Cutting time is a pivotal factor affecting herbage yield and nutritive value of forage crop monocultures. Therefore, our objectives in this lucerne study were to analyse temporal patterns of herbage yield, morphological development and quality parameters over growth season, and to relate these patterns to the time of cutting. A field experiment in split-plot design with two block replications was conducted in Ljubljana in 2016. Four growth cycles (C1-C4) were assigned to the main plots, and nine weekly intervals at which herbage yield was measured and herbage samples taken were assigned to the sub-plots. Dry-matter herbage yield accumulated faster during the first half of the season than during the second one. It peaked early in each of the last two growth cycles and after that started to decrease. Statistical analysis showed that linear regression models are acceptable to describe time patterns of morphological development stages (MSW) and contents of crude protein (CP), neutral detergent fibre (NDF) and net energy for lactation (NEL). MSW increased faster during the summer than during the spring or autumn, but only C1 was distinct in this pattern. Lucerne forage quality was generally the highest in C1 mainly due to slower morphological development. This high quality reflected more in NDF and NEL than in CP. In respect of the quality, only C4 at the beginning of the growth was equivalent to C1. Considering yield and content of NEL optimal age of lucerne at cutting was from 28 to 35 days in spring and summer and from 35 to 42 days in autumn.
COBISS.SI-ID: v tisku
For all crop species, an accurate, quick, and simple method for determination of mean development stage of plants has a key role for scientific and practical use. The investigation was performed to validate a modified methodology for determination of mean stage of development in alfalfa (Medicago sativa L.). The modified methodology, mean stage by fresh weight (MSFW), assumes that mean stage by weight (MSW) could be determined by fresh, and not only by dry weight, as was required by the original methodology. A total of 198 alfalfa samples were collected in 2010 and 2011. Sampling completely covered three growth cycles: spring growth and first and second regrowths. The correlation (r) between MSW and MSFW was )0.99. In 92% of samples, absolute deviation between MSW and MSFW was (0.15 on a scale between 0 and 9. The equation for prediction of MSFW based on measured MSW, MSFWpredicted = 0.9808 × MSW, was developed with the data from the first year (n = 141) and tested with second-year samples (n = 57). Prediction error, expressed by root mean squared deviation (RMSD), was 0.045. As a simpler methodology, MSFW gives an opportunity to be more applicable in practice with all of the benefits of the MSW methodology.
COBISS.SI-ID: 4936040
In two experiments we studied the changes in the chemical composition, energy value, the content of ß-carotene and vitamin E during the wilting, condensation drying, ensiling and storage of alfalfa in round bales. During the ensiling, condensation drying and field drying, the content of the net energy for lactation (NEL) declined by 3 to 13, 7 to 16 and 12 to 13%, the content of ß-carotene by 64 to 75, 52 to 91 and 98% and the content of vitamin E by 66 to 82, 35 to 70 and 86 to 87%. During the condensation drying the concentration of sugars declined to a greater extent than during the ensiling of wilted alfalfa. The lower concentration of sugars was found in alfalfa hay. Crude protein content has not changed during the ensiling, condensation drying and during the field drying of alfalfa. On the basis of the content of available fibre protein it can be concluded that in terms of protein utilization in ruminants, drying of alfalfa is more favourable than ensiling. In favourable weather conditions, the reduction of the energy value during the ensiling and condensation drying is more extensive than during the field wilting of forage. Reduction of ß-carotene level was more extensive in adverse weather conditions than under conditions which permit the rapid moisture evaporation. We have found that it is very difficult to reach an appropriate dry matter content of hay by the means of field drying. The ensiling and condensation drying can reduce the dependence of alfalfa harvesting on weather conditions.
COBISS.SI-ID: 5128040
Changes in protein value of alfalfa during the wilting, ensiling, condensation drying, field drying and storage in round bales were studied in two experiments. The concentrations of crude protein were not changed during the wilting, ensiling, condensation drying and field drying. However, there were changes in concentrations of individual protein fractions as well as in ruminal protein degradability. Based on ruminal protein degradability and concentrations of acid detergent insoluble protein it was concluded that drying of alfalfa is more favourable than ensiling. In fresh alfalfa digestible undegradable protein represented 20.7% of total protein, in wilted alfalfa 27.1%, in silages from 7.3 to 13.7%, in condensation dried alfalfa from 9.8 to 21.8% and in hay 26.1 and 28.9% of total protein. Range in protein degradability of condensation dried alfalfa indicates that protein value is influenced by drying conditions on drying device. Protein degradability of alfalfa in the rumen was related to available fibre protein.
COBISS.SI-ID: 5391720