Soil moisture is an important factor that affects terrestrial vegetation ecosystems and biological growth and development, and water deficit is one of the major environmental factors threatening vegetation restoration in the Loess Plateau. To determine the change in the soil water deficit characteristics from farmland to forestland on the Loess Plateau, in this study, we measured the soil water storage and deficit in abandoned grassland, shrubland, pioneer forestland and climax forestland along with vegetation succession. The results showed that the soil water content and the soil water storage with natural vegetation recovery from the abandoned grassland to shrubland and forestland showed a gradual declining trend, while on the contrary, the soil water deficit was increasing during succession, it was more severe in the deep soil than in the shallow soil layers, and the soil water deficit in July and September of the rainy season as well as that the vigorous growing period of plants was more serious than that in May and November, which are in the non-rainy season of the Chinese Loess Plateau. The vegetation types, soil texture and soil depth were the key factors affecting the soil water deficiency status in the process of vegetation succession. The results could have great potential in the sustainable development of forestry and provide a theoretical basis for effective water management and reasonable vegetation restoration in arid and semiarid loess regions.

The vegetation restoration is very important for the stability of the ecological system structure and function in the loess region of North Shaanxi Province. Natural restoration and artificial restoration are the two primary modes for vegetation recovery and soil quality improvement in this region. In this study, two adjacent watersheds with similar ecological environment conditions but different restoration modes were selected for research; and one watershed adopted natural restoration (He Gou watershed) and the other adopted artificial restoration (Chai Gou watershed). According to the study of soil stoichiometric characteristics and soil quality after the vegetation restoration in these two watersheds, the results showed: (1) Compared with the natural restoration, artificial restoration was more effective in increasing the content of SOC and TN, but insignificantly effective in increasing the content of TP. (2) The ratios of soil C:N, C:P and N:P showed a decreasing trend with the soil depth increased at these two restoration modes. (3) in the 0 -60 cm soil layer, the soil quality using the artificial restoration mode was better than the natural restoration, especially for the soil layer beneath 20 cm. (4) The minimal data set on the soil quality evaluation in the study area included 5 indicators including SOC, CWHC, AK, SWC and AP. The minimal data set showed a linear relation with the total index data set (y=0.829x+0.058，R 2=0.76) and the minimal data set can reflect the soil quality more sensitively than the total indicators data set.

Soil moisture is an important factor that affects terrestrial vegetation ecosystems and biological growth and development, and water deficit is one of the major environmental factors threatening vegetation restoration in the Loess Plateau. To determine the change in the soil water deficit characteristics from farmland to forestland on the Loess Plateau, in this study, we measured the soil water storage and deficit in abandoned grassland, shrubland, pioneer forestland and climax forestland along with vegetation succession. The results showed that the soil water content and the soil water storage with natural vegetation recovery from the abandoned grassland to shrubland and forestland showed a gradual declining trend, while on the contrary, the soil water deficit was increasing during succession, it was more severe in the deep soil than in the shallow soil layers, and the soil water deficit in July and September of the rainy season as well as that the vigorous growing period of plants was more serious than that in May and November, which are in the non-rainy season of the Chinese Loess Plateau. The vegetation types, soil texture and soil depth were the key factors affecting the soil water deficiency status in the process of vegetation succession. The results could have great potential in the sustainable development of forestry and provide a theoretical basis for effective water management and reasonable vegetation restoration in arid and semiarid loess regions.