The poplar saplings survival in re-claimed mineland depending on clone and root treatment.

Abstract

The genus Populus L. is one of the promising energy plants for growing on marginal lands. To assess its potential under steppe conditions, growth morphological parameters of 9 hybrid poplar clones grown over two years on a mix of loess-like loam and red-brown clay have been studied. In the first year, the degree of the sapling survival and the intensity of development were explored. At the end of the year, two clones which showed the best results (Ijzer-5 and Robusta), were selected for further breeding and rearing. Researches of the second year were devoted to the effect of biological agents on the survival and growth of these two clones. The treatments with vermicomposting extract (VCE), trichodermin, mycorrhiza and mixture of these agents were applied. The experiment with poplar clones Ijzer-5 showed a positive effect of all bioagents on the growth morphological parameters. The increase of the length and diameter of an annual shoots, leaf area and total assimilation surface from 10 to 38% was revealed. The treatment with vermicomposting extract gave the best result. For clones Robusta, only three agents out of four had a positive effect. The rise in morphological parameters was at the level of 9-55%. The best results were noted in the experiment with a mixture of agents. Treatment with trichodermin caused an inhibitory action on most of the growth characteristics of the clone Robusta. To obtain the wood thermal stability information a comparative thermogravimetric analysis of poplar wood samples grown on different soil types was carried out. A larger value of DTG at all stages was observed in a sample of poplar grown on sod podzolic soil. The difference in the value of the rate of mass loss is explained by the larger content of humus in sod podzolic soils, than in the phytomeliorated mix of rocks.