|Authors: ||B.C. Strik, A.J. Vance|
|Keywords: ||Rubus, tissue sampling, nutrient standards, nutrient management|
Leaf tissue sampling is a critical aspect of a nutrient management program in commercial blackberry production.
Current, published recommendations for time of sampling and nutrient sufficiency levels are generally defined for all caneberries (raspberry and blackberry), including floricane- and primocane-fruiting types.
In blackberry, floricane-fruiting trailing, erect, and semi-erect cultivars and primocane-fruiting erect cultivars differ in fruiting season and pruning or training method.
Thus, tissue nutrient levels and sampling requirements may differ among these blackberry types.
Two studies were conducted to assess the impact of blackberry type and cultivar on tissue nutrient concentration of leaves sampled every 2 weeks over two growing seasons.
In 'Prime-Jan'® and 'Prime-Jim'®, primocane-fruiting blackberry, the best time to sample primocane leaves coincided with a phenological stage (green fruit on the primocane) rather than on a given calendar date (standard method). In the second study, we examined leaf nutrient levels in trailing, erect, and semi-erect cultivars.
Blackberry types differed in leaf nutrient concentrations.
Within each type of blackberry studied, cultivars frequently differed in nutrient concentration throughout the season.
We thus confirmed the importance of sampling cultivars separately.
In many cultivars, primocane leaf nitrogen, phosphorus, potassium, calcium, magnesium, and copper were consistently below the current published sufficiency levels.
New sufficiency levels and recommended sampling times based on blackberry type are presented.
Fertilizer recommendations based on leaf nutrient sufficiency levels specific to the diverse types of blackberry grown will aid growers, potentially reducing over application of fertilizer nutrients.
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