Artikkelit jotka sisältää sanan 'concentration'

The effects of potassium (K) fertilisation on the nutrient status and growth of Scots pine (Pinus sylvestris L.) stands on drained peatlands were studied on three field experiments in northern central Finland. The Scots pine stands were at a sapling or pole stage with a dominant height of 3–8 m when the experiments were set up. The stands differed from each other in their nutritional status, for example, the foliar K concentration varied considerably between the experiments. The experiments were fertilised with potassium chloride, rock phosphate (P 42kg ha-1) and urea (N 46kg ha-1) between 1979 and 1980. The potassium doses in terms of elemental K, were 50, 100, 200 and 400kg ha-1. The foliar samples were taken three times during the study period: 7–9 years, 14–15 years and 19–20 years after fertilisation. The stand measurements were done 19–22 years after the fertilisation. The rate and magnitude of stand response due to fertilisation depended essentially on the nutritional status of the trees. The strongest effect of PK-fertilisation was obtained on a nitrogen-rich peatland, where the stands suffered from severe phosphorus and potassium deficiencies (foliar P concentration < 1.2 mg g-1, K concentration < 3.5 mg g-1). During the study period, the annual stand volume growth on fertilised plots ranged from 3.9 to 5.4 m3 ha-1 a-1, and that of the unfertilised plots was 0.78 m3 ha-1 a-1. In other sites, where the lack of phosphorus and potassium was not so drastic, nor did the trees suffer from shortage of nitrogen, the effect of PK-treatment on tree growth was weak or almost non-existent. The foliar K concentrations rose with the amount of potassium chloride applied. The fertilisation effect of the dose of 100kg K ha-1 lasted 15–20 years, after which the foliar K concentration dropped close to the deficiency limit. The effect of the larger doses (200–400kg K ha-1) on the needle K concentration was more pronounced and still visible at the end of the study period. However, the stand growth responses gained with larger potassium applications were not essentially greater than those with the 100 kg ha-1 dose.

• Pietiläinen, Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Vesala, Sähköposti: ei.tietoa@nn.oo

The purpose of this study was to determine critical nutrient concentration values for interpreting foliar analysis of Norway spruce stands growing on drained peatlands. During 1987–91, a total of 162 spruce needle samples from various peatland sites in Finland were taken and analysed for N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn. The mean height growth of the two preceding growing seasons was used as the growth parameter for multiple and simple regression analyses. Foliar concentrations significantly explained height growth. Simple regression analysis was used to estimate the following critical values indicating severe to moderate nutrient deficiencies for the main nutrients: N 1.15–1.30%, P 1.70–2.30 mg g-1 and K 5.40–6.60 mg g-1. Also the following tentative critical concentrations are suggested: Cu 2.0 mg kg-1, Fe 13.0 mg kg-1, Mg 0.80 mg g-1 and Zn 16.0 mg kg-1. Results for B are in accordance with previous, but unsubstantiated, critical values (6–8 mg g-1).

• Veijalainen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo

Rosetta Branch of river Nile is subjected to severe pollutants of domestic, sewage, agricultural and industrial pollution. In this study, the distribution of heavy metals (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured in surface river water and the bed sediments of Rosetta Branch and the impacts of heavy metals on the water quality were monitored. The heavy metal concentrations in river water and their contents in the bed sediments were studied three times before, during and after winter period (low flow conditions) from August 2007 to April 2008. The heavy metal concentrations in the river sediments were remarkably high, but varied among sampling points, and the concentrations in water were mainly within the permissible limits. The heavy metal contents in bed sediment were highest during closure of winter period. Attention should be paid to mitigate element mobilization from sediments as their effects may become significant during seasons and years of low water flow in the river. Constant monitoring of the Nile river water quality is needed to record any alteration in the quality and mitigate outbreak of health disorders and the detrimental impacts on the aquatic ecosystem.

• El Bouraie, Mohamed M. El Bouraie, Central Laboratory for Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), Cairo, Egypt, email: mido.chemie@gmail.com Sähköposti: ei.tietoa@nn.oo
• El, Sähköposti: ei.tietoa@nn.oo
• Yehia, Sähköposti: ei.tietoa@nn.oo
• Motawea, Sähköposti: ei.tietoa@nn.oo