Relationship Analysis on Leaf Nutrient of Blueberry Cultivars and Soil Nutrient in Guangdong Province

Objective  Blueberry (Vaccinium spp.) is a plant species with no root hairs, resulting in weak uptake capacity of roots. Southern China is an emerging production area of blueberry. Therefore, the study aimed to investigate whether the soil conditions in southern China are suitable for blueberry growth and development, and whether the plant nutrients are balanced.

Method  With four blueberry cultivars in Heyuan, Guangdong Province as tested plants, the nutrient balance and levels in plants were studied with the method of Diagnosis and Recommendation Integrated System (DRIS) on the basis of leaf and soil analysis. The mycorrhizal colonization rate was determined, and the soil chemical properties affecting plant nutrient status were analyzed.

Result  There were significant differences in plant nutrient levels between cultivars, and the nutrient level of 'Sharpblue' was the highest. The contents of nitrogen, phosphorus and potassium in leaves were 15.90, 0.76 and 6.58 g/kg, respectively, and the iron content in leaves was 63.73 mg/kg.The total nutrient requirement of plants ranked as P>N>K. The levels of P and N were at a low range while that of K was at a normal range. It was noteworthy that there was no significant correlation between soil nutrient level and leaf nutrient level. The mycorrhizal colonization rate in roots was low (15.0%-26.7%), which led to a weak uptake capacity of roots.

Conclusion  The nutrient levels of blueberry plants in southern China are unbalanced, which are related to the weak root absorption capacity and low mycorrhizal colonization level. It is recommended that the application of P and N fertilizers, especially in organic forms, be increased and the application of mycorrhizal fungi be inoculated to improved the nutrient uptake efficiency.