Sustained crop yields: Part Two …beware of elements that reduce crop harvests


By Elton Ziki

FOR the farmer to protect his or her yield, there must be an understanding of the key threats to a harvest from the harvesting, transporting, drying, processing the harvested grain or crop by grading, packaging and storage standards. 

By anticipating the likely possible threats to harvest/goho/ isivuno, the farmer must be aware of the elements that reduce crop harvests. 

Pests, rodents, quelea birds, locusts, army and fall worms, wild and stray domestic animals as well as weather-related elements threaten the mature crop ready for harvest right from the field to produce marketing. 

These threats affect the crop during transportation to the storage stages after harvesting and marketing the agricultural commodity. 

At storage, weevils are a harvest’s number one threat.

For pests and rodents, farmers, in liaison with agricultural extension services experts as well as agronomists, can recommend pesticides that protect grain harvests as well as rodent control and bait mechanisms. 

However, farmers must adhere to sustainable usage of pesticides so as not to harm the environment, humans and livestock. 

Weather-related elements that can affect a farmer’s yield include rain on grain, cotton and tobacco crops. 

Farmers should prepare sufficient and appropriate storage facilities and have tarpaulin or plastic tents to protect yields from unexpected rain, excess humidity and frost that may affect the yield, which is usually measured by weight.

Once farmers are capable of effectively and consistently minimising harvest and post-harvest losses for at least five consecutive seasons, then we have strong foundations for guaranteed surpluses. 

The surplus agro-produce will feed into the agro processing and manufacturing industries value chain of the economy, creating jobs and processed food stuffs for consumption as well as stock feed. 

Farmers, therefore, should consider the following techniques and methods to increase crop yields.

Effective and early planting

Farmers must choose the right time to plant. 

The most suitable strategy to increase yields once the field is prepared is early planting. 

Test your soil to ascertain if it is ready for planting. 

Scientific agronomic practices aimed at soil and moisture conservation should be adhered to, to improve productivity.  

Modern hybrid seed varieties create a sustainable product, but knowing if your field is ready for early planting is important for every farmer. 

Planting early can result in increased yields by taking advantage of ideal soil conditions and unexpected early rains.

It is also important to understand how planting recurring crops can affect overall crop yield. Planting maize, for instance, in consecutive years has been proven to be less effective for optimal yields. 

Farmers may need to consider planting alternative crops in alternating years, such as legume crops. Planting alternating crops helps to diversify the demands on your soil. 

This results in more crop yield year-in-year out. 

Conservation tillage 

Farmers must consider conservation tillage practices such as the Pfumvudza/Intwasa Programme spearheaded by the Government of Zimbabwe this 2020/2021 farming season. Applying conservation tillage practices saves time, fuel and machinery wear, at the same time protecting the environment and conserving the soil.

Potential field yield

It is not sufficient to plant seeds and hope for the best. 

Farmers should appreciate the field’s growth potential. Understanding the type of crops one is planting and the kind of seed varieties is equally important when assessing field yield potential. 

Crop producers ideally have an estimated yield potential of their seeds. Understanding this will help manage not only farmer expectations, but whether or not field yield potential is matching actual production?  

Many factors, working in combination, account for crop yield differences. 

Hence, the genetic potential of a plant is a factor farmers must pay attention to. 

Yield-determining factors fall into three categories that are technological, biological and environmental.

Technological factors relate to skills, management and knowledge to implement farming operations thereby impacting crop yields. 

Biological factors linked to plants include pests, diseases and insects. Environmental conditions include altitude, terrain, temperature regime, rainfall patterns as well as the impact of climatic and weather patterns on crop yields.

Field scouting

Another way to increase crop yields is by scouting fields on foot. 

This will provide a chance to assess soil conditions, noticing any weeds cropping up and checking that crops are growing healthy. 

There is a lot one can miss when passing by crops at high speed, so hitting the ground and examining crops is an important step towards a stronger crop yield for every farmer.

Appropriate Water Drainage

Water management is essential to crop survival and maximising crop yield potential. It’s highly essential to ensure crops get sufficient water, but also that they aren’t being over-watered. Developing a drainage system in a field helps prevent water logging and salinisation or leaching in soils, both of which can stifle crop growth and production. 

Appropriate irrigation

With the growing effects of climate change on weather patterns, more irrigation will be needed in the country, of which major strides are currently being embarked on by the Second Republic. Average yields on irrigated farms are 90 percent higher than those of rain-fed farms, according to research.

Smart water management, through using of drop-by-drop or sprinkler irrigation systems, can increase crop yields by up to 50 percent.

Fertiliser Usage

Cultivating with fertilisers is an important part of maintaining optimum soil conditions for crops on farmland. 

Fertilising crops at the time of seeding can help provide the seeds with essential nutrients like potassium, phosphorous and calcium. 

The root-zone at the base of crops is the most important area to facilitate growth so your crop can thrive and produce an impressive and satisfactory yield. 

Nitrogen is the key element needed for good plant growth. Efficient use of nitrogen can increase crop yields by 22 percent. 

Increase the use of fertilisers as soil fertility deteriorates. Government, through Extension services, can ensure the right type of fertilisers are available at the right price and at the right times for farmers to access conveniently as was the case with the Presidential Inputs Scheme which were timeous this season. 

This contributed to the bumper harvest projected at 2,7 million metric tonnes this farming season. 

Fertiliser education lessens the environmental impact and an analysis of such training programmes in East Africa found they boosted average incomes by 61 percent.


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