Land use effects on microbial biomass C, 尾-glucosidase and 尾-glucosaminidase activities, and availability, storage, and age of organic C in soil
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- 作者：David Sotomayor-Ram铆rez ; Yusmary Espinoza and Veronica Acosta-Mart铆nez
- 关键词：Organic matter ; Soil organic carbon ; δ ; 13C ; Soil aggregates ; Tropical soil ; Vertisols ; Enzyme activities ; Soil microbial biomass
- 刊名：Biology and Fertility of Soils
- 出版时间：May, 2009
- 出版年：2009
- 期刊代码：15_0178-2762
- 类别：ear
- 卷：45
- 期：5
- 页码：487-497
- 数据来源：sp
摘要
Microbial biomass, β-glucosidase and β-glucosaminidase activities, and availability, storage, and age of soil organic C were investigated after 26 years of conversion from sugarcane (Saccharum officinarum) to forest (Eucaliptus robusta or Leucaena leucocephala), pasture (mixture of tropical grasses), and to vegetable cropping (agriculture) in a vertisol in Puerto Rico. Soil organic C (SOC) at 0–100 cm was similar under Leucaena (22.8 kg C/m2), Eucalyptus (18.6 kg C/m2), and pasture (17.2 kg C/m2), which were higher than under agriculture (13.0 kg C/m2). Soil organic N (SON) at 0–100 cm was similar under the land uses evaluated which ranged from 1.70 (under agriculture) to 2.28 kg N/m2 (under Leucaena forest). Microbial biomass C (MBC) and N (MBN) of the 0–15-cm soil layer could be ranked as: pasture > Leucaena = Eucalyptus > agriculture. The percentages of SOC and SON present as MBC and MBN, respectively, were nearly 1%in pasture and less than 0.50%in forest under Leucaena or Eucalyptus and agricultural soil. The activity of β-glucosidase of the 0–15-cm soil layer could be ranked as: Leucaena = Eucalyptus > pasture > agriculture; while β-glucosaminidase activity was ranked as: Eucalyptus > Leucaena = pasture > agriculture. The soil δ 13C changed from 1996 to 2006 in forest under Eucalyptus (18.7‰ to 21.2‰), but not under Leucaena (20.7‰ to 20.8‰). The soil under Leucaena preserved a greater proportion of old C compared to the forest under Eucalyptus; the former had an increased soil mineralizable C from the current vegetation inputs. The soil under agriculture had the lowest enzyme activities associated with C cycling, lowest percentage of SOC as MBC, highest percentage of SOC present as mineralizable C, and highest percentage of MBC present as mineralizable C compared to the other land uses.