Wendy Madzura

Correspondent

The onset of a new farming season brings with it a new ray of hope for better farming prospects. In Zimbabwe, wheat is the second most important cereal crop after maize.

The annual wheat consumption for Zimbabwe is above 400 000mt yet wheat imports of around 80 percent are made each year.

Farmers are implored to increase local wheat production, which will feed into the Sustainable Development Goals, SDG number one (No poverty) and SDG two (Zero hunger) by 2030.

For any cropping venture to be successful it is important to START ON TIME. The highest yields are obtained when establishment is done within the 1st two weeks of May. Planting on time enables farmers to:

Avoid frost conditions during critical growth stages (flowering),

Avoid high disease and pest pressure after

Harvest their crop before the summer cropping season.

Harvest their crop before onset of the rains

Wheat is grown in winter under irrigation in Zimbabwe.

The total amount of water required to irrigate a wheat is in the ranges on 450mm to 600mm from establishment to harvesting.

It is important to note that poorly serviced farm machinery impacts negatively on planting operations, resulting in poor germination, establishment and ultimately yields.

A good plan is indeed the key ingredient in profitable wheat production.

Farmers should bear in mind that yield is a function of two things — yield per plant and yield per unit area. In the yield matrix, there are a thousand reasons for low yields and only two reasons for high yields, these are:

1) Good Genetics/Seed

2) Good Agronomic Practices (GAP’S)

Starting with the right seed variety suitable for a particular cropping region is key in increasing productivity. When selecting wheat varieties farmers should consider the following factors:

Yield potential

Crop stature (Reduced risk of logging)

Disease tolerance

Tolerance to moisture stress

Farmers should select modern, innovative seed technologies that couple high yielding capabilities with climate smart traits.

Wheat yields differ depending on altitude. In Zimbabwe, white seeded wheat varieties are most commonly grown and have a high yield potential of (5t-10t) depending on altitude with highest yields recorded in the Highveld, where altitudes are greater than 1 200 meters above sea level (masl) followed by the middle veld (900-1 200masl) while lower yields are achieved at altitudes below 900 masl.

Modern wheat varieties are equipped with defensive agronomic traits like a short-statured stem and good tolerance to periods of dry spells owing to irregular irrigation.

Short-statured wheat varieties enable farmers to punch in high plant populations without the risk of lodging, resulting in high yields.

Modern wheat varieties on the market include SC Select.

For farmers to unlock the genetic potential of good wheat varieties on the market there is need to employ Good Agronomic Practices (GAP’S).

Soil conditioning is best achieved after soil sampling to ascertain the state of the soil in terms of pH and the soil nutrient status.

Land preparation should be done until a fine tilth is obtained to promote good seed to soil contact.

During land preparation conservation tillage is encouraged to promote sustainable agricultural practice, however, some farmers still use conventional tillage.

What is important is to obtain a fine tilth for good seed to soil contact which results in a high germination percentage and crop stand.

After land preparation the next step is to irrigate to field capacity before or soon after planting. This results in good crop establishment. The seed rate for wheat depends on the method of planting to be used.

When a precision tool like a seed drill is used the seed rate ranges from 110- 125kg per ha, while 125 to 135kg per ha is used when using a broadcasting tool like a vicon spreader.

Other farmers are establishing at higher seed rates, however, we recommend that a cost benefit analysis be done to understand the cost implications of increasing the cost of production versus the yield level to be obtained.

Farmers are encouraged to come in with light irrigation or light disking at 4 to 5 days after planting, particularly in soils with a high silt content to break the cark/crust layer formed on the surface of the ground.

This layer may affect germination of the wheat resulting in a poor crop stand.

Once germination is complete farmers should starve their wheat crop of irrigation water to promote tillering and initiate the development of crown roots.

This critical stage is termed “hardening” and it differs for sand soils and clay soils because of differences in water holding capacity. In sandy soils, hardening can last for about 10 days and 14 days in clay soils.

The aim is to strengthen the wheat seedling and not force them into permanent wilting, hence farmers should exercise caution during this stage.

Once hardening is complete the crop should be irrigated first before any operation is conducted to avoid further stressing the crop.

Top dressing fertiliser is then applied at a rate of 350 to 500kg/ha of Ammonium Nitrate or Urea. It is recommended to apply top dressing fertiliser in two splits, especially in sandy soils.

After top dressing, post emergence herbicides are applied depending on weed spectrum to reduce competition. Regular scouting is a MUST to determine insect pest problems before they reach economic threshold levels.

Common insect pests in wheat include aphids and bollworms.

Insect pressure increases as temperatures become warmer after the winter season hence adhering to recommended planting dates becomes paramount.

Selection of disease resistant varieties reduces the need to spray for new strains of leaf rust and powdery mildew with a net effect of reducing production costs and increasing the return per dollar invested.

Clearly, profitable wheat production STARTS WITH THE RIGHT SEED.

The writer Wendy Madzura is an agronomist with Seed Co