How Adding Biochar Helps Bacteria Boost Nutrients in Spinach Grown with More CO2

Jim Crocker
17th August, 2024

How Adding Biochar Helps Bacteria Boost Nutrients in Spinach Grown with More CO2

Image Source: Natural Science News, 2024

Key Findings

  • The study by Nanjing University found that biochar application at 1.5% significantly increased beneficial soil bacteria under elevated CO2 conditions
  • Biochar improved soil nutrient levels, notably nitrogen, phosphorus, and potassium, under higher CO2
  • Spinach grown with biochar under elevated CO2 showed enhanced growth, photosynthetic pigments, and higher essential nutrient concentrations in roots and shoots
Global climate change is anticipated to shift soil bacterial community structure and plant nutrient utilization. A recent study conducted by Nanjing University[1] investigated the effect of biochar amendment on soil bacterial community structure, spinach growth, physiology, and soil and plant nutrient status under two CO2 concentrations (400 and 600 μmol mol-1). This study provides valuable insights into how biochar can be used to enhance nutrient use efficiency in crops under elevated CO2 conditions. Biochar is a carbon-rich product obtained from the pyrolysis of organic materials such as agricultural waste. It has been known to improve soil health and productivity by enhancing water holding capacity, pH buffering, and nutrient storage[2]. However, the underlying mechanisms by which biochar influences soil bacterial communities and nutrient enhancement under elevated CO2 have not been well understood. In the study, biochar was applied at rates of 0%, 0.5%, and 1.5% to soil planted with spinach. The researchers observed that biochar application at 1.5% significantly increased the abundance of bacterial communities responsible for growth and nutrient uptake, such as Firmicutes (42.25%), Bacteroidetes (10.46%), and Gemmatimonadetes (125.75%), compared to the control under elevated CO2 conditions. Interestingly, the abundance of Proteobacteria decreased by 9.18% under the same conditions. This shift in bacterial community structure suggests that biochar creates a favorable environment for beneficial bacteria, which in turn enhances nutrient availability and uptake by plants. The study also found that soil available nitrogen (N), phosphorus (P), and potassium (K) significantly increased in higher biochar-amended treatments under elevated CO2. This is consistent with previous findings that biochar can improve nutrient retention in soils[3]. In the context of climate change, where elevated CO2 levels are expected, such improvements in nutrient availability can be crucial for maintaining crop productivity. Spinach plants grown under elevated CO2 and biochar conditions exhibited notable enhancements in growth and photosynthetic pigments compared to those grown under ambient CO2 conditions. However, there was variability in leaf gas exchange attributes, indicating that while biochar and elevated CO2 can promote growth, they may also affect physiological processes differently. One of the significant findings of the study was the enhanced concentration of essential nutrients in spinach roots and shoots due to biochar amendment under elevated CO2. The concentrations of zinc, magnesium, manganese, potassium, calcium, copper, and iron in the plant tissues increased substantially. For example, zinc concentration increased by 494.99% in roots and 155.33% in shoots, while iron concentration increased by 717.63% in roots and 177.90% in shoots. This nutrient enhancement is crucial because elevated CO2 has been shown to reduce nutrient concentrations in plants[4]. Therefore, biochar amendment can counteract the negative effects of elevated CO2 on nutrient content. The study's findings align with previous research that has shown biochar's potential in improving soil properties and nutrient retention. For instance, biochar has been found to reduce nitrogen leaching and increase microbial biomass and enzyme activities in tea soils[3]. These microbial responses to biochar are likely driven by changes in soil pH, which strongly correlate with microbial biomass and activity. In conclusion, the study by Nanjing University provides valuable insights into how biochar amendment can enhance soil bacterial community structure and nutrient use efficiency in crops under elevated CO2 conditions. By increasing the abundance of beneficial bacteria and improving nutrient availability, biochar can help mitigate some of the adverse effects of climate change on crop productivity. These findings contribute to a deeper understanding of ecological dynamics and offer promising pathways for future research and agricultural practices.

AgricultureEnvironmentPlant Science

References

Main Study

1) Effect of biochar amendment on bacterial community and their role in nutrient acquisition in spinach (Spinacia oleracea L.) grown under elevated CO2.

Published 14th August, 2024

https://doi.org/10.1016/j.chemosphere.2024.143098

Related Studies

2) Evaluating fundamental biochar properties in relation to water holding capacity.

https://doi.org/10.1016/j.chemosphere.2023.138620

3) Microbial mechanism of biochar addition on nitrogen leaching and retention in tea soils from different plantation ages.

https://doi.org/10.1016/j.scitotenv.2020.143817

4) Climate Change, Crop Yields, and Grain Quality of C3 Cereals: A Meta-Analysis of [CO2], Temperature, and Drought Effects.

https://doi.org/10.3390/plants10061052


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