Yankin gandun daji mai yanke yankewa ya mamaye yanki mai yawa na Eurasia da Arewacin Amurka. Ainihin, waɗannan gandun daji suna cikin yanayi mai yanayi tare da leaching ruwa a filayen. A cikin waɗannan gandun daji akwai bishiyoyi da kudan zuma, hornbeams da bishiyoyin toka, lindens da maples, shuke-shuke iri-iri da bishiyoyi. Duk wannan furannin yana girma ne a kan ƙasa mai ruwan toka da ƙasa mai duhu da launin toka mai duhu. Wasu lokuta gandun daji suna kan kyawawan kayan kwalliya.
Burozems
An kafa ƙasa mai daɗin ruwan kasa lokacin da humus suka taru kuma shuke-shuke suka ruɓe. Babban mahimmin shine ganyen da ya faɗi. An wadatar da ƙasa tare da nau'o'in humic iri-iri. Soilasar ƙasa mara kyau tana cike da ma'adanai na sakandare, waɗanda aka samar da su sakamakon hanyoyin sinadarai da na biochemical. Ofasar wannan nau'in tana cike da ƙwayoyin halitta. Haɗin burozem kamar haka:
- matakin farko shi ne zuriyar dabbobi;
- na biyu - humus, yana kwance santimita 20-40, yana da launin toka-ruwan kasa;
- mataki na uku ba shi da kyau, daga launin ruwan kasa mai haske, ya yi kusan santimita 120;
- na huɗu shine matakin dutsen iyaye.
Forestasa mai ruwan kasa tana da yawan haihuwa. Zasu iya girma da nau'ikan nau'in bishiyoyi, nau'ikan shrubs da ciyawa.
Grey ƙasa
Dajin yana da halin ƙasa mai toka. Sun zo ne a cikin rashi da yawa:
- launin toka mai haske - ya ƙunshi 1.5-5% na humus a gaba ɗaya, suna ƙoshi da fulvic acid;
- launin toka-toka - an wadatar da su sosai tare da humus har zuwa 8% kuma ƙasa ta ƙunshi acid na humic;
- launin toka mai duhu - ƙasa tare da babban matakin humus - 3.5-9%, ɗauke da daskararriyar acid da allurar neoplasms.
Don ƙasa mai ruwan toka, duwatsu masu daɗaɗawa sune loams, moraine adibas, loesses, da yumbu. A cewar masana, an samar da kasa mai launin toka sakamakon lalacewar chernozems. An kafa ƙasa ƙarƙashin tasirin tafiyar sod da ɗan ci gaban podzolic. Haɗin ƙasa mai toka an wakilta shi kamar haka:
- Launin zuriyar dabbobi - har zuwa santimita 5;
- humus Layer - 15-30 santimita, yana da launin toka launin toka;
- humus-eluvial haske launin toka mai haske;
- launi mai launin launin toka-launin ruwan kasa;
- illuvial horizon, launin ruwan kasa;
- tsarin canji;
- dutsen iyaye.
A cikin dazuzzuka masu ƙarancin katako, akwai ƙasa mai dausayi sosai - burozems da sulfur, da sauran nau'ikan. An wadatar dasu daidai a cikin humus da acid kuma an samar dasu akan duwatsu daban-daban.
