Black Chalk with humic acids - for humus restoration and pH regulation
Deacidification and humus restoration in one
An innovative combination of lake chalk with organic carbon and humic acids. The product not only regulates pH but also supports water retention in the soil. It improves the soil's crumb structure and increases its ability to hold water in the root zone.
Deacidification and humus restoration in one
Product parameters
| CaCO₃ content | 82% |
|---|---|
| Reactivity | 96% |
| Organic carbon and humic acids | up to 15% |
| Granule size | 3–6 mm |
| Spreading width | up to 36 m |
Why choose Black Chalk?
Bluebird Black Chalk is an organic-mineral fertilizer based on unique lake chalk. Reactive lime instantly regulates pH and reduces aluminium (Al³⁺) toxicity, while the addition of organic carbon plus humic acids — humin and fulvic — acts as a biological nutrient for soil microorganisms.
Humic acids modify the soil structure, gluing fine particles into larger aggregates and creating a crumb structure. As a result, water stays in the root zone much longer.
The synergy of soft lake chalk and organic carbon strongly stimulates root system development, while releasing phosphorus locked in the soil and activating microbiological life.
- Deacidification + humus restoration
- Increases water retention in the soil
- Activates microbiological life
- Releases locked phosphorus
Application
See in which situations Black Chalk performs best.
Rapid increase in soil pH.
Active support for the soil microbiome.
Fast release of phosphorus chemically bound in the soil.
Intervention use at any stage of plant development.
Support for the decomposition of crop residues.
Frequently asked questions
Practical answers about this product. Match rate and timing to the soil test, crop and current product label.
Can Black Chalk be applied as an intervention treatment during crop growth?
Yes, the Bluebird product description lists intervention use at any stage of plant development. The suitable rate and method still depend on the crop, soil condition and current product label, so intervention use should not be treated as a universal dose recommendation.
Is Black Chalk certified for use in organic farming?
The product is presented in Bluebird's organic category and described as intended for organic farming, but the site does not replace the current certification documentation. A certified farm should verify the product's present status and permitted use with its certification body before application.
How does Black Chalk improve soil water retention during drought?
Black Chalk combines lake chalk with organic carbon and humic acids. Bluebird describes these components as supporting crumb structure and larger aggregates, helping water remain in the root zone longer; the size of the effect depends on soil texture, organic matter and rainfall.
What role do humic and fulvic acids in Black Chalk play in soil structure?
The product description says that humic and fulvic acids help join fine soil particles into larger aggregates and support a crumb structure. This can improve the soil's ability to retain water, but the outcome depends on the starting soil and the wider management system.
How does Black Chalk help rebuild soil humus and biological life?
Black Chalk supplies organic carbon and humic substances; Bluebird describes them as a biological support for microorganisms and as part of rebuilding humus. It can support soil biological activity, but rebuilding humus also requires long-term organic-matter and soil-management practices.
Need technical documentation?
In the Attachments section you will find product data sheets, safety data sheets, EU declarations of conformity and technical specifications available to download as PDF files.