Carbono e nitrogênio de um Argissolo Vermelho sob floresta, pastagem e mata nativa

Organic Carbon, Nitrogen and the Stability of Soil Aggregates in Areas Converted From Sugar Cane to Eucalyptus in the State of Alagoas

“…Analysing the values for N stock throughout the soil profile (0-80 cm), a significant increase can be seen under the E6 system. The high values for N stock seen in the oldest area of Eucalyptus (E6) is possibly related to the greater proportion of woody material (mainly in the branches) deposited in the litter, and to the higher concentration of phenolic compounds, cellulose and lignin, with notably greater quantities of N (Pillon et al, 2011;Barreto et al, 2014). The variation in N values between systems may have occurred due not only to the age of the eucalyptus plantations, but also to the clay content and to environmental factors, especially temperature, humidity, soil type and relief (Rodrigues et al, 2013).…”

“…These factors contribute to an increase in soil organic matter (SOM) and consequently to the maintenance of organic carbon (OC) sinks (Ibiapina et al, 2014). It is said that eucalyptus plantations, when properly managed, can store between 50 and 400 Mg C ha -1 (Pulrolnik et al, 2009;Pillon et al, 2011), however, the fixation and storage of C in the soil depends on various factors, such as, the type of soil, local climate conditions, cropping system and management. (Gatto et al, 2010;Ibiapina et al, 2014;Marques et al, 2016).…”

C and N stocks in Brazilian woodland savanna (Cerradão) under different land uses, and their dynamicas in the soil

“…The higher values of soil nitrogen variables in the uppermost layer could be explained by a higher organic matter content and microbial activity in that layer (Kizilkaya and Dengiz, 2010), as the most common factors affecting soil nitrogen cycling are substrate quality and quantity, size of microbial biomass pool, availability of soil carbon, and soil moisture content . decomposition and the nutrient cycling (especially for C and N) due to the presence of antibacterial substances (Bruna et al, 1989) and high litter C:N ratios (Pillon et al, 2011), which can reduce the bacteria population (including nitrifying bacteria). In fact, the lowest values of NH4-N and PMN are found in the Eucalyptus plantations.…”

“…According to Pegoraro (2007), high quantities of more coarse and lignified plant residues are found in Eucalyptus stands, while pasture litter has less lignin and tannin and is easier to decompose by microbes . Besides, Eucalyptus leaves have antibacterial substances that hinder organic matter decomposition (FIorenzano, 1957;Bruna et al, 1989), as well as high C:N ratio (Pillon et al 2011), that reduces bacteria populations (including nitrifying bacteria) (Ferreira et al, 2016).…”