Mineralização do resíduo da pupunheira em condições de campo e laboratório

Abstract

RESUMO:Objetivou-se, neste trabalho, estudar o processo de decomposição do carbono (CO) e nitrogênio orgânico (NO) dos resíduos da pupunheira, em condições de campo e laboratório, e em duas formas de aplicação: com incorporação ou em disposição superficial no solo. O experimento de campo foi conduzido em Cambissolo Háplico Tb distrófico latossólico (CXbd), nas condições climáticas tropicais do período de primavera/verão, na cidade de Viçosa-MG, Brasil. Os resíduos foram incubados em condição de campo e laboratório, durante 112 dias, período no qual foram retiradas amostras para a análise das concentrações mineralizadas do CO e NO. A degradação do resíduo foi mais intensa em condição de campo que na de laboratório, e a incorporação do resíduo no solo acelerou a degradação nas duas condições de incubação do material. Os métodos utilizados para a estimativa dos coeficientes e frações de mineralização do CO e disponibilização do nitrogênio inorgânico, em condição de laboratório, geraram resultados condizentes com os obtidos na condição de campo, contudo subestimaram consideravelmente os valores obtidos. PALAVRAS-CHAVE:degradação, matéria orgânica, fração de decomposição. MINERALIZATION OF PEACH PALM WASTE UNDER FIELD AND LABORATORY CONDITIONSABSTRACT: The objective of this study was to evaluate organic carbon (OC) and organic nitrogen (ON) decomposition in peach palm waste under field and laboratory conditions. Application was performed by both incorporating and releasing the waste onto soil surface. Field experiment was carried out on an Inceptisol under tropical conditions during the spring and summer seasons in Viçosa -MG, Brazil. The waste was incubated under field and laboratory conditions for 112 days within which samples were taken for analysis. We noted that waste was more intensely degraded under field conditions than in lab environment. Moreover, waste incorporation into soil accelerated the degradation under both incubation conditions. The estimation methods for coefficients and fractions of OC mineralization, inorganic nitrogen availability under lab condition produced results consistent with field ones; however, they were considerably underestimated.

Coffee straw mineralization applied to the soil surface

“…5b). This fact was also verified by Pereira et al (2015) and Paula et al (2013), when studying the mineralization of several residues in the soil. Paula et al (2013) concluded that the levels of inorganic nitrogen and, consequently, of organic nitrogen, are subject to the OCeo-easily oxidized organic carbon; TOC-total organic carbon; TN-otal nitrogen; MN-mineral nitrogen; ON-organic nitrogen; MfOCeo-mineralized fraction of organic carbon; MfON-mineralized fraction of organic nitrogen strong influence of climatic variations and, for this reason, have generated unreliable estimates of the mineralized fraction of the organic residues studied, as occurred in the present study.…”

“…Comparing these results with those obtained by other authors, although they used other organic residues, it is verified that the organic carbon mineralization process in the present work was slower. When studying the decomposition process of organic carbon and organic nitrogen in peach-palm residues applied superficially to the soil or incorporated, at field and laboratory conditions, Pereira et al (2015), verified that the estimated mineralized fraction of OCeo was 50.98% after 28 days of incubation of the residue when it was applied on soil surface. Paula et al (2013), when analyzing different methods of estimating the mineralized fractions of cattle, pig and poultry manure, as well as sewage sludge and urban waste compost, incorporated or disposed superficially on a Dystrophic Red-Yellow Latosol (LVAd), verified that the estimated OCeo mineralized fractions were, after 30 days of incubation of the residue, higher than 75.6%, in the superficially disposed residues.…”

“…Among other benefits, the correct disposal of organic residues in the soil improves the structure and stabilization of aggregates, increasing total porosity, ameliorating physical water-related conditions, boosting water retention capacity and complexation/chelation of toxic substances. On the other hand, if the amount of organic residues disposed is above the soil supporting capacity or the crops nutrient requirements, it can generate environmental problems such as nitrogen losses, increase in the population of pathogens and vectors and in the concentration of heavy metals, as well as soil salinization (Pereira et al, 2015).…”

“…Therefore, studies were carried out aiming to evaluate the mineralization and degradation of some residues in the soil (Pereira et al, 2015;Paula et al, 2013;Diniz et al, 2016), being the mineralized fraction an important variable to prescribe the doses or amounts of organic matter that should be used in the fertilization program (Paula, 2012). Obtaining this is, however, complex.…”

Uso de Substrato Compostado na Produção de Mudas de Eucalyptus dunnii e Cordia trichotoma

“…A menor relação C/N no SC (18,6) e nos substratos provenientes da compostagem (RRU e LPF) provavelmente contribuiu para o maior crescimento das mudas de E. dunnii devido à maior disponibilidade de nitrogênio proveniente da mineralização da fração orgânica que, segundo Pereira (2013), apresenta relação inversa entre a relação C/N e a disponibilidade de nitrogênio no substrato. Nos substratos com elevada relação C/N (RLD e DLB), provavelmente a baixa disponibilidade de nitrogênio devido à imobilização do nutriente pelos microrganismos no processo de decomposição dos resíduos orgânicos tenha sido o fator que afetou o crescimento das mudas de E. dunnii (Andreani et al, 2011).…”