Data/hora: 22/06/2024 00:22:08

Biblioteca(s): | Embrapa Soja.
Data corrente: | 02/02/2011
Data da última atualização: | 03/08/2017
Autoria: | BABUJIA, L. C.; HUNGRIA, M.; FRANCHINI, J. C.; BROOKES, P. C.
Afiliação: | L. C. BABUJIA, UEL; MARIANGELA HUNGRIA DA CUNHA, CNPSO; JULIO CEZAR FRANCHINI DOS SANTOS, CNPSO; P. C. BROOKES, Rothamsted Research.
Título: | Microbial biomass and activity at various soil depths in a Brazilian oxisol after two decades of no-tillage and conventional tillage.
Ano de publicação: | 2010
Fonte/Imprenta: | Soil Biology and Biochemistry, Oxford, v. 42, n. 12, p. 2174-2181, Dec. 2010.
DOI: | 10.1016/j.soilbio.2010.08.013
Idioma: | Inglês
Conteúdo: | The advantages of no-tillage (NT) over conventional tillage (CT) systems in improving soil quality are generally accepted, resulting from benefits in soil physical, chemical and biological properties. However, most evaluations have only considered surface soil layers (maximum 0?30 cm depth), and values have not been corrected to account for changes in soil bulk density. The objective of this study was to estimate a more realistic contribution of the NT to soil fertility, by evaluating C- and N-related soil parameters at the 0?60 cm depth in a 20-year experiment established on an oxisol in southern Brazil, with a soybean (summer)/wheat (winter) crop succession under NT and CT. At full flowering of the soybean crop, soil samples were collected at depths of 0?5, 5?10, 10?20, 20?30, 30?40, 40?50 and 50?60 cm. For the overall 0?60 cm layer, correcting the values for soil bulk density, NT significantly increased the stocks of C (18%) and N (16%) and microbial biomass C (35%) and N (23%) (MB-C and -N) in comparison to CT. Microbial basal respiration and microbial quotient (qMic) were also significantly increased under NT. When compared with CT, NT resulted in gains of 0.8 Mg C ha?1 yr?1 (67% of which was in the 0?30 cm layer) and 70 kg N ha?1 yr?1 (73% in the 0?30 cm layer). In the 0?5-cm layer, MB-C was 82% higher with NT than with CT; in addition, the 0?30 cm layer accumulated 70% of the MB-C with NT, and 58% with CT. In comparison to CT, the NT system resulted in total inputs of microbial C and N estimated at 38 kg C ha?1 yr?1 and 1.5 kg N ha?1 yr?1, respectively. Apparently, N was the key nutrient limiting C and N stocks, and since adoption of NT resulted in a significant increase of N in soils which were deficient in N, efforts should be focused on increasing N inputs on NT systems.
Thesagro: | Biologia do solo; Conservação do solo.
Thesaurus Nal: | Soil biology; Soil conservation.
Categoria do assunto: | P Recursos Naturais, Ciências Ambientais e da Terra
Registro original: | Embrapa Soja (CNPSO)
Exemplares: | CNPSO - (31811-1) - UPC - AP - PP - 11958 -  - 11958 - DIS