Humus characteristics of alluvial dark-humus soils of Krasnoyarsk forest-steep

Alluvial soils are specific formations, whose profiles form under the simultaneous influenceof zonal and interzonal processes. The soils are the least investigated in spite ofthe great importance in view of high fertility. This article is devoted to the alluvial soilsof representative parts of the Berezovka, the Buzim, the Kacha and the Esaulovka floodlandsin the middle flow of rivers. The investigated objects are located on the territory ofKrasnoyarsk forest-steep. The alluvial soils specialties were founded with macro morphologicalstudies and ascertainment of physical-chemical and chemical properties.Mineralogical compositions were studied for soils and matrixes. The quantity, compositionand properties of humus were determined. Free or brown humic acids were investigated.The main optical features of humic acids preparations from the upper horizonswere determined; there are individual absorption bands, extinction coefficients, refractioncoefficient, chromatic coefficients for the studied profiles horizons with the mostquantity of organic carbon. The regularities of humus characteristics and other propertieschanges were established. Consequently, it was determined that alluvial dark-humusgleyey and alluvial dark-humus hydrometamorphized soils have formed in the river valleysof the Berezovka, the Buzim, the Kacha and the Esaulovka on the territory of Krasnoyarsk forest-steep. The soils are similar to soils with polynomial profiles, where soilhorizons of different development alternate with the river drifts. The matrixes are loosesands and cohesive sands for soils of the Esaulovka and the Kacha rivers and light loamand loamy clay for soils of the Buzim and the Berezovka rivers. Quartz, potash feldsparsand plagioclases dominate in mineralogical compositions. The investigated soils arecharacterized with neutral or alkalescent mediums; high quantity of mobile phosphorusin the upper horizons (to 100 mg/kg); high quantity of sum exchange bases on average inprofiles 41 mg-equivalent/100 g (to 53 mg-equivalent/100 g); high quantity of mobileforms of iron (to 0,5%); quantity of carbonate is in all parts and about 2% (to 5%). Thecontent of humus, its composition and allocation depends mainly on extent and type ofthe flood; grain-size of bringing material; extent of development of vegetation on the surface.The presence of P-type humic acids is caused by periodical floods and abundantmoistening. The level of optical density of humic acids preparations shows that relativelynew humic acids with a low carbon condensing extent and developed peripheral chainsdominate.

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