不同土地利用方式对棕壤有机氮组分及其剖面分布的影响

Effect of different land use systems on the form and distribution of organic nitrogen in brown soil

研究了典型棕壤不同土地利用方式对有机氮组分及剖面分布的影响。结果表明,三种利用方式对耕层(0—20 cm)有机氮各组分影响最大。有机氮各组分含量总体趋势为林地>柞树林地>耕地,林地与柞树林地有机氮组分都是随剖面的加深而降低且基本达显著水平,耕地有机氮各组分在剖面中分布则明显不同。三种利用方式下土壤有机氮组分均以酸解性氮占主体,其占全氮的比例随利用程度的加强和剖面的加深而降低,非酸解性氮则相反。有机氮各组分占酸解氮的比例林地与柞树林地相同,均为氨基酸氮>酸解未知态氮>酸解氨态氮>氨基糖氮;耕地为酸解未知态氮>氨基酸态氮>酸解氨态氮>氨基糖态氮,其中酸解氨态氮的比例在0—40 cm土层明显高于林地、柞树林地。

Influence of different land use systems （naturally needle broad-leaved secondary forest, tussah woodland, and tilth land） on organic nitrogen form and distribution in brown soll were studied under field condition. Soil samples （0- 20, 20-40, and 40-60 cm） were collected from each of land use system. Results showed that the influence of different land use systems on the organic nitrogen forms was the strongest on 0-20 cm soil layer. The content of all the organic nitrogen forms in naturally needle broad-leaved secondary forest land was the highest, followed by tussah woodland and tilth land. Contents of all forms of organic nitrogen decreased significantly with increasing of the depth for naturally needle broad-leaved secondary forest land and tussah woodland, but the distribution of different forms of organic nitrogen under tilth land use system showed a big variation. The result also indicated the proportion of organic nitrogen forms was ammo acid-N 〉 hydrolysable unknown-N 〉 ammonia-N 〉 ammonia sugar-N under second forest land and tussah woodland land use systems, but land use of tilth was different which was hydrolysable unknown-N 〉 ammo acid-N 〉 ammonia-N 〉 ammonia sugar-N. The proportion of ammonia-N under tilth land was larger than second forest land and tussah woodland at 0- 40 cm soil layer.