Organic production is one of the fastest growing food sectors globally. However, average yield in organic vegetable production is up to 33% lower than in conventional production. This difference could be due to higher fertilization rates in conventional, compared to organic, farming. We aimed to compare yield and quality characteristics of carrots produced under equal nitrogen fertilization rates over four years in organic and conventional conditions. We found a 14.5% higher marketable, and 10.0% lower discarded, yield in the organic compared to the average conventional treatments. In addition, carrots managed organically had 14.1% lower nitrate and 10.0% higher vitamin C content than carrots managed conventionally. There were no convincing effects of cultivation system on the nitrogen, total sugar, or dry matter content of carrots. Organically managed carrots were free of pesticide residues, while several residues were found in carrots managed conventionally. Our study reveals that organic management of carrots may exceed that of conventional methods in yield and several quality characteristics, while being free of pesticide residues. Organic fertilizer gave an advantage over mineral fertilizer, when equal rates of nitrogen were used in both production systems.

Pyrenophora teres (net blotch) and Cochliobolus sativus (spot blotch), the most widely spread diseases in the Northern Baltic region, have high impact on cereal production. The effect of three levels of fertilisation and two fungicide treatments on the severity of barley diseases, grain yield and quality traits (protein content, test weight, thousand kernel weight (TKW), grading) was tested during a period of three years. Weather conditions during the growing season highly determined disease severity, yield and quality. In addition, the infection level of P. teres was more dependent on fungicide treatment (p ≤ 0.001) and barley variety (p ≤ 0.001) while C. sativus infection was influenced more by fertilisation (p ≤ 0.001) and year x fertilisation interaction (p ≤ 0.001). Fungicide treatment had no influence on grain yield and protein content, but slightly improved TKW (p ≤ 0.05), test weight (p ≤ 0.001) and grading (p ≤ 0.001). However, these quality traits were mostly influenced by barley variety (p ≤ 0.001). TKW and test weight were highest at fertilisation level N80P12K43. The effect of year and fertilisation contributed significantly to the grain protein content. Grain yield and protein content were highest at the maximum fertiliser application (N100P15K54).

Acreage of oat (Avena sativa L.) in Europe was steadily declining during the last century due to less breeding progress compared to other cereals. However, oat remains a valuable crop for food and feed, as well as for sustainable crop rotations. To unravel the genetic and phenotypic diversity in oat breeders' germplasm collections, a diversity panel including 260 accessions was investigated by molecular markers and in multi-environment field trials. Due to the large genetic variation in the present diversity panel, high heritabilities were observed for most agro-morphological traits, even for complex traits such as grain yield. Population structure analyses identified three subpopulations which were not straightforwardly related to the geographic origin of the accessions. Accessions from France, Germany, and the Czech Republic in particular were present in approximately equal proportions among all three subpopulations. Breeders' selection after one year of field trials was mainly based on grain yield, grain weight, grading, plant height, and maturity and did not result in a loss of genetic diversity. However, the low number of polymorphic markers must be considered in this case. The present study provides basic knowledge for further oat improvement through the identification of valuable genetic resources which can be exploited in breeding programs as e.g., parental genotypes in crossings.

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Using cover crops in fallow periods of crop production is an important management tool for reducing nitrate leaching and therefore improving nitrogen availability for subsequent crops. We estimated the short-term effect of five cover crop species on the yield of successive spring barley (Hordeum vulgare L.) for two years in Estonia. The cover crop species used in the study were winter rye (Secale cereale L.), winter turnip rape (Brassica rapa spp. oleifera L.), forage radish (Raphanus sativus L. var. longipinnatus), hairy vetch (Vicia villosa Roth), and berseem clover (Trifolium alexandrinum L.). The results indicated that out of the five tested cover crops, forage radish and hairy vetch increased the yield of subsequent spring barley, whereas the other cover crops had no effect on barley yield. All cover crop species had low C:N ratios (11-17), suggesting that nitrogen (N) was available for barley early in the spring.