Two consecutive wet harvests, coupled with prolonged spells of winter rain, have left soils across the regions in poor condition, says Brendan Paul of Agrii. The problem has been exacerbated in cases where growers were forced to abandon drilling last autumn, leaving the bare land at increased risk of compaction and water-logging.
The first task of the season should be to assess soil structure damage, he advises.
“This can be carried out simply by using a spade and examining the soil profile. There is also the option of using the new soil mapping technology, which will give a picture of what is going on underneath the surface.
“Another consideration is farmyard manure, which by law must be incorporated into the soil within 24 hours of application. This practice will enhance organic matter levels, but ploughing it in will lead to the destruction of microflora, which help to break down the material in the soil. It is possible a spring application may not be fully utilised by the maize, but the next crop will definitely benefit from this treatment.”
Mr Paul’s advice on other aspects of seedbed preparation – which he regards as the single most important determinant of maize performance – depends on farm location.
“While many parts of the country have experienced heavy rainfall, there are areas in the East where moisture conservation will remain be one of the principle aims,” says Mr Paul. “Maize is a thirsty plant and once growth gets underway, it will remove high volumes of water from the soil. In Eastern locations, a one-pass system using a rotavator and drill is likely to be the best way to establish the crop.
“For many growers in the West, there will be little option but to wait until the land dries out, before ploughing. Soils which have become saturated with water will be anaerobic and heavily compacted; maize will not thrive under these conditions. After ploughing, a power harrow can be used prior to drilling,” he adds.
KWS UK has launched a new, web-based service which provides useful daily updates on soil temperatures, to help with decision making related to field operations such as sowing times. According to the company’s John Burgess, soil temperature has a significant effect on early growth right up to the 4-5 leaf stage, when air temperature becomes more critical.
“Research confirms crops require a minimum of 8degC for germination and temperatures should be rising for three to four consecutive days before drilling should be contemplated,” says Mr Burgess.
“On heavier soils, the advice is to wait for temperatures to rise still further, to 12degC, to promote emergence. At the same time, growers will need to ensure the soil surrounding the seed has enough moisture to initiate germination. The land must not be compacted and needs to contain sufficient oxygen, for optimum establishment.”
To access the new soil temperature service, growers enter their farm postcode, to find the soil temperature range at 10cms depth, using data from their five closest weather stations. The service also gives surface temperatures, to highlight any risk of frost.
“In the past, Met Office soil temperature information has been based on temperatures at 30cms. The move to 10cm depth is more appropriate, as it gives an indication of the soil conditions that the young maize roots are experiencing.
“2013 saw the polarisation of maize crops; plants drilled in early April remained relatively inactive, while later-drilled crops – sown in early May – benefited from the warmer conditions further on in the season.
“While we have seen significant advances in early vigour in varieties such as Ramirez, Sergio, Rodriguez and Severus over the likes of Kentaurus or Kaspian, this stronger growth is only beneficial on farms where the crop has germinated in a warm seedbed,” says Mr Burgess.
Francis Dunne of Field Options says milk producers planning to use a high inclusion of maize in rations should bear in mind that overall starch content, in terms of dry matter, should not exceed 25 per cent.
“This is the maximum recommended level for dairy cows; beef cattle can efficiently utilise much higher levels of starch, but the risk of acidosis will be greater. If a ration is already close to 25 per cent starch in dry matter terms, then the rest of the diet will need to be balanced carefully.
“On farms where maize forms a significant part of a mixed ration, we recommend that producers select maize varieties with high cell wall digestibility. This quality has come under increased focus in recent years, as breeders have made great strides on this element of plant genetics.”
Disregarding the cob, a maize plant can vary in digestibility from a low D-value of 50, up to a maximum of 62 D-value. This allows for the development of varieties with the potential to achieve good ME content, without the crop also containing high levels of starch.
“Farmers in Denmark and the Netherlands feeding rations at more than 60 per cent maize consider high ME crucial, but they feel very high starch can be a disadvantage and therefore they will select for fibre digestibility.
“As fibre digestibility declines as the leaf and stem mature, growers in these countries optimise digestibility by harvesting early, at relatively lower dry matter levels. If they were looking for high starch content, harvest would be delayed slightly.
“Cutting later can increase both the starch percentage and the ME of a crop, but this will be at the expense of cell wall digestibility. Since ruminants have evolved to digest fibre, we believe that high fibre digestibility is always one of the most desirable characteristics.”
Mr Burgess reminds growers to make use of the new, web-based KWS-UK heat units service, which is also free of charge and can be accessed without the need to register or supply a password. Updated weekly and operating from April to October, it offers local data on temperature levels. By uploading their postcode, growers can use a drop-down box to highlight the varieties most suited to their region.
Over time, it will give a valuable indication of which varieties perform well in specific areas of the country.
For more information, go to www.kws-uk.com