Expert advice for successful maize growing – Farmers Weekly – Jim Clark
Farmers Weekly and crop specialist Hutchinsons organised a roundtable to discuss growing maize in difficult conditions ...
The maize area is predicted to increase by 20% this year to combat the shortfall in winter cereals drilling, following the wet autumn. Here, growers and experts discuss the challenges and solutions of growing maize in the wake of last year’s difficult growing conditions.
- Varying seasons: 2018 was very dry but 2019 was wet.
- Farmers tend to change their maize variety based on the previous year’s growing conditions.
- Last year, some farmers opted for ultra-early maturing varieties and were caught out.
- Never take a knee-jerk approach when it comes to variety selection.
- Select a range of maturity dates to spread risk.
- Pick varieties from local trials that you know will suit the local climate and soil type.
- When looking at variety maturity dates (FAO score), only compare numbers from the same breeder, as each breeder will measure FAO differently.
- If soil erosion is a risk, avoid picking a late-maturing variety.
- The variety you choose accounts for about 10% of the yield. But remember yields can reduce the further north you are as it is harder to grow larger biomass varieties that will not mature in time. The early-maturing varieties tend to be a slightly lower yield.
Preventing soil erosion
- After a wet autumn and flooding this year, soil erosion may be an issue and can be a particular concern where the land runs near a watercourse.
- Some crops could not be harvested in 2019 because the land was so wet.
- Take care when selecting a site. The Maize Growers Association (MGA) has a tool that will give a risk score based on several factors including rainfall and field. For more information, visit maizegrowersassociation.co.uk
- Undersow with a forage crop. Trials in Cumbria found that using a tall, self-propelled sprayer to broadcast grass on to the growing maize crop in June/July gave a cover that looked good enough to graze lambs on, and helped prevent soil erosion.
- If there is a lack of moisture in the soil, drilling grass may be a better option. But it can only take place up to leaf-eight growth stage, as the machinery can damage a taller crop.
- If fields are prone to soil erosion or you have had difficulty cutting maize, think about harvesting grain maize-it is easier to get the crop off the field in wet conditions if you don’t need a forager or tractors and trailers.
Drying out fields and dealing with compaction
- Some fields may still be very wet.
- Compaction could be an issue where the crop was harvested in wet conditions.
- Let fields dry out before sowing. Light, shallow cultivations will allow surface water to drain; don’t go too deep as this can force water downwards.
- Dig a hole to find the plough pan (normally 8-10in down). This is the layer of soil that becomes compacted when ploughing or cultivating to the same depth. Then set your cultivator to break it up.
- There is no need to go any deeper than 1in below the plough pan in most circumstances.
- Drill seeds east to west to maximise the crop’s exposure to the sun.
- Lighter land may need to be cultivated more than once to allow it to dry thoroughly.
- Beware of overcultivating if using film. You will want a finer, firmer seed-bed to improve pre-emergence efficacy and minimise weeds.
- Soil nutrients may have been washed away by prolonged rain and flooding.
- Lighter soils are more likely to experience higher levels of leaching.
- You can send the MGA your soil type and history to receive nitrogen recommendations.
- Take a soil sample of your fields to assess their nutrient status.
- No nitrogen may be required in the seedbed where fields have received manure. However, potash is very important.
- Maize is different to other cereal crops as it uses nitrogen later in the summer. Applying farmyard manure (FYM) or anaerobic digestate makes residual nitrogen available to the crop at the right time during the tasselling stage.
- Dairy farmer Tom Fisher is applying FYM and no artificial P+K. His aim is to have a pH of 6.5. Liquid or solid nitrogen may be applied later in the growing season depending on crop requirements. No starter fertiliser is applied as maize is grown under film. In a trial, Mr Fisher applied liquid N and saw a 3% improvement in the crop dry matter yields at harvest. The best time to apply late N, either as liquid or solid, is late June/early July. This helps grain fill and cob development, which starts in late July/August.
- Alistair Wannop uses a slow-release fertiliser. This can help the crop mature earlier.
Weeds and pests
- Weed control under film can be difficult due to timing of applications.
- Weeds were more of a problem in 2018 with the prolonged dry weather and reduced effectiveness of pre-emergence herbicide applications.
- One of the main seed treatments, Mesurol, which is a bird repellent, has now lost its registration, so there will be few seeds available with the treatment this season.
- Ideally, crops should be treated with both pre-and post-emergence sprays. The same applies to maize grown under film, although you may have to wait until the weeds and the maize have broken through the film before the second spray is applied.
- Anyone who applies only a pre-emergence spray is taking a risk. Delaying spraying by two weeks can also cost 1-2t/ha.
- Film can be cut in weeks four to five to allow spraying, but this should only be done where weeds are causing an issue. The seed treatment Korit can still be used as a bird repellent, but care must be taken when handling it.
Who was at the meeting?
- Host farmer Alistair Wannop and his farm manager James Irvine, Linstock Castle, Carlisle. They grow 121ha of maize under film feeding an AD plant and are averaging 13.5t DM/ha and 43t/FW/ha.
- Tom Fisher, Smalmstown Farm, Longtown. Running a large dairy herd. Grows 121ha of maize under film. He averages 16t DM/ha and 46t FW/ha at 30%DM.
- Willian Tuer, system manager at Tinwald Power. Growing 69ha of maize for an AD plant and looking to double the amount grown. Averaging 13.5t DM/ha.
- Jim Clark, Hutchinsons area agronomist.
- Jonathan Bellamy, area sales manager for Corteva.
- Simon Draper, Maize Growers Association.