Effect of a cellulose decomposing bacterium, humic acid, and wheat straw on Cucurbita pepo L. growth and soil properties

Abstract

Due to the increasing need for food security across the world, it has become urgent to develop a combination of different agricultural inputs that can enhance higher crop productivity under plant growth limiting environment. Thus, the effects of a cellulose decomposing bacterium (Geobacillus stearothermophilus SSK-2018), humic acid, and wheat straw were evaluated on the growth of Cucurbita pepo L. (squash) under an arid land condition during a two-year (2020 and 2021) field trials. Laboratory analysis revealed that G. stearothermophilus SSK-2018 was a gram-positive bacterium capable of promoting plant growth by producing indole-3-acetic acid as well as enzymatic activities including cellulase, amylase, protease, gelatinase, and phosphatase. Consequently, the inoculation of SSK-2018 significantly increased (P ≤ 0.05) squash’s fresh stem, leaf, and root weights by 14.70%, 18.63% and 11.13%, respectively, compared to the uninoculated control. Humic acid significantly (P ≤ 0.05) increased fresh stem, leaf, and root weights by 78.78%, 62.5% and 63.74%, respectively, compared to the control. Wheat straw also significantly increased (P ≤ 0.05) fresh stem, leaf, and root weights by 52.68%, 30.32% and 42.30%, respectively, compared to the control. Furthermore, the combinations of the treatments, including humic acid and straw, SSK-2018 and straw, and humic acid, SSK-2018 and straw, significantly increased the growth of squash. Soil properties including bulk density, moisture content, and basic cations were also significantly (P ≤ 0.05) improved by humic acid, SSK-2018 and wheat straw. This study suggests that like NPK, bio-organic treatments including SSK-2018, humic acid and straw, can equally improve plant’s fresh stem, leaf, and root weights as well as soil’s bulk density, moisture content, and basic cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺). Therefore, the present study recommends the continuous use of bio-organic amendments to achieve a sustainable improvement in plant growth and soil properties under arid land conditions. However, the continuous use of soil bio-organic amendments should be regularly monitored for potential increase in greenhouse gas emissions that may be at par with that of N fertilizers.

Keywords:

• food security
• Geobacillus stearothermophilus
• squash growth
• organic materials
• cellulose decomposition
• arid land

Acknowledgments

This research work was funded by Institutional Fund Projects under grant no. (IFPIP: 685-155-1443). The authors gratefully acknowledge technical and financial support provided by the Ministry of Education and King AbdulAziz University, DSR, Jeddah, Saudi Arabia. Notes on contributors Suleiman Kehinde Bello had his PhD in Field Crops and Soil Science from the Department of Arid Land Agriculture, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. Samir Gamil Al-Solaiman is a Professor of Soil Chemistry and Fertility at the Department of Arid Land Agriculture, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. Kamal Ahmed Mohamed Abo-Elyousr is a Professor of Plant Pathology at the Department of Arid Land Agriculture, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/23311932.2023.2246182.

Additional information

Funding

This research work was funded by Institutional Fund Projects under grant no. (IFPIP: 685-155-1443) by the Ministry of Education and King AbdulAziz University, DSR, Jeddah, Saudi Arabia.