天津盐渍化土壤水溶性氮素组成及分布特征

Composition and Distribution of Water-Soluble Nitrogen in Salinized Soils in Tianjin City,China

对天津不同程度盐渍化农田（n=4）和荒地（n=4）土壤水溶性有机碳（SOC）和水溶性氮素组成与分布特征进行了研究。结果表明：农田和荒地土壤水溶性有机碳（SOC）含量分别为26.1-46.4mg/kg和19.6-77.8mg/kg,由表层向下呈现出降低-升高-稳定的变化趋势。农田土壤具有较高溶解性总氮（TSN）、硝氮（NO-3—N）和水溶性有机氮（SON）含量,分别是荒地土壤的0.8-5.9、0.8-10.5和0.9-8.7倍。NO-3—N和SON是TSN的主要组成部分,分别占农田土壤TSN的38%-72%和26%-60%,荒地土壤的32%-75%和16%-58%。NO-3—N、SON在农田土壤剖面中主要积累在土壤表层和底层,而在荒地土壤剖面中主要积累在土壤表层,且在农田土壤中具有较高的淋溶风险。

An investigation on composition and distribution of water-soluble carbon and nitrogen in farmlands（ n = 4） and wastelands（ n= 4） of different salinized soils in Tianjin City,China was carried out. Results show that the soluble organic carbon（ SOC） ranges from 26. 1-46. 4 mg / kg and 19. 6- 77. 8 mg / kg in farmlands and wastelands,respectively. SOC has a trend of drop-rise-stable from topsoil to subsoil. The total soluble nitrogen（ TSN）,NO-3- N and soluble organic nitrogen（ SON） in farmlands appear higher than in wastelands,and the average contents in farmlands are 0. 84-5. 9,10. 8-10. 5,and 0. 9-8. 7 times as in wastelands,respectively. The NO-3-N and SON are the main form of TSN,accounting for 38%-72% and 26%- 60% of the TSN in the farmlands,and 32%- 75%and 16%-58% of the TSN in the wastelands,respectively. The NO-3-N and SON are mainly accumulated in topsoil and subsoil in farmland profiles,but mainly in topsoil in wasteland profiles,and have a higher risk of leaching losses in farmlands.