黄土区人工牧草地有机氮组分变化研究

Research on Variety of Soil Organic Nitrogen Components in Artificial Herbage Land on Loess Plateau

黄土区人工牧草地 18年苜蓿连作对土壤耕层水解总氮、氨态氮、氨基酸氮及氨基糖氮含量有很大影响 ,不施肥条件下苜蓿连作能明显增加土壤耕层水解总氮、氨基酸氮和氨基糖氮含量。连续施 P处理根层水解总氮、氨态氮、氨基酸氮和氨基糖氮含量分别比对照增加 4 13.5 5 m g/ kg、5 8.39mg/ kg、16 9.83m g/ kg和 10 7.0 1mg/ kg;NPM处理土壤耕层水解总氮与对照相比增加 192 .5 8mg/ kg、氨基酸氮增加 2 2 3.4 4 mg/ kg、氨基糖氮增加 2 5 .6 6 m g/kg,而氨态氮含量则大幅度降低 ;在 6 0～ 10 0 cm不同处理的各形态氮含量接近且随土层加深逐渐减少。粮草轮作系统中不同苜蓿生长年限对土壤的水解总氮。

Continually planting 18 year alfalfa continuous cropping has important effect on soil hydrolysable N, ammoniacal N, aminoacid N, and amino sugar N in region of Loess Plateau, and alfalfa can increase evidently contents of hydrolysable N, aminoacid N and amino sugar N in topsoil under non fertilization compared with CK. Long term applying P separately increases contents of hydrolysable N, aminoacid N and amino sugar N in topsoil by 415.55 mg/kg,58.39 mg/kg, 169.83 mg/kg and 107.01 mg/kg;NPM separately increases hydrolysable N,aminoacid N and amino sugar N in topsoil by 192.58 mg/kg, 223.44 mg/kg and 25.66 mg/kg,but ammoniacal N content is decreased. N components contents of different treatments vary little within 60~100 cm soil layers and gradually decrease with the depth of soil layers. Experiments show that different alfalfa ages can evidently increase soil hydrolysable N, ammoniacal N and aminoacid N contents in food grass rotation systems.