Effect of N, P and K fertilization on the species succession of an established grass sward during a decade

Abstract

Eff ects of diff erent soil N, P and K supply levels and their combinations were examined on the species composition of a grass sward between 2006 and 2015 in a fi eld experiment. Th e grass was established in autumn of 2000 with seed mixture of eight grass species. Th e calcareous chernozem loamy soil of the growing site contained around 3% humus, 3-5% CaCO 3 , 20-22% clay in the ploughed layer and was originally moderately supplied with available N and K, and relatively poorly supplied with P and Zn. Th e trial included 4N×4P×4K=64 treatments in 2 replications, giving a total of 128 plots. Th e cover of grass species was surveyed every year at the end of May before the fi rst cut. Perennial ryegrass (Lolium perenne), timothy (Phleum pratense), meadow fescue (Festuca pratensis) and red fescue (Festuca rubra) disappeared from the experiment in the fi rst few years. Crested wheatgrass (Agropyron cristatum) expanded through the years and required higher N and P supply to thrive. Smooth brome grass (Bromus inermis) was not a sown species, but established and expanded through the years. It benefi ted from N and K fertilization up to the highest supply, whereas a moderate P supply level was already satisfactory. Tall fescue (Festuca arundinacea) was the dominant species in the fi rst years, but was continuously supressed. It required moderate N fertilization, since higher doses reduced the cover below the level of N control. P control treatment was the most favourable, whereas K had a slightly positive eff ect. Th e cover of cocksfoot (Dactylis glomerata) also showed a decreasing trend. Moderate N supply was the most eff ective, whereas P and K had only a slight eff ect. Reed canarygrass (Phalaris arundinacea) could not really spread, but remained present sporadically during the studied period. It preferred fertilized plots over control plots. Cover of other plant species, primarily herbs, increased continuously from 2% to 30-37% through the years mainly on control, especially on N control plots. Th e species composition was considerably modifi ed by N, P and K supply of the soil.

Effect of Different Macronutrient Supply Levels on the Drought Tolerance of Rainfed Grass Based on Biomass Production, Water Use Efficiency and Macroelement Content

“…The evolution of the sward composition examined here was described earlier [42], and a previous study showed that, among the N, P and K treatments, K had the least effect on biomass production in this soil [43]. The objectives of the present study were to reveal the extent to which the soil N, P and K supplies improved the biomass production and WUE of the grass, and whether better macroelement supplies resulted in a significant biomass increase even in drier periods, when nutrient uptake may be inhibited.…”