A continuous long-term field experiment (2008–2018) was conducted in Xinjiang, north-western China, to assess the impact of farmyard manure (FYM) and inorganic fertilizers on the sustainable biomass yield of sweet sorghum cultivar (Xingaoliang No3)and soil chemical properties. Seven treatments, associated with nitrogen (N), phosphorus (P),potassium (K), FYM, and their different combination, were compared with the control plot (CK). As a result, the treatments NP, PK, NK, NPK and NPKM significantly increased the average biomass yields by 30-48% over CK. The 12 t/ha FYM per year with NPK (NPKM) increased both the yield and total soluble solids (TSS) by 48% and 7.9% respectively, while the 18 t/ha/year application rate of FYM had an adverse effect on yield. Stem TSS, soil available N and K for all treatments decreased while soil organic carbon, soil total salt and the available P for FYM ap- plied treatments increased over the years. The soil pH stabilized at 7.8–8.2 at the end. In conclusion,the 12 t/ha/year of FYM is the most efficient rate for a single application or incorporation with inorganic fertilizers. A more reason- able application rate of N and K fertilizer to increase the yield and irrigation rate to reduce soil salt needs for further investigation.
