Does Eucalyptus determine agricultural soil quality?

Abstract

AbstractThe agricultural system that incorporates eucalyptus is used by 75% of the agricultural producers in the east of DR Congo (Walungu and Kabare). However, the latter’s perception and results from some studies on the effect of eucalyptus exploitation on soil quality bring out a negative balance. This study characterized the state of soils by determining the soil quality index (SQI) in three land-use types to guide soil fertility management policies. A survey was conducted to collect preliminary data on the historical effect of eucalyptus on the soil from 300 producers. Subsequently, the soils were sampled in the three land-use types and analyzed to assess SQI through a statistical approach based on principal component analysis (PCA). Using R 4.05 package software and crop exploitation as the baseline, the three land-use types were compared using analysis of variance. Out of the 13 considered crucial for SQI assessment, findings highlighted nine soil quality indicators (Al3+, pH, silt, SOC, CEC, H2O, sand, clay, and BD). Soils with eucalyptus (SQI = 0.486 0.07) and crops (0.539 ± 0.034) alone had low SQIs, suggesting unfavorable soils for better production, whereas soils with crop-eucalyptus association had SQI equals to 0.655 ± 0.034, indicating moderate soils. The calculated SQI highlighted soils’ acidity, their ability to maintain plants’ chemical nutrients equilibrium, and clay and sand content as soil quality determinants. To further improve soil conditions, we raised the need to understand the long-term effects of eucalyptus on soils and the appropriate soil management as a result of the aforesaid results.

Keywords

• soil quality index
• soil suitability
• agroforestry
• soil fertility
• eucalyptus
• Walungu