Understanding plant uptake of organic and inorganic nitrogen for optimal fertiliser application in forestry

土壤中的氮以有机和无机两种形式存在。植物可以吸收无机氮——硝态氮和铵态氮——但是，平均而言，这些只占土壤中可溶氮的5%。最近的证据表明，植物可能能够利用有机形式中95%的氮中的一部分。我们将通过追踪细菌、真菌和桉树对不同形态氮的吸收来研究两种桉树人工林有机氮吸收的重要性。这些信息将重新定义“有效氮”的含义，并将指导土壤氮状态新测试的开发。

Nitrogen (N) in soils occurs in both organic and inorganic forms. Plants can take up inorganic N - nitrate and ammonium - but, on average, these account for only 5% of the soluble N in soils. Recent evidence suggests that plants may be able to tap into some of the 95% of N that occurs in organic forms. We will investigate the importance of organic N uptake for two plantation Eucalyptus species by tracing the uptake of different N forms by bacteria, fungi and eucalypts. This information will redefine what is meant by 'available N' and will guide the development of a new test for soil N status.