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Agronomist's notebook: Here’s how to grow maize for higher yields

Saturday October 27 2018

William Koros in his maize farm in Endebess.

William Koros in his maize farm in Endebess. When using drip irrigation system in farming, one should ensure the soil is wet to get high yields in the long run. FILE PHOTO | NMG 

ANN MACHARIA
By ANN MACHARIA
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In my daily engagements as an agronomist, one thing I have observed with many farmers who grow maize is that they have stuck to the old way of growing the crop.

This involves growing the staple crop without observing the rotational programmes and until recently, some used farm-saved seeds and no fertiliser or spraying against pest.

Then the spacing is usually 75cm by 60cm and they plant three seeds per hole. This results to about 20 90kg bags per acre for the lucky ones.

Well, there are more ways of growing maize, which offer higher and healthy yields, thus, a farmer gets more money.

A recent visit took me to a farm in Kiserian, where a farmer is using drip irrigation system to grow maize. This means the farmer can grow the crop all-year-round without relying on rain.

In this method, one grows 10 plants per meter square. This is achieved by planting one seed per hole at a spacing of 20cm inter crop and 60cm inter row. The planting depth varies from 5cm to 10cm depending on the soil type.

With the method of maize farming, one increases the production per unit area compared to the 60cm by 75cm spacing, with an acre offering you up to 45 90kg bags

Then one must apply DAP during planting and top-dress using CAN when the maize is at knee-high.

But for better results, one must plant the variety of seeds suited for the ecological conditions of his region.

Soil test and analysis is important and must be done. The farmer I visited, like others growing the crop on small-scale, did not bother about soil test.

Now, this made me talk to her about why it is important to perform a soil test. You see, with a soil test, you are farming from the point of knowledge since you know the nutrients lacking in the soil, therefore, you develop a fertiliser programme in line with the crop nutrients requirements.

Second, a soil test helps you identify the soil pH since it affects the nutrients uptake by the plant. Knowing the soil pH would make you know if the soil is acidic for instance, then you can lime or apply any other corrective measure. If the soil pH is high, one can lower using gypsum. The optimum soil pH is 5.5-6.8.

SPRAYING BEST DONE EARLY IN THE MORNING

While using drip irrigation system, one should ensure the soil is wet to get high yields in the long run. This is achieved by watering the crop twice per week for two hours, but this is affected by the pressure and the weather conditions. If it is too hot, then the frequency of watering should be increased.

A simple soil moisture test can be done by picking a handful of soil, hand roll it into balls. If the findings are: soil forms a ball — this indicates the soil does not require irrigation while soil not forming a ball indicates the soil requires irrigation.

The drip irrigation systems also helps to curb soil erosion thus enabling the crop to get the necessary nutrients.

However, it is important to note that growing maize using this method does not cushion one from pests like the fall armyworm, stem borers, cutworms.

On the Kiserian farm, the predominant pest which has white inverted Y-shaped suture on the front of the head was present.

The crop’s leaves appeared to have tattered edges and had holes. The fall armyworm larva is the destructive stage. The larva destroys leaves in funnel, tassels and burrows the maize ears.

She had applied chemicals to help manage the pest but the high temperatures in the region were working against her as they were enabling rapid multiplication of the pest.

For effective control of fall army worm, key measures should be applied in an integrated management approach. For example, early planting allows maturity of maize before high pest population build up. With regular scouting and monitoring, the pest is identified and control measures put in place before rapid multiplication.

Mechanical control method such as handpicking and crashing the caterpillars and application of suffocating materials such as wood ash, dry soil has proven to be effective, especially among small-scale farmers.

Being a nocturnal pest, spraying is best done early in the morning or late in the evening when the larvae are active, with the sprays targeting the funnel and top leaves.

It should be repeated 2-3 times to target young larvae that emerge after the first spray. Several pesticides are effective, this include Lufenuron and Emamectin Benzoate. Alternation of the active ingredient is key to prevent pesticide resistance.