Soil cover improves soil quality in a young walnut forest in the Sichuan Basin, China - Tie, Liehua (Centre de Recerca Ecològica i d'Aplicacions Forestals) ; Feng, Maosong (Sichuan Agricultural University. College of Forestry) ; Huang, Congde (Sichuan Agricultural University. College of Forestry) ; Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals) ; Sardans i Galobart, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals) ; Bai, Wenyu (Sichuan Agricultural University. College of Forestry) ; Han, Dongmiao (Sichuan Agricultural University. College of Forestry) ; Wu, Tao (Sichuan Agricultural University. College of Forestry) ; Li, Wenbing (Sichuan Agricultural University. College of Forestry)