Effects of fertilization and neighbour removal on biomass allocation and fruit production in Cistus ladanifer

Abstract

The aim of this article was to assess short-term (11 months) changes in vegetative biomass allocation and in reproductive output in response to increased nutrient availability and to different intra-specific competition scenarios in adult C. ladanifer plants. We performed a factorial field experiment with four treatments: (1) no fertilization and no neighbour removal, (2) fertilization (400 kg ha71 of controlled release NPK fertilizer) and no neighbour removal, (3) no fertilization and neighbour removal (all vegetation growing within a 2 m radius around the target plant were cut) and (4) fertilization and neighbour removal. We found a significant interaction between fertilization and neighbour removal affecting patterns of biomass allocation; plants without neighbours allocated relatively more biomass to leaves and less to branches only in the nonfertilized group, with no evident effect on the fertilized one. Furthermore, the positive effects of neighbour removal on number and biomass of fruits were appreciable regardless of nutrient conditions, which suggest that competition intensity was independent from soil fertility.