Ultra Early Maize Competes with Plastic at 750 Feet in South Shropshire

That’s the conclusion from crops, monitored by KWS UK in south Shropshire last season and taken through to yield and cob/plant analysis.  

They confirm that even in marginal conditions, an ultra early variety such as Kentaurus can come to maturity in the first week of October and provide a respectable 6.3t/acre and 28% whole plant DM performance.

In comparison, Justina under plastic in a neighbouring field provided a 2t/acre yield advantage over the new high yielding maturity class 12 variety.  However, the additional £105/acre costs of plastic gave cost/t production figures of £32 compared to £26.

According to KWS UK’s maize specialist, John Burgess, while one should not judge performance on one season and one trial, the indications are that ultra early varieties can produce the goods.

“Growing maize on cold soils at such an altitude is not easy and in a more catchy year the benefits of plastic do allow you to gain an extra couple of weeks to plant up cereals.

“However, varieties like Kentaurus now give us a great opportunity to cut costs especially in less extreme growing situations, gain from high quality silage in the clamp and still get following crops in, in good time,” he said.

The comparison saw both crops drilled into north west facing heavy clay loams virtually in the shadow of Clee Hill at Bitterley near Ludlow.  The Justina sown at 40,000 seeds/acre was drilled under Samco plastic on 19^th April, the Kentaurus nine days later at 43,000 seeds/acre.

The Kentaurus – grown by Mark Gatehouse - had 100cwt of MAP applied as a starter fertiliser ‘down the spout’ plus 8t/acre farmyard manure, while the Justina received 2ta/cre broiler litter before drilling under plastic.

Weed control varied.  The Kentaurus received Calaris plus an additional foliar phosphate at the three-leaf stage to boost early growth, the Justina under plastic had a standard 1l/ha of residual herbicide pendimethalin.

According to Mr Burgess, while the Kentaurus benefitted from a good application of farmyard manure and starter fertiliser mixes, the argument is that more nitrogen is mineralised in the warmer soils under plastic and so less nutrient need be applied.

Open field establishment, does though allow you to utilise fertiliser placed around the seed and again, applied to the leaf at a later date to ensure supplies are not limiting and make certain that strong rooting and early growth is encouraged.  That said, broiler litter is also very nitrogen rich and on the heavy clay soil it is unlikely that nutrition was limiting the growth of either crop.

While there was little option under plastic, on the Kentaurus, where soils were relatively dry a post-em spray was applied.  “Again, there is greater flexibility than you have under plastic,” he said.

 “As a breeder, we know that varieties such as Kentaurus can do over 7t/acre in NIAB trials but we wanted to test it at 750 feet above sea level in more marginal conditions”.

“These trials suggest that you can get up to levels approaching this in what was a fairly good season.  And if you can secure 6.3t/acre on these soils in these conditions, Kentaurus will deliver virtually wherever it is placed.”

In comparison, Mr Burgess calculated that you need an extra 6t/acre fresh weight to cover the costs of plastic.  “This is quite a challenge.  While the crop under plastic, though initially struggling to get through the protective cover was more advanced and a fortnight earlier to tassel, the Kentaurus caught up and wasn’t far behind when cut.”

At maturity, whole plant dry matters on Oct 2^nd were 28% for Kentaurus and 32% for Justina and cob dry matters were 44 and 50% respectively.  So, while plastic gives you an advantage in the early season, this is not always the case during maturity.

“It’s a case of horses for courses and growers will adopt what suits them.  Extra yield is not guaranteed and if drilling date for the following wheat crop is not absolutely critical then you really do have to look at the extra costs involved with plastic. It may not be worth it.”

 

Contract Costs (£/acre)	Kentaurus	Justina
Seed	£62.00	£55.00
Drilling	£16.80	£35.00
Plastic	n/a	£105.00
Fertiliser	£14.50	£0.00
Sprays	£19.20	£22.50
Harvest and Ensiling	£51.00	£49.00
Total	£163.50	£266.50
Yield (t/ac DM)	6.3 t/ac	8.4 t/ac
Cost per Tonne	£26.00	£32.00