Humus state and energy stocks of soilsof technogenic landscapes of the south of Primorye

The process of mineral extraction in the south of Primorye contributes to theformation of, in particular, technogenic quarry-dump landscapes. The purpose of thework is to identify general regularities in the change of the humus-energy parameters ofsoil of technogenic landscapes, depending on the temporary stage in their development.The investigations were performed in the Pavlovsky brown coal deposit, located inMichalovsky area of Primorsky Krai.Spontaneous revegetation occurs gradually on dump breeds. At the dump there canbe distinguish four stages of the formation of plant and soil cover: the first is pioneervegetation on initial litostrat lasting up to 3 years. The second is the stage of a simpleplant grouping on the organo-accumulative litostrat, up to 12 years; the third stage is acomplex group of plant on the sod litostrat, lasting up to about 15 years and the fourthis the stage of the development of an ecosystem with a closed plant group on the humusaccumulativelitostrat marked on the dumps, whose age is over 15 years. Dependingon the temporary stage of the development, litostrats differed by differentiation ofsoil profile and the degree of manifestation of formed organic horizons. A progressiveincrease in humus is noted in the surface soil horizons with lengthening the timeperiod of soil formation from 0.25% in the initial litostrat to 0.75-1.1 in the organoaccumulativeand sod, and to 8.0% in the humus-accumulative.With lengthening of the time period of litostrats formation there was noted anincrease in stocks of humus from 6 to 65 t/ha, the degree of humification of organicmatter (from low to high) and a decrease in «aggressive» fractions of fulvic acidsin surface horizons. The type of humus varies from very fulvate in the initial, up tohumate-fulvate in the sod and fulvate-humate in the humus-accumulative litostrats. Thecontent of the first fraction of humic acids tend to decrease in the development processof litostrats.The content of humic acids associated with Ca2+ is estimated as very low andlow, the content of the third fraction of humic acids is high in all the litostrats. Lowvalues of optical densities testify the dominance of peripheral groups in molecules ofhumic acid, indicating chemical «youth» of the molecules of humic acids in litostratesof the early development stages. While the litostrats pass the main developmentstages, an integral reflection of soils (from 65% in the surface horizons of initiallitostrats up to 30-43% in organo-accumulative and sod litostrats and up to 23% ingumus-accumulative) decreases whereas energy stocks of soils increase from 13 to136 МДж/м2. A tight correlative connection between the integral reflection and thehumus content (-0.80) is established. This allows using an index of integral reflectionas a criterion for estimating the humus content and the stage of humus formationprocess on breeds dump.

Keywords

Authors

References