A scientific approach to optimising crop yields

Word From The Market with Adalph Chikaka

As farmers prepare for the upcoming 2024-25 summer cropping season, adopting good agronomic practices is crucial for optimising crop yields and ensuring sustainable food production.

This article aims to equip farmers with knowledge necessary for a successful harvest, focusing on soil management, fertiliser application and crop rotation strategies.

Scientific basis for soil sampling and analysis

Soil sampling and analysis form the foundation of informed agricultural decision-making.

The chemical, physical and biological properties of soil directly influence crop growth, nutrient availability and overall farm productivity.

Scientific research consistently demonstrates that understanding these soil properties is essential for optimising crop management strategies.

Key reasons for soil sampling and analysis include:

Nutrient status assessment — Soil tests accurately determine the levels of essential nutrients such as nitrogen (N), phosphorus (P) and potassium (K), as well as secondary nutrients and micronutrients.

 pH determination — Soil pH significantly affects nutrient availability and microbial activity.

Most crops thrive in a pH range of 6.0 to 7.0, with some variation depending on the specific crop.

Organic matter content — This crucial soil component influences water retention, nutrient cycling and soil structure.

 Texture and structure analysis — Understanding the proportion of sand, silt and clay in your soil helps in determining water retention capacity and potential management practices.

Samples can be analysed at reputable laboratories, providing farmers with detailed information about their soil’s characteristics.

Fertiliser application: A science-based approach

Proper fertiliser application is a critical aspect of crop management, backed by extensive agronomic research.

The goal is to provide crops with the right nutrients, in the right amounts, at the right time and in the right place —a concept known as the “4R Nutrient Stewardship”.

Crop rotation: A proven practice

Crop rotation is a well-established agronomic practice supported by extensive research. By alternating crops, particularly cereals like maize and wheat with legumes like soya beans, farmers can achieve multiple benefits:

1. i) Improved soil fertility — Legumes fix atmospheric nitrogen, reducing the need for N fertilisers in subsequent cereal crops.
2. ii) Pest and disease management — Rotation disrupts the life cycles of crop-specific pests and pathogens, reducing their populations.

iii) Enhanced soil structure — Different crop root systems improve soil structure and organic matter content.

1. iv) Increased biodiversity — Rotation supports a more diverse soil microbiome, contributing to overall soil health.
2. v) Potential yield increases — Research consistently shows that crops grown in rotation often yield more than those in monoculture systems.

Role of extension services

Extension services, provided by the Government’s Agricultural Extension Services (Agritex) and the Agricultural Marketing Authority (AMA), play a vital role in disseminating scientific agricultural knowledge and practices. These services bridge the gap between agricultural research and on-farm implementation.

Key responsibilities of extension officers include:

1. a) Soil sampling and interpretation — Collecting soil samples and translating laboratory results into actionable recommendations.
2. b) Fertiliser recommendations — Providing specific, science-based fertiliser recommendations tailored to each farm’s soil conditions and crop choices.
3. c) Crop rotation planning — Assisting farmers in designing evidence-based crop rotation plans that maximise agronomic and economic benefits.
4. d) Pest and disease monitoring — Conducting regular field visits to identify and address potential pest or disease issues early.
5. e) Technology transfer — Introducing farmers to new crop varieties, technologies and farming practices based on the latest agricultural research.
6. f) Record keeping — Emphasising the importance of detailed farm records for continuous improvement and decision-making.
7. g) Market linkages — Facilitating connections between farmers, input suppliers and potential buyers to support the entire agricultural value chain.

 Climate-smart agriculture

In response to challenges posed by climate change, the concept of climate-smart agriculture has emerged.

This approach aims to increase productivity sustainably, enhance resilience and reduce greenhouse gas emissions where possible. Key practices include:

Conservation agriculture

Minimises soil disturbance, maintains permanent soil cover and practices crop rotation to improve soil health and water retention. This is extensively practiced through Pfumvudza/Intwasa.

Use of drought-tolerant varieties – Planting crop varieties bred to perform well under water stress conditions.

Water harvesting

Implementing techniques like contour ridges and small dams to capture and store rainwater for use during dry spells.

Agroforestry

Integrating trees into croplands to improve soil fertility, provide additional income streams and sequester carbon.

Crop diversification

Growing a variety of crops to spread risk and improve overall farm resilience.

Importance of continuous learning and adaptation

Agricultural science is continually evolving, with new research findings and technologies emerging regularly. Successful farming in today’s world requires a commitment to ongoing learning and adaptation. Farmers are encouraged to:

1) Regularly engage with local extension officers for up-to-date, science-based advice.

2) Attend field days and agricultural exhibitions to learn about new varieties and technologies.

3) Participate in farmer-to-farmer learning opportunities to share experiences and best practices.

4) Keep detailed records of farm activities, inputs and yields to inform future decision-making.

By embracing scientifically proven agronomic practices, leveraging available support services and remaining open to new evidence-based ideas and technologies, farmers can optimise their productivity while ensuring long-term sustainability.

As preparations for the summer cropping season begin, remember that the foundation of successful farming lies in understanding and applying sound scientific principles to your unique farm conditions.

Mr Adalph Chikaka is the Agricultural Marketing Authority (AMA)’s business development manager. He can be contacted on email: achikaka@ama.co.zw. Word From The Market is a column produced by AMA to promote market-driven production