21 May 2021

Growing Maize Silage Considerations

Eighty percent of maize in Ireland is grown specifically for the production of maize silage and can be used as a winter feed in both dairy and beef production systems. While grass is the most popular winter feed, Eamonn Dempsey, Teagasc Advisor outlines why maize silage might be worth considering

Open sowing or Under plastic

Grass is the most popular winter feed but maize silage with a higher dry matter yield and content than grass, that produces little or no effluent may be worth considering for winter fodder. Maize requires a warm well drained soil with a PH of 6.5 – 7.0, while maize will grow in most soils, brown earths and sandy loams are the most suitable. Maize is not frost hardy resulting in many farmers growing maize under plastic which increases soil temperatures to the ideal 10 degrees for germination. Maize sown under polythene can be sown much earlier from March 25^th with a germination time of 7 days, while with open sowing the ideal sowing date is April 15^th to May 10^th with a germination time of 21 days. It is important to get maize germinating early to take advantage of warm, sunny weather in June which will lead to an increase in grain yield.

Not all varieties are suitable for covering and growers should consult the DAFM recommended list when deciding on what varieties to grow. The recommended list for both under plastic and open sowing gives information on each variety on yield of dry matter, starch content, plant height and earliness of maturity. This information is key in choosing a variety to suit site location and ideal harvest date. When the maize seed is covered in polythene moisture is locked in and soil temperatures increase, this will encourage rapid root development as well as increasing the availability of phosphorus.

Soil Fertility

In choosing a field to sow maize, it’s important to have an up to date soil analysis to identify the fertility status and lime requirement of the soil. Maize has the ability to utilise large volumes of slurry which should be spread in March if soil conditions are good and ploughed in before sowing. Apply the recommended rates of nutrients N, P and K which will depend on the soil index. Trace elements magnesium, zinc and manganese are the most important trace element deficiencies in maize and should be included in the soil analysis.

Weed Control

Maize grown under plastic also encourages weeds to grow, so weed control must be achieved by herbicide application at the time of sowing to prevent weeds from germinating. For controlling weeds such as nightshade in uncovered maize silage, pre emergence herbicide should be applied ideally within 2 days of sowing and a post emergence application when the crop is between the 4 to 6 leaf stage. At this stage the majority of the weeds will have emerged but will not have started to compete with the crop. Maize is a dominant crop and is not badly affected by weeds, disease and pests if controls are put in place to prevent damage.

Pests & Diseases

Crop establishment is the main risk period for pests such as wireworm, slugs, leather jackets and frit-fly. Wireworm can be a problem if maize is grown after grassland, so it is important to ensure seed has an effective seed dressing for the anticipated pests and crops are regularly inspected to identify pest issues especially at crop establishment. Maize can suffer from a range of fungal diseases including eyespot, Fusarium Stalk and Ear Rot, which brings us back to the DAFM recommended list and the importance of choosing resistant and tolerant varieties. If choosing to sow maize its important to understand its agronomy so you can grow and harvest high quality forage which is palatable to livestock.