Climate Control of Topsoil Potassium, Calcium, and Magnesium Concentrations in Urban Forests Across Eastern China

Abstract

AbstractPotassium (K), calcium (Ca), and magnesium (Mg) are essential nutrients that have important biological and ecological functions. However, little is known about the large‐scale patterns of soil K, Ca, and Mg concentrations across urban forests that provide crucial ecosystem services. By measuring total K, Ca, and Mg concentrations of topsoil samples (0–10 and 10–20 cm) from forest patches in 27 urban parks across nine large cities in eastern China, we analyzed their spatial trends and main drivers. Our results indicate a decrease of topsoil K concentration in urban forests from cities in the north to cities in the south, while topsoil Ca and Mg concentrations both showed a unimodal trend along with the latitude. The spatial trend of topsoil K concentration was mainly explained by mean annual temperature (MAT) and preurban soil order, while the spatial variations of topsoil Ca and Mg concentrations both were controlled by mean annual precipitation (MAP) and MAT. Other factors, including nitrogen deposition, gross domestic product per capita, the area and age of each park had an unimportant role in shaping the spatial trends of topsoil K, Ca, and Mg concentrations. Our findings suggest a predominant control of climate on the large‐scale patterns of topsoil K, Ca, and Mg concentrations in urban forests and highlight a risk of base cationic nutrient deficiencies in urban forests in southern China.