Fig. 4. Surface (0–20 cm) soil moisture contents (g water/100 g soil, i.e., %) during the summer of 1991 for high FN plots receiving cover crop and kill-date treatments of: rye killed early (RYP) or late (RYL), vetch killed late (VTL), vetch–rye mixture killed early (MXP) or late (MXL), or no cover (CKL).