Weed Infestation and Health of Organically Grown Chamomile (Chamomilla recutita (L.) Rausch.) Depending on Selected Foliar Sprays and Row Spacing

Chamomile is a herbal plant of very high economic importance worldwide. Its organically grown raw material is particularly valuable. Under organic farming conditions, weeds and fungal diseases are an important problem in a chamomile plantation. Seeking agronomic solutions designed to eliminate the occurrence of these pathogens in chamomile crops is constantly valid. The aim of the present study was to evaluate the effect of some foliar sprays (enhancing the condition of the crop plant and its competition against pathogens) and different row spacing of two chamomile cultivars on weed infestation and health of a chamomile plantation. The study results presented in this paper were collected from field experiments carried out in the organic system in the village of Dys (the central Lublin region, Poland) over the period 2014–2016. Experiments were conducted on podzolic soil (class III) as a split-block design in 3 replicates in plots with an area of 525 m2 (6.25 m2 a single plot). This study included two chamomile cultivars (“Zloty Łan”, “Mastar”). The second experimental factor was single or double foliar application of three bioproducts (Herbagreen Basic, Bio-algeen, Effective Microorganisms—EM Farming). The other experimental factor was a different row spacing of chamomile (40 cm and 30 cm). The obtained study results show that 10–16 annual weed species and 1–3 perennial species occurred in both chamomile cultivars. Foliar application of the bioproducts contributed to a reduction in the total number of weeds in the crop, but at the same time to greater weed species diversity. In the control treatments (without the bioproducts), the dominance of several weed species (Viola arvensis, Galeopsis tetrahit, Spergula arvensis, Juncus bufonius, Scleranthus annuus) and lower biodiversity of the weed flora were observed. The largest reduction (by about 20%) in the number of annual weeds was found under the influence of the bioproducts Herbagreen Basic and Bio-algeen applied once. Bio-algeen and Effective Microorganisms (EM), in turn, had a significant effect on decreasing the weed weight. A narrower (30 cm) row spacing of chamomile had a significant impact on reducing the weight of weeds in chamomile crops compared to the wider spacing, which was 40 cm. It should be concluded that infection of the chamomile plantation with fungal diseases was overall at a low level. Significantly higher infection with fungal diseases was found in the case of the cultivar “Mastar”, regardless of the experimental factors. A statistically proven decrease in infection of chamomile plants with fungal diseases was determined under lower crop density conditions (a row spacing of 40 cm). Chamomile plants were found to exhibit better health under the influence of double application of the biofertilizers Herbagreen Basic and Bio-algeen.