Table 2 NO3−−N, NH4+−N and TN contents in the soil.

From: Pipe experiment elucidates biochar application depth affects nitrogen leaching under crop present condition

(a) NO3−–N (mg kg–1)

Depth (cm)

Control

A

B

C

Initial

Last

Initial

Last

Initial

Last

Initial

Last

5

1.29

2.85 ± 0.37

1.27

3.47 ± 1.30 ns

1.23

1.42 ± 0.63 ns

1.29

2.71 ± 0.81 ns

30

1.29

0.93 ± 0.38

1.29

0.74 ± 0.25 ns

1.23

0.63 ± 0.07 ns

1.27

0.65 ± 0.25 ns

55

1.29

0.63 ± 0.02

1.29

0.64 ± 0.06 ns

1.29

0.71 ± 0.16 ns

1.29

0.60 ± 0.01 ns

(b) NH4+–N (mg kg–1)

Depth (cm)

Control

A

B

C

Initial

Last

Initial

Last

Initial

Last

Initial

Last

5

5.81

21.98 ± 8.47

6.80

16.71 ± 6.23 ns

7.25

22.02 ± 2.40 ns

5.81

26.20 ± 9.07 ns

30

5.81

1.27 ± 0.25

5.81

1.56 ± 0.04 ns

7.25

2.76 ± 0.74 ns

6.80

1.03 ± 0.05 ns

55

5.81

1.10 ± 0.09 s

5.81

1.67 ± 0.10*

5.81

1.71 ± 0.10*

5.81

1.26 ± 0.16 ns

(c) TN (g kg–1)

Depth (cm)

Control

A

B

C

Initial

Last

Initial

Last

Initial

Last

Initial

Last

5

0.65

1.02 ± 0.09

0.63

0.84 ± 0.04 ns

0.63

0.90 ± 0.03 ns

0.65

0.89 ± 0.03 ns

30

0.65

0.74 ± 0.02

0.65

0.72 ± 0.03 ns

0.63

0.75 ± 0.02 ns

0.63

0.76 ± 0.02 ns

55

0.65

0.76 ± 0.09

0.65

0.72 ± 0.01 ns

0.65

0.72 ± 0.03 ns

0.65

0.66 ± 0.05 ns

  1. Control: no biochar; A: surface application; B: plow layer application; C: subsurface application. Values represent the means of three replicates. The initial and final values refer to the values before the experiment and the conditions on the last day, respectively. ± represents standard error. * and ns indicate significant difference (p < 0.05) and non-significant difference compared with the control, respectively.
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