A field experiment was established in 1984 at Changwu, Shaanxi, China, to determine the long-term effects of three annual fertiliser and/or manure treatments [no fertilisation (CK), application of phosphorus (P) fertiliser alone at 26 kg P ha–1, and application of P fertiliser at 26 kg P ha–1 + nitrogen (N) fertiliser at 120 kg N ha–1 + animal manure at 75 Mg ha–1 (PNM)] to alfalfa (Medicago sativa L.) on forage dry matter yield (DMY) from 1985 to 2008 (24 growing seasons), and some soil properties (moisture content, and concentration of organic matter, total N, total P and available P in soil) in 2001, 2004 and 2006. Compared with the unfertilised CK, application of fertiliser and/or manure resulted in a significant increase of forage DMY in 19 of 24 years, with a maximum DMY usually in the PNM treatment. Cumulative DMY over 24 years (from 1985 to 2008) increased linearly in all three treatments, and it was higher by 22.72 Mg ha–1 with PNM and only by 7.78 Mg ha–1 with P compared with the CK treatment. Soil moisture contents in deep soil profiles did not differ among treatments in most cases. Soil organic matter, total N, total P and available P in soil increased with fertiliser and/or manure treatments, especially when PNM was applied over a long period. In conclusion, the findings suggest that combined applications of inorganic fertilisers and organic manure to alfalfa can provide substantial benefits in terms of both forage yield and stand longevity, while also improving soil quality on the Loess Plateau of northern China.