Key management practices to reduce the risk of the occurrence of Rumex obtusifolius in productive grasslands

Rumex obtusifolius (broad-leaved dock) is a problematic weed that reduces yield and nutritional value of forage in grasslands of temperate regions worldwide. We conducted an on-farm study to identify management practices and environmental factors that influence the risk of the occurrence of R. obtusifolius in high densities in permanent, productive grasslands used for forage production. Following a common protocol, a paired case–control design was implemented in Switzerland (CH), Slovenia (SI), and United Kingdom (UK) to compare parcels with high densities of R. obtusifolius (cases, ≥1 plant m−2) with nearby parcels free of or with very low densities of the species (controls, ≤4 plants 100 m−2). A total of 40, 20, and 18 pairs were recorded in CH, SI, and UK respectively. Parameters measured included data about management practices and history, vegetation cover and composition, and soil nutrients and texture. Across countries, increased vegetation cover reduced the relative risk of R. obtusifolius occurrence. By contrast, increased soil phosphorus and potassium and high soil bulk density raised the relative risk. These effects were consistent across countries, as no interactions between country and any of the factors were observed. The two indicator species for case parcels, Plantago major and Poa annua, were typical species of disturbed areas and fertile soils, while indicators for control parcels were characteristic of grasslands under medium to high management intensity (e.g., Festuca rubra, Cynosorus cristatus, Anthoxantum odoratum). We conclude that the risk for grassland infestation with R. obtusifolius can be significantly affected by management practices. Prevention measures should target phosphorus and potassium fertilisation to the forage plants' requirements, minimise soil compaction, and maintain dense swards

Potential of different common (Fagopyrum esculentum Moench) and Tartary (Fagopyrum tataricum (L.) Gaertn.) buckwheat accessions to sustainably manage surrounding weeds

Twenty-nine accessions of two buckwheat species (Fagopyrum esculentum Moench (common buckwheat) and Fagopyrum tataricum (L.) Gaertn. (Tartary buckwheat) were evaluated for their allelopathic potential against two resistant weeds, the monocot Lolium rigidum Gaud. and the dicot Portulaca oleracea L. The bulking use of synthetic herbicides and their consequent contamination of the environment and resulting increment of herbicide-resistant weeds, imminently requires a solution to achieve sustainable weed management without chemical inputs. The results obtained in this study suggest that buckwheat accessions can sustainably manage weeds through plant interference as competition or allelopathy. This research showed that accessions differ in their potential for sustainably managing both weeds with F. esculentum accessions being more effective against L. rigidum and F. tataricum accessions against both, monocot and dicot weeds. The chemical profile of buckwheat accessions was evaluated to know the content of polyphenols in common and Tartary buckwheat accessions and to know more about their ability to manage weeds sustainably. Differences in the chemical profile between the two buckwheat species were clear. While common buckwheat accessions showed more orientin, vitexin and hyperoside, Tartary buckwheat accessions had higher amounts of rutin, quercetin and kaempferol. We propose that the screening and selection of accessions with strong polyphenol content and vigorous growth can be a step towards organic farming due to its relation to the weed management.Universidade de Vigo/CISU

Influence of soil amended with zeolite and/or mineral N on agronomic performance and soil mineral N dynamics in a soybean–winter triticale crop rotation field experiment

Although there are numerous studies describing the positive infuence of legumes as cereal pre-crops, little information exists on the specifc crop rotation soybean–triticale. Besides that, fertilization of soybean is very complex due to its symbiosis with rhizobia where mineral nitrogen could have negative efect, therefore new soil conditioners, e.g. zeolite, need to be examined. An investigation in growing seasons 2017 and 2017/2018 was established to study these knowledge gaps in a combined feld experiment, where soil mineral nitrogen (SMN) was also monitored. Firstly, the infuence of soybean seed bacterial inoculation (inoculated and non-inoculated seeds) as factor 1, and four fertilization treatments (1—no fertilizer, 2—600 kg zeolite/ha, 3—30 kg mineral N/ha (at sowing)+additional 70–90 kg/ha of mineral N, and 4—combination of treatments 2 and 3) as factor 2 on soybean yield performance and nutritional composition was evaluated. Neither factor infuenced soybean seed yield (average 3128 kg/ha). However, zeolite had favourable efect on root nodulation where the number of nodules and nodule dry mass per plant were signifcantly increased. Secondly, winter triticale was sown after soybean harvest on the same plots. Only 40 kg N was applied at BBCH 30 (beginning of stem elongation) to the whole experiment. Interaction of soybean experimental factors signifcantly infuenced the triticale grain yield. Finally, regression analysis revealed that triticale grain yield (average 5537 kg/ha) was highly dependent (R2=0.927) on initial SMN content, left after soybean harvest