Biomassa microbiana de carbono e de nitrogênio de solos sob diferentes coberturas florestais
Loading...
Files
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Revista Brasileira de Ciência do Solo
Abstract
O método da fumigação-extração foi utilizado para estimar a biomassa microbiana de carbono (BM-C) e de nitrogênio (BM-N) de um latossolo vermelho-amarelo, sob diferentes coberturas florestais, na região de Viçosa (MG), em amostras de solos coletadas em abril de 1994. Os solos sob eucalipto e pinheiro apresentaram valores maiores de BM-C (223,72 e 207,39 mg kg-1 de C no solo respectivamente) do que os solos sob angico e capoeira (82,94 e 79,47 mg kg-1 de C no solo respectivamen-te). Resultados semelhantes foram obtidos para a serapilheira acumulada. Por outro lado, a taxa de respiração específica da biomassa microbiana (TR-BM) foi maior no solo sob angico e capoeira. A BM-N variou de 8,05 a 16,08 mg kg-1 de N no solo entre as coberturas florestais. A TR-BM apresentou correlação negativa significativa com o N total do solo (r = -0,76**) e com a serapilheira acumulada (r = -0,68*). BM-N apresentou correlação negativa significativa com o N da serapilheira (r = -0,52*) e com o N mineral do solo (r = -0,71*). BM-C, BM-N e respiração acumulada (RA) foram positivamente correlacionadas com o C orgânico (r = 0,63*, r = 0,71* e r = 0,76* respectivamente). O N total correlacionou-se com BM-C e RA (r = 0,77* e r = 0,60* respectivamente). BM-C e BM-N, associadas aos teores de C orgânico, N-total e TR-BM, mostraram ser indicadores sensíveis para aferir a dinâmica desses elementos sob as coberturas vegetais estudadas, mostrando o menor potencial de decomposição da matéria orgânica nos solos sob eucalipto e pinheiro.
The fumigation-extraction method was used for measuring soil microbial biomass of C (BM-C) and N (BM-N) in a red-yellow latosol under different forest types. Soil samples from eucalypt and pine plantations presented higher values of BM-C (223.72 and 207.39 mg kg-1 of C in the soil, respectively) than samples from Piptadenia rigida and regenerating secondary forest (82.94 and 79.47 mg kg-1 of C in the soil, respectively). Similar results were obtained for the litter layer. On the other hand, the rate of the specific respiration of microbial biomass (TR-BM) was the highest in soil samples collected from the Piptadenia rigida plantation and regenerating secondary forest. The BM-N ranged from 8.05 to 16.08 mg kg-1 of N in the soil. The TR-BM was negatively correlated with soil nitrogen content (r = -0.76**) and with the amount of litter layer (r = -0.68*). The BM-N was also negatively correlated with the nitrogen content of the litter layer (r = -0.52*) and with soil mineral nitrogen content (r = -0.71*). BM-C, BM-N and respiration rate (RR) were positively correlated with soil organic carbon content (r = 0.63*, r = 0.71* and r = 0.76*, respectively). Soil nitrogen content showed significant positive correlation with BM-C and RR (r = 0.77* and r = 0.60* respectively). The results showed that BM-C and BM-N associated to soil organic carbon, soil total-N and TR-BM are sensitive indicators of the dynamics of these elements in the soil, indicating the lower potential of organic matter decomposition in soils under eucalypt and pine.
The fumigation-extraction method was used for measuring soil microbial biomass of C (BM-C) and N (BM-N) in a red-yellow latosol under different forest types. Soil samples from eucalypt and pine plantations presented higher values of BM-C (223.72 and 207.39 mg kg-1 of C in the soil, respectively) than samples from Piptadenia rigida and regenerating secondary forest (82.94 and 79.47 mg kg-1 of C in the soil, respectively). Similar results were obtained for the litter layer. On the other hand, the rate of the specific respiration of microbial biomass (TR-BM) was the highest in soil samples collected from the Piptadenia rigida plantation and regenerating secondary forest. The BM-N ranged from 8.05 to 16.08 mg kg-1 of N in the soil. The TR-BM was negatively correlated with soil nitrogen content (r = -0.76**) and with the amount of litter layer (r = -0.68*). The BM-N was also negatively correlated with the nitrogen content of the litter layer (r = -0.52*) and with soil mineral nitrogen content (r = -0.71*). BM-C, BM-N and respiration rate (RR) were positively correlated with soil organic carbon content (r = 0.63*, r = 0.71* and r = 0.76*, respectively). Soil nitrogen content showed significant positive correlation with BM-C and RR (r = 0.77* and r = 0.60* respectively). The results showed that BM-C and BM-N associated to soil organic carbon, soil total-N and TR-BM are sensitive indicators of the dynamics of these elements in the soil, indicating the lower potential of organic matter decomposition in soils under eucalypt and pine.