Comparing sugarcane fields and forest fragments: the effect of disturbance on soil physical properties and nematode assemblages

Abstract

Comparisons of agricultural and natural ecosystems reveal the magnitude of the effects of agricultural practices on the diversity and abundance of soil nematodes. Consequently, there is the need for testing ecological hypotheses, specifically with regard to nematode ecology, in natural and agricultural soils to seek strategies for biological control and environmental monitoring. We studied soil nematode assemblages and soil physical attributes of five soil layers (0-10, 10-20, 20-30, 30-40 and 40-50 cm) from sugarcane plantations and forest remnants in the sugarcane zone of Pernambuco State, Brazil. Structure and composition of the nematode assemblage and soil properties differed between forest and sugarcane soils, even in the same locality. The soil bulk density and the abundance of all nematodes and the diversity of plant-parasitic nematodes were greater whereas soil porosity, soil respiration and abundance of predator nematodes were smaller in sugarcane than in forest areas. We suggest that sugarcane management practices result in changes in the soil properties and concomitantly alter the composition and structure of the nematode assemblages. Co-inertia analysis indicated that others environmental factors also might be affecting the nematofauna.

Nematode abundance and diversity in sugarcane fields in Brazil

“…The relatively low number of omnivores corroborates other studies in sugarcane fields (Rodrigues et al 2011;Cardoso et al 2015), reflecting the human intervention (Freckman and Ettema 1993;Gomes et al 2003). The low numbers of Mononchus (predator) are characteristic of this agricultural system as well (Cardoso et al 2015).…”

“…In Brazilian northeastern, these environments have been cultivated with sugarcane for several decades, modifying the ecosystem and increasing the number and ratio of plant-parasitic nematodes, especially the endoparasitic Meloidogyne and Pratylenchus, which is probably due to a more suitable condition inside roots. Genera Criconemella, Helicotylenchus, Trichodorus, and Paratrichodorus are common in the region (Chaves et al 2003;Moura 2005;Rodrigues et al 2011;Cardoso et al 2015), though in low numbers (Spaull and Cadet 2005). The plant-parasitic nematodes are prevalent in sugarcane growing fields around the world (Berry et al 2007;Stirling et al 2010;Berry et al 2011;Steven et al 2014;Cardoso et al 2016;Zhang et al 2017) as well as in northeastern Brazil (Chaves et al 2002(Chaves et al , 2003Barros et al 2005;Vicente et al 2016).…”

“…The sandy soils, with high temperatures and low levels of organic matter increases the effect of water deficit on plant stress and therefore intensify the damage of the plant-parasitic nematodes (Omarjee et al 2008;Kimenju et al 2009). The use of a sugarcane genotypes susceptible to nematodes (Chaves et al 2007;Silva et al 2012;Silva et al 2016) also contributes to the dominance of Meloidogyne and Pratylenchus, although the ectoparasites Helicotylenchus and Criconemella are found in the fields, but in low levels (Cardoso et al 2015).…”

Agricultural intensification and urbanization negatively impact soil nematode richness and abundance: a meta-analysis

“…Soil nematode assemblages can serve as ecological indicators since different nematode taxa vary in their sensitivity to disturbances in a terrestrial ecosystem (Bongers, 1990;Neher et al, 2005). Extensive research has been conducted on abundance and richness of nematode assemblages in different ecosystems but very few studies have been conducted to compare the impact of disturbances on nematode abundance and richness among two or more ecosystems (Neher et al, 2005;Briar et al, 2007;McSorley and Wang, 2009;Cardoso et al, 2015). Recently, meta-analysis was conducted using the literature published on soil nematodes to analyze soil energy pathways in different ecosystems (Zhao and Neher, 2014) and the effect of organic and inorganic fertilizers on soil nematodes in croplands (Liu et al, 2016).…”

“…However, there is no single consensus about the pattern of nematode abundance and richness in different ecosystems across the published literature. Some authors have reported that richness is high in forest ecosystems and abundance is high in agricultural ecosystems (Yeates and Ferris et al, 2001;Yeates, 2007;Cardoso et al, 2015) but others have stated the converse (Neher et al, 2005;Briar et al, 2007;Darby et al, 2007;Kimenju et al, 2009). The existence of a large body of literature with diverse results creates the need to synthesize quantitative summaries in order to draw general conclusions across studies and test key hypotheses regarding patterns and processes governing soil biodiversity.…”