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Long‐term effects of nitrogen and phosphorus fertilization on soil aggregate stability and aggregate‐associated carbon and nitrogen in the North China Plain
Author(s) -
Zhang Huayan,
Niu Ling'an,
Hu Kelin,
Hao Jinmin,
Li Fan,
Wang Xiang,
Chen Hong
Publication year - 2021
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.1002/saj2.20197
Subject(s) - subsoil , soil carbon , fertilizer , nitrogen , human fertilization , nutrient , phosphorus , agronomy , silt , soil organic matter , carbon sequestration , chemistry , soil water , environmental science , environmental chemistry , zoology , soil science , geology , paleontology , organic chemistry , biology
Soil aggregates and carbon storage are important in soil conservation, nutrient supply, and climate change mitigation. The long‐term responses of aggregate‐associated organic C (OC) and nitrogen (N) in surface versus subsoil to N and P fertilization remain unclear. We examined the effects of different N and P fertilization rates on aggregate stability and the associated soil OC (SOC) and N in the North China Plain through a 35‐yr double‐crop field experiment, hypothesizing that higher rates of mineral fertilizer would promote aggregate stability and increase C/N ratios in large macroaggregates. The OC and N were highest in the silt + clay fraction, accounting for 34 to 48% of bulk SOC and 28 to 47% of bulk soil N at 0 to 20 cm, and 38 to 62% of bulk SOC and 40 to 62% of bulk soil N at 20 to 40 cm. After 35 yr, N + P fertilization increased SOC (16–35%) and N (21–27%), especially the 540 kg N + 67.5 kg P treatment; the N + P fertilizer also increased the OC and N of the macroaggregate, microaggregate, and silt + clay fractions at 0 to 20 cm. The N + P fertilizer treatments increased bulk soil C/N ratios; the C/N ratios of large macroaggregates decreased. Nitrogen and P fertilizer did not affect aggregate stability. Long‐term N and P fertilization increased SOC concentrations, and altered OC and N distributions in aggregates. Quantifying the impacts of long‐term fertilization strategies on organic matter sequestration and soil stabilization is important.