Location: Horticultural Crops Research UnitTitle: Uptake and partitioning of nutrients in blackberry and raspberry and evaluating plant nutrient status for accurate assessment of fertilizer requirements
|STRIK, BERNADINE - Oregon State University|
Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2015
Publication Date: 9/1/2015
Citation: Strik, B.C., Bryla, D.R. 2015. Uptake and partitioning of nutrients in blackberry and raspberry and evaluating plant nutrient status for accurate assessment of fertilizer requirements. HortTechnology. 25(4):452-459.
Interpretive Summary: Growers typically base nitrogen (N) fertilization decisions in blackberry and raspberry on results of tissue analysis of primocane leaves taken in late July to early August (northern hemisphere), soil tests every few years, and observations of annual growth (cane number, diameter, and height and fruiting lateral length), yield, color of leaves, and fruit quality (amount of rot and drupelet set). Research on N uptake has shown that caneberry plants require fertilizer N in early spring for primocane growth and for growth of floricanes (fruiting laterals and fruit). Stored N is remobilized from roots, crown, and over-wintering primocanes for growth of fruiting laterals and fruit. Nutrients are also remobilized from senescing floricanes, offering an advantage when pruning is delayed. Peak accumulation of other nutrients primarily occurs immediately before maximum growth. Annual fertilization with N, phosphorus (P), potassium (K), and boron (B) is recommended to replace the nutrients lost with fruit harvest and pruning, considering nutrient source and fertilizer uptake efficiency. Monitoring plant growth and plant nutrient status is recommended to adjust nutrient programs.
Technical Abstract: Raspberry and blackberry plantings have a relatively low nutrient requirement compared to many other perennial fruit crops. Annual total N accumulation ranged from 62-110 lb/a in red raspberry and 33-39 lb/a in blackberry. Primocanes rely primarily on fertilizer N for growth, whereas floricane growth is highly dependent upon stored N in the over-wintering primocanes, crown, and roots; from 30% to 40% of stored N was allocated to new growth. Plants receiving higher rates of N fertilizer took up more N, often leading to higher N concentrations in the tissues, including the fruit. Accumulation of other macro- and micronutrients in plant parts usually preceded growth. Primocanes generally contained the highest concentration of most nutrients during the growing season, except Ca, Cu, and Zn, which often were more concentrated in roots. Roots typically contained the highest concentration of all nutrients during winter dormancy. Nutrient partitioning varied considerably among elements due to different nutrient concentrations and requirements in each plant part. This difference not only affected the proportion of each nutrient allocated to plant parts, but also the relative amount of each nutrient lost or removed during harvest, leaf senescence, and pruning. Macro- and micronutrient concentrations are similar for raspberry and blackberry fruit, resulting in a similar quantity of nutrient removed with each ton of fruit at harvest; however, yield may differ among cultivars and production systems. Nutrient removal in harvested red raspberry and blackberry fruit ranged from 11-18lb/a N, 10-19 lb/a of K, 2-4 lb/a of P, 1-2 lb/a of Ca, and 1-4 lb/a of Mg. Pruning senescing floricanes in August led to greater plant nutrient losses than pruning in autumn. Leaf nutrient concentrations differ with primocane leaf sampling time and cultivar. In Oregon, the recommended sampling time for leaf tissue testing is late-July to early August for primocane and floricane raspberry and floricane-fruiting blackberry and during the green fruit stage in primocane-fruiting blackberry.