Optimizing Nitrogen Application Rates for Organic Bok Choy Production in Subtropical Sandy Soils
Year: 2026
Type: article
Abstract: Organic systems rely on nitrogen (N) supplied through organic sources that must be mineralized before uptake. The timing and rate of N release are often difficult to synchronize with crop demand, especially for short-duration crops like bok choy. We evaluated the response of bok choy to N rates in Florida sandy soils using five N rates (0, 56, 112, 168, and 224 kg N ha−1) in a randomized complete block design. Yield, N uptake, apparent N recovery, N balances, and in-season crop indicators (SPAD, sap nitrate) were measured across three years. N applications significantly increased yield in 2023 and 2025 (with no significant differences in yield above 112 kg N ha−1), but not in 2024, highlighting the variability in crop response, likely due to environmental conditions. Higher N rates increased plant N accumulation but reduced N recovery and increased N surpluses, indicating a greater potential for N losses. SPAD and sap nitrate measurements were positively related to yield and could be used as rapid indicators of in-season crop N status, with SPAD having the advantage of being non-destructive. Overall, these findings help to optimize N management to better match crop demand in organic leafy green production systems, improving productivity while minimizing environmental costs.
Source: Agronomy
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7212116703