Lucerne (Medicago sativa L.) requires four or more cuttings at early bud stage per growing season to optimize the amount of crude protein and digestible fibre for feeding high‐producing dairy cows. However, there is potential to generate a nutrient‐dense feed from lucerne regardless of developmental stage by harvesting its protein‐rich leaves separate from its fibrous stems. In order to determine whether fractionated lucerne can be effectively ensiled under high‐moisture conditions and be nutritionally competitive with wilted whole‐plant silage, leaf and stem fractions, harvested at three developmental stages (early bud, 10%–20% bloom and >50% bloom), were directly ensiled in mini‐silos. At day 0, 1, 3, 21 and 140 of ensiling, silages were analysed for protein and non‐protein nitrogen fractions as well as their fermentation products and carbohydrate composition. Silages from unwilted leaves and stems were more heterofermentative than wilted whole‐plant silages; their fermentation shifted from primarily lactic acid to acetic acid production after 21 days. In leaf silages, the high degree of protein degradation into non‐protein nitrogen (~55%) was most likely due to fermentation quality. Nevertheless, at 140 days of ensiling, leaf silages had 21%–25% higher (p < 0.01) available protein (peptide amino acids, soluble and insoluble protein) content than wilted whole‐plant silages, regardless of developmental stage. Achievement of a more rapid pH decline and improved fractionation may further increase the nutritional value of leaf silages.

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Wildfires can represent a major disturbance to ecosystems, including soil microbial communities belowground. Furthermore, fire regimes are changing in many parts of the world, altering and often increasing fire severity, frequency, and size. The boreal forest and taiga plains ecoregions of northern Canada are characterized by naturally-occurring stand-replacing wildfires on a 40-350 year basis. We previously studied the effects of wildfire on soil microbial communities one year post-fire across 40 sites, spanning a range of burn severity. Here, we return to the same sites five years post-fire to test a series of hypotheses about the effects of fire on bacterial community composition. We ask the following questions: (1a) Do the fundamental factors structuring bacterial community composition remain the same five years post-fire? (1b) Do the effects of fire on bacterial community composition decrease between one and five years post-fire? (1c) Do shifts in bacterial community composition between one and five years post-fire suggest resilience? (2a) Does the importance of fast growth diminish between one and five years post-fire? (2b) Do short-term post-fire responders continue to dominate the community five years post-fire? We find the following: (1a) Five years post-fire, vegetation community, moisture regime, pH, total carbon, texture, and burned/unburned all remained significant predictors of bacterial community composition with similar predictive value (R2). (1b and 1c) Bacterial communities became more similar to unburned sites five years post-fire, across the range of severity, suggesting resilience, while general structure of co-occurrence networks remained similar one and five years post-fire. (2a) Fast growth potential, as estimated using predicted 16S rRNA copy numbers, was no longer significantly correlated with burn severity five years post-fire, indicating the importance of this trait for structuring bacterial community composition may be limited to relatively short timescales. (2b) Many taxa that were enriched in burned sites one year post-fire remained enriched five years post-fire, although the degree to which they were enriched generally decreased. Specific taxa of interest from the genera Massilia, Blastococcus, and Arthrobacter all remained significantly enriched, suggesting that they may have traits that allow them to continue to flourish in the post-fire environment, such as tolerance to increased pH or ability to degrade pyrogenic organic matter. This hypothesis-based work expands our understanding of the post-fire recovery of soil bacterial communities and raises new hypotheses to test in future studies.

Fractionation of alfalfa (Medicago sativa L.) into leaves and stems can reduce cutting frequency while producing a high-value feedstuff. A difficulty with fractionation is the higher moisture content at ensiling due to the inability to wilt leaves without substantial dry matter loss or financial cost. To evaluate whether the silage quality of fractionated alfalfa is competitive with conventional methods under long-term storage conditions, high-moisture leaves (250–280 g·kg−1 dry matter, DM) and stems (190–240 g·kg−1 DM) were ensiled for 21 and 350 days and compared to wilted whole-plant silage for two alfalfa developmental stages. At 21 days, leaf and whole-plant silage fermentation characteristics indicated suitable lactic acid bacterial fermentation through decreased pH, high lactic acid–to-acetic acid ratio, and a lack of clostridial fermentation. At 350 days, leaf silage fermentation and nutritional quality decreased due to sustained proteolysis, but true protein still exceeded that of whole-plant silage. High-moisture stem fractions fermented poorly; at 21 days, stage 3 stems had significant amounts of butyric acid, while stage 5 stems became clostridial at 350 days. Long-term storage of high-moisture leaf silages can produce good-quality silage despite exceeding moisture contents typically recommended for alfalfa, while wilting is required for stem silages.