Growing maize in 2014? What you need to know

Published 27 March 14

Top Ten Pointers for Growing Maize in 2014

Producers wishing to get more from their maize in 2014 need to focus on the following key points, suggests Grainseed technical director, Neil Groom.

1. Be realistic about available heat units

Key to successful maize crops is choosing varieties that will achieve the critical 30% DM and this means being realistic about your field’s available heat units.

Looking at 2013, although the first half of the year was cold and wet, most maize growing areas experienced significantly higher levels of sunshine in July and August compared to the 30 year average.

Some areas were over 10% higher, in fact. Northern, North Western and North Eastern regions not only experienced more sunshine hours but far better accumulated maize heat units too – around 6 to 7% above the 30 year average.

But, as well as considering average regional data, it’s essential to factor specific local conditions into the equation. For example, around 25 heat units are lost for every 30m (100’) above sea level and a field’s level of exposure to prevailing winds could have a marked impact on true heat units available.

Consider everything and if in doubt go for an earlier variety than you feel you might need and always look for a good cob ripeness score.

2. Revisit whether plastic is worth considering

Maize has to mature properly to be a cost-effective feed and if you’re in a part of the country that is marginal for sufficient heat units to achieve this, establishing the crop under plastic might be worth revisiting.

Plastic can often benefit growers who might not consider their location needs it – especially if they’re quite far south but on higher or more exposed land. No matter where you are, if you don’t have enough heat units for even an ultra early variety, plastic will be your only option.

Weed control is often a challenge when growing under plastic. Because you’re putting your primary herbicide on with the drill, you need to work with a good agronomist to understand what the likely weed challenges are and use a good mix of herbicide actives to control the target weeds. A good drill operator is essential too.

All is not lost if you don’t achieve total control first time, however, as you can always use a post emergence herbicide in June. In fact approx. 50% of maize crops grown under plastic have to have a second herbicide application.

3. Correct damage done by this winter’s wet conditions

Wet conditions are a challenge, if the soil has been wet for a long period of time it is likely to have turned anaerobic (lost its oxygen) which is essential for plant roots and growth. Ploughing or deep cultivation will be needed to break up the structure and any pans but field conditions will determine what can be achieved.

If there is still water ponding in an area on the field then a tined cultivator that breaks through the compacted layer can often allow water to drain through the soil but it all depends on the soil type. A sandy loam will drain much better than a heavy clay.

Powerharrows can smear the bottom of the cultivated zone if the soil is wet at depth, so consider using a tined cultivator or tillage train to create your seedbed.

Sands and loams should create a good seedbed and are forgiving, whereas soils containing clay will rapidly change from being too wet to too dry in a short space of time. Timeliness is key to getting a good seedbed on heavier soils.

4. Get your rotations right

If you grow maize in the same location each year, you’re going to get more weed build up, which becomes increasingly costly to manage. The ideal situation is to rotate maize around the farm.

As well as making weed control easier, this has significant advantages for following crops, including continued release of N from the organic manures used. The fact that the land has probably been flat-lifted, combined with the deep rooting nature of the crop, improves soil structure and condition as well.

If you’re in a high rainfall area, the most productive rotation is probably to take an early cut of Italian ryegrass before growing maize and then go straight in to wheat. That’s three crops in one year.

If you’re in the west of the country, good rotations are increasingly important now with the loss of the Neonicotinoid-based seed treatment Poncho, used to control leatherjackets and wireworms in maize crops following longstanding pasture.

5. Wise up about soil pH

The relationship between maize growth and soil pH is something that is becoming better understood. The optimum soil pH for maize is between 6.5 and 7.0 and either side of this the availability of key nutrients can be affected.

It’s probably worth going for a more expensive test, rather than a basic one, as this provides a lot more data. A simple test could reveal you have a pH of 6.7, which looks fine at first glance but a more detailed test could show high calcium levels, for example, which would have a very detrimental effect on trace element availability.

If soil pH is lower than 6.5, fine ground liming products, such as Calcifert, can be used to rapidly and effectively address this.

6. Check for soil compaction

Ideally, a maize plant needs to put down as much depth in roots as there is growth above the ground, so any soil compaction is bad news.

Because the wet conditions of autumn 2012 continued across the country, right through to spring 2013, there was no real opportunity to flatlift land and use a subsoiler to get proper heave in the soil structure last year, so compaction could be a problem in many maize fields this spring.

A compaction pan is usually visible at around 30-45cm (12-18”) of depth, so get a spade out and check if you have a problem. If you do, plan your cultivations between now and drilling to use any dry weather to remove these layers.

7. Think about placement fertilisers

Phosphate is one of the key engines for early plant establishment and growth but unlike Nitrogen and Potash – which are water soluble and are freely available in the soil system – Phosphate only moves about 6mm a year within the soil.

To benefit from Phosphate, you’ve got to make it available to the roots as soon as they emerge so using a placement fertiliser is well worth thinking about. This will help the root structure develop quickly, which in turn allows the plant to take up other nutrients and promotes rapid early growth.

New fertiliser technologies that protect Phosphate from soil lock up are included in products such as MaxiMaize. This allows half the amount of Phosphate (25kg/acre) to be applied as well as the micronutrients Zinc, Magnesium and Calcium.

8. Plan your nutrition properly

Drymatter (DM) content of slurry is critical. If you’ve got an acre’s worth of roof on your buildings all leading into the slurry store, your slurry will be about 2% DM. If you’re able to exclude rainwater, you could in theory get up to 10% DM. Most slurry is around 6% DM.

You have to be realistic about the nutrient values of muck and slurry too so don’t guess them – get material tested and make a plan based on facts rather than assumptions.

To avoid any Nitrogen loss from volatilisation, always ensure it’s incorporated in the soil within 24 hours.

Many people now believe it’s better to spread slurry on top of ploughed land and use a cultivator to work it into the top 10cm (4”) rather than apply it on bare land and then plough it in. That way the nutrients are in the same soil layer as the seed rather than buried some 30cm (12”) below ground.

If you are on an umbilical system, there is also the opportunity to wait and spread material on the emerging crop. This can be done right up to the seedling being 2-3” high and provides nutrients directly to the growing plant.

9. Keep an eye out for Eyespot

Traditionally, of concern to growers on the western side of the country, Eyespot is now a potential threat for most maize growers as it moves across the country. This is due to a tenfold expansion in maize grown in eastern counties, predominantly for AD plants.

Although it wasn’t the threat many feared last year due to the hot, dry summer, everybody needs to be vigilant in 2014. Look out for roundish spots with a light brown centre surrounded by a purplish brown ring on leaves – these can coalesce to produce dry, dead leaves with a devastating effect on yield of up to 30%.

If you’re in the west, fungicide should be applied in July as a protectant but elsewhere you need to be aware of the problem and seek early advice from an agronomist, as control options are becoming more limited with the revocation of flusilazole. Wherever you are, good crop hygiene and burying all trash as soon as possible after harvest, are essential.

10. Chop forage longer

You’ve got to get a good ‘scratch factor’ in your rations to stimulate the rumen and this means cutting maize longer than you might have previously. Around 20mm is the optimum length for cows.

But this longer cut means you will also have to think more carefully about achieving optimum compaction. If you’ve got the space it’s worth running a tractor on top of the clamp ‘across the grain’ to achieve this, ie either diagonally or even at right angles to the loading direction if the clamp size allows it.

As harvesters get bigger and filling becomes quicker, clamp management and loading needs scrutiny.  A good rule of thumb is to have 25% of the weight of material coming into the clamp as steel compacting the materials on top. So, if you have 100 tonnes/hour of silage coming in, ideally you should have 25 tonne of tractors doing the compacting and rolling.

For the last 100 tonnes of material, it’s worth having a shorter chop for a good seal on the top of the clamp.

11. Be prepared to invest more in forage analysis.

If you want to get the most out of your maize, you’ve got to understand more about what’s in it.

Maize generally has a high level of rumen undegradable starch but rations need to be balanced carefully to make sure any low pH is managed properly.

It’s worth getting maize silage tested regularly and using a more comprehensive test than a basic one. If in doubt about pH, material should be tested every 30 days or so and you should be prepared to use rumen buffers such as sodium bicarbonate if necessary.

Care also needs taking with starch and energy balance, so cereals should be analysed also to make sure they are not adding too much starch. Again, a more detailed test is worth doing – especially as the FAA (Forage Analytical Assurance Group) has recently expressed concerns over wide inconsistencies in tests estimating the energy values of maize.