Response of grassland vegetation composition to different fertilizer treatments recorded over ten years following 64 years of fertilizer applications in the Rengen Grassland Experiment

Abstract

QuestionsFertilizer application is a key driver affecting the diversity and conservation value grassland vegetation. Using a long‐term fertilization experiment in mountain grassland, we addressed the following questions: (a) what is the effect of long‐term fertilizer applications on species richness and plant species composition, and (b) is there any detectable trend in plant species composition during ten years of continuous observation?LocationThe Rengen Grassland Experiment, Eifel Mountains, Germany (established in 1941).MethodsFive treatments including different fertilizers applied annually and one unfertilized control were analysed: Ca (718 kg Ca ha−1); CaN (752 Ca and 100 N kg ha−1); CaNP (752 Ca, 100 N and 35 P kg ha−1); CaNP‐KCl (752 Ca, 100 N, 35 P and 133 K kg ha−1); CaNP‐K2SO4 (752 Ca, 100 N, 35 P and 133 K kg ha−1). The experiment included five replicates per treatment in a fully randomized block design. All treatments were cut twice a year in late June or early July, and in mid‐October. Percentage cover of individual plant species was estimated by visual observation in each plot in late June in the years 2005–2014.ResultsDespite inter‐annual variability in the cover of the individual vascular plant species, the multivariate data analyses revealed a relatively similar response of the plant community to the different fertilizer applications throughout the ten years. With phosphorus application, no differences in botanical composition among treatments were found; however, they did differ from other treatments without phosphorus application. In the unfertilized control, there was a certain directed trend in plant species composition in response to ongoing nutrient impoverishment.ConclusionSpecies‐rich grasslands of high nature conservation value were only maintained under P limitation in the control without fertilizer application (Violion caninae) and in the liming treatment (Polygono‐Trisetion), but also in the treatment with liming and pure N addition. It seems that after 74 years, some stage of equilibrium of the grassland community was achieved in all treatments receiving any type of fertilizer application, but less so in the unfertilized control treatment.

Effect of 15‐year sward management on vertical distribution of plant functional groups in a semi‐natural perennial grassland of central Europe

“…For instance, Festuca rubra (one of the dominant grass species in our experimental site), which has many ecotypes (Grime et al, 1988) in comparison with other common grass species, is well adapted to various abiotic conditions including drought. Its variability in time can be explained by compensatory dynamic (Lepš et al, 2018) in which cover of species like Festuca rubra can increase even under dry conditions (Titěra et al, 2020) while compensating for the possible decline in cover of other species like Poa trivialis, which is less tolerant to drought (Peeters et al, 2004). Gaisler et al (2018) also reported similar results from a long‐term experiment (13 years) in which different functional groups such as tall graminoids and tall forbs fluctuated without any clear stable trend for any particular treatment.…”

“…These disparities between different studies may be explained by differences in experimental sites’ environments such as nutrient supply, water or light/shade conditions (Milchunas & Lauenroth, 1993; Borer et al, 2014). Especially leguminous species are generally known for their positive response to P and K and negative response to the high inputs of N, NP or NPK (e.g., Čop & Eler, 2019; Titěra et al, 2020).…”

Applied Vegetation Science: Editorial 2021

“…The second article we want to mention (Titěra et al ., 2020) focused on one of the oldest continuously running ecological experiments on the European mainland: the Rengen Grassland Experiment in western Germany, established in 1941 (Hejcman et al ., 2007). For 10 years (2005–2014), the authors recorded plant species composition and covers of individual species in permanent plots with different fertilizer application treatments.…”

Why westillneed permanent plots for vegetation science

“…If long‐term experiments like the Park Grass (see above) or the Rengen Grassland Experiment (Hejcman et al ., 2007; Titěra et al ., 2020) are rare, even rarer is the possibility to compare the consistency of results, using comparable set‐ups, across different regions of the world. Ward et al .…”