黄土旱塬降水向土壤输入的氮素  

Mineral nitrogen introduced into soil by precipitation on Loess dryland

作　　者：李生秀[1] 寸待贵[1] 高亚军[1] 贺海香 李世清[1] 

机构地区：[1]西北农业大学,陕西杨陵712100

出　　处：《干旱地区农业研究》1993年第S1期83-92,共10页Agricultural Research in the Arid Areas

摘　　要：在乾县典型的沟壑丘陵农业生态条件下,收集了连续两年的降水,并对其中的矿质氮素进行了测定。结果表明,降水能给每亩土壤输入相当数量的氮素:1990年为1.98kg;1991年为0.96kg。输入的氮素以铵态氮为主,约占总氮量的3/4—9/10。硝态氮数量少,在降水中的含量相对稳定,浓度大小和降水季节无关。铵态氮在降水中的浓度较高,变动又较大。浓度高低显然和降水季节有关:降水中最高浓度出现在7,8,9三月,其它月份则较少。根据测定结果可以看出,硝态氮可能由风刮起的土壤微粒所带入。而铵态氮除来自于土壤微粒,煤碳柴草燃烧的烟尘以外,施入的铵态氮肥中的氨的直接挥发是一个重要来源。Under typically hilly agricultural condition with large gullies in Qian County, precipitationwas collected in successive two years and NH_4^+-N as well as NO_3^--N in it were analysed. Theresults have shown that precipitation had brought large amount of mineral nitrogen into soil: itwas 1. 98 kg N per mu in 1990, and 0.96 kg N Per mu in 1991. The main form of N introducedby precipitation was NH_4^+-N, about 3/4 to 9/10 of the total mineral N. The amount of NO_3^--N was much low as compared with NH_4^+-N, and its concentration in rain was relatively stable,having no relationship with season. However, the concentration of NH_4^+-N was high in precipi-tation, being variable with seasons: the highest concentration appeared in July, August, Septem-ber, and in the rest of other months the concentration was low. It coulp be seen from the resultsobtained that the NO_3^--N might originate from soil dust blown into sky by winds. However, thedirect volatilization of ammonia from fertilizers might be one of the main sources for NH_4^+-N,in addition to soil dust and smoke dust by fuel burning.

关 键 词：黄土旱原降水 NH₄⁺-N NO₃^--N 

分 类 号：S423[农业科学—植物保护]