Available soil phosphorus in semi-natural grasslands: Assessment methods and community tolerances

Abstract

(2009). Available soil phosphorus in semi-natural grasslands: assessment methods and community tolerances. Biological Conservation, 142 (5) To test which methods are most suitable for measuring available P in soils of mesotrophic 20 grasslands, a bioassay experiment was undertaken to compare seven extraction methods with 21 the growth and P uptake of grassland species. Five species were grown together on a soil treated 22 to create a range of conditions of pH, mycorrhizal infection and P availability. 23 24 Olsen P and Bray P were found to be significantly correlated with P uptake in plant growth 25 across the range of soil treatments whilst ion exchange membrane P and resin P were 26 significantly correlated with P uptake in plant growth in all but the calcareous soils. The acid 27 extractions of Truog, acetic acid and EDTA-ammonium acetate were found to be less correlated 28 with P uptake in plant growth. All extraction methods correlated more strongly with P uptake in 29 the sterilised treatments than in those inoculated with mycorrhizal spores. 30 31The method of Olsen was therefore selected to analyse P availability in soils supporting a range 32 of mesotrophic grassland communities from eleven sites across England. At each sampling 33 location, the species composition of the vegetation was assessed and classified using the British 34 National Vegetation Classification (NVC). Species-rich hay meadows across a range of 35 alliances were found to occur on soils with low phosphorus availability. Olsen's method of P extraction is recommended for analysing soils of areas identified for 41 habitat creation; values of less than 10 mg kg -1 will give the greatest potential for the restoration 42 of species-rich mesotrophic grassland. 43

The yield and composition of reed canary grass biomass as raw material for combustion

“…A higher carbon content leads to a higher heating [20,21,29]. In our study higher nitrogen fertilization means higher carbon content in the first and second year of reed canary grass swards use (Table 2).…”

“…The carbon content of biomass is around 45%, while coal contains 60% or greater [21]. A higher carbon content leads to a higher heating [20,21,29].…”

“…The ash content of biomass is very important because when ash concentration is increased by 1%, the calorific value is reduced by 0.2 MJ kg -1 [18]. Because of poor quality of available biomass significantly lower energy value of biomass yield is available; it depends on worse conversion and lower calorific value [19,20,21]. Straw, grain, herbs and various other waste have relatively large amounts of N, Cl and S, which act to form a variety of pollution and corrosion promoting compounds [22,23].…”

“…In our study, however, only in the first year of usage concentration of S was higher in fertilization with higher amount of nitrogen fertilizers (Table 2). Each other year of fertilization at higher N fertilizer rates resulted in N and S element decrease.The carbon content of biomass is around 45%, while coal contains 60% or greater [21]. A higher carbon content leads to a higher heating [20,21,29].…”

Plant species richness in a natural Argentinian matorral shrub-land correlates negatively with levels of plant phosphorus

“…Due to the intrinsically low N levels in Patagonian soils (Diehl et al 2003), a small difference in N availability could have a considerable effect on the productivity of the system and consequently on the species richness. It has also been shown that low P availability is a prerequisite for high diversity (Critchley et al 2002;Gilbert et al 2009;Janssens et al 1998;McCrea et al 2004;McCrea et al 2001). An essential difference between the N and P soil cycles is that the available forms of N are easily lost from the system by leaching, fires, and denitrification, while P is bound to the soil.…”