Research data for "Effects of nitrogen application rate on productivity, nutritive value and winter tolerance of timothy and meadow fescue cultivars

This dataset contains field experiment data collected as part of a study on the effects of nitrogen (N) application rate on productivity, nutritive value, and winter tolerance of timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis Huds.) cultivars in Finland. The dataset includes measurements of grass yield and quality obtained under different mineral nitrogen fertilizer application rates.

Data were collected during 2015–2017 at two research sites in Finland: Maaninka (63°09′N, 27°20′E) and Ruukki (64°41′N, 25°09′E). The experiments followed an incomplete split-plot design with four replicates. Eight nitrogen application rates were applied annually: 0, 150, 200, 250, 300, 350, 400, and 450 kg N ha⁻¹ which were divided between three cuts according to a ratio 0.44 – 0.36 – 0.20. Plot size was 12 m2.

The dataset provides average values over four replicates (LSMeans-data from statistical analysis, outliers removed) that enable analysis of nitrogen response functions, yield formation, nutritive value, and winter survival under current climatic conditions and modern cultivation practices. The data can be used for agronomic modeling, fertilizer optimization, and comparison with historical grassland experiments conducted in Finland.

The dataset includes comprehensive measurements for:
- Plant Material: Two timothy (Phleum pratense L.) cultivars ('Nuutti', 'Grindstad') and one meadow fescue (Festuca pratensis Huds.) cultivar ('Valtteri').
- Yield & Productivity: Annual and cut-specific dry matter (DM) yields.
- Nutritive Value: Crude protein (CP), D-value (digestible organic matter), organic matter digestibility (OMD), neutral detergent fiber (NDF), water-soluble sugars, and nitrate-N content.
- Winter hardiness: Autumn and spring sward density, overwintering loss percentage.
- Physiological Data: Chlorophyll content (SPAD), Leaf Area Index (LAI), specific leaf area (SLA), and botanical fractions (stem/leaf proportions).
- Soil Characteristics: pH, texture (clay/silt/sand), organic matter content, and plant-available P and K for both sites.