Abstract Recent climatic trends in the Southern microregion of Nyírség in Hungary indicate an increase in aridity, which threatens the persistence of native woody vegetation over the next 50–100 years. Black locust ( Robinia pseudoacacia L.) is gaining ecological and silvicultural importance due to its rapid growth, drought tolerance, and ability to develop and survive in degraded sandy soils. This study evaluated the effects of various organic and inorganic fertilization treatments on the early growth of black locust seedlings and rhizosphere soil properties in a small-plot open-field experiment near Debrecen. Shoot height, basal stem diameter, soil organic carbon (SOC), pH and AL-extractable macro elements (K, P, Ca, and Mg) were monitored over 2.5 years. Low-dose mineral fertilizer, high-dose humic acids, sewage sludge in compost, and wool pellets significantly enhanced growth relative to the control. In contrast, bacterial inoculants showed moderate effects, consistent with slower microbial action. Strong correlations between soil pH, SOC, AL-extractable nutrients—especially Mg—and sapling growth parameters emerged from the second sampling onward. Notably, a positive correlation between soil pH and AL-extractable Ca strengthened over time (1st : r = 0.253, p = 0.63, 2nd : r = 0.311*, p = 0.021; 3rd : r = 0.789**, p < 0.001; 4th : r = 0.874**, p < 0.001). These results highlight the crucial role of soil nutrient availability in the early development of woody plants. Organic amendments, such as sewage sludge compost and wool pellets, offer viable alternatives or supplements to mineral fertilizers, supporting the preservation of soil quality and sustainable nutrient management in reforestation and land reclamation.
Kocsis et al. (2026) studied this question.