Survey of NPK (Nitrogen, Phosphorus, Potassium) Absorption (g/m²) by Growth Stage for Potato

Overview

This report summarizes N (nitrogen), P (phosphorus), and K (potassium) absorption (g/m²) for each major growth stage of potato—Sprouting, Emergence, Vegetative growth, Tuber Initiation, Tuber Bulking, and Flowering—based on domestic and international academic papers, public institution materials, and agricultural guidance documents, as specifically as possible. Where direct stage-by-stage absorption data are unavailable, estimation methods, basis, and assumptions are stated explicitly.

Total NPK Absorption and Fertilizer Recommendations (Annual Totals)

• Recommended fertilizer rates and total absorption vary by production region and cultivar, but general guidelines are:
  • Nitrogen (N): 150–200 lb/acre (approximately 17–22 g/m²)
  • Phosphorus (P): 10–30 kg/ha (approximately 0.1–0.3 g/m²)
  • Potassium (K): up to 7 kg/Mg (about 7 kg per ton; peak uptake exceeds 5 kg/ha/day = 0.5 g/m²/day)
• In Japan, major production region guidance (e.g., Hokkaido) indicates similar or slightly lower total fertilizer rates [1][2][3][4][5][6].

NPK Absorption Dynamics by Growth Stage (Overview)

Sprouting and Emergence

• NPK absorption is very low in this period; plants rely mainly on nutrients within the seed tuber.
• Less than 10% of total potato uptake. P is important from this stage for root and early tuber formation, but absorption rate remains low [1][4][7][9].
• Estimated absorption (approximately 5–10% of total):
  • N: 1–2 g/m²
  • P: 0.01–0.03 g/m²
  • K: 1–2 g/m²

Vegetative Growth

• Absorption increases with rapid above-ground growth. N uptake becomes particularly active.
• By the end of this stage, up to approximately 30% of total uptake is consumed.
• P becomes more important for root and early tuber formation, though absolute amounts remain small.
• K demand rises gradually for carbohydrate transport and disease resistance [1][4][5][8][10].

Tuber Initiation

• Absorption increases sharply; N and K demand rises markedly.
• Some sources indicate 60–80% of total N and K uptake occurs from tuber initiation through bulking.
• P surges in this period and is critical for tuber number and establishment (peak P absorption) [2][6][7][9][11].

Tuber Bulking

• The largest amounts of N and K are absorbed; P increases slowly after its peak.
• Peak daily uptake rates:
  • N: 0.45–0.52 g/m²/day
  • P: 0.03 g/m²/day
  • K: 0.6 g/m²/day
• Absorption rate is exceptionally high for a period. Nearly 70% of total K uptake is concentrated in this stage [4][5][6][7].

Flowering

• Flowering overlaps with early to mid tuber bulking; N and K absorption remain high.
• N uptake tends to peak somewhat earlier and is directly linked to tuber growth.
• K remains in a major demand period [1][4][5].

Estimated NPK Absorption by Stage (g/m²)

Growth stages are aligned with a typical cultivation calendar; estimates below are derived from measured uptake, daily absorption rates, and cumulative distribution rates.

Growth Stage	Estimated Period	N (g/m²)	P (g/m²)	K (g/m²)
Sprouting	Planting–10 days	0.5–1.0	0.005–0.01	0.5–1.0
Emergence	10–20 days	0.5–1.0	0.005–0.01	0.5–1.0
Vegetative	20–35 days	2–5	0.015–0.04	2–4
Tuber Initiation	35–50 days	5–7	0.05–0.12	4–8
Tuber Bulking	50–85 days	10–13	0.08–0.18	10–16
Flowering	60–75 days	2–4	0.01–0.03	2–4

*Estimates are based on total uptake, cumulative curves, daily uptake, and seasonal distribution in the literature. Actual values vary greatly with growing period, weather, fertilization, and cultivar; figures are standard assumptions.

Estimation Method and Basis

• Cumulative absorption curves and peak daily uptake rates from multiple agronomic papers, public posters, and fertilization guides are multiplied by stage duration [4][5][6][7][9].
• Early stages (sprouting, emergence) with very low uptake are set at 5–10% of total; later stages are allocated according to cumulative absorption rates.
• P absorption of 40–50% in early to tuber initiation stages and sharp K increase after tuber initiation are reflected from reported data.
• Interval totals are adjusted to match total uptake cited in the literature.

Reflection of Domestic Literature

• MAFF and prefectural fertilization guides emphasize P for early root development and tuber number, and K for overall growth and especially tuber bulking—consistent with absorption peaks [8][9][10][11].
• Specialist journals classify potato as a relatively high-uptake crop; absorption curves are well studied in large-scale Hokkaido-type cultivation.

Conclusion

• Complete direct measurements of stage-by-stage NPK absorption are difficult to compile, but approximate guideline values can be obtained from daily uptake curves, cumulative distribution, and domestic and international agronomic sources.
• For fertilization and cultivation management, early P supply and substantial staged N and K application from mid-season onward align logically with absorption curves.
• In actual cultivation, optimal values differ by cultivar, climate, and soil; presented values should serve as a starting point and reference baseline for design.

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Sources

[1] A Summary of N, P, and K Research with Potato in Florida: https://edis.ifas.ufl.edu/publication/CV233
[2] Growth and phosphorus uptake of potato (Solanum tuberosum L.) in ...: https://stud.epsilon.slu.se/10081/1/weimers_k_170411.pdf
[3] Critical potassium dilution curve for potato crops - ScienceDirect.com: https://www.sciencedirect.com/science/article/abs/pii/S0378429024002454
[4] Nutrient Uptake and Partitioning by Potatoes in Manitoba (PDF): https://www.gov.mb.ca/agriculture/crops/soil-fertility/pubs/soil-fert-poster-25.pdf
[5] Potato | Nutrien eKonomics (PDF): https://nutrien-ekonomics.com/wp-content/uploads/2024/10/EKO_2024_CropGuide_Potato.pdf
[6] Effect of Irrigation and Nitrogen Management on Potato Growth ...: https://www.mdpi.com/2073-4395/14/3/560
[7] Facebook (potato tuber bulking stage K uptake): https://www.facebook.com/groups/926416337842161/posts/2170649233418859/
[8] Comparison of phosphate absorption characteristics of major field crops - AgriKnowledge: https://agriknowledge.affrc.go.jp/RN/2030853636.pdf
[9] Soil improvement and fertilization management II - Japan Soil Association: https://www.japan-soil.net/BOOKLET/TK24/TK24_A4.pdf
[10] Current status and practical applications of sensing and ICT for fertilization management: https://www.jstage.jst.go.jp/article/dojo/89/1/89_890113/_pdf
[11] Improving potato yield and quality by increasing nutrient absorption efficiency: https://www.meikyo-shoji.co.jp/library-4411/