You can download previous versions of our magazine from our archives.
Follow on facebook
Maize in the North
by Lewis Mckerrow, Agrovista
Maize, a crop which is normally associated with warm humid climates is advancing north, and has now reached as far as Aberdeenshire. Advances in varieties and establishment methods over the last 20 years have enabled the crop to move much further north than previously thought possible. Ayrshire and Northern Ireland are seen as the most northerly locations growing significant acreages of forage maize, however a few growers further north are keen to evaluate the possibility of growing the crop.
Two farmers in Aberdeenshire are growing maize this year – both with very different end uses for the crop.
Neil Barclay, from Harestone, Banchory is looking for high quality forage for his beef cattle, and is keen to assess the forage quality and yield of maize.
Magnus Sinclair, from Fiddesbeg, Ellon however is looking at maize as the highest yielding gas producing crop for a new anaerobic digestion plant that he is currently in the process of planning.
Overseeing the agronomy of the crop is Agrovista agronomist Lewis McKerrow. To give the crop the best chance possible he got in touch with Samuel Shine at Samco Engineering, a company making specialist maize drills that sow the seed under plastic.
Samco kindly supplied a demonstrator drill complete with plastic and Pioneer supplied a number of varieties to assess in each situation.
“The benefit of the Samco system is that it provides the crop with an early ‘micro’ climate to germinate and establish. It also reduces the risk of a late frost catching the crop, this gives it an excellent boost and the opportunity to be well established ready for the milder weather” says Mr McKerrow.
In terms of variety choice Pioneer has been at the forefront of development varieties suited to growing under plastic. Justina and PR39V43 are the two tried and tested varieties already being grown commercially, whilst not the earliest varieties on the list, they have provided consistent results in a range of conditions.
The other main variety being grown is Kaspian; this is the earliest variety on the recommended list and is termed ‘Ultra early.’ This variety should cob earlier than others – important as the growing season is shorter.
“With some maize sown with the Samco system and the rest sown conventionally with a one pass air drill it provides a useful comparison.” Mr McKerrow continues.
The air drill was set up to sow double rows at 75cm spacing, the double row minimising any variance or gaps that could appear with a single row.
The Early impressions were that the plastic was having a huge benefit; after 7 days the crop had germinated well and by day 14 the plants had 2 leaves. Temperatures under the plastic on a normal day were measured between 25-35 degrees Celsius, with outside air temperatures between 9-15 degrees Celsius. As expected the conventionally sown seed got off to a slow start and at any given point was approximately 3 weeks behind the plastic.
Currently, after 5 weeks, the plants are 50-60% emerged from the plastic, with the conventional sown plants at the 3 leaf stage and physically much smaller.
With the Samco system, all of the weed control was completed pre-emergence. Products used were Cinder (pendimethalin) + Templar (bromoxanil + terbuthylazine) + Grounded (residual adjuvant). The Samco drill has an integrated spray tank which applies the herbicide under the plastic and to the ridge between bouts. This is an important part of the system as the plastic acts as a ‘greenhouse’ for weeds, quickly smothering out the crop in weedy sites.
Herbicide strategy with the open crop was slightly different, Cinder + Grounded were applied pre-emergence, with a follow up spray of Calaris (mesotrione + terbuthylazine), planned to tidy up any broad leaved weeds remaining. As with many spring residuals they rely on soil moisture to be most effective, therefore a mixture of residual and contact chemicals is often necessary.
In terms of agrochemical input, once the weeds have been controlled then no further passes should have to be made. The only other input sprayed on to the crop with the post emergence will be P-Kursor, which is a fast acting foliar phosphite to improve root growth and vigour.
So are these farmers being optimistic expecting maize to grow this far north? Mr McKerrow is keen to point out that even in Ayrshire, maize is not a guaranteed success and stresses that the weather, specifically sunshine hours and warmth in the months of June and July are vital to ‘make or break’ the crop regardless of location. He believes that the crop will grow but does question whether ultimate yield and quality will be high enough to justify the cost and risk of the crop.