Ecological Archives E086-177-A3

M. Knorr, S. D. Frey, and P. S. Curtis. 2005. Nitrogen additions and litter decomposition: a meta-analysis. Ecology 86:3252–3257.

Appendix C. Studies within each subdivision of the categorical variables. See Appendix A and Appendix B for study location and site characteristics.

Categorical variable

Studies within each categorical subdivision

Rate of N addition (kg ·ha-1·yr-1)

 

   <75

1, 2, 4, 5, 11, 12, 13, 16, 20, 21, 24

   75–125

4, 8, 9, 12, 13, 17, 24

   >125

3, 6, 7, 10, 11, 12, 14, 15, 18, 19, 22, 23

   

Rate of N addition (relative to ambient N deposition; kg ·ha-1·yr-1)

   <5

1, 2, 4, 12, 16, 21, 24

   5–10

4, 11, 12, 24

   11–20

3, 10, 11

   >20

5, 7, 8, 9, 12

   

Fertilizer type

 

NH4NO3

2, 3, 4, 5, 6, 10, 11, 12, 13, 15, 23, 24

Urea

7, 18, 19, 22, 23

NH4NO3 + Urea

8, 9

N:P:K

17, 22

(NH4)2SO4

1, 14, 20, 21

NaNO3

21

Ca(NO3)2

7

KNO3

16

   

Ambient N deposition (kg ·ha-1·yr-1)

 

   <5

5, 7, 8, 9

   5–10

4, 11

   >10

1, 2, 3, 10, 12, 16, 21, 24

   

Litter decay period (months)

 

   <6

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19, 20, 21, 22, 23, 24

   6–12

1, 2, 3, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20

   13–24

1, 2, 3, 4, 5, 7, 8, 9, 11, 12, 13, 15, 17, 18, 19

   >24

2, 3, 4, 8, 11, 13, 15, 17, 18, 19

   

Litter quality

 

   low

4, 10, 12, 16, 20

   intermediate

1, 2, 3, 4, 6, 8, 9, 11, 15, 20, 21, 23

   high

1, 2, 4, 5, 7, 8, 9, 10, 11, 13, 17, 18, 19, 20, 21, 24

   

Litterbag mesh size (mm2)

 

   <1

2, 3, 5, 7, 8, 9, 10, 11, 12, 14, 16, 17, 18, 19

   >1

1, 4, 6, 13, 15, 22

   

Mean annual temperature (°C)

 

   <8

2, 3, 5, 10, 13, 14, 15

   8–15

1, 4, 6, 7, 10, 12, 18, 19

   >15

8, 9, 11, 16, 17, 20, 21, 22, 23, 24

   

Mean annual precipitation (mm/yr)

 

   <500

2, 4, 5, 6, 10, 12, 13, 14, 15, 17, 23

   500–1000

1, 3, 7, 11, 16, 18, 19, 21

   >1000

8, 9



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