The effects of the farming system (conventional-organic-abandoned) and soil management (native cover crop vs tillage) on vascular plant species were analyzed in sloping olive groves (>20%) in 20 different locations in Andalusia, SE Spain. The soil management techniques included Organic Tillage (OT), Organic Cover Crops (OC), Conventional Tillage (CT), Conventional Non-Tillage (CNT), Abandoned Cover Crops (AC) and Abandoned Woody (AW). Data for the vascular plant species were recorded through three line transects of 30 m with a bar perpendicularly touching every 1 m of the measuring tape. Environmental variables were also recorded at plot level to assess their influence. Dependent variables, such as species abundance, richness and diversity indexes were studied using univariate analysis (one-way ANOVA, Kruskal–Wallis test) while multivariate statistics (ANOSIM, SIMPER, DCA) were used for analyzing the data matrices. We found that the different combinations of farming system and soil management affect biological diversity in terms of individual abundance, plant cover, species richness and diversity, species and family composition. Life forms and species distribution patterns are also affected. The main environmental variables affecting the plant taxa were those related with soil and climate characteristics, slope, olive age and intensive land uses at landscape level, including the percentage of artificial surfaces. The lowest levels of biodiversity (e.g., species richness) were found in the tilled olive groves (CT = 8.1 sp. ± 2.2, OT = 10.0 sp. ± 5.4). Surprisingly, the organic tilled groves (OT) were very poor in species compared to those with native plant cover (OC = 27.9 sp. ± 3.0). The latter, however, showed similar species richness to the abandoned olive groves (AC = 21.2 sp. ± 3.7, AW = 27.2 sp. ± 3.0). Possible solutions for increasingly uncompetitive sloping olive groves include conversion to organic with native plant cover or abandonment for rewilding.

Weedy rice is a problematic weed that infests paddy fields worldwide. Differing populations, with varying physiological and morphological traits, characterize this weed. In particular, seed dormancy makes its control difficult. The objective of this study was to evaluate the germination behavior of five Italian weedy rice populations (two awnless, two awned, and one mucronate) after exposure of seeds to different field storage conditions (flooding, burial, and dry soil surface) during winter in two sites (Grugliasco and Vercelli, Italy). Seed samples were taken from each population, storage condition, and site, every 15 d for petri dish germinability testing. The two sites displayed slightly different germination patterns, which were probably due to the differing climatic conditions. One of the awned populations showed the highest (always exceeding 80%) and fastest germination percentage in all field conditions and sites, compared with the other four populations. Although flooding promoted germination in one awnless population, it delayed germination in two others (one awned and one awnless), attaining only 20% germination after more than 100 d. In all populations, burial delayed germination, whereas seed placement on the dry soil surface enhanced it. Our study indicated that autumn tillage that promotes weedy rice seed burial should be discouraged; spring tillage that exposes seeds to the soil surface and cause their depletion should be encouraged. The tested technique of winter flooding can also improve weedy rice control, despite its varying efficacy among populations. Cycles of flooding and drying followed by spring tillage might improve weedy rice seed control.