Comparative Effects of Three Different Fertilizers on Improving Soil Characteristics and Growth Performances of <em>Mahonia fortunei </em>(Lindl.) Fedde in Rocky Desertification Areas in Guangxi Zhuang Autonomous Region, China

Rocky desertification is a form of land degradation occurring in tropical and subtropical regions, characterized by the destruction of vegetation and soil erosion caused by natural or anthropogenic factors, resulting in extensive areas of exposed bedrock. Field tests were conducted in three townships—Bolin, Longlai, and Longlei—within Fengshan County, Guangxi Zhuang Autonomous Region, China, to evaluate the effects of various fertilizers (compound fertilizers, slow-release fertilizers, and bio-organic fertilizers) on soil fertility, enzyme activity, bacterial diversity, and the growth performance of Mahonia fortunei (Lindl.) Fedde, aiming for ecological restoration and economic development. The findings indicated that the use of bio-organic fertilizers significantly enhanced soil fertility and enzyme activities, specifically urease, sucrase, and acid phosphatase, followed by slow-release fertilizers, and subsequently compound fertilizers. In comparison to the use of compound fertilizers, bio-organic fertilizers can enhance the organic matter content by 30.4%, 15.73%, and 21.83%, and the total nitrogen content by 19.4, 3.82, and 2.66 g/kg in the Bolin, Longlai, and Longlei regions, respectively. In the Bolin and Longlai regions, the utilization of bio-organic fertilizer yielded the maximum total phosphorus concentration, surpassing compound fertilizer by 85.45% and 53.37%, respectively. In the Longlei region, the total phosphorus concentration in the soil was about equivalent to that of compound fertilizer and bio-organic fertilizer, measuring 1.107 and 1.113 g/kg, respectively. Furthermore, the soil&#039;s available nitrogen, phosphorous, and potassium reached their peak levels when bio-organic fertilizers were applied. Urease activity increased by 181.82%, 29.29%, and 25.83%, while sucrase activity rose by 201.52%, 33.13%, and 26.22%, respectively, compared to the administration of compound fertilizer. The activity of acid phosphatase increased by 27.85%, 25.59%, and 40.49%, individually, when compared to the application of compound fertilizer. Unlike compound fertilizer, bio-organic fertilizer improved the diversity and abundance of beneficial soil microorganisms while promoting the growth of Mahonia fortunei (Lindl.) Fedde. In Bolin, Longlai, and Longlei, the concentrations of Boron (B), Copper (Cu), Zinc (Zn), and Iron (Fe) in the soil peaked with the application of slow-release fertilizers. Specifically, the Cu content increased by 151.65%, 69.97%, and 24.51%, respectively, in comparison to the use of compound fertilizers; the levels of these micronutrient elements were more comparable when bio-organic fertilizers and compound fertilizers were utilized. In the Longlei region, the use of slow-release fertilizers resulted in Mahonia fortunei (Lindl.) Fedde achieving a maximum plant height and ground diameter of 3.62 cm and 4.5 cm, respectively, surpassing the measurements obtained with compound fertilizer by 9.04% and 18.42%. This research illustrated the application of bio-organic fertilizer and slow-release formulations. Fertilizer significantly contributed to the amelioration of rocky desertification and the enhancement of vegetation, thereby offering a more effective solution for the restoration of rocky desertification flora, particularly for the cultivation of understorey cash crops.