GROWTH, PHOTOSYNTHESIS, AND NUTRIENT UTILIZATION RESPONSES OF SALIX INTEGRA TO FERTILIZATION IN A PLANTATION ALONG THE HUAIHE RIVER IN CHINA

Salix integra Thunb.(Salicaceae) is a perennial deciduous shrub that grows mainly in the riparian areas of the Huaihe River basin in China.where it plays a vital role in conserving water and soil.To optimize the development of S. integra production and devise appropriate fertilization strategies for plantation management, we studied the plant's responses to different nitrogen (N) and phosphorus (P) fertilizer levels in S. integra in the lowland areas in Bangang in Yingshang County, Anhui Province, China.Fertilization experiments were conducted on two-year-old S. integra stands under six treatment levels: T1 (30 g Nm -2 ), T2 (20 g Nm -2 + 15 g Pm -2 ), T3 (30 g Nm -2 + 15 g Pm -2 ), T4 (45 g Nm -2 + 15 g Pm -2 ), T5 (60 g Nm -2 + 15 g Pm -2 ), T6 (15 g Pm -2 ) and a control (CK).The results showed that fertilization significantly enhanced the shrub's growth and photosynthesis.T5 represented the optimal nutrient input for desirable S. integra growth, at which fertilization level the biomasses of the stems, roots, and root stumps were at their maximum.The total biomass under the different treatments was ranked as CK (20.42 thm -2 ) < T2 (21.76) < T1 (22.67) T3 (22.95) T6 (22.96) < T4 (30.20) < T5 (37.64).The applied ratios also considerably impacted the distributions of carbon, nitrogen, phosphorus, potassium, calcium, and magnesium in the roots, root stumps, stems, and foliage of the S. integra stands.Significant differences in soil-available nutrients were also observed across various fertilizer types and amounts, with T5 resulting in the highest NH 4+ -N and NO 3--N concentrations.These findings indicate that supplemental 60 g Nm -2 and 15 g Pm -2 could be applied to young S. integra plantations along the Huaihe River for optimal forest management.