Ecological Archives A015-048-A2

Kathleen A. Lohse and Pamela Matson. 2005. Consequences of nitrogen additions for soil losses from wet tropical forests. Ecological Applications 15:1629–1648.

Appendix B (Table B1). Effects of first-time and long-term N additions on soil N dynamics with depth at the 300-yr-old and 4.1-Myr-old sites.

   
300-yr-old site
4.1-Myr-old site

Soil Pool/rate

Depth (cm)

C

FTN

LTN

C

FTN

LTN

               

NH 4 +

0–10

1.13

12.11

13.75

5.91

25.00

37.00

 

 

(0.23)

(5.28)

(7.87)

(2.41)

(13.04)

(20.26)

 

10–20

0.16

0.83

1.7

3 .57

0.97

1.24

 

 

(0.038)

(0.43)

(0.93)

(0.091)

(0.22)

(0.36)

 

20–30 (50)

2.10

1.96

3.47

 3.53

4.57

13.70

 

 

(0.82)

(0.78)

(1.23)

 (0.55)

(1.09)

(8.74)

               

NO 3 -

0–10

0.017

7.56

19.34

3.58

6.31

6.33

 

 

(0.017)

(4.26)

(9.77)

(1.43)

(1.44)

(3.28)

 

10–20

0.057

1.48

4.89

 1.31 a

2.12 a

4.57 b

 

 

(0.02)

(1.14)

(2.83)

(0.24)

(0.58)

(0.53)

 

20–30 (50)

0.50

0.62

6.01  

2.49 a

8.07 a

29.57 b

 

 

(0.34)

(0.46)

(4.66)

(0.92)

(2.08)

(12.92)

               

Total mineral N

all depths

4.232

24.54

49.17

 17.39

47.04

92.41

 

 

(0.34)

(11.00)

(13.8)

 (2.96)

(13.34)

(25.79)

               

Net mineralization

0–10

-0.03

0.12

0.74

0.58

0.80

0.72

 

 

(0.012)

(0.063)

(0.45)

(0.27)

(0.17)

(0.49)

 

10–20

-0.01 a   

-0.07 b

0.012 a

0.088

0.26

0.27

 

 

(0.005)

(0.025)

(0.026)

(0.01)

(0.08)

(0.05)

 

20–30 (50)

-0.31

-0.15

0.75  

0.64

1.17

1.04

 

 

(0.12)

(0.03)

(0.76)

(0.30)

(0.29)

(0.34)

               

Net nitrification

0–10

-0.0018

0.10

0.61

0.75

1.43

1.36

 

 

(0.002)

(0.11)

(0.40)

(0.24)

(0.23)

(0.37)

 

10-20

-0.007 a

-0.03 a

0.079 b

0.14 a

0.31 b

0.39 b

 

 

(0.002)

(0.017)

(0.044)

 (0.01)

(0.07)

(0.08)

 

20–30 (50)

-0.044 a

-0.01 a

0.18 b  

0.90

1.27

1.66

 

 

(0.026)

(0.003)

(0.10)

(0.33)

(0.23)

(0.44)

   Notes: Mean inorganic N pools and rates of net mineralization and nitrification (± 1 SE) were measured three weeks after N fertilization. Lowercase subscript letters indicate significant differences at P < 0.05 for treatment effect within site (n = 4 except old LTN).  Control indicated by C, first-time fertilized by FTN, and long-term fertilized by LTN. Soil pool units are kg N/ha and rates are in kg N·ha -1·d -1.  

† At the old site, soil depth was 20–50 cm depth. At the young site, ANOVA test results showed rates of net mineralization and nitrification were significantly elevated in the subsurface horizon from 10-20 cm, F2,9 6.65, P = 0.017 (net min) and   F2,9 4.49, P = 0.045 (net nit) and nitrification was slightly significantly elevated from 20–30 cm F2,9 3.53, P = 0.07.  At the old site, ANOVA test results showed soil nitrate pools were significantly elevated in the subsurface horizon from 10-20 cm, F2,8 11.89, P = 0.004 and rates of nitrification were significantly elevated from 10-20 cm (F2,8 4.85, P = 0.041) and 20-50 cm (F2,8 5.07, P = 0.038).  



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