Increasing maize yield

Once a variety has been selected matching the local growing conditions, maize is planted at a density allowing the development of one maize cob per plant. To achieve high maize yields, it is important to maximize the number of grains per cob and to increase the grain weight . Through a balanced crop nutrition program, growers would be able to accomplish this.

Crop nutrition and maize yield

Nitrogen is important to securing high maize yields. It fuels crop growth and development and needs to be readily available.

Phosphorus is particularly important for root development and good crop establishment. Potassium, like nitrogen, also boosts crop development, and large amounts are taken up by the growing plant. Supplies need to be balanced alongside those of nitrogen. Good potassium nutrition can also help minimize the effects of frost damage and reduces lodging.

Potassium is most important for stomatal closure and low supplies result in loss of water from the plant.

Magnesium, sulphur and iron increase photosynthetic activity and maintain good growth for high yields.

Calcium ensures good plant strength, protecting root, leaf and stalk production.

Boron is required for pollen tube growth and good grain set.

Zinc is important for photosynthetic activity.

Unavailability of any other micronutrient can also restrict growth processes and subsequent maize yield.

Other crop management practices to increase maize yield

• Maintenance of an optimum soil pH ensures nutrients are readily available and maximizes growth. The preferred pH is in the range of 6 – 7.2 (Measured in water). maize has poor tolerance of low (<5.0) pH soils when aluminum toxicity reduces root development and manganese toxicity reduces plant development.
• Use of lime to increase soil pH, and gypsum to improve soil structure and calcium saturation, will help to increase maize yield. The sulphur from gypsum complexes with free aluminum, reducing the toxicity to the plants.
• Good soil structure is essential for strong root development and good growth – maize is particularly sensitive to soil compaction.
• Spacing, planting density and rotation with other crops help increase maize yield by minimizing disease, pest and weed incidence.
• Weed control is essential to ensure a good, competitive start and pest and disease control will minimize damage to root and productive leaf area. Water supply particularly around silking is important for grain set.