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Anthropogenic inputs of nitrogen (N) and phosphorus (P) to terrestrial ecosystems alter soil nutrient cycling. However, the global‐scale responses of soil P fractions to N and P inputs and their underlying mechanisms remain elusive. We conducted a global meta‐analysis based on 818 observations of soil P fractions from 99 field N and P addition experiments in forest, grassland, and cropland ecosystems ranging from temperate to tropical zones. Our global meta‐analysis revealed distinct responses of soil P fractions to N and P enrichment. For studies using the Chang and Jackson inorganic (Pi) method, we found that high N addition promoted the transformation of immobile Pi fractions into Ferrum/Aluminum‐bound Pi and available Pi in surface soils through soil acidification. However, this acid‐induced transformation of Pi fractions by N addition was observed only in Calcium‐rich soils, while in acidic soils, further acidification led to increase P binding. In contrast, additions of P alone or combined with N significantly increased all soil Pi fractions. Regarding the Hedley P fractions, N addition generally decreased labile organic P by enhancing soil acid phosphatase activity. The responses of other P fractions were influenced by soil pH, fertilization rates, ecosystem type, and other factors. P addition increased most soil P fractions. Overall, both P fractionation methods consistently demonstrate that N inputs deplete soil P and accelerate P cycling, while P inputs increase most soil P fractions, alleviating P limitation. These findings are crucial for predicting the effects of future atmospheric N and P deposition on P cycling processes. Plain Language Summary: Human activities have increased the amount of nitrogen (N) and phosphorus (P) in the environment, which has led to changes in the soil nutrients cycle. This study examined the global‐scale responses of soil P fractions to N and P inputs using a data set from 99 field experiments worldwide. The findings revealed distinct responses of soil P fractions to N and P enrichment. High N input resulted in the transformation of immobile inorganic P (Pi) fractions into available Pi in surface soils. This transformation was observed in calcium‐rich soils due to soil acidification. In contrast, in acidic soils, the acidification led to increased Pi binding. Moreover, N input generally decreased labile organic P, potentially by enhancing soil enzyme activity. Addition of P alone or combined with N significantly increased soil P fractions. These findings have important implications for predicting the effects of future N and P deposition on P cycling processes in the terrestrial ecosystems and understanding the impacts of nutrient enrichment on soil carbon storage and eutrophication. Key Points: Nitrogen inputs can accelerate phosphorus (P) transformation in Calcium‐rich soils but promote P binding in acidic soilsSoil acidification reduces inorganic P bioavailability by increasing the P fixation of Ferrum and Alumiium oxidePhosphorus input increases soil labile, moderately labile, and occluded inorganic P, enhancing soil available P [ABSTRACT FROM AUTHOR]

Both macronutrients and micronutrients are essential for tree growth and development through participating in various ecophysiological processes. However, the impact of the nutritional status of trees on their ability to withstand drought‐induced mortality remains inconclusive. We thus conducted a comprehensive meta‐analysis, compiling data on 11 essential nutrients from 44 publications (493 independent observations). Additionally, a field study was conducted on Pinus sylvestris L. trees with varying drought‐induced vitality loss in the "Visp" forest in southern Switzerland. No consistent decline in tree nutritional status was observed during tree mortality. The meta‐analysis revealed significantly lower leaf potassium (K), iron (Fe), and copper (Cu) concentrations with tree mortality. However, the field study showed no causal relationships between nutritional levels and the vitality status of trees. This discrepancy is mainly attributed to the intrinsic differences in the two types of experimental designs and the ontogenetic stages of target trees. Nutrient reductions preceding tree mortality were predominantly observed in non‐field conditions, where the study was conducted on seedlings and saplings with underdeveloped root systems. It limits the nutrient uptake capacity of these young trees during drought. Furthermore, tree nutritional responses are also influenced by many variables. Specifically, (a) leaf nutrients are more susceptible to drought stress than other organs; (b) reduced tree nutrient concentrations are more prevalent in evergreen species during drought‐induced mortality; (c) of all biomes, Mediterranean forests are most vulnerable to drought‐induced nutrient deficiencies; (d) soil types affect the direction and extent of tree nutritional responses. We identified factors that influence the relationship between tree nutritional status and drought survival, and proposed potential early‐warning indicators of impending tree mortality, for example, decreased K concentrations with declining vitality. These findings contribute to our understanding of tree responses to drought and provide practical implications for forest management strategies in the context of global change. [ABSTRACT FROM AUTHOR]