Phosphate fertilization and liming in a trial conducted over 21 years: A survey for greater forage production and Pampa pasture conservation

Phosphorus fertilization and liming are alternatives used to increase forage production in Southern Brazil grasslands (Pampa grasslands) avoid its replacement by cultivated exotic crops. However, changes natural soil fertility can significantly affect the equilibrium of vegetation communities. We hypothesized that triple simple superphosphate limestone using would lead greater dry matter botanical composition richness Pampa grassland plant species than use lesser soluble P sources (phosphate rock) or no treatment. To test our hypotheses, we assessed a 21-year-old field trial identify pattern, based on application. The was studied 2009 2018, following variables: Shannon Pielou indices, richness, groups (species grouped growth form, life period, photosynthetic pathway, morphology growing season). Soil chemical properties 0–10 cm layer were also evaluated 2018. According long-term evaluation, two high yield periods observed after (55 % 25 higher yield, average). Each these followed decreased regardless source. Species did not show overtime, although there turnover species. Soluble fertilizer usage resulted increased large proportions species, mainly tussock grasses forbs groups. contribution legume for due combined effect phosphate fertilizers limestone. maintaining levels without phosphorus requires regular supply fertilizers, which, present case, cannot exceed three years.