Soil carbon and nitrogen in pasture soil reforested with eucalyptus and guachapele

Revista Brasileira de Ciência do Solo

Fabiano De Carvalho Balieiro²  Marcos Gervasio Pereira¹  Bruno José Rodrigues Alves¹  Alexander Silva De Resende¹  Avílio Antonio Franco¹ 

[1] ,Embrapa SolosRio de Janeiro RJ

关键词: Mixed plantations;    Pseudosamanea guachapele;    Eucalyptus grandis;    soil organic matter;    13C natural abundance;    plantios mistos;    Eucalyptus grandis;    Pseudosamanea guachapele;    matéria orgânica do solo;    abundância natural do 13C;   

DOI  :  10.1590/S0100-06832008000300033

来源: SciELO

【 摘 要 】

In spite of the normally low content of organic matter found in sandy soils, it is responsible for almost the totality of cation exchange capacity (CEC), water storage and availability of plant nutrients. It is therefore important to evaluate the impact of alternative forest exploitation on the improvement of soil C and N accumulation on these soils. This study compared pure and mixed plantations of Eucalyptus grandis and Pseudosamanea guachapele, a N2-fixing leguminous tree, in relation to their effects on soil C and N stocks. The studied Planosol area had formerly been covered by Panicum maximum pasture for at least ten years without any fertilizer addition. To estimate C and N contents, the soil was sampled (at depths of 0-2.5; 2.5-5.0; 5.0-7.5; 7.5-10.0; 10.0-20.0 and 20.0-40.0 cm), in pure and mixed five-year-old tree plantations, as well as on adjacent pasture. The natural abundance 13C technique was used to estimate the contribution of the soil organic C originated from the trees in the 0-10 cm soil layer. Soil C and N stocks under mixed plantation were 23.83 and 1.74 Mg ha-1, respectively. Under guachapele, eucalyptus and pasture areas C stocks were 14.20, 17.19 and 24.24 Mg ha-1, respectively. For these same treatments, total N contents were 0.83; 0.99 and 1.71 Mg ha-1, respectively. Up to 40 % of the soil organic C in the mixed plantation was estimated to be derived from trees, while in pure eucalyptus and guachapele plantations these same estimates were only 19 and 27 %, respectively. Our results revealed the benefits of intercropped leguminous trees in eucalyptus plantations on soil C and N stocks.

【 授权许可】

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