Data/hora: 12/06/2024 05:34:49

Biblioteca(s): | Embrapa Agrobiologia; Embrapa Pantanal.
Data corrente: | 15/02/1995
Data da última atualização: | 27/06/1995
Autoria: | ELLIOTT, E. T.; PALM, C. A.; REUSS, D. E.; MONZ, C. A.
Título: | Organic matter contained in soil aggregates from a tropical chronosequence: correction for sand and light fraction.
Ano de publicação: | 1991
Fonte/Imprenta: | Agric. Ecosyst. Environ., v.34, p.443-451, 1991.
Idioma: | Inglês
Conteúdo: | A cultivation sequence of Ultisols (sandy loam) from the Amazon Basin of Peru was physically fractionate using wet sieving followed by heavy liquid separation and total organic C and N analysis. Soils were sampled to an equivalent plow depth (22.5) in a cultivation chronosequence containing the following treatments: an old growth forest (75 plus years) a 13-year fallowed forest, a 3-year continuous cultivation corn-soybean rotation following a 10-year forest fallow and a 16-year intensively managed corn field. The soil was air dried and re-wetted (misted) to field capacity before shaking for 10 min and wet sieving into five size classes: <0.02, 0.02-0.05, 0.05-0.212, 0.212-1.0 and >1.0 mm. The weight of soil, total organic C and N and percent sand was determined on each size class. Subsamples of each size class were gently stirred in sodium metatungstate (specific gravity=1.8), left overnight and the floating material removed by aspiration. The removed material was filtered through pre-ashed glass fiber filters and analyzed for total organic C and N. The sand content of size classes ranged from 45 to 95%. Light fraction C comprised 24, 28, 14, 5 and 2% of the total C of the size classes ranging from the largest to smalles particle sizes. Total C concentrations were highest in the largest and smallest particle size classes. Within any size class, all treatment had similar C concentration except for the <0.02-mm particles where the 75-year forest has lower concentrations. When corrected for sand content (i.e., expressed on a silt plus clay basis) and with light fraction C subtrated, the organic C content was, with few exceptions, not different among size classes or treatments. However, when all treatments whitin a size class were averaged, the 0.020-0.053-mm class had a higer concentration of C.
Thesagro: | Carbono; Matéria Orgânica; Nitrogênio; Solo.
Thesaurus Nal: | organic matter; soil.
Categoria do assunto: | --
Registro original: | Embrapa Agrobiologia (CNPAB)

Exemplares:

CNPAB - (18194-1) - ADC - SP - -- -  -  - 16291 - DIS
CPAP - (27764-1) - ADD - SP - PP - SP14138 -  - 14138 - DIS