Using Biogas Slurry to Control Root-Knot Pests and Change Soil Ecosystems

Jim Crocker
15th May, 2024

Using Biogas Slurry to Control Root-Knot Pests and Change Soil Ecosystems

Image Source: Natural Science News, 2024

Key Findings

  • The study by the Beijing Academy of Agriculture and Forestry Sciences tested biogas slurry and soil heating to control root-knot nematodes (RKNs) over two years
  • Biogas slurry treatments (BS70 and BS100) significantly reduced RKN disease and promoted watermelon growth, especially in the second year
  • Biogas slurry increased soil nematode diversity but did not enhance the overall complexity of the soil food web
Root-knot nematodes (RKNs) are a significant threat to crop production, causing severe yield losses across various agricultural systems. A recent study conducted by the Beijing Academy of Agriculture and Forestry Sciences explored an innovative method for controlling these pests using biogas slurry and soil heating[1]. This two-year field experiment aimed to assess the effectiveness of this method in suppressing RKN disease, promoting plant growth, and influencing the soil nematode community. The study involved four treatments: an untreated control (CK), a local control method for RKN (CC), soil flooded with 70% biogas slurry (BS70), and soil flooded with undiluted biogas slurry (BS100). In the first year, all three RKN control treatments significantly reduced the root-knot index, with BS70 and BS100 showing continued effectiveness in the second year. Notably, BS70 demonstrated a relative control effect of 74.6%. Interestingly, the application of biogas slurry initially inhibited the plant height of watermelon in the first year. However, in the second year, all RKN control treatments promoted watermelon growth, with stem diameters significantly greater than the untreated control. This suggests a potential delayed positive effect on plant growth following biogas slurry application. The study also examined the impact of biogas slurry on the soil nematode community. Both BS70 and BS100 treatments significantly increased nematode richness and the Shannon index in the second year, indicating a more diverse nematode population. However, the structure index, which measures the complexity of the soil food web, showed no significant difference among treatments. This suggests that while biogas slurry application altered the nematode community, it did not enhance the overall complexity of the soil food web. Principal component analysis revealed that biogas slurry application, particularly under BS70, had a lasting influence on the nematode community. Despite initial concerns about soil pollution from high levels of NH4+-N, heavy metals, and arsenic in the first year, these risks disappeared in the second year, indicating that the soil's natural processes mitigated these effects over time. This study builds on previous research highlighting alternative methods for nematode control. For instance, trans-2-hexenal, a plant volatile, has shown efficacy against Meloidogyne incognita, a common RKN species, in both pot tests and field trials[2]. The use of biogas slurry offers a comparable, environmentally friendly alternative, potentially reducing the need for traditional nematicides, which pose risks to human health and the environment. The findings also align with a broader understanding of the economic and scientific importance of RKNs, which top the list of plant-parasitic nematodes affecting global agriculture[3]. Effective management of these pests is crucial for maintaining crop yields and ensuring food security. Additionally, the study's results are relevant in the context of invasive plants serving as reservoirs for nematodes. For example, the invasive moth plant, Araujia sericifera, has been identified as a host for Meloidogyne incognita in Italy, complicating nematode management efforts[4]. The use of biogas slurry could potentially be integrated into broader pest management strategies, addressing both crop and invasive plant-related nematode issues. In conclusion, the application of biogas slurry combined with soil heating presents a promising method for controlling RKNs and promoting plant growth. This study by the Beijing Academy of Agriculture and Forestry Sciences provides valuable insights into sustainable agricultural practices, offering an effective alternative to traditional nematicides and contributing to the ongoing efforts to manage plant-parasitic nematodes in a more environmentally friendly manner.

AgricultureEnvironmentPlant Science

References

Main Study

1) Flooding soil with biogas slurry suppresses root-knot nematodes and alters soil nematode communities.

Published 15th May, 2024

https://doi.org/10.1016/j.heliyon.2024.e30226

Related Studies

2) Nematicidal Activity of trans-2-Hexenal against Southern Root-Knot Nematode (Meloidogyne incognita) on Tomato Plants.

https://doi.org/10.1021/acs.jafc.6b04091

3) Top 10 plant-parasitic nematodes in molecular plant pathology.

https://doi.org/10.1111/mpp.12057

4) First Report of the Southern Root-Knot Nematode Meloidogyne incognita on the Invasive Weed Araujia sericifera in Italy.

https://doi.org/10.1094/PDIS-06-14-0584-PDN


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