a whole debate about the rhizosphere and its effect on different varieties in soils that have not been inverted.”
The current line of thought is varieties that perform best in a no-till situation are ones that also thrive in adverse environments and this has been borne out by the results of KWS trials, says Ms Potter.
Yield reductions “We’ve been concentrating on finding the best varieties for reducing the pain in terms of yield reductions and the potential loss of added-value marketing opportunities during the transition period when growers move from full cultivation to a no-till approach.
“With this in mind, our work has been focused on the second wheat situation as this is the most valuable to farmers and breeders alike.
“In the direct drilled situation with second wheat you would have all stubble and straw present and all the associated issues with residues – not least of which is nitrogen lock-up because the carbon to nitrogen ratio has shifted.
“We really wanted to create a ‘worst case scenario’ and knew the second wheat approach with lots of straw to deal with would present the biggest challenge for the varieties,” says Ms Potter.
“If we had gone after winter beans or winter rape, for example, the ground might have been a bit tight but there would be no problem with residues, so the growing conditions would be less extreme.”
The results to date have shown that the best varieties for no-till tend to be those that perform well in the late drilling slot.
“The Group 2 variety KWS Extase and Group 4 KWS Cranium have undoubtedly been the standout varieties.
“Even in a year where yields were generally down because of very poor establishment conditions, clear advantages could be seen.
“In a normal year, both the Cranium and Extase would have been approaching yields of 12 tonnes per hectare, but the difficult autumn stopped that.
“While the yield of KWS Cranium was 7.97t/ha in the full-till situation despite the obvious challenges throughout the growing season, it was only 0.2t/ha behind at 7.78t/ha in the no-till situation.
Conditions “KWS Extase was the highest yielding variety in both situations, with a no-till yield of 7.96t/ha compared to 8.74t/ ha with full cultivations.
This was still only a difference of 0.8t/ha in what were truly awful conditions.
“Interestingly, it means growers changing to no-till do still have marketing options.
They have a traditional barn filling Group 4 variety in KWS Cranium or can hit high quality markets with the high yields of KWS Extase.
“That should provide a lot of peace of mind by reducing much of the potential early productivity and financial losses when switching over to no-till.”
The results are not that surprising considering the characteristics of both varieties, she adds.
“In addition to high vigour, both have outstanding agronomic packages – strong septoria resistance with KWS Extase and class-leading yellow rust resistance with KWS Cranium – which is obviously going a long way to protecting the plants as they grow.”
The bounce-back of these varieties in terms of ear numbers counted was also interesting, says Ms Potter.
“Low establishment seen across virtually all the varieties tested in a no-till situation was all but reversed, with the KWS Extase and the KWS Zyatt looking particularly good.
“The no-till Extase was significantly better than in the full-till situation in the early stages.
Recovery “All varieties produced a reasonable ear number considering there was such a low plant population, which shows how well they had recovered, and if recovery is what we’re looking for in a no-till variety then this is very encouraging – particularly with varieties like KWS Extase.
“Ear counts are helpful because they show what yields could be possible before crops are affected by environmental impacts on grain fill and as such are a very good indication of a variety’s genetic potential.”
Planned transition approach plays dividends
Agrii senior agronomist Andrew Richards believes it is essential to have a planned approach to introducing no-till to a farm and this could take several years to complete fully.
“The most important question to start with is whether the land itself is suitable for no-till,” he says.
“While studies suggest up to three-quarters of the UK arable area could be suitable for no-till, careful consideration needs to be given to ground where permanent grass dominated.
“These could be in lower lying areas without proper drainage systems, but drainage is an important question whatever the history of the land and this is best judged after periods of significant rainfall when underlying problems will be evident.
“Rectifying these issues could be as simple as clearing out ditches or jetting existing land drains, with heavy clay soils likely to benefit from mole draining, even where permanent under-drainage isn’t in place.
Investment “Or it might be necessary to make a larger investment in drainage, which is probably best done rotationally over time to spread both the cost and impact.
“Once any underlying drainage problems have been dealt with you can start looking at where you are in terms of pH and take the appropriate actions to correct it.”
It’s important to look at the organic matter content of the soils in question and consider incorporating manures before you cut back on tillage, he adds.
“Cover crops and to a lesser extent crop residues, can be valuable in protecting soils and maintaining soil structure in no-till regimes.
“But there is extensive trial evidence that roots alone are unlikely to improve the structure more than marginally and while cover cropping can build soil organic matter, this will be a very slow process.
“Looking at ways in which extra diversity can be introduced into the whole rotation and keeping active roots in the ground with a wider array of crop species could increase the diversity of soil biology more efficiently.”
This can also have a positive impact on organic matter, soil structure and overall soil health without necessarily compromising margins, says Mr Richards.
“Moving to no-till can also offer valuable reductions in fixed costs, especially in cultivation costs, given the now highly-inflated red diesel prices, but with the UK’s often wet Augusts, compaction can still happen and will need rectifying if yields are not to be compromised.
“As for variable costs, a healthier, more resilient and efficient soil will enable more efficient use of inputs, either to be taken as savings or to be seen in higher yields and more profitable crops,” says Mr Richards.
In the field Russell McKenzie, Bedfordshire
According to Cambridgeshire grower Russell McKenzie, the last thing you need for no-till is a slow-developing variety.
He says: “It’s particularly important for us as we have to drill in October because of black-grass, but in an ideal world we would be aiming for a September drilling slot.
“Having a bit of get up and go in spring is also good, but autumn vigour is what’s really important.
“In no-till situations, you don’t get that oxidation of nitrogen through cultivating, so while slower-developing varieties usually catch up by spring, they can stay too open and let black-grass through.”
Excellent disease resistance is important too, with KWS Extase being the standout performer in recent years, he says.
“It’s got good speed of development and provides all important rapid ground cover too.
“We’ve grown it in a number of difficult situations, including our wettest, heaviest field and it established really well.
It’s definitely very hardy and suits no-till well.”
Considerable effort has been put in to finding the best varieties for the system over the six years of no-tilling on the 900-hectare arable unit.
“We’ve hosted a number of variety trials for the past three or four years plus for the past couple of years we’ve had strip trials which have been established with no-till.
“They’ve been really good to help pick out differences in autumn vigour and also identify those varieties that put out more leaves to cover the ground and provide more competition against black grass,” says Mr McKenzie.