A.EC和 B.pH和 C.EC和pH
A.0.02,0.2 B.0.05,0.5 C.0.08,0.8
A.100m,2m B.50m,2m C.100m,1m
A.20cm,较大 B.30cm,较大 C.20cm,较小
A.1,60B.2,70C.3,80