Advances and perspectives of research on soil moisture response to afforestation: A review

The soil moisture (SM) balance was affected by afforestation. In this study, the CiteSpace software was used to review the literatures on the impact of afforestation on SM, and we further present research findings on the Loess Plateau (LP) as follows: 1) the spatio-temporal heterogeneity of SM varies depending on the research scale; 2) the presence of a dried soil layer significantly hinders deep SM recharge; 3) the accumulation of net primary productivity (NPP) may be occurring at the expense of SM. The following research topics are discussed: 1) the recharge and consumption of deep SM in LP; 2) the green water footprint and its shortage degree of non-crop greenery for evaluating SM allocation and use; 3) the development of inclusive models encompassing different spatial scales to assess the limits of Soil Water Carrying Capacity for Vegetation (SWCCV).