A review of nitrogen, phosphorus, potassium, calcium, and magnesium nutrition in red raspberry and blackberry

Relative to most fruit crops, raspberry and blackberry (Rubus sp.) plants have relatively low requirements for N and other macronutrients. Depending on the cultivar and production system, field-grown plants in Oregon, USA accumulated 70-123 kg ha^‑1 N, 7-9 kg ha^‑1 P, 49-59 kg ha^‑1 K, 33-48 kg ha^‑1 Ca, and 11-14 kg ha^‑1 Mg year^‑1 in raspberry and 44-93 kg ha^‑1 N, 6-12 kg ha^‑1 P, 47-91 kg ha^‑1 K, 43-65 kg ha^‑1 Ca, and 8-13 kg ha^‑1 Mg year^‑1 in blackberry. Fertilizer requirements in these crops can be estimated from annual losses in fruit, senesced leaves, and pruned floricanes, although nutrient in leaves and floricanes may be returned to the field through nutrient cycling. Tissue analyses indicated that nutrient losses in fruit varied with yield and ranged from 14 to 19 kg ha^‑1 N, 2-4 kg ha^‑1 P, 12-20 kg ha^‑1 K, 1-5 kg ha^‑1 Ca, and 1-2 kg ha^‑1 Mg. Losses of N, P, K, Ca, and Mg in the leaves and pruned floricanes averaged 30, 2, 15, 23, and 6 kg ha^‑1, respectively, in ‘Meeker’ raspberry and 35, 5, 41, 34, and 7 kg ha^‑1, respectively, in ‘Black Diamond’ and ‘Marion’ blackberry. Application of ¹⁵N-depleted fertilizer revealed that N applied at budbreak in raspberry was partitioned to primocanes, fruiting laterals, and fruit, whereas N applied 2 months later was partitioned predominately to primocanes. The results also indicated that primocanes relied primarily on fertilizer N for growth, while floricanes relied on N stored in overwintering primocanes, crown, and roots (≈30-40% of stored N was allocated to new growth). Delaying pruning of senescing floricanes increased N remobilized to these storage tissues. Leaf nutrient sufficiency standards were updated based on our research and can be used for nutrient management of raspberry and blackberry in conventional and organic production systems.