Taking stock of the summer season

21 Jan, 2018 - 00:01 0 Views

The Sunday Mail

Peter Gambara
It is that time of the year to take stock of summer, looking back and ahead: How did cropping preparations go? Did we achieve targets? What has been the rainfall outlook?

Many farmers faced challenges in accessing inputs and other necessities.

It is, therefore, unsurprising that many farmers battled to prepare land and plant maize and soya beans well into the New Year.

While Government has intervened to spur fertiliser production, it will be difficult to meet set maize production targets.

Farmers should, however, be cautioned against continuing to plant maize way after the ideal planting period.

Planting late into January is bad practice that should be discouraged. Ideally, planting should be completed by December 22 as a maize crop planted in January risks failing to reach maturity.

Short-season varieties require 127 days (end of April) to reach maturity and rains could have stopped by then.

Only those with irrigation facilities will be able to supplement rainfall for their crops to reach maturity.

Farmers should also be conversant with heat units.

Zimbabwe’s longest day is December 22 as we are in the Southern Hemisphere, and the sun will be directly above the Tropic of Capricorn.

On the next day, the sun starts moving back to the Equator en route to the Tropic of Cancer in the Northern Hemisphere.

Consequently, Zimbabwe’s heat units decrease as the sun moves from the Southern Hemisphere, making December 22 the last ideal planting day.

Farmers in hotter areas like those in Natural Regions III and IV (Mutoko, Gokwe, Sadza and others) stand a better chance of planting late and getting their crop to reach maturity than those in Natural Regions IIa and IIb (Marondera, Hwedza, Rusape and Headlands).

Besides, these areas become cold too early, thereby curtailing crop growth.

Farmers keen on establishing a crop in January should consider sorghum or soya beans. Sorghum can be planted up to mid-January and requires only 110 days to reach maturity.

Soya beans can also be planted up to end of January as they have a shorter maturity period (90 days).

As I travelled to my rural home in Mutoko for Christmas, it was evident that most early-planted crops suffered moisture stress. A good number of farmers were hesitant to weed, fearing crops would die.

They resigned themselves to a a bad season.

Sadc weather experts and Zimbabwe’s Meteorological Services Department indicated a “normal-to-below-normal rainfall season” before January and a “normal-to-above-normal season” after New Year’s Day.

A wet Christmas is common in most parts of Zimbabwe and Mutoko was no exception last Christmas.

I am sure the rains continued for a few more days.

Some areas have reported “worm” attacks on maize, with confusion over whether these pests are the fall armyworm or the usual stalk-borer.

The fall armyworm attacks almost all locally-grown crops like maize, sorghum, millet, rice, wheat, cowpeas, groundnuts, potatoes, soya-beans and cotton.

It pretty much prefers maize and other plants of the grass family, though.

The pest, which is also in South Africa, Namibia, Zambia and Malawi, can cause up to 70 percent damage to crops.

It is believed it came from West Africa and could have been introduced into Zimbabwe via grain imports as either eggs or pupae.

Farmers are advised to take worm samples to local Agritex staff for identification.

Pesticides such as Kombart, Karate, Lambda and Dipterex can control the stalk-borer, while the fall armyworm can be controlled by Ampligo 150 ZC, Coragen, Superdash and Tide Plus 5WG, among other chemicals.

A chemical called Ecoterex can control the two.

In both instances, farmers should always endeavour to ensure the chemical is sprayed into the maize funnel as this is where the pests hide.

The stalk-borer waits for the cob to develop before attacking: damage will only be realised on harvesting.

The fall armyworm multiplies in peace and then returns the following season to wreak more havoc.

In January, most farmers concentrate on weed-control and application of top-dressing fertilisers.

Weeds compete with the crop for nutrients, water and light. Therefore, ineffective weed-control can contribute considerably to yield reduction.

Weed-control should not be left until crops have started turning yellow. Dealing with overgrown weeds is cumbersome; time-consuming.

Farmers should explore herbicides in controlling weeds.

Heavy and continuous rains that normally fall in late December and January often cause crops, especially maize, to turn yellowish.

This yellowing is worse in sandy soils where nutrients are easily leached by rains, and leaching is worse where the crop will not have received adequate basal fertiliser.

Farmers normally top-dress with either Ammonium Nitrate or urea.

However, caution should be observed on urea.

While AN can be applied easily by dropping it next to the plant, urea needs to be incorporated or applied under moist conditions as it requires water to react and release nitrogen.

Some urea is prilled or looks like AN given its recent granular form.

Many farmers have, therefore, mistaken this to mean that they can just place it on top of the soil next to plants as is the case with AN.

Urea applied in that manner risks volatising into the air as ammonia gas and will smell like rotten substances.

This is especially true if it remains on the soil surface for extended periods in warm and dry weather.

It is thus important for farmers to apply urea under moist conditions as moisture will enable it to convert to ammonia (NH3) or ammonium ions (NH4+) which can easily be absorbed by plants.

The key to efficient urea use is incorporating it into soil or applying it under moist conditions, usually very early in the morning after some showers.

To incorporate urea, a farmer should dig a small hole next to the plant or, alternatively, use a sharp long stick to drill a hole next to the plant and place urea there.

Some small-scale farmers use ox-drawn cultivators or ploughs to cover the holes.

That way, the urea is unlikely to escape into the air and will react with soil moisture, producing the nitrogen required by plants.

Where small holes will have been dug, farmers should cover that area by simply stepping on the holes.

Using urea as a top-dressing fertiliser is problematic if it is to be applied over big areas.

 

Peter Gambara is an agricultural economist and consultant based in Harare. He wrote this article for The Sunday Mail

 

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