Effects of Fertilizer Sources and Tillage Regimes on Weed Species Composition and Functional Diversity in the 4‐Year of Durum Wheat–Potato Rotation

Designing environmental‐friendly approaches to mitigate weed pressure in agroecosystems is an urgent priority. A field experiment was conducted in 2014/2015 and 2015/2016 to evaluate fertilizer source and soil tillage on weed community composition in durum wheat–potato rotation. Experimental treatments included: (i) two fertilizer sources (mineral and organic fertilizers [MF and OF]) and (ii) three tillage regimes (plowing [CT], spading [RT1] and subsoiling [RT2]). A randomized complete block design with three replications was adopted. Weed characteristics were measured at the wheat tillering and potato flowering stage. In durum wheat, weed biomass ranged from 73.6 g m −2 (MF‐CT) to 131.4 g m −2 (OF‐RT2). In potato, weed biomass was the highest in OF‐RT2 (156.3 g m −2 of DM), while weed density ranged from 29.0 n m −2 (MF‐CT) to 46.5 n m −2 (OF‐RT2). Overall, annual weeds were more abundant under OF compared to MF (75.3 vs. 64.5 n m −2 ), regardless of tillage treatments. Within MF treatments, annual weed density was higher under RT2 than RT1 and CT (71.3 vs. 61.1 n m −2 ). Relative frequency of perennial broadleaf species was highest in OF‐RT2, with perennial weeds generally increasing under RT2 and RT1, regardless of the fertilization source. Across both crops, biomass production was higher under MF than OF. A negative relationship was observed between crop biomass and the density of broadleaf weeds ( R 2 = 0.3894, p < 0.001) and perennial weeds ( R 2 = 0.2156, p < 0.01). Further studies are required to investigate the long‐term implications of these practices and refine weed management approaches across different cropping systems.