Stable nutrient flows in sustainable and alternative cropping systems of globe artichoke

The conventional cultivation of globe artichoke causes high nitrogen (N) balance surpluses. The planning of more sustainable open-field horticultural systems (with no synthetic fertilizer supply) can contribute to the reduction of the nutrient surplus. We hypothesized that an artichoke conventional system could be shifted to a sustainable system through mineral fertilizer supply based on expected plant nutrient uptake, return of crop residues in well-defined growth phases, use of fertility-building crops, and crop rotations. Over a 10-year field experiment, three management systems, differ-ing in fertilizer rates, crop sequence (monoculture/rotation with cauliflower), and legume cover crop adoption and management, were compared: (i) improved conventional, (ii) alternative monoculture, and (iii) biannual rotation. We monitored soil conditions at a sampling interval of approximately 3 years. We calculated gross N, P, and K balances for each growing season, and we also monitored soil respiration over the last two growing seasons. On average, the biannual rotation resulted in a well-balanced N budget (72 kg ha -1 N surplus) compared with improved conventional (160 kg N ha -1 N surplus) and alternative monoculture (- 34 kg ha -1 deficit) systems. By contrast, compared with the improved conventional system (133 and 116 kg ha -1 for P and K budgets, respectively), alternative monoculture and biannual rotation systems had negative budgets for P (- 9 kg ha -1 for both alternative systems) and K (- 58 and - 51 kg ha -1 for alternative monoculture and biannual rotation systems, respectively) in nine of ten growing seasons. Our results show for the first time that long-term biannual rotation with cauliflower coupled with cover crop use can optimize nutrient fluxes of conventionally grown globe artichoke. Overall, the study proposes a re-design of artichoke cropping systems, provides novel information useful for growers, and verifies that introducing a legume species cover crop is also the most promising approach to foster long-term sustainability.