Long-term cardoon (Cynara cardunculus) productivity under reduced irrigation and weed control inputs

Abstract

ABSTRACT The long-term productivity data for the energy crops under reduced inputs are decisive for farmers’ decisions. An 11-year field study was conducted in central Greece to evaluate the productivity of two cardoon varieties under reduced irrigation and weed control inputs. During the initial six plant stage ages, the cardoon total dry biomass, seed, oil and potential energy yields, averaged 21.65, 1.92 and 0.53 t ha−1, as well as 364.719 GJ ha−1, respectively, with the var. C12, in most cases, the most productive. Both conditions of non-irrigation and weed competition caused a slight reduction in cardoon yield components. However, during the next five plant stage ages, the corresponding yields were dramatically reduced and averaged 11.10, 0.52 and 0.15 t ha−1, as well as 185.153 GJ ha−1, mainly due to reduced regrowth and the shorter height of cardoon stems. In this period, irrigation and weed management did not affect in most cases cardoon productivity. So, the under-reduced inputs cultivation of cardoon after the sixth year may not be economically acceptable for farmers. Conclusively, cardoon can be cultivated under reduced inputs, at least for 6 years, constituting one of the eligible energy crops for farmers in the hot and semi-arid Mediterranean fields.