Caring for summer crops
Adequate crop care fundamental
As temperatures increase, the transpiration and evaporation rates on the leaf surfaces of the crops and the soil tend to increase.
It is essential for farmers to care for their crops throughout the summer growing season as it directly influences crop yields and significantly impacts the quality of produce that will reach the market.According to Agribank’s technical advisor for crops and poultry, Hanks Saisai, adequate crop care is fundamental for farmers aiming to achieve above-average yields that offer good-quality produce.
He said as temperatures begin to rise due to the change in seasons, it becomes essential for crop farmers to implement strategies that enable them to care for their crops. “Crop care is fundamentally associated with activities undertaken to ensure the healthy growth of crops.”
According to him, the starting point is to realise that as temperatures increase, the transpiration and evaporation rates on the leaf surfaces of the crops and the soil tend to increase. To mitigate this, farmers can apply mulch on the seed beds and spray water over the foliage (leafy part) of the crops to create a cool environment, he said.
“However, this practice is discouraged for tomatoes as it may lead to fungal diseases.”
Mulching has the benefit of reducing evaporation by keeping the soil underneath the mulching material cool, Saisai noted.
Irrigation plan
Another crop care strategy involves implementing an irrigation plan to ensure crops are watered early in the morning and late in the evening when the environment is cool, he said.
It is important to avoid irrigating crops during the peak sunlight hours of the day - between 11:45 and 16:45 - when it is extremely hot as it may lead to high rates of evapotranspiration, Saisai said. “Essentially, it is always advisable to consider the water requirements of the crop grown so that an effective irrigation schedule can be developed.”
Saisai noted that overwatering can cause problems such as leaching in sandy soils and waterlogging in clayish soils. Leaching is when essential water-soluble nutrients are washed away from the root zone due to excessive rain or irrigation, making them inaccessible to crops.
He further explained that waterlogging restricts gaseous exchange, which is essential for the movement of carbon dioxide into the roots and the release of oxygen through the leaves of the crops.
Minimal tillage
Another important strategy that can be implemented is minimal tillage of the soil.
Saisai said this approach is crucial in extremely hot areas where daily average temperatures exceed 32°C. “Moreover, to ensure that soil moisture is retained for a longer period in the crop field or garden, it is advisable to avoid tilling the soil as it exposes the soil to warm temperatures that trigger fast evaporation of moisture from the soil.”
He urged farmers to only till the soil when incorporating manure or fertiliser and when trying to increase the levels of carbon dioxide to stimulate photosynthesis in the leaves of the crops.
Furthermore, farmers should have a scouting plan to detect pests and diseases early.
Saisai said this will help them develop regular spraying programmes to keep pests and diseases under control. With warm temperatures, there is a high possibility of increased pest infestation and disease occurrence, he said.