Vincent de Leijster

44 Chapter 3 3.3.1 Ecosystem services 3.3.1.1 Nutrient cycling CT plots had the lowest enzymatic activity for all four enzymes. We found significantly higher glucosidase activity for NT and CM, compared to CT (Table 3-3). The phosphatase activity was significantly higher for NT, GM and CM compared to CT. The urease activity was higher for NT than for CT and GM. There was no significant effect of treatment for dehydrogenase activity. CM had significantly higher soil N and K content than all the other treatments; however, we found no significant effect of treatment for soil P content. CM also resulted in the highest leaf nutrient contents. For CM, leaf P and K content were significantly higher than for CT, NT and GM. We found no differences in leaf N content across treatments. 3.3.1.2 Carbon stock CM plots contained significantly higher SOC content, than NT and GM plots, but there was no difference with CT. The carbon stock in understory was significantly higher for GM and NT than for CT. Soil carbon content (0-20 cm depth) was 12 to 44 times higher than the carbon content in the understory. 3.3.1.3 Habitat provisioning We recorded 7026 individual plants and identified 126 plant species in 138 transects. The most abundant species were Vicia ervilia (bitter vetch), Lolium rigidium (ryegrass), Vicia sativa (common vetch) and Hordeum vulgare (barley), of which all except L. rigidium had been sown in GM. L. rigidium, Anacyclus clavatus (whitebuttons) and Bromus rubens (red brome) were the abundant wild species. Both NT and GM treatments had significantly more understory cover than CT and CM; NT also had higher plant species richness than CT and CM (Table 3-3). The arthropod abundance was higher for CM than for GM, but no significant effects of treatment were found for both arthropod abundance and richness. In total, we recorded 987 individual arthropods, the most abundant arthropod orders being Hemiptera, Thysanoptera and Coleoptera.