Effects of tillage, crop systems and fertilization on weed abundance and diversity in 4-year dry land winter wheat

The arable fields in central Spain have been dominated by cereal production, especially winter wheat. In this area, the defined action of weed management program requires a clear understanding of the factors and mechanisms conditioning weed community dynamics in agro systems. This study evaluated the effects of different agricultural management systems on the abundance and diversity of weed communities in winter wheat crops.Weed density and composition of weed species were sampled over four years; comparing monoculture wheat and rotational wheat in three agricultural management systems: (1) direct drilling (no-tillage, NT); (2) chisel ploughing (minimum tillage 15 cm depth, MT) and (3) mouldboard ploughing (traditional tillage 20 cm depth, CT). With the aim to be able to improve weed management in agro systems with semiarid environments; within each of the agricultural management systems, we examined the impact of mineral fertilization (traditional and balanced) as a tool for reducing the external inputs in arable cereals.Weed diversity was assessed using the three common diversity indices: Shannon's index, evenness index and species richness. The data collected showed total weed density was different per tillage system and each year of the study, but we did not find significant differences between crop systems over the study.The abundance, diversity and evenness of the weed community in the arable field, were significantly increased in NT systems. Within the direct drilling (NT) plots, rotational wheat showed the highest levels of weed infestation and diversity. Comparing traditional and balanced mineral fertilization of soil did not reveal a significant effect on weed abundance and diversity observed in field.

► We examine the weed community response to changing agronomic practices.
► It is desirable know the relationship between diversity and edaphic factors.
► The fertilization could influence on change of species in arable field.
► The correct management of nutrients could be an interesting tool for reduced the inputs in the field.