The influence of windbreak on the content of heavy metals in soil of windbreak and adjacent fields

Abstract

Windbreaks as an important part of agrobiocenoses detain snow on the inter-band space which causes the accumulation of pollutants in the soil including heavy metals (HM). The article presents the results of studies for 2001.2008 in the Republic of Mordovia on study the effect of windbreaks on the distribution of highly toxic HM in the layers of chernozem leached heavy loam (in the layers 0-20 cm, 30-40 cm, 50-60 cm) under conditions of windbreak and the protected field on the windy side. Age of deciduous trees is more than 50 years. Sampling points: windbreak, 10, 30, 50, 100, 150 and 250 m (background) from the strip. The soil contamination of the forest stripe with TM is more than in the field and indicates its ability to filter technogenic emissions. In the 0-20 cm layer of the windbreak the content of TM is 1.09 - 5.07 times higher than in the plowland of the geochemical area where the field is located; only Cu is less than the estimated permissible concentrations of HM. Therefore it is dangerous to collect mushrooms in forest belts around cities. The total content of HM varied in the soil layers of the field up to 60 cm. The redistribution of the maxima of the relative proportions of the HM content in the layers at a different distance from the strip depending on the metal was noted: 50 m for Pb, Zn, Cu, Co; in 250 m - more differentiated for Zn, Ni, Co. The content of HM in the soil of the background site is significantly lower than in the soil of the band across all layers for Pb, Zn, Ni; in the 0-20 cm layer for Cu; in the layers 0-20 and 30-40 cm - for Co. It is recommended to grow raw materials for dietary products and baby food in the center of the fields. The eluvial-accumulative coefficient shows the aerial and hydrogenic types of soil contamination associated with the distribution and quality of the snow cover in the field protected by the strip.