The Rengen Grassland Experiment: relationship between soil and biomass chemical properties, amount of elements applied, and their uptake

Abstract

The Rengen Grassland Experiment (RGE) was established in the Eifel Mountains (Germany) on a low productive Nardetum in 1941. Since then, the following fertilizer treatments have been applied with a late two-cut system: unfertilized control, Ca, CaN, CaNP, CaNPKCl and CaNPK 2 SO 4 . We aimed to understand how concentrations of macro (N, P, K, Ca and Mg), micro (Cu, Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were affected by long-term fertilizer application, soil chemical properties and biomass production. In 2008, biomass samples from the first cut (early July) and the second cut (mid-October) were collected and analyzed. The simultaneous application of N, P and K decreased nitrogen concentration in the aboveground biomass, but substantially increased biomass production. Late cutting management decreased forage quality in highly productive more than in low productive plant communities. The concentrations of P and K in the plant biomass were positively related to P and K application and, therefore, to plant available P and K concentrations in the soil. The concentrations of some micro (Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were negatively correlated with the amount of elements supplied by fertilizers and biomass production, probably because of the dilution effect. Long-term fertilizer application resulted in the accumulation of macro (P, Ca and Mg), micro (Fe and Mn) and trace (As and Cr) elements in the soil, but in many cases this accumulation was not connected with an increase in the concentrations of these elements in the plant biomass. Nutritional status, as indicated by the biomass N:P ratio, was consistent with N or P limitation as indicated by the nitrogen and phosphorus nutrition indices. Furthermore, additional K (co-) limitation was indicated by the N:K and K:P ratios in the biomass from the NP treatment. The results from the RGE indicate that there is no simple positive relationship between the applied elements and their concentrations in the plant biomass.

Community Seasonal Development Enables Late Defoliation Without Loss of Forage Quality in Semi-natural Grasslands

“…Therefore, on the basis of our results it is not possible to declare that the described seasonal patterns of forage quality are typical for these vegetation units in general. But Hejcman et al (2010c) recently reported from a long-term fertilization experiment that late cutting management decreases forage quality more in highly productive (Arrhenatherion elatioris) than in low productive (Violion caninae) plant communities and this is consistent with our results.…”

Effects of grazing on seasonal variation of aboveground biomass quality in calcareous grasslands

“…For all nutrients, we found a significant decline from April to July. Decreasing nutrient concentrations during the growing season are a well-known phenomenon and could be traced back to ongoing senescence of plant tissues, changes in the leaf:stem ratio, nutrient allocation to roots and losses of, e.g., nutrient-rich seed biomass (Bobbink et al 1989;Marschner 2005;Hejcman et al 2010b;Mládek et al 2011). Reduced growth of young nutrient-rich plant tissues because of summer drought may also be a relevant factor (Kahlert et al 2005).…”

Can Festulolium, Dactylis glomerata and Arrhenatherum elatius be used for extension of the autumn grazing season in Central Europe?

“…Due to the low N fertilizer levels, the species that were developed for relatively intensive management conditions such as Festulolium had an extremely low CP content. This can be an effect of senescence and retranslocation of N into storage organs (Hejcman et al 2010). Archer and Decker (1977) determined that the CP content in Festuca arundinacea was lower compared to Dactylis glomerata in the autumn.…”