摘要
在大田试验条件下,研究了施肥方式（滴灌施肥和沟施）和施氮量（单次每株25、50、75 g）对欧美108杨人工林土壤氮素垂向运移动态的影响.结果表明：不同施肥方式和施氮量下,土壤中铵态氮和硝态氮含量均随土层深度的增加而降低;滴灌施肥下铵态氮和硝态氮主要集中在0~40 cm土层,随时间变化呈先升后降的变化趋势,分别于施肥后第5天和第10天达到最大值（211.1和128.8 mg·kg-1）.沟施下铵态氮和硝态氮主要集中在0~20 cm土层,硝态氮含量随时间呈逐渐增加的变化趋势,于施肥后第20天达到最大值（175.7 mg·kg-1）,但铵态氮随时间无显著变化;滴灌施肥下氮素在土壤中的有效时长约为20 d,而沟施下氮素在土壤中有效时长超过20 d.滴灌施肥下,土壤中铵态氮和硝态氮的含量和运移距离均随施氮量的增加而增加;沟施下,施氮量越高土壤中硝态氮含量越高,但对铵态氮含量无显著影响.滴灌施肥下林地土壤中尿素的水解、硝化速率和运移深度均高于沟施,且施氮量越大,氮素在深层土壤的积累量越高.结合欧美108杨根系和土壤氮素分布特征,滴灌施肥能够为更大的细根分布区提供氮素,更适用于人工林培育.当单次施氮量为每株50 g时,既可保证细根主要分布区内有较高含量的氮分布又不会造成淋溶,肥料利用效率可能更高.
A field experiment was conducted to investigate the effects of fertilization methods, i.e., drip （DF） and furrow fertilization （GF）, and nitrogen （N） application rates （25, 50, 75 g N · plant-1 · time-1） on the dynamics of soil N vertical migration in a Populus x euramericana cv. ＇ Guariento＇ plantation. The results showed that soil NH4＋-N and NOa--N contents decreased with the increasing soil depth under different fertilization methods and N application rates. In the DF treatment, soil NH4＋-N and NO3--N were mainly concentrated in the 0-40 cm soil layer, and their contents ascended firstly and then descended, reaching their maximum values at the 5th day （211.1 mg · kg-1） and 10th day （128.8 mg ·kg-1） after fertilization, respectively. In the GF treatment, soil NH4＋-N and NOa--N were mainly concentrated in the 0-20 cm layer, and the content of soil NO3--N rose gradually and reached its maximum at the 20th day （ 175.7 mg · kg-1 ） after fertiliza- tion, while the NH4＋-N content did not change significantly after fertilization. Overall, N fertilizer had an effect within 20 days in the DF treatment, and more than 20 days in the GF treatment. In the DF treatment, the content and migration depth of soil NH4＋-N and NO3--N increased with the N ap- plication rate. In the GF treatment, the NO3--N content increased with the N application rate, but the NH4＋-N content was not influenced. Under the DF treatment, the hydrolysis rate, nitrification rate and migration depth of urea were higher or larger than that under the GF treatment, and more N accumulated in deeo soil as the N aoolication rate increased. Considering the distribntion charcte-ristics of fine roots and soil N, DF would be a better fertilization method in P. euramericana cv. ＇ Guariento＇ plantation, since it could supply N to larger distribution area of fine roots. When the N application rate was 50 g · tree-leach time, nitrogen mainly distributed in the zone of fine roots and had no risk of deep leaching, con
出处
《应用生态学报》
CAS
CSCD
北大核心
2015年第6期1641-1648,共8页
Chinese Journal of Applied Ecology
基金
中央高校基本科研业务费专项资金项目(BLX2013018)资助
关键词
滴灌施肥
沟施
土壤氮素运移
铵态氮
硝态氮
drip fertigation
furrow fertilization
soil nitrogen migration
ammonium nitrOgen
ni-trate nitrogen.
