Characterizing Early-Season Nitrogen Fertilization Rate Effects on Growth, Yield, and Quality of Strawberry

Shinsuke Agehara

doi:10.3390/agronomy11050905

Abstract

In winter strawberry (Fragaria × ananassa Duch.) production, early-season nitrogen (N) fertilization greatly affects fruit earliness and yields, especially when pre-plant N is not applied. The objective of this study was to characterize the dose-responses of canopy growth, yield, and fruit quality to early-season N fertilization in ‘Florida Radiance’ and ‘Florida127’ strawberry. Field experiments were conducted in west-central Florida, United States. Treatments included four (0.56, 0.84, 1.12 and 1.40 kg ha−1 d−1) and five (0.22, 0.67, 1.12, 1.57, and 2.02 kg ha−1 d−1) early-season N rates in the first and second growing seasons, respectively. Increasing the early-season N rate increased early and total season yields by up to 62% to 65% and 56% to 58%, respectively, in the two cultivars. The total season yield had high positive correlations with leaf area and shoot DW. Model fitting analysis revealed cultivar-dependent dose-responses. Yield and berry size responses in ‘Florida Radiance’ were linear increases, whereas those in ‘Florida127’ were quadratic with peaks occurring at N rates of 1.21 or 1.57 kg ha−1 d−1. In ‘Florida Radiance’, soluble solids concentration showed a linear dose-response with a slope of –0.91 (0.91 °Brix decrease per 1 kg ha−1 d−1 N increase) during the early season. These results suggest that optimization of early-season N fertilization is an important production strategy to improve the profitability of winter strawberry production. Furthermore, fertilizer management that takes into account cultivar-dependent dose-responses can improve fertilizer use efficiency while minimizing fruit quality loss and environmental pollution risks.

Highlights

Strawberry (Fragaria × ananassa Duch.) is one of the most important fruit crops in the world, and it is grown widely in temperate and subtropical climates
The slope in the linear model indicates that the increase was relatively small (1.12% increase per 1 kg ha−1 d−1 N increase), misshapen fruit is a practical issue that requires attention for this high-value crop, in which visual fruit quality is of great importance
The plant growth assessment was performed only in the 2014–2015 season, high correlations of mid-season canopy growth variables with total season yield indicate the importance of establishing a productive canopy during the early season

Summary

Introduction

Strawberry (Fragaria × ananassa Duch.) is one of the most important fruit crops in the world, and it is grown widely in temperate and subtropical climates. Global strawberry production was 8.89 million tons in 2019, a 41% increase from 2010 [1]. In the United States, strawberry production in 2019 was 1.02 million tons on 18,130 ha [2]. California and Florida are the top strawberry-producing states, generating farmgate values of $2214 and $307 million, respectively [2]. In both states, strawberry is typically grown as an annual crop on raised beds covered with polyethylene mulch. Irrigation and fertilization are performed through one or two drip lines per bed, based on local growing conditions, soil types, and cultivar requirements [3]

Objectives

Methods

Findings

Discussion

Conclusion