Organik moddalar tuplanadigan (akkumulyativ) gorizont (A) tuproq profilining yuqori qismida yashil o’simliklarning qurigan biomassasi tuplanishidan hosil bo’ladi. Bu gorizont o’zining ifodalanishi, xarakteriga kura - gumusli - akkumulyativ gorizont, tuproqning yuqori mineral qatlamida hosil bo’lib, ularda mineral moddalarning parchalanishi va ishqorsizlanishi ifodalanmagan; A1- gumusli-elyuvial, tuproq profilining yuqori gorizonti hisoblanib, unda morfologik va tarkibi jihatdan mineral moddalarning parchalanishi va ishqorsizlanishi ifodalangan (urmon, urmon-dasht, dasht zonalarida yaxshi shakllangan). A va A1 gorizontlari odatda boshqa gorizontlarga nisbatan ancha tuq, qoramtir tusli bo’lib, bunda eng ko’p miqdorda organik moddalar (gumus) va oziq moddalar tuplangan. Ishlov beriladigan tuproqlar profili odatda haydalma gorizontdan (Ah) boshlanadi. Bu gorizont tuproq gumusli qatlam va qisman pastki gorizontlarning haydalishi tufayli hosil bo’ladi. CHimlanish jarayoni yaxshi boradigan quriq yerlarda (qora tuproqlar, kashtan va bo’z tuproqlarda) chim qatlami (Ach) yaxshi ifodalanadi.
Organic ingredients together (akkumulyativ) horizon (A) on top of the soil profile is formed by green plants dry biomass congestion. According to the nature of this horizon expressed his akkumulyativ humus horizon, the upper layer of mineral soil, where the collapse of the mineral and ishqorsizlanishi; A1 - humus-elyuvial, the profile of the soil horizon of the morphology and composition of mineral substances decay and expressed ishqorsizlanishi (forestry, forestry-steppe, and steppe zones as well).
A and A1 horizontally relative to the generally horizontal tick , a dark shade , with the maximum amount of organic matter ( humus ) and tillering . Cultivated soils are usually expelled from the horizon ( Ah ) . The horizon of the soil humus layer , and partly due to the lower horizontal expelled . To try to build a good soil ( black soil , chestnut and gray - brown soils ) and grass cover ( Ach ) is expressed in the well .
