Soil C and N stocks as affected by cropping systems and nitrogen fertilisation in a southern Brazil Acrisol managed under no-tillage for 17 years

被引：213

作者：

Diekow, J

Mielniczuk, J

Knicker, H

Bayer, C

Dick, DP

Kögel-Knabner, I

机构：

[1] Univ Fed Rio Grande do Sul, Fac Agron, Dept Solos, BR-90001970 Porto Alegre, RS, Brazil

[2] Tech Univ Munich, Lehrstuhl Bodenkunde, D-85350 Freising Weihenstephan, Germany

[3] Univ Fed Rio Grande do Sul, Inst Quim, Dept Quim Fis, BR-90001970 Porto Alegre, RS, Brazil

来源：

SOIL & TILLAGE RESEARCH | 2005年 / 81卷 / 01期

关键词：

C stock; N stock; cropping systems; legumes; N fertilization; no-tillage;

D O I：

10.1016/j.still.2004.05.003

中图分类号：

S15 [土壤学];

学科分类号：

0903 ; 090301 ;

摘要：

Soil organic matter is an ecosystem component with agronomic and environmental functions and is affected by soil management. The objectives of this study were to evaluate (i) soil organic C and N losses during a period of conventional cultivation (1969-1983) that followed on native grassland and (ii) the potential of four long-term (17 years) no-till cereal-and legume-based cropping systems (bare soil, oat (Avena strigosa Schreb.)/maize (Zea mays L.), lablab (Lablab purpureum L. Sweet) + maize and pigeon pea (Cajanus cajan L. Millsp.)+maize) with different N fertilisation levels (0 and 180 kg N ha(-1) year(-1)) to increase the C and N stocks of a southern Brazilian Acrisol. Samples were taken from 0 to 107.5 cm depth, in 10 soil layers. The C content in the 0-17.5 cm layer of grassland decreased by 22% (8.6 Mg C ha(-1)) during the period of conventional cultivation. Meanwhile, N decreased by 14% (0.44 Mg N ha(-1)). Additional C and N losses occurred after the establishment of bare soil and oat/maize (no N). With N fertilisation, the C and N stocks of oat/maize were steady with time. Legume-based cropping systems (lablab + maize and pigeon pea + maize) increased C and N stocks due to the higher residue input. Although the major soil management effects were found in the 0-17.5 cm layer, up to 24% of the overall C losses and up to 63% of the gains of the whole 0-107.5 cm layer occurred below the 17.5 cm depth, reinforcing the importance of subsoil as a C source or sink. The average C sequestration rate of legume-based cropping systems (with N) was 0.83 Mg C ha(-1) year(-1) in the top 0-17.5 cm layer and 1.42 Mg C ha(-1) year(-1) in the whole 0-107.5 cm layer, indicating the remarkable potential of legume cover crops and N fertilisation under no-tillage to improve SOM stocks and thus, soil and environmental quality in humid subtropical regions. (c) 2004 Elsevier B.V. All rights reserved.

引用

页码：87 / 95

页数：9

共 25 条

[1] Organic matter storage in a sandy clay loam Acrisol affected by tillage and cropping systems in southern Brazil [J].