Organic fertilization and hayseed application in traditional hay meadows : a pathway to biodiversity and ecological sustainability

In Central Europe, low-intensity and low-input agriculture has fostered biodiverse landscapes and species-rich semi-natural grasslands, but implementation and ecological context of historical land-use practices remain poorly understood. We investigated meadow management practices that enhance hay productivity and quality in Poienile de sub Munte, Romania, a village with well-maintained historical land-use patterns. Specifically, we examined: (i) the implementation of manuring, ash fertilization, and hayseed application; (ii) their effects on plant species composition and diversity; and (iii) their potential in modern grassland conservation and restoration. Our study analyzed 47 vegetation plots, 30 hayseed samples, and land-use data from 30 farmers. Manure was mainly applied on gentle slopes, whereas ash was used in steep and hard-to-access areas. Hayseed was applied in 47 % of one-cut meadows and 33 % of two-cut meadows. Vegetation composition was primarily influenced by mowing frequency, soil calcium content, and the frequency of manuring and ash fertilization. Manuring decreased species richness by seven species through competitive exclusion favoring nitrogen-demanding species. In contrast, ash fertilization promoted oligotrophic specialists, including rare and vulnerable species, while increasing species richness by approximately seven species. Regular hayseed application enhanced richness through propagule supply without significant effect on vegetation composition. Hayseed composition differed from standing vegetation and was influenced by mowing time, with first-cut hay containing significantly more species and marginally more seeds than second-cut hay. Hayseed application creates a resilient system through continuous local seed reintroduction, effectively buffering historical disturbances and management variations. While this homogenizes vegetation composition across landscapes, it simultaneously maintains local diversity through enhancing functional connectivity, further supported by manuring and grazing. Traditional practices offer low-cost, accessible tools for restoring degraded grasslands, particularly when combining ash fertilization with locally-sourced hayseed under appropriate grazing regimes.