Table 2. Effects of different tillage depths on root morphology traits of rice.

Treatment	Root length (m)	Projected area (m2)	Surface area (m2)	Mean diameter (mm)	Root volume (cm3)	Root tip number
TD14	154.18c	0.07b	0.21b	0.46a	24.24ab	69,590b
TD17	211.33a	0.08a	0.27a	0.41b	27.46a	111,036a
TD20	178.66b	0.07b	0.21b	0.38b	20.87bc	87,496b
TD23	196.53ab	0.07b	0.21b	0.34c	17.15c	112,971a
Y	ns	ns	ns	ns	ns	ns
TD	*	ns	ns	ns	*	*
Y*TD	ns	ns	ns	ns	ns	ns

Note:

Different letters in the same row within the same means the significant differences in P < 0.05. * indicate significant correlations at the 0.05 levels. TD, tillage depth; TD14, tillage depth 14 cm; TD17, tillage depth 17 cm; TD20, tillage depth 20 cm; TD 23, tillage depth 23 cm; Y, year.