Storage of carbon, nitrogen and phosphorus in temperate shrubland ecosystems across Northern China

Abstract

Aims: Studying storage of carbon (C), nitrogen (N) and phosphorus (P) in ecosystems is of significance in understanding carbon and nutrient cycling. Previous researches in ecosystem C, N and P storage have biased towards forests and grasslands. Shrubland ecosystems encompass a wide gradient in precipitation and soil conditions, providing a unique opportunity to explore the patterns of ecosystem C, N and P storage in relation to climate and soil properties. Methods: We estimated densities and storage of organic C, N and P of shrubland ecosystems in Northern China based on data from 433 shrubland sites. Important findings: The main results are summarized as follows: the average organic C, N and P densities in temperate shrubland ecosystems across Northern China were 69.8 Mg·hm-2, 7.3 Mg·hm-2 and 4.2 Mg·hm-2, respectively. The average plant C, N and P densities were 5.1 Mg·hm-2, 11.5 × 10-2 Mg·hm-2 and 8.6 × 10-3 Mg·hm-2, respectively, and were significantly correlated with precipitation and soil nutrient concentrations. The average litter C, N and P densities were 1.4 Mg·hm-2, 3.8 ×10-2 Mg·hm-2, 2.5 ×10-3 Mg·hm-2 and were significantly correlated with temperature and precipitation. The average soil organic C, N and P densities in the top 1 m were 64.0 Mg·hm-2, 7.1 Mg·hm-2 and 4.2 Mg·hm-2, respectively and the former two were significantly correlated with temperature and precipitation. The total organic C, N and P storage of shrublands in Northern China were 1.7 Pg, 164.9 Tg and 124.8 Tg, respectively. The plant C, N and P storage were 128.4 Tg, 3.1 Tg and 0.2 Tg, respectively. The litter C, N and P storage were 8.4 Tg, 0.45 Tg, 0.027 Tg, respectively. Soil is the largest C, N and P pool in the studied area. The soil organic C, N and P storage in the top 1 meter were 1.6 Pg, 161.3 Tg and 124.6 Tg, respectively.