Effect of late-season fertilization on nutrient reserves and carbohydrate accumulation in bareroot Larix olgensis seedlings.

摘要

It is not clear about the interactive effects of nitrogen, phosphorus, and potassium additions on carbohydrate accumulation in tree seedlings in the late-season of fall. In late September of 2009, 0 or 60 kg nitrogen ha-1 urea (46-0-0) was applied with 30 and 60 kg phosphorus ha-1 potassium hydrogen phosphate (0-41-45) to transplanted bareroot Changbai larch (Larix olgensis Henry) seedlings. One month after first fertilization, seedlings receiving nitrogen addition had higher nitrogen and phosphorus, but lower potassium, concentrations in combined stems and roots. The higher rate phosphorus and potassium treatment increased nitrogen concentration in coarse roots (diameter >5 mm) without nitrogen addition and improved potassium reserves. Fertilization did not affect seedling growth and whole-plant carbohydrate accumulation. In conclusion, we recommend a fertilizer regime of 60 kg N ha-1 urea and 60 kg phosphorus ha-1 potassium hydrogen phosphate applied in fall to improve nutrient reserves and increase root carbohydrate accumulation in Changbai larch seedlings.