摘要
本研究以黄土高原长期放牧草地和围封7年的草地为对象,分析了土壤铵态氮和硝态氮含量的季节变化,并应用RDA冗余分析法分析了土壤水分、植被地上绿色生物量以及土壤微生物生物量碳对土壤铵态氮、硝态氮的影响。结果表明,铵态氮是围封与放牧草地土壤有效氮的主要组分;两样地0-10cm土层土壤铵态氮与硝态氮均主要受植被地上绿色生物量的影响;围封草地10-20cm土层土壤硝态氮主要受土壤水分与植被地上绿色生物量的共同影响,而放牧草地10-20cm土壤铵态氮和硝态氮主要受植被地上绿色生物量的影响;土壤铵态氮与硝态氮之间呈极显著正相关(P<0.01);放牧草地围封7年后,较高的生物量使得凋落物及土壤有机质增加;另外,围封后土壤水分在多数季节显著增加(P<0.05),这些因素共同促进了土壤氮素的矿化。
A study was conducted in fenced grassland（F,fenced for 7years）and grazed grassland（G）on the Loess Plateau to investigate the seasonal variation of the contents of soil ammonium nitrogen（NH_4^＋-N）and nitrate nitrogen（NO_3^--N）.Redundancy analysis was also used to study the effects of soil water content,aboveground green biomass and microbial biomass carbon on NH_4^＋-N and NO_3^--N contents.The results showed that NH_4^＋-N was the main component of soil available nitrogen in both fenced and grazed grasslands.In the0-10 cm soil layers of the two sites,soil NH_4^＋-N and nitrate nitrogen were mainly controlled by above-ground green biomass.In the 10-20 cm soil layers,soil NO_3--N and nitrate nitrogen were mainly controlled by both of soil water content and above-ground green biomass in fenced grassland,while soil NH_4^＋-N and NO_3--N were mainly controlled by above-ground green biomass in grazed grassland.There was significantly positive correlations（P〈0.05）between NH_4^＋-N and NO_3--N in the two sites.The results indicated that the higher above-ground biomass after fencing for 7years increased litter inputs and soil organic matter,thus increased substrate for nitrogen mineralization.In addition,soil water content significantly increased in most seasons（P〈0.05）and all of these factors promoted the nitrogen mineralization in the soil.
出处
《草业科学》
CAS
CSCD
北大核心
2016年第6期1044-1053,共10页
Pratacultural Science
基金
长江学者和创新团队发展计划(IRT13019)
国家自然科学基金(31201837)
兰州大学中央高校基本科研业务费专项资金(lzujbky-2014-78)
草地农业生态系统国家重点实验室开放基金(SKLGAE201401)
广东省省级科技计划项目(2015B090904008)
关键词
围封草地
放牧草地
铵态氮
硝态氮
fenced grassland
grazed grassland
ammonium nitrogen
nitrate nitrogen
