Background In hilly-gullied area of northern Shaanxi, the soil and water erosion is serious, Returning Farmland into Forest and Grassland is an important policy to improve the environment, brings great positive changes to the ecological environment. Northern Shaanxi including Yulin and Yan'an is one of the serious soil erosion regions, thus northern Shaanxi was selected as the pilot area to implement the policy of Returning Farmland into Forest and Grassland in 1999, and it was completely proceeded in 2002. To study the impact effects of this policy, this research focused on the ecosystem service value (ESV) of northern Shaanxi affected by this policy, and analyzed the characteristics of the ESV changing pattern of northern Shaanxi.

Methods The studied area of northern Shaanxi is located at E 107°15'-110°15' and N 35°02'-39°35. The data was from the database of 1:10 land use in China in 2013. The ESV equivalent coefficient per unit area of northern Shaanxi terrestrial ecosystem was firstly revised by appropriate biomass factors, and then refined using the proportional relation between type of land use and subtype of land use. The ESV per unit area of northern Shaanxi terrestrial ecosystem was calculated by grain production. Then ESV was calculated by multiplying the area of different type of land use in northern Shaanxi by ESV per unit area.

Results 1) In northern Shaanxi, the land-use change occurred in the cultivated land, the forest and grassland, the cultivated land area reduced by 2 811 km² from 1985 to 2013, the rate of change was -9.98%. The area of forest and grassland increased by 1 392 km² and 2 417 km² respectively in 1985-2013, the rate of change was 12.85% and 7.10%, respectively. The areas changed clearly in 2000-2013, the areas increment of forest and grassland in 2000-2013 was 7 times and 2 times of that in 1985-2000 respectively. The construction of land use in northern Shaanxi was observably influenced by the policy of Returning Farmland into Forest and Grassland. 2) The ESV of northern Shaanxi was improved clearly in 1985-2013, the ESV increment of forest and grassland was 2.52 billion and 1.39 billion Yuan respectively, the increment of 2000-2013 was three times of the increment of 1985-2000.

Conclusions The ESV transformation of forest, grassland and arable land was drastic in 2000-2013, it was corresponding to the time of Returning Farmland into Forest and Grassland energetically, and the ESV perunit area of northern Shaanxi terrestrial ecosystem is positively influenced by the policy of Returning Farmland into Forest and Grassland.