Soil organic matter quantity and quality of land transformed from arable to forest

Abstract

Comparative studies on quantitative and qualitative characteristics of soil organic matter were studied in arable and afforested in 1964 Stagni-Haplic Luvisol in Arboretum Mlyňany (Slovakia). The studies were conducted at three stands -arable soil located next to Arboretum (control), under thuja trees (Thuja orientalis L.) and under junipers (Juniperus Chinensis L.). Results of the studies showed, that in A horizons, 50 years of thuja and juniper trees growing on formerly arable land, had resulted to the significant (by 69% under thuja and by 126% under juniper) increase of total organic carbon (C ox ) compared to control arable land. KMnO 4 oxidisable carbon (C L ) and mainly hot water-soluble carbon (C hwd ) had higher contents in soil under studied trees than on arable land. The conversion of cropland to forest led to lowering of soil organic matter quality, assessed as the ratio of total carbon and nitrogen (C ox /N T ), which was in arable soil 10.2, under thuja trees 13.9 and under junipers 12.0. Surprisingly, the quality of humus between examined sites differed only minimally, since the change of humus quality is a long term process. (Juniperus Chinensis L.) boli porovnané s pôdou, ktorá zostala ornou, nachádzala sa hneď vedľa Arboréta a predstavovala kontrolné stanovište. Bolo zistené, že vplyvom výsadby tují a borievok na ornej pôde došlo za 50 rokov v A horizontoch k preukaznému zvýšeniu celkového obsahu organického uhlíka (o 69% pod tujami a o 126% pod borievkami) v porovnaní s kontrolnou ornou pôdou. Obsah organického uhlíka oxidovateľného s KMnO 4 (C L ), no najmä obsah v horúcej vode rozpustného uhlíka (C hwd ) bol vyšší v pôde pod skúmanými drevinami v porovnaní s ornou pôdou. Premenou ornej pôdy na lesnú došlo ku zníženiu kvality pôdnej organickej hmoty, určenej ako pomer celkového uhlíka a dusíka (C ox /N T ), ktorý mal v ornej pôde hodnotu 10,2, pod tujami 13,9 a pod borievkami 12,0. Kvalita humusu sa medzi skúmanými stanovišťami líšila minimálne, nakoľko zmena kvality humusu je dlhodobý proces. Premenou ornej pôdy na lesnú došlo ku zníženiu kvality pôdnej organickej hmoty, určenej ako pomer celkového uhlíka a dusíka (C ox /N T ), ktorý mal v ornej pôde hodnotu 10,2, pod tujami 13,9 a pod borievkami 12,0. V labilných formách uhlíka a dusíka boli rozdiely ešte výraznejšie. Prekvapivo, kvalita humusu skúmaná ako pomerné zastúpenie humínových kyselín a fulvokyselín bola nepatrne vyššia pod porastmi stromov, keď pomer v pôde pod borievkami bol 0,78 a pod tujami 0,65, kým v ornej pôde 0,63. Farebné koeficienty humusových látok aj humínových kyselín potvrdili vyššiu kvalitu humusu len pod tujami.Celkovo, vplyvom výsadby tují a borievok na ornej pôde došlo už v priebehu 50 rokov v A horizontoch ku značnému zvýšeniu celkového obsahu organickej hmoty a najmä jej labilných foriem a zároveň ku zníženiu kvality pôdnej organickej hmoty -čo je typické pre lesné ekosystémy v porovnaní s agroekosystémami. Na druhej strane, kvalita humusu sa medzi skúmanými stanovišťami líšila minimálne, nakoľko zmena k...

The impact of different land uses in urban area on humus quality

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Labile and Stable Fractions of Organic Carbon in a Soil Catena (the Central Forest Nature Reserve, Russia)

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