Effects of management intensity and soil chemical properties on Rumex obtusifolius in cut grasslands in Lower Austria

Abstract

Rumex obtusifolius (broad-leaved dock) is a widely distributed weed in managed grasslands and is an indicator for excessive grassland management. Especially in organic farming, its control is highly labour and energy intensive. The effects of management extensification on R. obtusifolius were investigated by on-farm trials with reduced cutting frequencies and manuring amounts from 2004 to 2006 at three sites in Lower Austria. The sites distinctly differed in their nutrient availabilities (LiClextract; Ca: ranged from 1,380 to 2,062 mg/kg DM, Mg: 211-611 mg/kg, P: 4-40 mg/kg, K: 57-334 mg/kg). At one site reduced management intensity had a significant decreasing effect on R. obtusifolius infestation, whereas at the other sites no effect was observed. Consequently, extensification as a measure for controlling this weed can be effective under certain conditions. Soil analyses indicated that Ca and Mg concentrations were negatively correlated to R. obtusifolius density, and the site where infestation declined under reduced management was characterised by abundant Ca and Mg in the topsoil. K showed a weak positive correlation with plant density development and P was not related to R. obtusifolius. According to the literature, an abundance of Ca and Mg in the soil could reduce the competitiveness of the species. Consequently, high concentrations of these nutrients might enhance the probability for an effective R. obtusifolius control by management extensification. Further research is required to clarify the influence of Ca and Mg on the competitiveness of R. obtusifolius, and may lead to recommendations for the management of this weed.

Effects of nutrient availability on performance and mortality of Rumex obtusifolius and R. crispus in unmanaged grassland

“…Higher mortality under low nutrient availability and no mortality under high nutrient availability in unmanaged grassland are consistent with results from the cut grassland: 13% mortality in unfertilised treatment and no mortality in NPK treatment (Strnad et al 2012). The mortality and life-span of individual R. obtusifolius plants is therefore highly affected by soil fertility in grasslands: this was also recorded by Humphreys et al (1999) or by Hann et al (2012). High mortality of R. obtusifolius recorded in unmanaged grassland by Martinkova et al (2009) was thus probably at least partly connected with shortage of nutrients, most probably N and/or P. In addition, high mortality can also be connected with high soil Ca status, as was recorded by Hann et al (2012).…”

“…Rumex obtusifolius and, in part, R. crispus are considered to require high nutrient supply (Grime et al 1988;Humphreys et al 1999;Jursík et al 2008; Křišťálová et al Calculated by one-way ANOVA, effect of treatment on sampling date was significant on 0.001 (***) probability level 2011), but the effect of nutrient availability on performance and mortality of both species has been investigated only in cut grasslands (Niggli et al 1993;Hopkins and Johnson 2002;Hann et al 2012;Strnad et al 2012). Cutting management can substantially affect life-span of individual plants, and therefore results from cut grasslands are not transferable into unmanaged grasslands (Martinkova et al 2009).…”

“…In Europe, R. obtusifolius is highly successful in grasslands supplied with high N, P and K application rates (Niggli et al 1993;Humphreys et al 1999;Hopkins and Johnson 2002;Strnad et al 2010). Reduction in fertiliser supply and cutting frequency can be an effective strategy for R. obtusifolius control, especially on basic soils heaving a high Ca and Mg status (Hann et al 2012).…”

“…obtusifolius L. (broad-leaved dock, hereafter referred to as R. obtusifolius) in temperate grasslands has received high research attention (Zaller 2004(Zaller , 2006Bayhan et al 2006;Van Evert et al 2009;Gilgen et al 2010;Stilmant et al 2010;Strnad et al 2010;Hrdličková et al 2011;Hann et al 2012). This is because R. obtusifolius is considered to be one of the most troublesome grassland weedy species worldwide due to: (1) its general avoidance by grazing livestock, especially cattle and horses; (2) its negative effects on forage quality, as it induces health problems if eaten in high quantity and (3) its negative effects on biomass production of desired forage species by competition for space, water and nutrients (Zaller 2004).…”

Effects of drought and subsequent rewatering on Rumex obtusifolius leaves of different ages: reversible and irreversible damages

“…It has been reported by several groups that substances present in the leaves of R. obtusifolius are able to suppress neighboring species (Carral et al 1988;Zaller 2006). In this context, it must be also borne in mind that the abundance of R. obtusifolius is known to be correlated with soil K concentration (Humphreys et al 1999;Hann et al 2012). Large amounts of K may leak in the rain from leaves of this species and may locally increase the K level in the soil around the R. obtusifolius plants.…”