Very Low Nitrogen Leaching in Grazed Ley-Arable-Systems in Northwest Europe

High input dairy farms that are located on sandy soils in northwest Europe are predisposed to substantial nitrate leaching during a surplus of winter precipitation. Leys within integrated crop-livestock systems play an important role in soil fertility, soil C sequestration and soil N mineralization potentials. Therefore, leys are a feasible option that can be utilized to reduce local N losses to the environment, especially following maize grown for silage. We hypothesize that grass-clover leys ensure low nitrate leaching losses even when grazed intensively. The extent to which NO3-leaching occurred across seven different pasture management systems in terms of their sward composition, cutting, grazing, fertilization and combinations thereof was investigated in integrated animal-crop grazing systems over three winter periods (2017/2018, 2018/2019 and 2019/2020). The observed grazed systems were comprised of cut-used- and grazed grass-clover swards (0, 1 and 2 years after establishment following cereals), a catch crop grazed late in the year as well as a cut-used permanent grassland for comparison. Overall, all treatments resulted in nitrate leaching losses that did not exceed the WHO-threshold (25 mg nitrate/L). The highest level of NO3-leaching was observed in the catch crop system and the lowest in cut-used permanent grassland, with NO3-N losses of 19.6 ± 5.3 and 2.1 ± 0.3 kg NO3-N ha−1 year−1. Annual herbage yields were in the range of 0.9 to 12.4 t DM ha−1 and nitrogen yields varied between 181 ± 51 and 228 ± 66 kg N ha−1 during the study period. The highest herbage-N-yields were observed from the 1- and 2-year-old grass-clover leys. The highest N-field-balance was observed for the grazed leys and the lowest for the cut-used permanent grassland. However, no correlation was found between the highly positive field-N-balance and the amount of NO3-leached. This indicates a high N carry-over from grass-clover swards to the subsequent cash crop unit instead of increasing the risk of groundwater contamination from grazed leys in integrated animal crop-systems and underlines the eco-efficiency of dairy farming based on grazed ley systems.

Achievements in breeding cereals with durable disease resistance in Northwest Europe

Breeding cereals in Northwest Europe for durable resistance has made an important contribution to control of almost all economically significant diseases and pests of wheat, barley and oats. Durable resistance to fungal diseases is largely polygenic and quantitative, with the important exception of mlo resistance to powdery mildew of spring barley. Resistance to powdery mildew of winter wheat, spring barley and spring oats, brown rust of winter barley and Septoria nodorum blotch of wheat has been especially effective and durable. Resistance to Barley yellow mosaic virus and orange wheat blossom midge has used single genes which have so far been durable. Plant breeders are increasingly producing varieties with high or moderate resistance to all the most important diseases, and have successfully combined durable resistance with other traits which are important to farmers and end-users, including high yield, marketable grain quality and desirable agronomic properties.

Powdery Mildew Resistance Phenotypes of Wheat Gene Bank Accessions

Powdery mildew (Blumeria graminis f. sp. tritici) is a common pathogen of bread wheat (Triticum aestivum L.), and genetic resistance is an effective and environmentally friendly method to reduce its adverse impact. The introgression of novel genes from wheat progenitors and related species can increase the diversity of disease resistance and accumulation of minor genes to improve the crop’s resistance durability. To accomplish these two actions, host genotypes without major resistances should be preferably used. Therefore, the main aim of this study was to carry out seedling tests to detect such resistances in a set of wheat accessions from the Czech gene bank and to group the cultivars according to their phenotype. Ear progenies of 448 selected cultivars originating from 33 countries were inoculated with three isolates of the pathogen. Twenty-eight cultivars were heterogeneous, and 110 cultivars showed resistance to at least one isolate. Fifty-nine cultivars, mostly from Northwest Europe, were resistant to all three isolates were more than three times more frequently recorded in spring than in winter cultivars. Results will facilitate a rational and practical approach preferably using the set of cultivars without major resistances for both mentioned methods of breeding wheat cultivars resistant to powdery mildew.

High-altitude migration of Psylloidea (Hemiptera) over England

Some species of psyllid (Hemiptera: Psylloidea) are known to make high-altitude windborne migrations, but compared with their sister superfamily, the Aphidoidea, our knowledge of these movements is rudimentary and unsystematised. Here we have extracted psyllid capture data from day and night aerial sampling carried out at a height of 200 m above ground at Cardington, Bedfordshire, UK, during summers between 1999 and 2007. These records were consolidated with high-altitude psyllid catches made over England during the 1930s and with some other trapping results from northwest Europe which were indicative of migration. Information on aerial densities, diel flight periodicity, and the sex-ratio of the aerial psyllid populations is presented. We also compared our results with those of a recent study which used the Rothamsted Insect Survey network of suction traps (sampling at a height of 12.2 m); this provided confirmative evidence that the suction-traps were indeed detecting migrating psyllids. Finally, both aerial netting and suction trap data were used to tentatively interpret the seasonal timing of migrations in terms of the breeding/overwintering cycles of some common psyllid species.