Agricultural and Food Science

Fifth survey on weed flora in spring cereals in Finland

Jukka Salonen — 2023-07-26

Regular weed surveys provide information on changes in weed communities. The composition of weed flora in spring cereal fields was investigated in southern and central Finland during 2020–2022. The survey was conducted in 16 regions, 226 farms and 549 fields. The occurrence of weeds was assessed in the second half of July from 90 organically cropped and 459 conventionally cropped fields. The weed flora was dominated by broad-leaved species, representing 81% of the total number of 138 identified species. The average species number per field was 21 in organic fields and 12 in conventional fields. The most frequent weed species in organic fields were Chenopodium album 99%, Erysimum cheiranthoides 84%, Viola arvensis 83% and Stellaria media 82%. In conventionally cropped fields, the most frequent species were Viola arvensis 83%, Stellaria media 65%, Galeopsis spp. 59% and Galium spurium 59%. The two most common grass species in both production systems were Poa annua and Elymus repens. The frequency and density of Poa annua had increased substantially in conventional cropping since the previous survey in 2007–2009. The average density of weeds was 384 plants m^-2 in organic fields and 147 plants m^-2 in sprayed conventional fields. The average air-dry biomass of weeds was 678 kg ha^-1 and 151 kg ha^-1, respectively. Elymus repens produced almost a quarter of the total weed biomass in both production systems. Changes in weed flora were minor in terms of frequency and density of the most common broad-leaved weed species. Increased infestation of Poa annua in conventional cropping calls for special attention. The dominance of Elymus repens decreased in both production systems since the previous survey.

A Quality assessment of cold dried chicken slices during storage in different packages and temperatures

Elif Aykın Dinçer — 2023-07-26

In this study, dried chicken slices were packaged in MAP (modified atmosphere packaging) and AP (atmospheric packaging), and stored at 4 °C and 25 °C. The CO₂ content of MAP packaged samples decreased as the storage temperature and time increased. The slices exhibited lower aw values when they were packaged in AP at 25 °C. The pH increased from 6.1 to 6.2, 2-thiobarbituric acid reactive substances (TBARS) increased from 10.6 to 37.3 µmol MDA kg^-1, and non-protein nitrogen (NPN) increased from 4.9 to 5.3 g 100 g^-1 in MAP for 90 days of storage. The microbiological quality of the samples was assessed by enumerating total aerobic mesophilic bacteria (TAMB), total psychrophilic bacteria (TPB), Micrococcus/ Staphylococcus, lactic acid bacteria (LAB), Enterobacteriaceae and yeast-mold, and was higher in the sample stored in MAP at 4 °C. Moreover, the sensory quality was determined by sensory evaluation with a 9-point hedonic scale. When the sensory and microbiological qualities were evaluated together, the shelf lives of the samples were determined to be 90 days at 4 °C and 75 days at 25 °C for MAP and 45 days at 4 °C and 30 days at 25 °C for AP. It could be concluded that the cold dried chicken slices can be stored in MAP for 90 days without much change in physicochemical, microbiological, and sensory quality.

Yield predictions of timothy (Phleum pratense L.) in Norway under future climate scenarios

Kristoffer H. Hellton — 2023-07-26

The perennial forage grass timothy (Phleum pratense L.) is the most important forage crop in Norway. Future changes
in the climate will affect growing conditions and hence the yield output. We used data from the Norwegian Value for Cultivation and Use testing to find a statistical prediction model for total dry matter yield (DMY) based on agro-climatic variables. The statistical model selection found that the predictors with the highest predictive power were growing degree days (GDD) in July and the number of days with rain (>1mm) in June–July. These predictors together explained 43% of the variability in total DMY. Further, the prediction model was combined with a range of climate ensembles (RCP4.5) to project DMY of timothy for the decades 2050–2059 and 2090–2099 at 8 locations in Norway. Our projections forecast that DMY of today’s timothy varieties may decrease substantially in South-Eastern Norway, but increase in Northern Norway, by the middle of the century, due to increased temperatures and changing precipitation patterns.

Shortened first regrowth interval of grass silage as a harvesting strategy to improve nutrient supply for dairy cows: a case study

Auvo Sairanen — 2023-07-26

Dairy cows have a highly valuable ability to convert grass into milk. A modification of the normal three-cut
harvesting strategy was evaluated consisting of shortened first grass regrowth period to increase the energy value of the silage crop over the whole growing season under Boreal conditions. Grass was ensiled from timothy-meadow fescue-red clover swards over two years at three consecutive harvests within the growing season. Diets based on the silages (D1, 1st cut; D2, 2nd cut and D3, 3rd cut) were fed to dairy cows in two milk production experiments using change-over designs and an average concentrate proportion of 0.41 on dry matter basis. Consistently high energy value in silages was achieved and despite minor differences in silage D-values, feed intake was highest for D1. The differences in energy-corrected milk yield between treatments were limited to an increase for D2 in Exp 2 so that feed energy conversion into milk was decreased with D1. A shortened first regrowth interval for grass silage harvest was a viable option, but forage area per animal and other farm specific factors should be considered when choosing the silage harvesting strategy.