Effect of nitrogen and phosphorus availability on the emergence, growth and over‐wintering of Rumex crispus and Rumex obtusifolius

Abstract

Rumex crispus and R. obtusifolius are known to be nitrophilous but it is not known whether either or both species require a high N supply at all developmental stages. Furthermore, it is not clear whether both species require a high P supply, attain flowering in the seeding year, or have similar levels of winter resistance. The effect of nutrient availability on the emergence, growth and over-wintering of both Rumex species was investigated in a pot experiment (ten N, P and K fertilizer treatments) in Prague, Czech Republic. In both species, emergence of seedlings was negatively affected by very high N, but positively affected by increased P availability in the soil. No effect of K supply on the emergence, or subsequent growth, was recorded. High flowering in the seeding season and high winter mortality of R. obtusifolius contrasted with no flowering and no mortality of R. crispus. Over-wintering was not markedly affected by N, P or K supply. Both Rumex species are sensitive to a very high N supply in early developmental stages but tend to require a high N supply from the fully developed rosette-stage onwards. In addition to high N requirements during stem growth, flowering and seed ripening, both species also require a high P supply. At least some Central European populations of R. crispus, in contrast to R. obtusifolius, do not flower in the seeding year. In Central Europe, the frequently reported high field winter mortality of R. obtusifolius can be caused by its low frost resistance.

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

“…Consequently, a reduced cutting frequency may also directly inhibit weed growth by giving the plants more time to produce inflorescences before they get cut. In a pot experiment, Křišt'álová et al (2011) confirmed a high winter mortality of R. obtusifolius which weakly tended to be alleviated by increased nutrient availability. Under field conditions, the death rate during severe winter seasons could increase in extensively managed grassland due to less nutrient supply and unrestrained grass competition.…”

“…The lack of any effect of management extensification on R. obtusifolius at the Ca-and Mg-rich site 2 may have been due to its naturally high K content. Křišt'álová et al (2011) reported a high phosphorus (P) requirement of R. obtusifolius in all life phases. In calcareous soils the plant availability of P is reduced by the precipitation of calcium-phosphates (Lee 1999;Tunesi et al 1999).…”

“…Potassium might play a particular role for the species competitiveness by sustaining the broad leaves (Bohner 2001) and facilitating the transport of energy reserves to the taproot (Humphreys et al 1999). Křišt'álová et al (2011) detected a positive effect of increased phosphorus availability on seedling emergence as well as a high phosphorus requirement during rosette growth, stem growth, flowering and seed ripening. Furthermore, the authors found that, in early developmental-stages, R. obtusifolius was negatively affected by high nitrogen supplies, whereas from the fully developed rosette-stage onwards the species showed high nitrogen requirement.…”

“…Since, in practice, cutting frequency and manure amount are usually linked, the hypothesis was that the combined reduction of cutting frequency and manure amount reduces R. obtusifolius density. Based on the literature (Humphreys et al 1999;Křišt'álová et al 2011) we expected a remarkable influence of soil conditions on the results. In order to get information on the relations between soil factors and the weeds performance at the three sites, we correlated R. obtusifolius densities with soil chemical properties.…”

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

“…The seedlings were grown from seeds of R. obtusifolius and R. crispus collected during autumn 2007. To ensure direct comparability of the results with results of two previous experiments [pot fertiliser experiment by Křišťálová et al (2011) and field transplantation experiment by Strnad et al (2012)], the same seeds were used. Seed material for seedling production was collected from three sites (roadside ditches and abandoned fields) close to Prague, Czech Republic.…”