Soil nematode assemblages in an acid soil as affected by lime application

Abstract

Liming can affect soil biota through alterations in soil pH and soil structure. Many earlier studies monitored the responses of soil nematode communities to lime application but they did not come to a consensus and did not use indices of soil nematode community and multivariate statistical approaches developed over the past two decades. The present research explored the short-term effects of lime application on soil nematode communities in an acrisol in threeEucalyptusplantations in southern China. Nematodes were sampled from control and lime-treated plots at three periods from October 2011 to February 2012 at 0-10 cm and 10-20 cm soil depths. Repeated measures ANOVA showed that lime application significantly reduced the abundance of herbivores at 10-20 cm depth during the study. Lime application tended to increase the bacterivore index at 0-10 cm depth over time. Principal response curves of soil nematode community structure, in terms of nematode trophic group composition, revealed that the differences between control and lime application treatments increased over time, primarily because of the decline of fungivores in plots treated with lime. The decline in fungivores resulted mainly from declines ofFilenchusandDitylenchus. The results suggest that the fungal-mediated decomposition channel in the soil food web was suppressed by lime application. Our study also demonstrated that the sensitivity of different nematode genera to lime application varied widely, even for genera within the same trophic group. In particular, the abundance of several bacterivorous genera (Prismatolaimus,Plectus,Wilsonema,Protorhabditis,DiploscapterandHeterocephalobus) gradually declined and that ofRhabditonemaat 0-10 cm depth gradually increased following lime application during the study; two herbivorous genera,TrophotylenchulusandHelicotylenchus, had opposite responses to lime application at 0-10 cm depth. Integrating univariate statistical approaches with multivariate approaches facilitated the analysis of soil nematode responses to lime application.