Effect of Straw Removal and Irrigation Systems on Mycorrhizal Activity

Resumo

Introduction: Sugarcane is a globally important crop, and management practices such as straw removal for energy production can directly impact soil quality and beneficial microorganisms. Arbuscular mycorrhizal fungi (AMF) are crucial for soil health, promoting nutrient uptake by plants and establishing symbiotic relationships that increase the crop’s resilience under environmental stresses. However, the effects of straw removal and different irrigation systems on mycorrhizal activity in soil are not well understood. Objective: The objective of this study was to evaluate the influence of different irrigation systems and straw removal regimes on mycorrhizal activity in sugarcane cultivation areas. Methodology: The study was conducted in sugarcane fields in the Goianésia region, Goiás, Brazil. Soil samples were collected from areas irrigated by sprinkler, pivot, and rainfed systems, with and without straw removal for one and two years. AMF spore density in the soil was determined using wet sieving and centrifugation techniques, while mycorrhizal colonization in the roots was assessed using root clearing and staining methods. Statistical analyses were performed to detect significant differences between treatments. Main Results: Results indicated that two years of straw removal significantly increased AMF spore density, especially in pivot-irrigated areas. However, the rate of mycorrhizal colonization in plant roots showed no statistical differences between treatments. This suggests that while straw removal influences spore production in response to environmental changes, plants did not experience significant stress, as indicated by the colonization rate. Long-term straw removal may create a more stressful environment for AMF, which increases spore production as a survival strategy. Conclusion: Prolonged straw removal affects mycorrhizal activity, increasing spore density in the soil. However, root colonization by mycorrhizae was not directly impacted, indicating that the environmental conditions created by different irrigation systems and straw removal regimes were not sufficiently adverse to induce significant plant stress. These findings highlight the importance of sustainable management practices to maintain soil health and agricultural productivity.