Table A3.

Rates of denitrification, nitrogen fixation, and carbon sequestration estimated as the mean of typical values from literature surveys. Rates for developed land use classes represent averages across Puerto Rico calculated for each watershed from urban lawn or urban tree rates. Curve numbers were based on the mean distribution of soil types in each land cover class.

	Denitrification¹	Nitrogen fixation²	Carbon in soil³	Curve
LULC	(g N/m²/yr)	(g N/m²/yr)	(g C/m²)	number⁴
Open Water	5.17	0.00	143	0.00
Developed, Open Space	1.26	0.01	12177.9	79.11
Developed, Low Intensity	0.92	0.01	8876.4	78.21
Developed, Medium Intensity	0.50	3.55 × 10⁻³	4826.5	88.59
Developed, High Intensity	0.15	1.05 × 10⁻³	1454.5	93.26
Barren Land	0.00	0.00	3380	89.88
Evergreen Forest	0.25	33.94	5861.7	60.05
Shrub/Scrub	0.00	0.00	5000	71.38
Herbaceous	0.00	0.01	5139.1	84.44
Hay/Pasture	0.89	0.97	4452.3	78.78
Cultivated Crops	38.33	0.68	4452.3	80.19
Woody Wetlands	17.53	0.00	11100	74.57
Emergent Herbaceous Wetlands	37.23	0.00	7798.9	88.17
Urban lawn	1.4	0.01	13460
Urban tree	–	–	180⁵

^1.

Reddy et al., 1989; Tsai, 1989; Walbridge and Lockaby, 1994; Chestnut et al., 1999; Mosier et al., 2004; Seitzinger et al., 2006; Raciti et al., 2011.

^2.

Carpenter et al., 1978; Espinoza, 1997; Freiberg, 1998; Ley and D’Antonio, 1998; Brenner et al., 1999; Grossman, 2003; Herridge et al., 2008.

^3.

Houghton et al., 1991; McGuire et al., 1995; Ravindranath et al., 1997; Houghton, 1999; Masera et al., 2001; Ni, 2001; Pouyat et al., 2002; Chabra et al., 2003; Grau et al., 2004; Silver et al., 2004; Li et al., 2005, 2006; Bernal and Mitsch, 2008; Marín-Spiotta et al., 2008, 2009; Ostertag et al., 2008.

^4.

USDA and NRCS, 2008a-b, 2009a,b, 2012a-b.

^5.

300 g C/m2 for urban trees (Pouyat et al., 2002), 60% of which is attributed to soil (Nowak and Greenfield, 2009).