How to evaluate impact of biochar in soil when growing spinach?

Application of biochar to improve soil health is one of the suggested way to get the better crop yield. At the same time, there is a need to know the specific amount of biochar to apply for the highest yield. A group of Ukrainian, Czech and Kazakstan plant researchers worked on this question and found the answer.
Maryna Kuzmenko, Co-Founder at Petiole
by Maryna Kuzmenko | 5th September 2022 | 2 mins read
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What is biochar and why to apply biochar?

Biochar is obtained by pyrolyzing biomass.  It is a black, carbon-rich material obtained after thermally treating of biomass materials in zero- or limited- oxygen conditions using a process called pyrolysis. By definition, biochar is applied in a way that avoids its rapid oxidation to CO2.

When applied to land, biochar is not only a carbon sink, but in fact can act as a soil improver by increasing the water and nutrient- holding capacity of the soil. This is why its use in agriculture includes fertilizer component or direct soil application. Additionally, biochar is applied for animal feeding, manure treatment (for example, as additive for bedding, composting, storage or anaerobic digestion).

Biochar looks like a charcoal and is made by burning organic material from agricultural and forestry waste

However, for swift implementation of pyrogenic carbon capture and storage (PyCCS), biochar use in agriculture needs to deliver co-benefits, for example, by improving crop yields and ecosystem services and/or by improving climate change resilience by ameliorating key soil properties. Agronomic biochar research is a rapidly evolving field of research moving from less than 100 publications in 2010 to more than 15,000 by the end of 2020. One of the recent research papers about the evaluation of the impact of varied biochars produced from M.  giganteus waste and application rate on the soil properties and physiological parameters of Spinacia oleracea L, features Petiole Pro as the digital leaf area meter.

Abstract of the research paper

The use of M.  giganteus in phytoremediation requires treatment of the contaminated biomass, which can be done by pyrolysis to produce biochar. Due to its potentially detrimental properties, the application of biochar in soil remediation must first be evaluated on a test plant to infer how the growth process was affected by the impact on soil parameters. The main goal of the current research was to investigate the effects of waste-derived Miscanthus biochars (from contaminated rhizomes (B1) and aboveground biomass (B2)) on soil properties and evaluate the impact of biochar doses and properties on Spinacia oleracea L. growth. It was revealed that incorporation of B1 at a dose of 5% and B2 at doses of 1, 3, and 5% increased soil organic carbon, pH, K (at 3 and 5%), and O5 (at 5% B2).

Spinacia oleracea L. - Spinach grown in a field

Cultivation of S. oleracea reduced organic carbon, soil pH as a function of biochar dosage, and K, O5, NH4, and NO3 content in all treatments tested. The highest biomass yield was recorded at 3% B2. The photosynthetic parameters indicated that the doses of 3 and 5% B2 led to dissociation of light-harvesting complexes. Increasing the biochar dose did not necessarily increase yield or improve photosynthetic parameters. S. oleracea adapted to the initial stress by incorporating biochar and managed to establish a balance between nutrients, water supply, and light. It is recommended that the effects of biochar on the development of the target crop be evaluated through preliminary trials before biochar is applied at field scale.

How does Petiole Pro help with evaluation of biochar application for spinach production?

As it is directly stated in the paragraph “2.5.2. Harvested parameters” of the Research Paper: The morphological parameters of S. oleracea were measured at the end of the experiment. Total leaf area (cm 2) was estimated using the mobile app Petiole Pro.

Leaf area was estimated with Petiole Pro at the end of the experiment in accordance with the timeline above

Based on the data, obtained with this mobile application the plant scientists have visualised physiological parameters of S. oleracea at the end of the experiment: (a) biomass DW, and (b) plant leaf total area. Different letters on the boxplots within one parameter indicate a significant difference between the values of the different treatments at (at least) p <0.05.

Physiological parameters of S. oleracea at the end of the experiment of biochar application: (a) biomass DW, and (b) plant leaf total area.

The total plant leaf area at harvest depended on the biochar varieties and doses, as presented in the visualisation. The peculiarities are similar to the variation in biomass: the largest leaf total area was recorded when B2 was incorporated at a dose of 3%, which was not significantly different from the result for a dose of 1%. The incorporation of B1 and B2 at a dose of 5% did not improve crop development despite improving the state of soil nutrition.

Our observation shows that an increase in biochar dose does not necessarily lead to enhancement of the plant biomass value at harvest. A similar tendency was shown by Khan et al. (2017). Obviously, before application of biochar at the field scale, preliminary testing of its impact on development of the target crop must be conducted.

Conclusions on biochar application for spinach production

• Biochar derived from waste is important for Spinacia oleracea L. development.

• Biochar from aboveground waste biomass showed better characteristics.

• 3% dose of biochar from waste biomass was the most effective compared to 1 and 5%.

• Biochar enhanced antagonistic interactions between elements’ pairs.

Leaf area estimation of spinach with mobile application Petiole Pro (leaf area meter)

Disclaimer: in this article we used direct quotes from the mentioned Research Paper, please, follow the link to read the full text of the work. **Here **you can get the full list of scientific papers with reference to mobile application Petiole, please.

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