Transformations of carbon and nitrogen in a Calciorthid soil amended with a range of organic residues

Abstract

A calcareous soil was treated with an organic fertilizer mixture of grape debris and peat, or with pig manure, chicken manure, city refuse or with aerobic or anaerobic sewage sludges. Changes in different fractions of carbon and nitrogen were followed by analysis of the soil, immediately after these additions, after they had decomposed for six months in the soil, after a maize harvest, and after a subsequent barley harvest.The various forms of carbon had decreased after six months. The rate of decrease varied with the nature of the organic materials. In all samples, the fulvic acids fraction decreased most. The main transformations happened during the first six months whether there was a crop growing or not, but the crops had no influence on the breakdown of the organic materials.The ratio of humic acids/fulvic acids had increased after six months of humification and, in general terms, the final values of the ratio oxidizable carbon/extractable carbon were lower than the initial ones, indicating a higher degree of humification in the organic matter by the end of the experiment.The total nitrogen level remained practically constant after the first six months of humification even after the second crop. Part of the organic nitrogen of the soil samples amended with chicken manure, city refuse or the two sludges was transformed into mineral nitrogen during the humification process. The extractable nitrogen values increased because of the fertilizer applied during the pot trials.

Bioremediation of Sewage Sludge by Composting

“…The composting process can avoid "nitrogen starvation" in the soil since the microorganisms would otherwise have an excess of labile substrates available, and increase their activity, thus consuming great quantities of nitrogen, which would not therefore be available to plants. [20,21] The carbon mineralization is principally due to the biosolid (sewage sludge) since wood shavings have a more consistent structure (lignin and lignocellulose type compounds) and are less accessible to microbial attack. [20,21] The carbon mineralization is principally due to the biosolid (sewage sludge) since wood shavings have a more consistent structure (lignin and lignocellulose type compounds) and are less accessible to microbial attack.…”

Qualidade De Grãos De Soja Transgênica Rr E Intacta Rr2 Pro Na Secagem

“…Para Smith (1994), a aplicação de N no solo diminui a relação C/N da palhada de gramíneas, o que pode ativar o processo microbiano de decomposição, realizado principalmente por bactérias e fungos, que são considerados os decompositores primários. Segundo Hernandez et al (1988), nesta condição haverá a mineralização do nitrogênio que é necessário para o crescimento dos microrganismos, que por sua vez irão decompor mais rapidamente a matéria orgânica do solo em função do baixo teor de carbono da água residuária da mandioca.…”

Plantas De Cobertura De Inverno E a Sua Influencia Sobre Os Componentes De Produção Da Cultura Da Soja

“…Para Smith (1994), a aplicação de N no solo diminui a relação C/N da palhada de gramíneas, o que pode ativar o processo microbiano de decomposição, realizado principalmente por bactérias e fungos, que são considerados os decompositores primários. Segundo Hernandez et al (1988), nesta condição haverá a mineralização do nitrogênio que é necessário para o crescimento dos microrganismos, que por sua vez irão decompor mais rapidamente a matéria orgânica do solo em função do baixo teor de carbono da água residuária da mandioca. Aita (1997) relata que a população e a atividade dos microrganismos decompositores são muito influenciadas pela quantidade de N no solo, e o aumento na disponibilidade de N pode favorecer a taxa de decomposição.…”