Nematode assemblages in banana (Musa acuminata) monocultures and banana plantations with Jucara palms (Euterpe edulis) in the southern Mata Atlantica, Brazil.

摘要

The composition of the nematode fauna at two different agrosystems (banana monocultures and mixed banana-palmito plantations) was investigated at six study sites on the coastal plain of southern Brazil. Nematode abundance was higher and the number of families was lower (25 compared to 33) in the soil of banana monocultures. The assemblages in the soil of the banana monocultures were dominated by bacterial feeders and plant parasites, whereas in the soil of the mixed plantations the proportion of the other trophic groups was higher. In the monocultures, the percentage of families categorised as colonisers (c-p 1 families) was higher and the persisters lower. The difference in the assemblage of c-p groups was significant between sites of the two different systems. Principal component analysis (PCA) ordination of the samples by nematode family composition showed site-specific assemblages, similarity between two sites of each system and significant dissimilarities between the two systems. The MI 1-5 and the MI 2-5 were lower in the banana monocultures. Additionally, the MI 2-5 of banana site B2 was significantly higher than that of the two other banana sites. The ratio F/B was higher and the ratio (F+B)/plant feeders was lower in the banana-palmito plantations. The differences between the systems in nearly all measured parameters indicate a higher degree of disturbance and nutrient enrichment of the soil under monocultures. However, a low number of plant parasites and dominance of c-p 3 taxa at both agroecosystems show that the soil of both agroecosystems seems to be of an advanced successional stage. This may be a result of a less intensive 'organic' cultivation without the use of plant protection products and fertilisers and with additional non-host plants. Despite many non-controlled variables in the smallholder systems, according to the results the nematodes can be regarded as suitable indicators of soil disturbance in banana and banana-palmito agro-ecosystems.