After the first five weeks of the 2016 tobacco marketing season, farmers have pocketed $240 million from 83 million kilogrammes of tobacco sold at an average price of $2, 87. Tobacco deliveries also increased by 35, 5 percent as compared to the same time last season while amounts paid to farmers has increased by 37 percent.Whilst farmers are reaping benefits of firm prices, and should be applauded for embracing good agronomic practices which have translated to six percent bale rejection rate, it is time to start preparing the seedbeds.
There are two methods of growing seedlings known as conventional seedling and float seedling.
Although a significant number of farmers prefer to stick to the conventional seedling method, the float seedling method has many advantages over the conventional.
These advantages include a five times reduction in seedbed area, easier transplantation, less chemicals, water and fertiliser requirements, production of superior, more uniform and drought tolerant seedlings.
Float seedlings take longer to wilt compared to conventionally produced seedlings, have improved survival and early growth of transplanted seedling with unused pulled seedlings being able to be inserted back in the trays and re-floated without consequence for a later planting.
The downside to the float tray system is a farmer needs to invest in the trays.
Ideal seedling which will produce high yield quality crops should have 15–17 cm long and 6–10 mm thick stems when transplanted, should be well hardened and should not have produced more than 8–10 leaves below the bud.
They should be strong, with a vigorous root system which should in turn be carefully removed from the seedbed and be protected from withering during transplantation.
Site selection for float seedlings is more or less the same as for conventional seedlings with seedbeds ideally being located at a warm site the only emphasis for float tray site being the site should be levelled before beds are constructed.
The width of the bed should be wide enough to fit three or four trays side by side widthwise, thus 1,05m for three trays and 1,4m for four trays.
Trays should neatly fit with no more than 1,5cm allowed between them so as to prevent sunlight from reaching water thereby discouraging algae growth.
Two courses of 4,5 inch farm bricks should be used either loose laid or set in position permanently with mortar then the bed is lined with 0,25mm gauge black plastic which is at least 0,5m wider and longer than the inside dimensions of the bed to allow for the plastic to be laid over the top of the wall bed and, at least partially down outside of the wall.
The bed should then be filled with water to a depth of 10cm and plastic should be flat against the bottom and firmly held between bricks.
Pine bark, sand and water can be mixed to form what is known as media and limited amounts of amended composed pine bark are available at Kutsaga as Growmix and prototypes of the required sand quality are also obtainable from Kutsaga.
When the grow mix and water are mixed and squeezed between fingers, the grow mix should crumble into two pieces and should neither be too wet as this causes too much compaction, promotes algae growth and spiral rotting nor should it be too dry.
The grow mix in a tray should be levelled once through the use of a flat plank and the tray should be lifted 20cm above a firm surface and dropped gently to the ground once to firm the media in the tray before the tray is refilled with grow mix.
A single pelleted seed can be sowed in the centre of each cell and the trays should be floated in beds soon after.
Alternatively one can sow with a watering can or boom in the normal way of 2, 5 g raw seed per hectare.
Mulching reduces seed emergency and should only be used in hot weather to reduce evaporation and subsequent salt injury.
Hydrofert and Kutsaga Float Fert are the two types of fertilizers recommended since Compound S and B have given inconsistent results.
The recommended fertilisers are applied in concentrations of 25, 50 and 75 mg N/litre of water in the bed at 7,21 and 35 days after sowing respectively and are diluted in 20 litres of water before being added to the float bed water.
Water is replenished regularly in beds to avoid trays and media drying and water requirements vary depending with time of sowing and environmental factors.
Good quality water, free from nematodes, pathogens, salts and other undesirables should be used.
Dam water can be used in the floating tray system provided the area has no history soil borne diseases such as black shank or there are no known pollution problems such as excessive amounts of chlorine while water from a freshly dug shallow well or borehole may be used if it has a pH value between 5,5 and 6,4 and does not have high concentrations of bicarbonate or carbonate which can lead to plant growth problems.
Upon germination, roots protruding through the tray into the water should not stick onto the tray as this is a sign of contamination.
Float seedlings, unlike conventional seedlings, become hardened as nutrients are depleted in float water, therefore if fertiliser application times are followed, no other hardening process is required.
The Tobacco Industry and Marketing Board in conjunction with AGRITEX and Farmers Development Trust (FDT) are conducting practical and participatory trainings on float seedlings and other agronomic practices for free for tobacco farmers in the districts.
For additional Information contact: TIMB at429 Glen Eagles Road, Southerton, Harare or write to us on P.O Box 10214, Harare or on telephone numbers 0772145166 /9 or 0279-22082 /21982 or 025-3439 or 067-24268 /29246 or 0277-2700 or 064-7280 or 0271-6772 or Toll Free Number 0731999999 or E-mail: [email protected]