adminPeter Gambara
It is that time of the year again when every farmer looks to the sky and is unsure as to whether to plant now or wait until the rain falls. If enough moisture is available, maize will normally germinate in about seven days. However, it is important to note that the moisture should be available throughout those seven days.If the maize seed is planted into wet soil or was dry planted, but gets a shower, there is the danger that the moisture will initiate germination, but will dry out before the seven days, resulting in the seed dying and failing to germinate. Some soils have a capping effect and if it dries before the seed germinates, the germinating seed will fail to penetrate the top soil and will simply curl back into the soil and rot.
It is therefore important for farmers to time their planting so that the seed gets enough moisture at the right time, otherwise it will rot and fail to germinate. Those farmers with irrigation facilities can irrigate to make sure the seed germinates.
Those without irrigation facilities should make efforts to check on the weather forecasts to see if there is a likelihood of good rains within the next few days before they decide to plant.
Most seed is at risk of failing to germinate because of placement. Farmers with access to planters are encouraged to use them. A correctly calibrated planter will place the seed and fertiliser at the right depth and distances. Most farmers do not have planters and therefore use a combination of simple machinery and labour to plant.
Such farmers are urged to ensure that they do not plant the seed too deep and that they place the seed at a safe distance from the fertiliser, especially if they do not have irrigation facilities or when planting in dry soil.
If planting with water or after rains, maize seed should be planted 50mm deep and if planting in dry soil, the depth should be increased to 75mm. Some farmers, especially small scale ones, soak seed before planting it. Such farmers should ensure that they have soaked it for a minimum 48 hours to stimulate the germination to an acceptable extend and more importantly, place it into moist soil.
If the moisture dries up, the seed will rot and fail to germinate. Soaked seed cannot be used with a planter. Farmers also need to make a decision on which maize seed to grow. There are now over 10 seed houses that offer maize seed on the market and the dilemma that farmers face is which one is best for their area. These seed houses include ARDA Seeds, Agriseeds, Mukushi Seeds, National Tested Seed, Pannar, Pioneer Seed Co, Sygenta, SIRDC Seed, Zadzamatura, etc.
Farmers are urged to use certified seed. Use of retained seed obtained from hybrid seed has its disadvantages. Whilst farmers can still get a harvest, in most cases the farmer will experience a certain percentage reduction in the yield potential of that maize due to the fact that seed will produce a lot of variants in terms of plant size, cob size, etc.
The reduction in yield gets more pronounced if maize retained from a hybrid maize crop is used for more than one season. If the loss in yield potential was say 20 percent during the first season, it could be 30 percent during the second season.
One requires 25kg of seed per hectare or 10kg per acre. There are several brands on the market and farmers should make sure they know the variety most suited to their areas. Those contracted on the Command Agriculture scheme are being provided with Seed Co varieties. Seed Co uses the letters SC as a short cut for Seed Co and then use three digits to identify the seed variety.
The first digit after the SC denotes whether the variety is a very short season, short season, medium season of long season variety. The lower the digit, the earlier the variety will mature. An SC 403 variety will therefore mature earlier than a SC513 variety.
An SC719 variety is a very long season variety that should only be grown by farmers with reliable rainfall or have access to irrigation and should be planted early. The last digit denotes whether the maize variety is white or yellow. All odd numbers, denote white varieties, whilst all even last digits denote a yellow variety. A short season variety that is planted a month later than a long season variety will mature at the same time with the long season variety.
If a farmer has to plant late, then they should use a short season variety. Get the details of the days to maturity from your seed agent. It must be noted that maturity does not mean that the crop is ready to be harvested, it will still need more time to dry. There are obvious advantages of planting a maize crop early. Most crops require a certain number of heat units, which units are derived from the heat generated by the sun.
The higher the temperatures, the higher will be the heat units and the faster the crop grows. Since we are in the southern hemisphere, the longest day is December 22nd and on that day, the sun is directly above the Tropic of Capricon.
After that day, the sun starts moving back to the equator on its way to the Tropic of Cancer in the northern hemisphere. After the 22nd December, therefore the heat units start decreasing as the sun moves away from the southern hemisphere and that day is the last ideal planting date for most summer crops.
Anything planted after that day should be considered to be a late crop and risks not getting enough heat units to reach maturity. Maize is susceptible to a lot of diseases that include Grey Leaf spot (GLS) and Maize Streak Virus (MSV. Most companies indicate the variety’s tolerance to these diseases with a scale of 1 to 5, with 1 indicating high tolerance and a 5, low tolerance.
GLS is prevalent in high potential areas like NR I and II, whilst MSV is normally a problem where there were greens during the winter period and therefore very early planted maize, like maize planted for green maize purposes, is susceptible to MSV and farmers are encouraged to treat the seed with gaucho if it has a low tolerance to MSV.
Most seed houses hire merchandisers at this time of the year to sell their seed in supermarkets and hardware shops. It is amazing how each one of them will always heap a lot of praise on their seed without giving you the best advice on which seed to buy for your area. Most of them are only temporal employees and know very little about maize agronomy, don’t believe everything they say. If in doubt, contact the seed houses’ agronomist instead.
Peter Gambara is an agricultural economist/consultant. He writes in his personal capacity.
Online Reporter