Miscellaneous Archives - Hygrotech (Zambia)

Biofumigation Explained

Hygrotech Zambia — Fri, 03 Jul 2026 13:08:51 +0000

Biofumigation has become an increasingly popular biological alternative for managing soil-borne diseases, nematodes, and certain weed seeds. By incorporating specific Brassica crops into the soil, growers can improve soil health while reducing pathogen pressure before planting the next crop.

“Biofumigation is the beneficial use of green manure crops, especially Brassicas, that release natural compounds capable of suppressing soil-borne pests and diseases.” – John N. Matthiessen, CSIRO Entomology, Australia

However, one common misconception remains: not all Brassicas are equally effective for biofumigation.

What Is Biofumigation?

Brassica crops naturally contain compounds called glucosinolates and an enzyme known as myrosinase. While these remain separate in a living plant, chopping and incorporating the crop into the soil causes them to react.

This reaction produces isothiocyanates (ITCs), natural compounds that are chemically similar to those found in some synthetic soil fumigants.

These ITCs can help suppress:

Soil-borne fungi
Harmful nematodes
Certain weed seeds

This makes biofumigation an effective tool for improving soil health before establishing a new crop.

Not Every Brassica Performs the Same

Many growers choose crops such as canola, rapeseed or mustard for biofumigation. While all belong to the Brassica family, research has shown that their ability to suppress soil pathogens varies considerably.

The three main mustard species used in biofumigation are:

White (Yellow) Mustard (Sinapis alba)
Indian (Oriental) Mustard (Brassica juncea)
Black Mustard (Brassica nigra)

Each species contains different levels and types of glucosinolates, resulting in varying concentrations of pathogen-suppressing ITCs.

Why Indian Mustard Stands Out

Research has consistently shown that Indian mustard (Brassica juncea) is one of the most effective biofumigation crops available.

Compared with Yellow Mustard, Indian Mustard contains:

Higher glucosinolate levels
More biologically active ITCs
Greater suppression of important soil-borne pathogens

These characteristics make it a superior option for biological soil management.

Research Proven Results

Trials comparing different Brassica species found significant differences in disease suppression.

Indian Mustard achieved:

100% suppression of:

Rhizoctonia solani
Phytophthora erythroseptica
Pythium ultimum

It also provided excellent suppression of:

White mould (Sclerotinia sclerotiorum)
Fusarium dry rot (Fusarium sambucinum)
Fusarium wilt (Fusarium oxysporum)

By comparison, Yellow Mustard produced substantially lower levels of disease control and, in some cases, performed worse than crops not traditionally used for biofumigation, such as barley.

Researchers concluded that Indian Mustard delivered the lowest disease incidence and the greatest overall reduction in soil pathogens.

Benefits Beyond Disease Suppression

Biofumigation with Indian Mustard offers more than pathogen control.

When incorporated correctly, it also helps:

Increase organic matter
Improve soil structure
Encourage beneficial soil microorganisms
Support healthier soil biology
Reduce reliance on chemical fumigation

Because beneficial microorganisms are less affected by ITCs than many harmful pathogens, Indian Mustard can help create a healthier soil ecosystem over time.

Choosing the Right Biofumigation Crop

Biofumigation can be a valuable addition to an integrated crop management programme, but its success depends on choosing the right species and managing it correctly. Research clearly shows that not all Brassicas provide the same level of disease suppression, making crop selection just as important as establishment and incorporation practices.

By understanding the strengths of different biofumigation crops, farmers can improve soil health, reduce disease pressure, and lay the foundation for healthier, more productive crops in future seasons.

Key Takeaways

Not all Brassica crops provide the same biofumigation benefits.
Indian mustard has consistently demonstrated higher pathogen suppression than Yellow mustard.
Biofumigation can help suppress soil-borne diseases, nematodes, and certain weed seeds.
Successful results depend on choosing the right crop and following good establishment and incorporation practices.
Biofumigation is most effective when used as part of an integrated soil health management programme.

(Written by JJ de Klerk, Technical Marketing Manager)

The post Biofumigation Explained appeared first on Hygrotech (Zambia).

Water Quality & Crops

Hygrotech Zambia — Thu, 07 May 2026 15:10:24 +0000

Understanding pH in Water

Water quality and pH are often mentioned in the same sentence. pH is an indication of the acidity of a solution. It is determined by the number of free hydrogen ions (H⁺) in a solution. The pH of water can vary between 0–14. Where pH < 7, it is acidic; when pH > 7, it is basic; and when pH = 7, it is neutral.

pH is a logarithmic function, which means that when the pH falls by 1 unit, the solution becomes 10 times more acidic. When the pH falls by 3 units, the solution becomes 1,000 times more acidic. The pH of spray water can easily be measured with a portable Eutech pH meter available at Hygrotech.

What is Electrical Conductivity (EC)?

A common mistake made by farmers is referring to water as “hard” based on a high pH and high salt content. Electrical conductivity (EC) measures the capacity of water to conduct an electrical current and is directly related to the total dissolved salts (TDS) in water. Salts dissolve into positively charged ions and negatively charged ions, which conduct electricity.

The EC of spray water can easily be measured with a portable Eutech EC meter available at Hygrotech. Although this test does not identify the ions present, it does show if there is a potential problem.

EC vs Hard Water

Do not confuse salt concentration with the hardness of water. Hard water is caused by positively charged minerals, primarily calcium (Ca²⁺) and magnesium (Mg²⁺), which are both multivalent ions.

Monovalent ions like Na⁺ and Cl⁻ also form part of the EC of a solution, but do not contribute to the hardness of water. It is possible to have an EC > 225 mS/m, which would normally be considered hard water, but it might be that only 25 mS/m comes from Ca²⁺ and Mg²⁺, in which case it should actually be considered soft water. Generally, spray water with an EC < 75 mS/m is considered soft water.

When the EC of spray water is higher than 75 mS/m, it is advisable to test for antagonising cations like calcium and magnesium at an external environmental laboratory.

How Hard Water Affects Pesticides

A greater concentration of Ca²⁺ and Mg²⁺ results in hard water. If a pesticide is negatively charged, these minerals will bind to the pesticide, reducing its effectiveness. Herbicides like Glyphosate are subject to these types of bonds in water.

To overcome this effect, ammonium sulphate (AMS) is used to increase the herbicide’s efficacy. AMS also binds to cations and adjusts the pH so that the herbicide is taken up across the leaf surface.

Understanding Buffer Capacity

It is also important to consider the buffer capacity of the spray water. Buffer capacity basically tells you how much acid or base can be added before the pH starts changing. You might find that when adding the recommended amount of acidifier to your spray water, the pH stays the same. You might even add double the recommended dose before the pH drops.

If your spray water has a high buffer capacity, you would need to add a large amount of acidifier before the pH starts to change. If your spray water has a low buffer capacity, the pH will drop instantly when adding an acidifier, and you might over-acidify the water without realising it.

Carbonates and Bicarbonates in Spray Water

Carbonate (CO₃²⁻) and bicarbonate (HCO₃⁻) ions are the main culprits influencing buffer capacity. This is because bicarbonates and carbonates react with the hydrogen ions (H⁺) from the acid, preventing them from lowering the pH. Once all the bicarbonates and carbonates have reacted with H⁺, the acid is free to lower the pH.

(Written by San-Mari Louw)

The post Water Quality & Crops appeared first on Hygrotech (Zambia).

Hygrotech Supports Upcoming Farmers

Hygrotech Zambia — Tue, 07 Jan 2025 14:11:37 +0000

Together we can grow quicker!

Hygrotech, with the support of the Limpopo Department of Agriculture and Rural Development in Venda under the coordination of Ms Prudence Nenweli, visited a group of farmers in Matangari village. Farmers were able to share the challenges they face in vegetable production.

On the second visit, 25 farmers were given gift packages as a support initiative.

The gift packages included hybrid seeds of high yield and quality seeds with good disease resistance, so as to observe their differences in performance compared to standard cultivars. Hygrotech was impressed by the attendance and enthusiasm farmers have in growing vegetables.

Image 1: Farmers excited about the generous gift boxes supplied by Hygrotech.

Image 2: Farmers sharing information, ideas and concerns.

Image 3: Farmers attended the project in numbers, with enthusiasm and willing to learn more about vegetable farming.

Image 4: What a way to start! Gift boxes filled with various high quality vegetable seeds.

Reach out for support

Hygrotech offers a professional team of Sales Representatives, ready to assist and help you find the right seeds for your needs.

Find a Sales Rep

(Written by Dr. Martin Maboko)

The post Hygrotech Supports Upcoming Farmers appeared first on Hygrotech (Zambia).

Pollinator Safety

Hygrotech Zambia — Tue, 06 Feb 2024 09:38:06 +0000

Do’s

Always follow the label instructions and pay special attention to pollinator warnings or precautions.
Interrogate Agri-Intel (www.agri-intel.com) for pesticides that are registered for the purposes required; the labels are, however, the final port of call for safety and use instructions.
Apply directly to the target plant and ensure minimal spray drift.
Apply early evenings when bees have returned to their hives.
Communicate with all beekeepers in the area and inform them of planned spray programmes.
Scout the area for pollinators before applying.
Be aware of spray residues and the amount of time they may still be toxic to bees.
Remember that systemic insecticides have long periods of residual activity.
Ensure that flowering plants or weeds that are attractive to bees are not in the area of application.
Familiarize yourself with the product. Insecticides are the most hazardous to bees while fungicides and plant growth regulators have less impact.
Ensure that equipment has been correctly calibrated for the application.
Ensure to practice integrated pest management and only apply pesticides when absolutely necessary.

Don’ts

Apply directly onto flowers. If no other option exists but to apply pesticides in bloom, do not apply directly onto the flowers.
Apply while pollinators are active in the area that needs to be treated.
Apply at night because inversion can prevent successful deposition of pesticides onto the target and cause serious drift.
Apply any product that is not registered for the specific crop or application method.
Apply during windy conditions, especially if foliar application is the only available option.
Mix pesticides with substances that could be a lure for pollinators.
Apply pesticides to standing water bodies.