Exponential Fertilization Regimes Improved Growth and Nutrient Status of Quercus nuttallii Container Seedlings

Abstract

Background: The conventional fertilization regime ignores the allometric characteristics of Quercus nuttallii seedlings, challenging them to meet the nutritional needs at each growth stage. This study was conducted to determine the impact of exponential fertilization on the growth and nutrient status of Q. nuttallii container seedlings. Methods: Two fertilization regimes (average/exponential) were performed on Q. nuttallii container seedlings, and varied gradients (0, 300, 500, 700, and 900 mg/seedling) of N supply were set for the two regimes. Result: N application promoted the seedling height, root collar diameter, total biomass, and N/P/K accumulation of Q. nuttallii, and the exponential fertilization obtained better effects in general. An appropriate amount of exponentially N application was beneficial to the growth of root system, whereas excessive dosages inhibited it. Judging from seedlings growth status and nutrient accumulation, 900 mg/seedling under exponential fertilization was adequate for Q. nuttallii seedlings. However, 500 and 700 mg/seedling under exponential fertilization may have advantages in improving seedlings’ stress resistance. Conclusions: Exponential fertilization did not only meet the nutrient requirements and promote the growth of Q. nuttallii seedlings, but also facilitated the root growth to indirectly accelerate the assimilation of N/P/K, therefore improving the afforestation quality.