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This study aimed to improve the phosphorus (P) use efficiency of various biowastes. To achieve this, we proposed the combination of placement and the acidification of biowastes for the development of P-efficient biobased fertilizers. Seven biowastes were used as P-fertilizers, including two meat and bone meals (MBM), two solid fractions of biogas digestate (BGF), and three sewage sludges (SS). Two acidification approaches were evaluated: pre-treatment with sulfuric acid (73.5 g sulfuric acid per kg fresh weight) and co-application with ammonium sulfate (15 mg N per kg soil). The treated materials were placed close to winter wheat (Triticum aestivum cv. Benchmark) seeds in a 42-day pot experiment in a growth chamber. The P use efficiency was compared to the corresponding untreated material homogeneously mixed or similarly placed in the soil. A 33P indirect labeling method was used to differentiate P uptake from soil and fertilizer. The negative control showed a shoot dry matter of 0.42 g ( ± 0.05) and a total P uptake of 0.62 ( ± 0.06) mg per plant. The placement of acidified sewage sludge did not show significant differences in shoot dry matter and P uptake compared to the negative control. On the other hand, the placement of acidified MBM significantly increased plant growth (MBM I: 2.93 ± 0.46; MBM II: 1.78 ± 0.09 g) and P uptake (MBM I: 7.38 ± 1.10; MBM II: 6.21 ± 0.53 mg) compared to the untreated MBM placed and the negative control. Similarly, the placement of acidified BGF showed promising results, with a 3-fold increase in P uptake from the fertilizer compared to untreated BGF mixed with the soil (7.74 ± 1.47 vs. 2.71 ± 0.26 mg). Therefore, our results demonstrate that the placement of acidified MBM and BGF can increase the P use efficiency of these biowastes and may provide a basis for formulating P-efficient biobased fertilizers using these materials.

Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collection of phenology measurements depicts the responses of plants at the colder extremes of our planet to experimental and ambient changes in temperature over the past decades. The database contains 150 434 phenology observations of 278 plant species taken at 28 study areas for periods of 1–26 years. Here we describe the full data set to increase the visibility and use of these data in global analyses and to invite phenology data contributions from underrepresented tundra locations. Portions of this tundra phenology database have been used in three recent syntheses, some data sets are expanded, others are from entirely new study areas, and the entirety of these data are now available at the Polar Data Catalogue (https://doi.org/10.21963/13215).

Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collec-tion of phenology measurements depicts the responses of plants at the colder extremes of our planet to experimental and ambient changes in temperature over the past decades. The database contains 150 434 phenology observations of 278 plant species taken at 28 study areas for periods of 1–26 years. Here we describe the full data set to increase the visibility and use of these data in global analyses and to invite phenology data contributions from underrepresented tundra locations. Portions of this tundra phenology database have been used in three recent syntheses, some data sets are expanded, others are from entirely new study areas, and the entirety of these data are now available at the Polar Data Catalogue (https://doi.org/10.21963/13215). Résumé Les observations des changements dans la phénologie ont fourni certains des signaux les plus forts des effets du changement climatique sur les écosystèmes terrestres. L’expérience internationale sur la toundra ITEX (International Tundra Experiment), lancée au début des années 1990, a établi un protocole commun pour mesurer la phénologie des plantes dans les zones d’étude de la toundra à travers le monde. Aujourd’hui, cette précieuse collection de mesures phénologiques décrit les réponses des plantes des régions les plus froides de notre planète aux changements expérimentaux et ambiants de température au cours des dernières décennies. La base de données contient 150 434 observations phénologiques de 278 espèces de plantes prises dans 28 zones d’étude sur des périodes allant de 1 à 26 ans. Les auteurs décrivent ici l’ensemble des données afin d’accroître la visibilité et l’utilisat