The Sunday Mail
Peter Gambara
As we celebrate Christmas, it’s that time of the year when we look at summer cropping so far and look ahead to the rest of the season.
Experts have said we should expect normal-to-above-normal rainfall during the 2016/ 17 season.
So far, the Heavens have opened up and most areas have received good rains.
Unfortunately, some parts of the country have experienced floods, resulting in loss of life.
Zimbabwe remains optimistic that it will receive good rains, hence good yields.
Traditionally, the country receives a lot of rainfall between December and February, with most crops being leached as a result.
This leaching is brought about by heavy rains, and largely impacts crops with inadequate basal fertiliser.
Farmers should, therefore, be aware of factors that will increase the amount of rain on their land, and try to encourage that rain to drain away as much as possible.
Rain water will accumulate if drainage is bad, and this normally happens when there are insufficient conservation works like contours or storm drains.
Storm drains are like “big contours” built at the top of the land to prevent water that might be coming from, say, a mountain or hill, rushing onto the land.
Contours, on the other hand, are placed at certain intervals and at slopes that will drain the water from the land.
Unfortunately, a lot of farmers continue to plough without any conservation work.
I have seen a lot of washed-up lands, some developing into small gullies and washing away crops.
Some farmers actually destroy contours, while others do not maintain them. As a result, water does not drain in the contour, but builds up on the land, breaking the contours and flooding fields.
Government came up with Command Agriculture in order to produce enough maize for the country.
The programme’s announcement came as a big relief to many farmers who were unsure of how they would farm this year.
Some farmers had already arranged to lease their land to a few white former commercial farmers as they could not fund operations.
Under Command Agriculture, Government sought to contract 2 000 farmers who were expected to each grow 200 hectares, producing at least 1 000 tonnes of maize apiece and bringing the national sum to two million tonnes.
While the scheme is a brilliant idea, its implementation has been very poor as some farmers are still to get basal fertilisers that are needed to plant the crop.
No adequate provisions were made for tillage as only diesel was made available.
Those who experienced breakdowns or do not own tractors faced a torrid time hiring the requisite equipment.
A lot of farmers are struggling to get top-dressing fertilisers too.
Such poor implementation will compromise outputs.
However, this provides a learning opportunity to the implementing agencies.
Firstly, such a programme needs to be planned on time; enough funds should be made available and inputs availed on time.
This year, a lot of farmers ended up failing to pick up lime as they were told to, for instance, go all the way to Rushinga to pick it up whereas no provision had been made for transport costs.
We can only hope that going forward, there will be enough top-dressing fertiliser in the New Year as most of the crop will need it.
Proper arrangements should also be made for the orderly crop harvesting and marketing.
A lot of combine harvesters will be required, and failure on this count will compromise winter cropping.
The planting season for maize should have closed on Unity Day.
On December 22, the sun is directly above the Tropic of Capricon, and starts moving back to the Equator on its way to the Tropic of Cancer in the northern hemisphere.
After that date, the heat units start decreasing as the sun moves away from the southern hemisphere and that day is ideally the last planting date for most summer crops.
Anything planted after that day should, therefore, be considered a late crop and risks not getting enough heat units to reach maturity.
Farmers should also be reminded about the number of days that a maize variety will take to reach maturity.
A late maturing maize variety like SC 719 will require about 158 days to maturity (DTM), whilst a medium maturing maize variety like SC 627 requires about 144 DTM.
An early maturing maize variety like SC 513 will require 134 days DTM.
A farmer should, therefore, always establish if there are still enough days for that crop to reach maturity, considering that rains normally end around March.
The biggest threat to Command Agriculture remains the control of weeds.
During the initial phases, only Atrazine and Glyphosate were being provided.
Subsequently, Stellar Star, Metalochlor (Dual), Nicosulfan and Halosulfuron were also available.
The effectiveness of these herbicides depends on application and the timing of operations.
Most herbicides are best applied when there is a bit of moisture on the ground.
The speed of the tractor or person applying the herbicide is also very crucial as the wrong speeds will result in the wrong amounts being applied.
Farmers should, therefore, constantly check that this is being done correctly.
It’s amazing how two farmers receive exactly the same herbicides, and one gets very clean fields and the other weed-infested fields.
If properly applied, Atrazine will control most broadleaf weeds.
Glyphosate (Round Up) was recommended for distribution because it will be able to control star grass and any green live weeds remaining after land preparation.
However, it is non-selective, meaning it will burn even the germinating maize.
Farmers should, therefore, strive to apply it soon after planting.
If applied when maize starts showing tips, it will burn the maize as it affects the whole plant system up to the roots.
Metalochlor (Dual) will work best as a pre-emergence herbicide and can be mixed with Atrazine so that whilst the Atrazine controls the broadleaves, the Dual will control most grasses.
Nicosulfan is meant for the notorious Shamva grass, whilst the Halosulfuron was meant for nutsedge.
It is important that farmers who are growing large areas of crops get herbicide application right as it will be an impossible task to hand-weed say 50 or 100 hectares.
Most farmers are used to top-dressing their maize crop just once, normally just before tasselling, but with sandy soils and the expected heavy rains, it is actually recommended that one split applies the top-dressing.
A farmer can apply top-dressing at two weeks, four weeks and six weeks after planting or at four weeks, six weeks and eight weeks after planting maize, depending on the state of the crop.
Farmers applying 300kg per hectare will, therefore, apply 100kg, three times during the season.
A single top-dressing fertiliser can easily be washed away, especially in sandy soils and with heavy rains.
The amount of fertiliser that one applies as top-dressing has always been a problem to some farmers.
A maize crop grown in sandy or sandy loamy soil will require around 300kg of Ammonium Nitrate (AN) per hectare whilst the same crop grown in red soil will require slightly less.
However, higher rates than these will definitely give better yield responses.
The method of top-dressing fertiliser will depend on how big an area a farmer needs to attend to, how much labour is available and the equipment available.
Farmers applying fertiliser to a small area can use labourers to place the desired cup of fertiliser per plant.
If a farmer wants to apply, say, 300kg AN per hectare (ha), he or she should first establish the plant population.
A between-row spacing of 0,75 metres and an in-row spacing of 0,2 metres gives a plant population of 66 000, that is (10 00 percent,75X0,2).
To arrive at the size of the fertiliser cup to be used, one should first convert the fertiliser rate into grammes, that is 300kg/ha X 1 000grammes=300 000 grammes/ha, then divide this by the plant population that is 300000 grammes/ha divided by 66 000 plants/ha=4,5 grammes per plant or cup number 5 per plant to the nearest.
Fertiliser cups are available for sale at most outlets that sell fertilisers.
They normally cost $1 per any five cups chosen.
However, those with large areas to attend to should consider other methods.
Farmers can ask workers to split a 50kg bag of fertiliser among two workers and then ask them to open up a hole at one corner of the sack and place a small tube that will enable the fertiliser to flow out easily and quickly.
A worker will then allow the desired amount of fertiliser by opening up the end of the tube and closing it as soon as adequate fertiliser has been applied.
This is popularly known as the “Chola” system.
The amount of fertiliser let out through such a system is obviously an estimate.
It is, therefore, important to train workers on the correct amount to be applied as well as to monitor them during application.
Some farmers use a vicon spreader to apply top-dressing fertiliser.
The advantage of a vicon is that it can be calibrated to apply the desired amount.
The only disadvantage is that the fertiliser will benefit both the maize and weeds.
Some farmers argue that they want the maize to benefit from top-dressing so that it quickly outgrows weeds, and once the maize has covered the available space, the weeds will be starved of sunlight and will no longer be a big threat. Such a method is not desirable.
When it is very wet, farmers can use top-dressing fertilisers like Urea, which slowly releases nitrogen.
However, farmers should be warned that Urea will easily evaporate into the air if it is not covered.
Unlike Ammonium Nitrate which farmers place besides the plant, it is essential for farmers to cover Urea with soil. It should also be applied when it is moist as it requires water to react and release nitrogen.
It cannot, therefore, be used by farmers with huge areas as they cannot easily cover it.
Even if farmers applied basal fertilisers, with heavy rains, especially in sandy soils, nitrogen, which is the most water soluble plant nutrient, is easily leached away.
The crop will turn yellow and there is definitely need for top-dressing.
Some farmers talk about applying a mixture of basal and top-dressing (what some farmers call “X”).
It is useless trying to apply such a mixture at that stage of the crop as the crop will only use the little nitrogen available in the “X” and the rest remains in the soil and can only be used by the next crop.
It’s also time we start thinking of winter cropping.
We should not repeat the late start as what happened in summer.
Efforts to rehabilitate irrigation schemes for winter cropping should start now.
Contractors should start identifying capable farmers now, ensuring the desired inputs will be available on time.
Fertiliser shortages should never be allowed to derail such important programmes again.
Let me sign off by wishing all farmers a Merry Christmas and Happy New Year and all the best in your farming endeavours.
Mr Peter Gambara is a Harare-based agricultural economist/consultant. He wrote this article for The Sunday Mail.
