Phosphorus cycle soils

Salas, A.M., Elliott, E.T., Westfall, D.C., Cole, C.V. and Six, j. (2003) The role of particulate organic matter in phosphorus cycling. Soil Science Society of America Journal 57, 1 81 -1 89. 

Ecologically, copper is a trace element essential to many plants and animals. However, high levels of copper in soil can be directly toxic to certain soil microorganisms and can disrupt important microbial processes in soil, such as nitrogen and phosphorus cycling. Copper is typically found in the environment as a solid metal in soils and soil sediment in surface water. There is no evidence that biotransformation processes have a significant bearing on the fate and transport of copper in water. 

Blank RR, Young JA (2002) Influence of the exotic invasive crucifer, Lepidium latifolium, on soil properties and elemental cycling. Soil Sci 167 821-829 Bolan NS (1991) A critical review on the role of mycorrhizal fungi in the uptake of phosphorus by plants. Plant Soil 134 189-207. doi http //dx.doi.org/10.1007/BF00012037 Bullock JM, Pywell RF, Burke MJW, Walker KJ (2001) Restoration of biodiversity enhances agricultural production. Ecol Lett 4 185-189... 

The continental cycle of phosphorus is determined by ten fluxes (Figure 4.1) closed by a single component Ps indicating the phosphorus supplies on land in soil-vegetation formations and in animals. The supplies of phosphorus in soils are replenished due to fluxes Hf (l = 2,4,5,8,9,10). The loss of phosphorus from the soil is determined by fluxes Hj ( / = 3,6,7,11). As the detailing of surface reservoirs of phosphorus and consideration of more ingenious effects in the interaction between these reservoirs gets more complicated, so the classification of the surface fluxes of... 

The Atmosphere. - The Hydrosphere. - Chemical Oceanography. - Chemical Aspects of Soil. - The Oxygen Cycle. - The Sulfur Cycle. - The Phosphorus Cycle. - Metal Cycles and Biological Methyla-tion. - Natural Organohalogen Compounds. -Subject Index. 

Cuevas, E., and E. Medina. 1990. Phosphorus/nitrogen interactions in adjacent Amazon forests with contrasting soils and water availability." In Phosphorus Cycles in Terrestrial and Aquatic Ecosystems, eds. H. Tiessen, D. Lopez-Hernandez, and I.H. Salcedo (Proc. SCOPE-UNEP Regional Workshop 3 South and Central America. Saskatchewan Institute of Pedology. Saskatoon, Canada), pp. 83-94. 

Coupled Iron-phosphorus Cycling. The affinity of phosphate for sorptive association with ferric oxide and oxyhydroxide phases, well documented in soil and freshwater systems (see Sections 8.13.3.1 and 8.13.3.2), is also a well-studied process in marine systems. Three distinct marine environments where coupled iron-phosphorus cycling has been identified as an important process are MOR systems, estuaries, and continental margin sediments. The purely physicochemical process of sorption is essentially the same in these three distinct environments, where an initial, rapid surface sorption phase is followed, given enough time, by a redistribution of adsorbed phosphate into the interior of iron oxyhydroxides by solid-state diffusion (Bolan et al., 1985 ... 

Lajtha K. and Schlesinger W. H. (1988) The biogeochemistry of phosphorus cycling and phosphorus availability along a desert soil chronosequence. Ecology 69, 24-39. 

The transfer of phosphorus from the terrestrial biomass to soil as dead organic matter has been estimated to be 136.4 TgP y 133.3 Tg P y is derived from plants and 3.1 Tg P y from animal material (Pierrou, 1976). The uptake of phosphorus by plemts from soil was calculated by Bazilevich (1974) to be 178TgPy while Stumm (1973) estimated it to be 236.8 Tg P y including that of the freshwater ecosystems. The terrestrial biota has been calculated to absorb 0.065 Tg P y from aquatic ecosystems and 0.063 Tg P y from industrially made foodstuffs and pharmaceutical products (Pierrou, 1976). An important aspect on which quantitative data are not yet available is the bacterial cycling of phosphorus within soils. This internal cycle helps in making phosphorus available for plants. 

Phosphorus is usually found in biological systems as the phosphate ion, which transits rapidly through plants and animals, but moves much more slowly through the soil and the oceans, making the phosphorus cycle overall one of the slowest biogeochemical cycles. The major mineral with an important phosphorus content is apatite [Ca5(P04)30H], but this is not a major source, and many organisms rely on soil-derived phosphorus released from dead organic matter for their phosphoms requirements. 

From Sec. 2 it can be concluded that, due to the highly weathered state and high phosphorus sorption capacity of many moist tropical forests soils, the level of readily plant available phosphorus is low. Discussion on whether this means that phosphorus availability actually limits productivity of moist tropical forests is reserved until Sec. 4.1. Here we limit our concerns to a discussion of the phosphorus cycle in moist tropical forests and methods by which plant phosphorus acciuisition can occur in environments characterized by low levels of available P. The main aim of this section is to cjuantify the amounts and annual input/output fluxes of P for leaves, branches, boles, and roots of moist tropical vegetation. The inputs of phosphorus into moist tropical forests from rock weathering and wet and dry deposition, as well as from leaching losses, are also considered. This information is then used for model simulations in Sec. 4.3. 

Phosphorus cycling in soils. The cycling of P in soils (see Fig. 1) has received much attention, both in terms of fertilization and the natural development of ecosystems. Of the approximately 122,600 Tg P within the soil/biota system on the continents, nearly 98% is held in soils in a variety of forms. The exchange of P between biota and soils is relatively rapid, with an average residence time of 13 years, whereas the average residence time of... 

E.M. Frossard, M. Brossard, M.J. Hedley and A. Metherell, Reactions controlling the cycling of phosphorus in soils. In H. Tiessen (ed.), Phosphorus in the global environment transfers, cycles and management. J. Wiley and Sons, New York, 1995, p. 107. 

Enzymatic hydrolysis of organic phosphorus is an essential step in the biogeo-chemical phosphorus cycle, including the phosphorus nutrition of plants and microorganisms (see Oberson and Joner, Chapter 7 Richardson et al., Chapter 8 Heath, Chapter 9, this volume) and the transfer of organic phosphorus from soils to water bodies (see Turner, Chapter 12, this volume). It also plays a role in gene fluxes in the environment by its effect on the residual extracellular DNA in soil, and in the degradation of... 

Microorganisms constitute a large pool of phosphorus in the soil and mediate several key processes in the biogeochemical phosphorus cycle. Microbial uptake of phosphorus and its subsequent release and redistribution strongly affect the availability of phosphorus to plants in natural and managed ecosystems, especially when the latter receive organic amendments (Walbridge,... 

Similarly, Joergensen and Castillo (2001) could not exclude the possibility that the fungi in the Nicaraguan soils they studied contained low ergosterol contents. Nevertheless, fungal-to-bacterial-biomass ratios are of interest because the two groups contribute differently to specific functions in the phosphorus cycle, react differently to environmental and nutritional factors, and in turn affect microbial phosphorus turnover (see below). 

Microbially Mediated Processes in the Soil Phosphorus Cycle... 

Our review would not be complete without a note on mycorrhizal phosphorus transport, which is another key microbial process in the phosphorus cycle. It consists of three distinct parts (i) fungal absorption of phosphorus from the soil solution (ii) translocation of phosphorus within extra-radical hyphae from the site of absorption to the site of exchange with the host plant and (iii) transfer from the fungus to the host plant [sensu Cooper and Tinker, 1981). This... 

McLaughlin, M.J., Alston, A.M. and Martin, J.K. (1988) Phosphorus cycling in wheat-pasture rotations. II.The role of the microbial biomass in phosphorus cycling. Australian Journal of Soil Research 25, 333-342. 

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