Minimizing Nutrient Leaching and Improving Nutrient Use Efficiency of Liriodendron Tulipifera and Larix Leptolepis in a Container Nursery System.

Fertilization is very important to seedling quality in nursery culture, but excessive fertilization can contaminate surface and ground water around the nursery. The optimal fertilization practice is that which maximizes seedling growth and minimizes nutrient loss. We tested three fertilization strategies: (1) constant fertilization (Fix), (2) a three-stage rate (Thr), and (3) exponential fertilization (Exp) on Liriodendron tulipifera and Larix leptolepsis containerized seedlings. Growth performance, nutrient uptake, and leached nutrient loss were measured for 11 weeks. Height, root collar diameter, and dry weight of both species were not significantly different among treatments even though the nutrient supply of Exp was half that of the Fix and Thr treatments. Generally, measured nutrient concentrations in leached solutions were higher in Fix and Thr than Exp treatments. Nitrogen use efficiency was calculated as the ratio of the nutrient content of the seeding to the amount of nutrient applied. The N use efficiency in the Fix, Thr, and Exp treatments was 59, 55, and 79% for yellow poplar and 32, 27, and 50% for larch. Similar results were obtained for phosphorus and potassium. Thus, the Exp treatment had the highest nutrient use efficiency as well as the least nutrient loss. Adjusting fertilization rates can reduce soil and water contamination around the nursery without compromising growth performance, which reduces both producer′s investments and environmental problems.