Maize variety choice will become more important

Although this year’s crop is still well away from harvesting, Richard Camplin from Limagrain UK is advising farmers to start planning ahead, saying correct variety choice will be essential to deliver maximum value from the crop next year.  He says recent experiences have shown selecting early varieties should be given very serious consideration by farmers looking to reduce risk and the cost of the feed in the clamp.

“The 2015 maize season was seriously affected by delayed harvest in many parts of the country, compromising yield, feed quality and the opportunity to manage successor crops,” he comments.  “After a difficult start to the current season maize crops in many parts of the country are catching up and currently looking good.

“Drilling was delayed by the cold spring with crops being planted anywhere between two and four weeks later than anticipated.  Crops in the east in particular struggled to get going.

“However, seed beds were generally warm and since then the mild, wet weather, particularly in the south west, has been ideal for vegetative growth.  Most crops were well established and ready to pull away when the weather warmed up at it did in late July.

“The key time for sunshine and heat units is at and around flowering, so provided we have a decent August there is no reason why crops will not perform well despite the shorter growing season. The issue will be whether we get sufficient heat units for crops to mature and this is particularly true for the late maturing varieties which may struggle.”

Mr Camplin says early maturing varieties require fewer heat units to reach maturity which gives them a particular advantage in short seasons, allowing them to be harvested at the optimum time.  He says waiting for late maturing varieties can present problems at harvest.

He says that in September crops typically accumulate dry matter at around 4% per week but this falls to 2% per week as the weather cools in October, so the later the variety that is grown, the greater the risk of extending harvest date beyond what would be considered reasonable.  At the same time the risk of a drop in feed quality is increased.  He advises farmers to assess their crop’s performance in the lead up to harvest this year and to consider whether any problems could be reduced by selecting an earlier variety for next year.

“Delaying harvest to allow a variety to mature increases the risk of harvesting in less favourable conditions.  This could have implications for resulting silage quality and also for management of stubbles”.

He says recent media coverage has drawn attention to the potential problems of managing maize fields post-harvest, particularly when the harvest is delayed.  He believes it is unlikely there will be any easing of environmental restrictions following the decision to exit the EU, so farmers must take all steps to mitigate the risk.

“With increased environmental pressure it will be essential to take steps to prevent soil run off.  A delayed harvest would increase the soil compaction risks from harvesting equipment travelling on wet soils or make it more challenging to establish a successor wheat crop.  If following maize with a spring crop the land should be chisel ploughed, which may not be ideal in wet conditions following a late harvest.  Clearly selecting the most suitable fields is a fundamental management decision, but variety selection can be equally important.”

He says there is a significant difference in days to harvest between early and late maturing varieties, commenting that on the BSPB/NIAB Descriptive List, early varieties are typically ready to harvest at least 15 days earlier. He suggests this can be the difference between a successful harvest and a struggle to get the crop in the clamp.

“These 15 days can make a huge difference to the quality and feed value of resulting silage provided.  As costs of growing and harvesting maize are largely fixed, crop success has to be measured on the basis of how effectively it is harvested and the quality of feed produced. A problematic harvest is likely to increase cost per tonne of dry matter silage produced, as well as diluting its feed value.”

Mr Camplin argues that feed quality is another area where early maturing varieties with improved digestibility have a significant advantage, suggesting they are better suited to the current requirements of dairy farmers.

“If farmers want to reduce costs of production, they need to produce quality forages.  In terms of maize, this means higher energy derived from starch content and high cell wall digestibility in every kilo of silage that will eventually be fed to the cows.  Most early maturing varieties tend to be slightly lower yielding than the later maturing ones, but have higher starch content improving feed quality. However, only a few early varieties such as Activate and the new variety Reason also have improved fibre digestibility due to improved cell wall digestibility that will result in a higher quality feed better suited to producing milk at a lower cost per litre.”

Mr Camplin believes producing high feed quality maize will be particularly important this year.  He says the initial results for first cut grass silages show feeds with lower digestibility, reduced energy levels and higher fibre levels, reflecting the milk winter and the increased proportion of overwintered grass.  They will be careful balancing to ensure effective rumen function and high intakes.

“Starch will be important to drive rumen function and maize can be an excellent source.  Add to this improved digestibility of fibre and you will be making the highest quality feed possible.  Another advantage of focusing on feed quality is that other potential energy sources such as cereals and molasses are all more expensive as a consequence of the exchange rate turmoil following Brexit.  Good quality maize will help reduce feed costs.

“Variety selection is central to driving economic production of maize, by which I mean the yield of nutrients that find their way from the field to the rumen.  The focus needs to move from thinking in terms of tonnes of dry matter and instead focusing on the yield of nutrients, particularly energy, and minimising the risk of a lower quality crop.

“Cost effective diets require consistent quality forage, rather than potentially higher yields of a lower quality feed.  In practice, this will mean an increased emphasis on early maturing varieties which can deliver better feed value more consistently.  When selecting varieties, the key parameters will be maturity date, starch content and fibre digestibility.  It is the combination of good starch content and high digestibility which drives feed value.

“By increasing the prospects of harvesting at the optimum time even in short seasons, combined with generally high feed values, the use of early maturing varieties should be the foundation of dairy systems based on maize silage.  At the same time they can help reduce any environmental impact and ensure any restrictions can be complied with.”