Grassland Management Affects Plant Leaf Nutrients Under Ambient and Future Climate

Climate change and agronomic management are major drivers altering Central European anthropogenic grassland ecosystems, but little is known about how these drivers interact in their effects on plant nutrient concentrations and ratios. This study was conducted in a climate change field experiment (higher temperature and changed seasonal precipitation pattern) in Central Germany with species-rich non-fertilized grasslands managed either by two times mowing (meadow) or three times sheep grazing (pasture) per year. In spring 2022, during peak plant growth, we collected leaves of five plant species per functional group (grasses, legumes, non-legume forbs) as well as topsoil samples and determined plant leaf and plant available soil nutrient concentrations (N, P, K, Ca, Mg, S) and ratios. Plant functional groups differed in leaf concentrations of all studied nutrients with the exception of sulfur. The future climate treatment (compared to ambient climate) resulted in lower leaf N:P ratios across both management types and did not show any other effects on leaf or soil nutrients. Independent of the climate treatment, leaf and soil K concentrations were higher, while leaf Ca concentrations were lower in pastures compared to meadows. In addition, grasses had higher leaf N, legumes higher leaf S concentrations but lower leaf N:P ratios, and forbs lower leaf S concentrations in pastures than in meadows. While we found no interactive effect of climate and management and little effects of the rather moderate future climate treatment, the observed differences between pastures and meadows indicate that management, even at low intensity, modifies plant and soil nutrients in grasslands.