Fertigation management of mixed-species plantation versus monoculture in plantation forestry: key aspects and future perspective.

According to the Forest European Process, the recent Climate Change Conference (COP26), and EU policies, conservation of forest ecosystems is a critical step in mitigating climate change and combating deforestation; accordingly plantation forests will be critical in achieving these goals. While limitations in monoculture plantation are well established in silvicultural practices and documented in research studies, in the face of intensifying climate change and resources scarcity, the need for knowledge on mixed-species plantations has grown. There has been also a recent develop in innovative and sustainable forest management practices, including irrigation and fertilization (fertigation) that aim to improve the productivity of forestry plantations, and therefore their carbon sequestration capacity, as well as the ecosystem services associated with healthy forests. However, the exact effects of fertigation on forests plantation have yet to be established. This study examines the growth patterns, productivity, and carbon storage capacity of four–year-old mixed-species and monoculture plantations in response to an intensive fertigation management. Particularly, our findings highlight differences in tree growth patterns and their performance in paired experimental plots based on different soil types. Such differences are associated varying soil moisture conditions due the interaction of fertigation and the soil water holding capacity. In general, trees growth is higher in sandy soil, due to the positive relation between high soil water diffusivity and fertigation. On the other hand, no such tree growth has been observed in clay soil, most likely due to the high susceptibility to waterlogging, which requires careful fertigation management to avoid limiting conditions for the healthy development of young forest plantation. Our research provides important insights into how young plantation trees respond to different soil moisture conditions, which can aid to in the design and fertigation management of mixed-species plantations resulting in more productive, biodiverse, economically viable, and healthier forests than monocultures.