Scottish grower Neil MacLeod has been looking for early autumn vigour in the varieties he is trialling on-farm this season. Abby Kellett reports.
For Neil MacLeod, farm manager at Southesk Farms, Montrose early season vigour is of huge importance in ensuring his oilseed rape crop grows away from slug pressure and has adequate plant numbers going into spring.
Last season, OSR yields on the estate averaged 4.4t/ha (1.8t/acre) but ranged from 3.7-5.1t/ha (1.5-2t/acre), which reflects the wide range of soil types across the 1600ha (3954acre) he manages. To maximise productivity from his variable soil types, he has to be flexible with his crop rotation.
Mr MacLeod says: “On our heavy land our rotation is very limited but on the lighter land, we can grow a full range of crops, so we have a very flexible approach to the rotation.
“On my poorer areas of land, I will not push the crop in the same way – it is about knowing your land and the poorer areas that drag the average down - these areas will not have had as much money spent on them so from a gross margin point of view they should be relatively similar.”
Crops grown on the estate include soft feed wheats, milling oats, malting barley and oilseed rape. Land is also rented out to grow potatoes and peas. OSR typically accounts for around 170ha (420acres), although this year the early harvest meant that Mr MacLeod was able to put a greater proportion of his cropping area into OSR, which is one of his more profitable crops.
“Usually after winter oats, I will sow winter barley in order to allow early entry of oilseed rape the following year, even though it is our least profitable crop. But this year, we started harvest on July 27, which is a lot earlier than usual and so there were a couple of blocks where I was able to get oilseed rape sown instead of winter barley and so our oilseed rape area this year is 170ha.”
Mr MacLeod aims to sow all his OSR by the end of August – sowing much later than this would risk poor establishment as a result of cold soil temperatures. While the estate does not suffer from high flea beetle populations, slugs have been particularly problematic this year.
“We are looking to get the crop in as early as possible to get the crop growing away from the slug pressure. This year, slugs have been a huge issue, probably due to the wet conditions we have experienced during the second half of harvest and late summer.”
To ensure adequate seed populations are achieved going into the spring, Mr MacLeod sows around 60 seeds per sq.m. While he would like to lower seed rates, the estate typically sees around 70,000 geese fly in the nearby Montrose Basin Wildlife Reserve every year – which can impact on the amount of OSR plants that survive over-winter.
Equally, the vast amounts of woodland in the area provide habitat for a number of other wildlife, leaving OSR vulnerable to attack. Therefore having a crop that is capable of establishing quickly is hugely beneficial. “You can manage a forward crop back but you cannot manage a backward crop forward – certainly not up here,” says Mr MacLeod.
Historically the plough was the main cultivation tool on the estate but over the past eight years Mr MacLeod has experimented with both min-til and direct drill based systems. This season, he has found that his best OSR crops are those established with the direct drill and his worst with the plough.
“Even though we have had loads of rain, the ploughed land was the first to lose moisture. The pre-emergence spray on the ploughed land got down to the roots far too quickly which checked the rape, while the direct drilled crops are noticeably ahead.”
Mr MacLeod believes slug populations have been highest on land that has been lightly cultivated to create a stale seedbed before being drilled, while direct drilled crops had far less slug damage.
“I don’t feel slugs can move around as easily in the direct drilled land. However we do remove all our straw, if we didn’t it might be a different ball game.”
He has also seen advantages in the furrow that is created by the front leg of his 4m wide grain and Vaderstad Strip Till drill. “The furrow not only helps retain moisture but helps shelter the plant when they are at the cotyledon stage, which helps the crop grow away from pest pressure.
“Each individual coulter applies 80psi of pressure above the seed and so I have also found that I don’t have to roll behind the drill, which is another cost saving”
Despite the fact the direct drill system seems to be working well across much of the estate, Mr MacLeod still values the flexibility that owning various pieces of kit allows.
“Because of the way the weather can be, you have got to be prepared to drop a system and to move to another – the direct drill will only work when the weather is on your side. When you are growing the area of rape that we grow, on the land types that we have got, one system cannot fit all.”
This season, Mr MacLeod is growing DSV variety Incentive and Syngenta’s SY Harnas in a 50:50 ratio. While he has never grown SY Harnas before, Incentive has made up his OSR area for the past three years and the two varieties show very similar characteristics including fast establishment.
But in order to ensure he is growing varieties that best suit his land, Mr MacLeod is taking part in a large scale grower plot trial alongside Bayer, to compare the performance of several varieties currently on the market.
Grant Reid, Bayers Commercial Technical Manager for the North of Scotland says: “One of the main limitations of small plot trials is their relevance to your farm system, soil type and local weather conditions. Despite this, replicated trials do produce large data sets and allow for statistical analysis, which provides a backbone to decision making in the industry.
“However, to truly recreate a ‘real-life’ scenario, on-farm trials are a natural progression. We currently judge OSR varieties based on their performance in small plot trials, often on different soil types using an alternative establishment method. This makes the all-important decision regarding varietal choice that much more challenging. Therefore, it was suggested that a large-scale OSR strip trial should be set-up at Southesk Farms this season to help cater for its unique challenges.”
The varieties under evaluation include:
All varieties have been sown in one acre plots using the direct drill on August 25. To date the agronomy of the plots has remained identical to standard farm practice, with 30kg of nitrogen placed below the seed and identical pre-emergence programmes used. This will continue as the season progresses.
Despite being only at an early growth stage on October 3, there was still differences to be seen between the plots. Mr MacLeod says: “Already I would say Exalte is not as forward as SY Harnas and Incentive. Incentive is an early, vigorous variety which is why I have been growing it. It was the top yielding variety in Scotland in 2015 and it is looking well in the field this season. As I would expect, SY Harness is looking very similar – both are starting to cover the ground well.”
However Mr MacLeod says the best looking crop currently is Bayer variety, InVigor 1035. “Although the plants are not quite as big as Incentive and SY Harnas, the plants are very even. In trials last year it was one of the higher yielding varieties averaging 5.2t/ha and it is looking one of the best this year so far.”
InVigor 1030 and 1020 are backward compared to the other varieties, however according to Mr Reid, InVigor 1030 boasts a high oil content. “it is slower to get growing away in the autumn but the advantage on 1030 is it is that It has a really high oil content – 43 to 45 per cent oil – which can result in a £25 premium.”
Mr MacLeod says: “InVigor 1020 is looking sparser and the plants are smaller than the other plots – it may well be a good variety for those in the south but perhaps not for the north.”
While SY Harnas, Incentive, DK Exalte and InVigor 1035 had grown away from the threat of slug damage, the varieties which were slower to establish were vulnerable to attack for longer, according to Mr MacLeod.
Although the development varieties did not appear as vigorous as some of the more established varieties, Mr Reid says “they may carry some important traits which could be useful for future breeding development.
“A huge amount of information on these varieties can be collected through modern aerial drone mapping, GAI assessments, on the ground plant counts and yield maps” explains Mr Reid. “Later on in the season we will be able to ascertain how LLS and lodging resistance has varied between the varieties, as well as their spring vigour and maturity. Ultimately, the final yield of each individual strip will tell us which variety has performed best. All this information, in conjunction with data sourced from research organisations, will allow Neil to make an informed decision on OSR varieties going forwards”.