Comparative Impacts of Organic and Inorganic Fertilizers on the Restoration of Rangeland in the Semi-Arid Regions of Saudi Arabia

Rangeland degradation in arid and semi-arid regions is a serious ecological challenge, damaging soil health and reducing plant growth. This study evaluated the comparative effects of Almarai organic and inorganic fertilizers on the growth performance of three native rangeland species across three semi-arid locations of Saudi Arabia, including Al-Tamiryyat (Al-Jouf), Al-Sahwa (Al-Madina), and Al-Fuhaihil (Thadiq), in a randomized complete block design. The study revealed that fertilization significantly influenced plant height and stem diameter, with organic fertilizers yielding superior results compared to inorganic treatments across most regions (p < 0.001). Specifically, plant height for Pl3 demonstrated a substantial increase of 71% and 159% under Almarai organic fertilization in the Al-Tamiryyat and Al-Fuhaihil regions, respectively, while inorganic fertilization yielded an improvement of 61% and 132% only in the Al-Tamiryyat and Al-Fuhaihil sites, respectively. Stem diameter also exhibited significant growth under both fertilizer types (p < 0.001), with the most significant increases observed in Pl1, particularly under organic amendment in Al-Tamiryyat (184%) and inorganic fertilizer in Al-Sahwa (151%). Conversely, the effect of fertilization on crown size ratio was minimal in Al-Tamiryyat and Al-Fuhaihil (p > 0.05) but was significantly improved in Al-Sahwa region (p < 0.001) under Almarai organic fertilization. Conclusively, results of current research suggest that organic fertilization is effective way of restoring rangelands in arid environments compared to inorganic amendments.