Effect of Fertilizer on Fine Root Density and Shoot Growth in Chilean Matorral

Plant Growth Forms of Chilean Matorral A Monocharacter growth form analysis along an altitudinal transect from sea level to 2000 M.A.S.L.

“…Due to the fact that most of the species were intimately known from previous investigations Montenegro et al, 1980 ;Kummerow and Montenegro, 1981) it was possible to determine practically ali the monocharacter growth form types. (Montenegro and Riveros, 1977 ;Avila and Aljaro, 1977 ;Montenegro et al, 1979 b ;Hoffmann and Walker, 1980 ;Montenegro et al, 1981 ;Aljaro and Montenegro, 1981 ;Avila et al, 1978 a ;Avila et al, 1978 b;Kummerow et al, 1982;Montenegro et al, 1982).…”

Carbon and nitrogen dynamics of pre- and post-fire chaparral exposed to varying atmospheric N deposition

“…5), and spatial patterns of biomass production and N uptake were no longer linearly related to N deposition exposure (Table 3). The differences in post-fire shrub growth observed between sites is presumably due to spatial variations in N deposition exposure; however, other factors such as historical differences in resource allocation to belowground structures (Sparks et al, 1993), limitations in other soil resources such as P or water (Kummerow et al, 1982;Moreno and Oechel, 1992), and/or differences in microclimatic conditions during stand recovery may also be important. Chamise re-sprouts from fire (Sparks et al, 1993) and shrubs that survived fire were rapidly re-sprouting 3-4 months after fire at SOFS and SBNF, and presumably, SDEF.…”

“…High population density and reliance on automobile transportation lead to the development of large spatial gradients in gaseous and particulate N pollutants, the majority (85-95%) of which fall as dry deposition during the summer when inversion conditions trap these pollutants near the land surface (Bytnerowicz and Fenn, 1996;Fenn et al, 2003a). Annual inputs of atmospheric N to exposed urban shrublands are on the order of 25-50 kg N/ha (Bytnerowicz and Fenn, 1996;Fenn et al, 2003a;Riggan et al, 1985); however, the spatial pattern of N deposition is highly variable and poorly understood and sites at slightly higher elevations can receive up to 145 kg N/ha y (Fenn and Poth, 2004 the capacity to significantly alter the N and C storage and cycling of chaparral ecosystems, which are considered to be N-limited (Fenn et al, 2003b;Gray and Schlesinger, 1983;Kummerow et al, 1982). For example, atmospheric N inputs can increase total and available N through direct fertilization and enhanced mineralization, reduce soil and vegetation C:N ratios, enhance soil acidification, and promote losses of N from gaseous efflux and leaching (Fenn et al, 2003b;Meixner and Fenn, 2004;Michalski et al, 2004;Padgett et al, 1999;Riggan et al, 1985;Vourlitis et al, 2007a, b).…”

Carbon and nitrogen storage in soil and litter of southern Californian semi-arid shrublands

“…Concentrations of atmospheric N in urban areas are 20 times higher than in remote areas resulting in 20-45 kg N/ha to be deposited to heavily polluted southern Californian shrublands annually (Bytnerowicz and Fenn, 1996;Riggan et al, 1985). This deposited N has the potential to enrich the soil and plant N of semi-arid shrublands (Egerton-Warburton and Allen, 2000;Padgett et al, 1999;Vourlitis et al, 2007), which are thought to be N limited (Fenn et al, 2003a;Gray and Schlesinger, 1983;Kummerow et al, 1982).…”