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Increasing Strawberry Fruit Yield - Nitrogen

Nitrogen is essential for plant growth being one of the main building blocks of proteins. It is important for biomass production and fruit production, maximizing photosynthetic assimilation leading to high strawberry yields (Figure 25).

During periods of rapid growth, leaves that are short of nitrogen remain small and turn pale green or yellow. However, too much nitrogen can lead to an excessive leaf area which is out of balance with the rest of the plant, and also produces too many runners and insufficient flowers. Strawberries are quite sensitive to excessive rates of N and so nitrogen supply needs to be closely monitored and balanced with other nutrients. The total rate of N required will vary with variety and growing system.

Timing of N is also critical and programs need to be tailored to deliver enough leaf growth and strong fruit set without creating issues during fruit fill and at harvest. In field grown strawberries, this will mean focusing upon nitrogen applications in the autumn and also early in the spring - to strengthen and build the plant and improve fruit production.

These N applications must be balanced with the expected release of N from any organic matter added to the soil in preparation for planting the strawberries.

Increase Yield with Autumn & Spring Nitrogen

Graph 18 - Macronutrient Uptake - Plant and Fruit — Uptake figures confirm that around 3-3.5kg of nitrogen per ton of fruit is required

Graph 17 - Macronutrient Uptake — Nitrogen uptake increases during the vegetative stage and reaches a peak just before the fruit starts maturing

Perennial systems can utilize N reserves held in the crown and roots, over the 2-3 years of production as a result of remobilization in the spring. Thus, annual production systems commonly require and consequently receive higher N rates than perennial systems. Relying on autumn applications only will not maximize production in spring. Spring N applications are essential to maximize yield, but they cannot compensate sufficiently if autumn application rates were too low (Figure 29).

Graph 31 - Nitrogen – Application Method

In soil cultivation systems, split application of N is recommended for what is a relatively shallow-rooted crop, commonly grown on light, leaching prone soils. Nitrogen is better utilized when applied by fertigation compared to broadcast application (Figures 30 and 31). A consistent low N rate applied by fertigation is much more effective than broadcasting N in one dose.

Recommended Yara Fertilizers for Soft Fruit

YaraLiva CALCINIT

15.5% N + 18.8% Ca - Fully water soluble nitrogen and calcium fertilizer which is a free flowing and dissolves quickly in water without any residues so is suitable for application through all fertigation systems.

YaraTera KRISTALON SCARLET

7.5-12-36 + 4.5% MgO 10% SO₃ - A water soluble NPK fertilizer for liquid feeding and contains a full range of chelated micronutrients ideal for all fertigation systems.

YaraTera KRISTALON RED

12-12-36 + 1% MgO 2.5% SO₃ - A water soluble NPK fertilizer for liquid feeding and contains a full range of chelated micronutrients ideal for all fertigation systems.

YaraTera KRISTALON LILAC LB

20-8-8 + 2% MgO 25% SO₃ - A water soluble NPK fertilizer for liquid feeding and contains a full range of chelated micronutrients ideal for all fertigation systems.

YaraTera KRISTA K PLUS

YaraTera KRISTA K PLUS 13.7% N 46.3% P₂O₅ - A fully water soluble nitrogen and magnesium fertilizer. It is a free flowing fine crystalline powder which dissolves quickly in water without any residues.

YaraTera KRISTA MAG

YaraTera KRISTA MAG - 11% N 15% MgO - A fully water soluble nitrogen and magnesium fertilizer. It is a free flowing fine crystalline powder which dissolves quickly in water without any residues.

YaraTera REXOLIN Q15

YaraTera Rexolin Q15 is a high performance microgranular EDDHA iron chelate containing 7% iron with 1.5% of the iron as the ortho-ortho isomer. The micro granular formulation is stable, fully water-soluble and non-dusting. Ideal for use in agriculture and horticulture in soil applications. The product is specifically formulated to provide maximum crop safety. This helps to ensure that application will not cause damage to the crop which can reduce it's market value. Analysis 7% w/w = 70 g/kg Fe (chelated by EDDHA) Pack Size 25kg Available in England and Wales, Scotland and Northern Ireland..