Both nursery and field performance determine suitable nitrogen supply of nursery-grown, exponentially fertilized Chinese pine

Abstract

Optimum fertilization levels are often determined solely from nursery growth responses. However, it is the performance of the seedling on the outplanting site that is the most important. For species seedlings, little information is known about the field performance of plants cultured with different nutrient rates, especially with exponential fertilization. In this study, Chinese pine ( Carr.) seedlings grown in 187 ml containers were fertilized exponentially in 6 treatments ranging from 10 to 120 mg N seedling for 25 weeks before outplanting. Dry mass and N content were measured at planting. Survival and field growth were monitored for two growing seasons. In the nursery, our data showed no difference in dry mass among the 40, 80, 100, and 120 mg N seedling fertilizer treatments; collectively, these treatments were significantly greater than at 10 and 20 mg N seedling treatments. Seedling N content was greatest for the 100 and 120 mg N seedling rates. These data suggested that nursery optimum N fertilization rate was no less than 100 mg N seedling. Outplanting height and root-collar diameter growth characteristics were not significantly different after two years, whereas maximum mean survival was best for seedlings nursery-fertilized at 80 mg N seedling. In consideration of both nursery and field performance metrics, our data suggest that exponentially fertilizing Chinese pine seedlings at 80 mg N seedling maximizes both nursery biomass accumulation and outplanting survival.Pinus Pinus tabulaeformis–1–1–1–1–1–1–1