Chinese Cabbage — NPK Absorption (g/m²) by Growth Stage

1. Introduction

Chinese cabbage (Brassica rapa) is a major leafy vegetable in Japan and Asia. Adequate nutrients at each stage are essential for high yield. This report summarizes NPK uptake (g/m²) at seedling, rosette, folding, heading, and flowering stages from literature, extension guides, and WOFOST model results.

2. Growth Stages and Nutrient Uptake

2.1 Stage Definitions

• Seedling (germination to ~5 true leaves)
• Rosette (horizontal outer leaves, plant establishment)
• Folding (inner leaves rise; initial head formation)
• Heading (dense head development)
• Flowering (flower initiation to seed)

Full cycle is typically 80–100 days in standard field production[1][2][3][4][5].

2.2 Temporal Uptake Pattern

Potassium uptake is highest, followed by N then P. Peak uptake occurs from rosette through early heading; rate declines toward flowering[6][7][8].

3. Stage-wise NPK Data (Measured and Estimated)

3.1 Direct Data Availability

Direct stage-wise N, P, K (g/m²) measurements are very limited; most sources give total uptake and stage percentages[6][8][9][10]. Allocation from totals is standard.

3.2 Estimation Method

• Total uptake example (4–5 kg/m² yield): N 30–35 g/m²; P 6–7 g/m²; K 40–45 g/m²[10]
• Stage shares (standard domestic model[8][9][10]): Seedling 10–15%; Rosette 30–35%; Folding 25–30%; Heading 15–20%; Flowering 5–10%

WOFOST validation shows similar sigmoid curves (rRMSE ~0.15)[9][11].

3.3 Estimated Uptake Table

Stage	Share (%)	N (g/m²)	P (g/m²)	K (g/m²)
Seedling	10–15	3–5	0.6–1.0	4–7
Rosette	30–35	10–12	2.0–2.5	12–16
Folding	25–30	8–10	1.5–2.0	10–13
Heading	15–20	5–7	1.0–1.5	6–9
Flowering	5–10	2–4	0.3–0.7	2–4

Based on totals N = 33, P = 7, K = 44 g/m². Flowering usually occurs after edible harvest[8][10][11].

4. Usage Notes

• Adjust for cultivar, season, weather, and fertilization; use local extension data where available[6][8][10].
• Fertilizer recovery efficiency (N ~30–40%, P ~10%, K ~40–50%) means applied rates exceed uptake[6].
• Values are whole-plant uptake; not all nutrients accumulate in the edible head[8][10].

5. Conclusion

Chinese cabbage stage-wise NPK can be estimated as total uptake × established stage percentages—a method validated by WOFOST and widely used for brassicas. Fertilization through heading is most critical for market production.

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Sources

[1] Response of nitrogen and phosphorus levels on the growth and yield of Chinese cabbage [Brassica rapa (L.) var. Perkinensis]: https://www.scitechnol.com/abstract/response-of-nitrogen-and-phosphorus-levels-on-the-growth-and-yield-of-chinese-cabbage-brassica-rapa-l-var-perkinensis-2902.html
[2] Response of nitrogen and phosphorus levels on the growth and yield of Chinese cabbage: https://www.researchgate.net/publication/215568226_Response_of_nitrogen_and_phosphorus_levels_on_the_growth_and_yield_of_Chinese_cabbage_Brassica_rapa_L_var_pekinensis_in_the_gangetic_plains_of_West_Bengal
[3] The Effects of Nitrogen and Potassium on the Growth of Brassica rapa: https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1054&context=biw
[4] Nutrient uptake, growth, and physiology of Chinese cabbage (Brassica rapa L. ssp. pekinensis) varieties under NaCl stress: https://www.researchgate.net/publication/381634433_Nutrient_uptake_growth_and_physiology_of_Chinese_cabbage_Brassica_rapa_L_ssp_pekinensis_varieties_under_NaCl_stress_1
[5] Nutrient Uptake and Yield of Chinese Cabbage (Brassica rapa L.): https://www.mdpi.com/2311-7524/8/3/196
[6] Soil management and fertilization by crop type - Japan Soil Association: https://www.japan-soil.net/BOOKLET/H23/H23_A4.pdf
[7] 4．Crop nutrition physiology and nutrient uptake: https://www.maff.go.jp/j/seisan/kankyo/hozen_type/h_sehi_kizyun/pdf/gum12.pdf
[8] Light vegetable cultivation manual (revised) - Ehime Prefecture: https://www.pref.ehime.jp/uploaded/attachment/26297.pdf
[9] Rethinking the WOFOST model to simulate growth and development of Chinese cabbage (Brassica rapa L. ssp. Pekinensis): https://www.sciencedirect.com/science/article/pii/S0308521X25002082
[10] Identifying major open-field vegetable production systems in Japan - J-Stage: https://www.jstage.jst.go.jp/article/cib/20/0/20_J-20-047/_pdf/-char/ja
[11] Rethinking the WOFOST model to simulate growth and development of Chinese cabbage (Brassica rapa L. ssp. Pekinensis) - Nutrient uptake simulation: https://ideas.repec.org/a/eee/agisys/v230y2025ics0308521x25002082.html