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Effect of harvest date on structural carbohydrates and lignin content in meadow sward in different pluvio-thermal conditions
The content of structural carbohydrates and lignin are important assessment criteria of the feed value of meadow plants. It is affected by many independent factors, including among others its development stage during the harvest as well as climatic conditions, especially the amount of rainfall. During the years 2014–2016, plant samples were harvested at weekly intervals, respectively five times from late April to late May. The effect of harvest date on cellulose, hemicelluloses and lignin contents was evaluated. The chemical composition of plants was varied, depending not only on harvest date but also on the year of study. Regardless of the course of meteorological conditions in subsequent growing seasons, the increase of cellulose (from 236.5 to 297.9 g∙kg–1 DM), hemicelluloses (from 159.3 to 210.8 g∙kg–1 DM), and lignin (from 31.5 to 43.1 g∙kg–1 DM) in the following dates of harvest were observed. These parameters were also positively correlated with the total rainfall from the begging of vegetation season to the date of plants sampling (R2 = 0.65, 0.12 and 0.44 for cellulose, hemicelluloses and lignin, respectively), and with the average daily air temperature in the moment of harvest (R2 = 0.66, 0.32 and 0.52 for cellulose, hemicelluloses and lignin, respectively). The cellulose and lignin content, regardless of the harvest date, were significantly higher in the first year of the study (2014), when moisture conditions for plant development were optimal.
Nutritional Status of Wood Melick (Melica uniflora Retz.) in a Natural Forest Stand in South-Western Poland
Melica uniflora Retz., commonly known as wood melick, is a grass species that is native to most of Europe. Melica uniflora grows in hardwood forests near Fagus species, providing vital food and shelter for forest wildlife. The nutritional status of wood melick is not sufficiently recognized. The study aims to identify the intrapopulation variability of Melica uniflora plants collected from natural forest habitats in Poland in terms of nutritional status variability in relation to stage development and the course of weather conditions. The research was conducted for two consecutive years: 2021 and 2022, in the area of the Ślęża Massif, near the town of Sobótka in Lower Silesia voivodeship (Poland). The material for analyses was collected from 10 natural forest sites twice: in July (I) and October (II). The content of nutritive components: crude protein (CP), crude ash (CA), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and water-soluble carbohydrates (WSC) was evaluated. Relative feed value (RFV), dry matter digestibility (DDM), dry matter intake (DMI), cellulose (CL), and hemicellulose (HCL) content were calculated based on ADF and NDF. Melica uniflora plants contained 75.2 g·kg−1 DM of CP, 290.6 g·kg−1 DM of CF, 120.0 g·kg−1 DM of CA, and 25.9 g·kg−1 DM of WSC. The content of NDF was 637.6 g·kg−1 DM, ADF 407.5 g·kg−1 DM, and ADL 58.0 g·kg−1 DM. The nutritional status of wood melick depended on the course of weather conditions in the following years and its location, which changed during the growing season. Plants collected in the first year of the study contained more CL, NDF, and ADF fractions and less CA, ADL, and WSC. Melica uniflora plants harvested in June were characterized by higher CP (102.1 g·kg−1 DM) and WSC (30.1 g·kg−1 DM) content and lower content of remaining nutrients. It can be concluded that Melica uniflora plants can be a valuable source of these nutrients in the forage of forest animals.