The Absorption, Utilization and Distribution of Nitrate 15N and Ammonium 15N in Populus Tomentosa Seedlings Changes on leaf oxalate content in buckwheat growing under different nitrogen forms Effects of elevated temperature and CO2 concentration doubling on soil total soluble nitrogen in subalpine coniferous forest of western Sichuan, China Relation of mineralizable N to organic N components A STUDY ON PHYSIOLOGICAL TRAITS IN NUTRITION OF CHINESE FIR (Cunninghamia lanceolata(Lamb)Hook)PLANTATIONS A Method for Measuring Nitrogen Chemical Properties of Tree Stem-Flow with UV Spectrophotometer Response of Soil Microbe Flora to Simulated Nitrogen Deposition at a Plantation of Cunninghamia lanceolata Removal of Ammonia Nitrogen in Aqueous Samples byBamboo Carbon Immobilized Microorganism Effects of inorganic nitrogen compounds and pH on the growth of duckweed Lemna aequinoctialis