Heavy metals nutrient type

The plant availability of some nutrients may be limited in both types of residues. Moreover, in certain cases the contents of some heavy metals (Cd, Pb, Cu, Zn, Ni, Cr and Hg) may exceed the legal thresholds (BioAbfV 2002). Nevertheless, the use of energy crop residues as fertiliser significantly reduces the need for mineral fertiliser. 

According to modem standards mineral fertilizers are partitioned into two groups standardized and non-standardized. The standardized fertilizers include nitrogen, phosphoms, potassium, complex, and micro-fertilizers that contain the nutrients at the standard basis. The non-standardized fertilizers are municipal wastewater effluents, municipal solid wastes, polluted river waters used for irrigation, etc., which are not characterized by standard content of nutrients. However one should add that in all fertilizers including standardized type there are the admixtures, which pollute the agrolandscape. The known examples are phosphoms fertilizers and any municipal waste and wastewater with a pool of heavy metals and various organic pollutants. 

Various workers have assembled relatively complete assessments of the annual input of the major biological nutrients (C, N, P), certain heavy metals (Mn, Cd, Pb, Cu), and petroleum hydrocarbons to Narragansett Bay. Other studies have developed inventories of the amounts of these materials in the sediments of the Bay. We have brought these data together with information on sediment accumulation rates in the Bay to determine the degree to which this one estuary serves as a sink for different types of materials in their passage between land and the coastal ocean. 

Figure 1 Three main types of heavy metal accumulation in plants schematic correlations between metal in soil (or nutrient solution) and metal in the plants.

Low energy content/ m space and m resource.Ihe resources are spread over large areas.The amounts of biomass available are dependent on regeneration time of the biomass,often with a seasonal availablity.complex chemical composition vhich varies with the growth cycle of the resource.Biomass normally contain small amounts of heavy metals and sulfurand has a low ash content.The amount of nutrients are dependent on type of biomass and time of the year.Environmental effects mainly on soil and water compartments of the ecosystems. 

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