Phosphorus (P) fertilizers have long been applied in agriculture. However, the influence of long‐term P addition on the evolution of soil P fertility and legacy P characteristics have not been well‐documented. Herein, literature data were collected from the Chinese National Knowledge Infrastructure Database (CNKI) to explore the evolution of soil P fertility after 33 years of application of P fertilizer; different soil samples were collected from cropland and adjacent uncultivated land to analyse the distribution of P fractions at different soil depths (0–0.8 m) using Guppy's sequential P extraction method. We found that soil Olsen‐P significantly increased by 3.6‐fold (from 7.2 mg kg−1 in 1981 to 25.9 mg kg−1 in 2013) after 33 years of P application, while total P increased slightly. The ratios of inorganic P fractions in cropland to those uncultivated land followed NaHCO3‐P (1.47) > NaOH‐P (1.38) > resin‐P (1.37) > residue‐P (1.17) > HCl‐P (1.11), suggesting that long‐term P addition contributed more to labile and moderately labile P rather than non‐labile P. Moreover, a principal component analysis could distinguish between cropland and uncultivated land, indicating that long‐term application of P fertilizer changed soil P characteristics. Compared to uncultivated land, soil NaHCO3‐P in cropland was closely associated with soil organic C, total nitrogen and carbonate. Collectively, our findings highlight that soil legacy P was notably increased after long‐term of P application, and a large portion of the applied P remained in labile and moderately labile forms. Therefore, soil legacy P can be recommended as a useful P management tool.
Application of nitrification inhibitors (NIs) has been widely used to inhibit nitrification and reduce N2O emissions. However, the impacts of NI addition on soil carbon transformation and carbon-degrading microbial communities have not been well explored. Here, a microcosm experiment was carried out, and four treatments were designed: (i) unfertilized control, (ii) urea alone, (iii) urea plus cattle manure, and (iv) urea plus cattle manure with nitrapyrin. The influence of nitrapyrin on soil CO2 emissions, carbon-degrading extracellular enzyme activities, and the abundance and diversity of the cbhI community was investigated. Compared to the treatment of urea plus cattle manure, nitrapyrin significantly decreased cumulative CO2 emissions by 51.8%. Moreover, cbhI community gene copies and their α-diversities (P < 0.05) were also significantly reduced by nitrapyrin application. A partial least squares path model showed that CO2 emission was positively associated with cbhI community α-diversity but negatively associated with nitrapyrin addition. We conclude that the mitigation of soil CO2 emissions by nitrapyrin can be ascribed to its effects on decreasing of cellulose-degrading gene community diversity. Our findings provide new insights into the side-effects of nitrapyrin on abating CO2 emission.
A new species, Berberis viridiflora X. H. Li, and a new variety, Berberis sanguinea Franch. var. viridisepala X. H. Li, L. C. Zhang & W. H. Li are described and illustrated from Baoxing County, a biodiversity hotspot located on the eastern edge of Hengduan Mountains in Sichuan Province, Southwest China. Both new taxa resemble B. sanguinea Franch. var. sanguinea, but B. viridiflora differs by the greenish flowers, and the petals being truncate, obtuse, or undulate at apex; while B. sanguinea var. viridisepala differs by the greenish or yellowish green flowers. Morphological features of the pollen grains of B. sanguinea and the two new taxa are revealed by scanning electron microscope. B. sanguinea var. sanguinea displays obvious similarities with a sympatric congener, Berberis multiovula T. S. Ying in the morphology of flowers, stems and leaves, especially its ovule number varies greatly from 2 to 9, thus, B. multiovula characterized by the 5-ovuled ovary is reduced to a synonymy of B. sanguinea var. sanguinea. On the basis of field surveys and study of herbarium specimens, a total of 16 species and varieties of Berberis are recorded from Baoxing County, and a key is provided. Among the 16 taxa, most phenotypic variations in Chinese Berberis can be displayed, including the habit of plants, most morphological variations of stems, branches and leaves, all types of inflorescences, all color types of flowers, and nearly all types of the shape and color of fruits. Baoxing County and its adjacent Sichuan Giant Panda Sanctuaries possibly constitute an active diversification center of Berberis in eastern Hengduan Mountains of China.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.