Crop–weed competition markedly reduces cereal yield. Integrative weed management approaches, involving the use of humic acid (HA) and seaweed extract (SWE), have gained attention as herbicide efficacy declines and environmental concerns grow. However, potential synergistic effects between HA and SWE have not yet been investigated. We evaluated the effects of HA, SWE, and their combination (HA+SWE) on the growth, yield, and competitive ability of cereals against wild weed beets (Beta vulgaris L.). A single-season field experiment was conducted using a split-plot design within a randomised complete block to assess the effects of treatment amendments on wheat, barley, and oats. The results showed that HA and HA+SWE organic amendments consistently improved grain yield and biomass across crop species. SWE responses varied across species, indicating species-dependent sensitivity. In addition, HA enhanced barley weed suppression, highlighting its dual roles in improving crop vigour and reducing weed proliferation. In contrast, SWE modestly increased spike length in oats, emphasising its effect on crop growth characteristics. Overall, these preliminary findings support targeted biostimulant use to enhance cereal yield and integrate weed management into sustainable cropping systems.

Purpose: The significance of potassium has been well documented as one of the major macronutrients for many crops, particularly wheat. Herbicide resistance in weeds and other environmental issues in the wheat crop has encouraged researchers to find alternative methods for weed management.Research methods: A field experiment was conducted during the winter season 2021-2022 at a private farm in North Samawah city, Iraq to examine the competitive ability of two European wheat cultivars against weeds as affected by potassium (K) levels. Treatments included two wheat cultivars (Milano and Pick-row), and three K fertiliser levels (0, 200 and 400 Kg K2O/ha).Findings: The results showed that Pick-row was a superior cultivar in terms of crop competitive ability with weeds compared with Milano. Pick-row was taller, produced the largest number of spikes, had the greatest grain yield, greatest crop biomass and least weed biomass about 61.5 cm, 70 spike/m2, 0.66 t/ha, 2.29 t/ha, and 52.5 g/m2 respectively. The increased K fertiliser level has a positive effect on crop production and weed biomass reduction, especially with Pick-row cultivar.Originality/ Value: It is implicated that Pick-row can be useful as a competitive cultivar under Al-Muthanna Province environments. Potassium K fertiliser is better to be increased and split into a number of equal doses and applied at different growth stages of wheat to avoid critical competitive timing risks.

Maize productivity and weed suppression are influenced by the combined use of tillage, nitrogen, and herbicide practices, but integrated evidence on crop and weed community responses to these management factors across growing seasons and tillage contexts remains limited. This study aimed to assess variation in total weed biomass, dicot and monocot weed abundance, dominant weed species, maize aboveground biomass, harvest index, and grain yield under conventional tillage (CT) and minimum tillage (MT), two nitrogen rates (74 and 147 kg N ha⁻¹), and five herbicide programs differing in active ingredient composition and application strategy, and to determine whether the relative importance of nitrogen and herbicide management varied with growing season and tillage context. Rainfed field trials were conducted in northwestern Hungary during the 2023 and 2025 growing seasons, and treatment-associated patterns were evaluated using exploratory analyses conducted separately for each year × tillage combination. In 2023, higher mean grain yield was observed at 147 than at 74 kg N ha⁻¹ under both CT (from 12.25 to 14.96 t ha⁻¹) and MT (from 11.95 to 15.41 t ha⁻¹). In 2025, exploratory ANOVA indicated herbicide-program-associated variation in grain yield under both tillage systems, and the highest yields were observed under the dicamba + nicosulfuron + prosulfuron treatment, reaching (21.02 t ha⁻¹) under CT and (14.82 t ha⁻¹) under MT. Total weed biomass also showed herbicide-program-associated variation in the exploratory analyses in 2025, with the lowest biomass observed under tembotrione in CT (17.56 g m⁻²) and dicamba + nicosulfuron + prosulfuron in MT (22.68 g m⁻²). Patterns of dicot and monocot abundance associated with herbicide program also differed among year × tillage contexts, and the dominant weed species differed between years and tillage systems. Crop biomass and harvest index varied less consistently and depended on year and tillage system. Nitrogen × herbicide interaction terms had exploratory p-values ≥ 0.05 for all response variables. Because treatments were not independently replicated, these non-significant interaction terms should not be interpreted as evidence that biological interactions were absent. Taken together, the observed treatment-associated patterns were linked more closely to nitrogen management in 2023 and herbicide program in 2025, while weed-group responses also varied with year and tillage system. By examining together crop performance and weed community responses, the study suggests that observed responses to nitrogen and herbicide management depended on context rather than being consistent across seasons and tillage systems.