Abstract: Understanding the nitrogeninduced changes of nutrient availability in bulk soils and soil aggregates is essential for studying soil nutrient supply as well as ecosystem structure and functioning under global change. Here, we reviewed research advances in elemental distribution of both bulk soils and soil aggregates as well as the mechanisms underlying their responses to nitrogen deposition in grassland ecosystems. A large number of studies have focused on soil carbon, nitrogen, phosphorus and sulfur availability, with the results depending on the form and duration of nitrogen addition as well as ecosystem types. Nitrogen deposition affects elemental bioavailability by altering the turnover of carbon, nitrogen, phosphorus and sulfur, as well as their distribution within soil aggregates. Relatively few studies have investigated the effects of nitrogen addition on exchangeable base cations and available micronutrients in bulk soils of grasslands. Soil acidification induced by N deposition causes imbalance in the leaching of calcium and magnesium among soil aggregates, with higher leaching losses in macroaggregates. Soil acidification is the main cause for higher availability of iron, manganese, and copper within soil aggregates.Nutrient concentrations in soil microaggregates are less sensitive to environmental changes. Currently, there are limited studies on the responses of soil aggregation and elemental availability within soil aggregates to nitrogen deposition. Further studies should focus on the coupled responses of elemental availability and enzymatic activities within soil aggregates, and analyze the feedback of soil physical structure and chemical composition to plant communities.

Key words: tomato, temperature, day and night temperature difference, yield, fruit quality.