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Comprehensive analysis of NPK (nitrogen, phosphorus, potassium) absorption (g/m²) at each growth stage of green pepper (Capsicum annuum)
Overview
When cultivating green peppers (Capsicum annuum), proper application of NPK (nitrogen, phosphorus, potassium) fertilizer is the key to improving yield and quality. However, regarding the actual amount of NPK absorbed (g/m²) at each growth stage (germination stage, seedling stage, growing stage, flowering stage, fruiting/swelling stage, maturation/coloring stage), there is limited direct quantitative data by stage in Japan and abroad. Therefore, this report systematically summarizes the absorption amount estimation method for each stage, its basis, and practical precautions based on Japanese and international literature, experiments, model data, administrative materials, etc., and provides a deep understanding and guidelines for application in the field.
1. Basic data on NPK absorption during all seasons of green pepper
Standard for total absorption (g/m²)
In standard green pepper cultivation in Japan, yield (1,000kg/10a; The recommended NPK absorption per 1,000kg/1,000m² (1kg/m²) is as follows [1]:
- Nitrogen (N): 3.0-5.2g/m²
- Phosphorus (P): 0.6-1. 1g/m²
- Potassium (K): 5.0-6.5g/m²
This is an average absorption value at economic yield level and is consistent with the values indicated by Japanese guidance institutions and fertilization standards [2][3].
2. Classification of each growth stage and growth period
Definition and characteristics of growth stages
The typical growth stages of green pepper can be divided as follows [2][3][8]:
- Germination stage (from sowing to germination) Immediately after budding): 2 to 7 days
- Seedling growing period (after germination to true leaf development and seedling planting): 20 to 40 days
- Growing period (vegetative growth period)(planting to first flowering) Around): 20 to 30 days
- Blooming period (first flowering to beginning of fruit set): 10 to 15 days
- Fruit set/enlargement period(fruit set to fruit enlargement/start of harvest): 3 0 to 50 days
- Maturity/coloration period (late harvest to coloration/maturity period): 20 to 30 days
The actual period will vary depending on the variety and cultivation environment, but this is a standard guide.
3. Estimation method and distribution ratio of NPK absorption amount by stage
Limitations of direct data and estimation approaches
In Japan, there are very few official documents or experimental data that systematically publish the amount of absorption by growth process, and it is necessary to calculate it backwards mainly from seasonal total values and fertilizer distribution ratios.[3][4] Therefore, the following estimation method is valid.
3.1 Estimation method based on total absorption
- Procedure:
- Based on the target yield/total NPK absorption per unit area (see above)
- Estimate the absorption amount for each stage by multiplying the biomass increase rate for each growth stage, the progress of differentiation, and the ratio according to the international absorption ratio model (see table below) [13][19][8]
3.2 Distribution ratio (recommended value from international models and previous research)
According to multiple domestic and international documents and simulations [13][8][19], the rough guideline for the NPK absorption ratio for each stage is as follows.
| Growth stage | Absorption rate (%) | Remarks |
|---|---|---|
| Germination stage | 0-2 | Very little | Seedling raising period | 5 to 10 | Low nutrient absorption capacity |
| Growing period (planting to flowering) | 20 to 25 | Rapid growth of stock |
| Blooming period | 15 to 20 | Growth + reproductive transition |
| Fruiting/enlargement stage | 30-40 | Most absorbed |
| Maturity/coloring stage | 10~ 20 | Quality formation |
The trends are similar for N/P/K, but potassium tends to be particularly abundant during the fruiting and thickening stages, and phosphorus tends to be used intensively during the growing and flowering stages.
4. Specific estimate of absorption amount (g/m²)—Standard case
Sample calculation (for yield 1,000kg/1,000m²)
Estimated absorption capacity for each stage based on the standard yield of 1,000kg/1,000m² under Japanese conditions and total absorption capacity is as follows. The distribution ratio is based on the average model value mentioned above, and the same ratio is used for all N, P, and K.
| Stage | N (g/m²) | P (g/m²) | K (g/m²) |
|---|---|---|---|
| 1. Germination period (2%) | 0.10 | 0.02 | 0.13 |
| 2. Seedling period (8%) | 0.40 | 0.07 | 0.52 |
| 3. Growing season (22%) | 1.10 | 0.22 | 1.43 |
| 4. Flowering period (18%) | 0.90 | 0.16 | 1.17 |
| 5. Fruiting/enlargement period (35%) | 1.75 | 0.33 | 2.34 |
| 6. Maturity/color stage (15%) | 0.75 | 0.13 | 0.98 |
| Total | 0.93 | 6.57 |
*For N=5g/m², P=0.93g/m², K=6.57g/m². Distribution ratio example: 2%/8%/22%/18%/35%/15%
*The absorption pattern is the same even when calculated from the lower limit value to the upper limit value.
Note
- In the early stage of seedling cultivation, the root mass and leaf area are small and the absorption capacity is limited
- Absorption increases explosively with growth, flowering, and fruit enlargement (especially N and K)
- Phosphorus is actively absorbed from the early stage to the reproductive transition stage and affects the number of fruit set and flower bud formation
- At the ripening stage, potassium affects fruit quality and color
5. Supplementary matters/Practical points
- Actual absorption varies depending on region, variety, cropping type, and weather. This is just a guideline [2][5]
- Japanese fertilization methods usually recommend a design that concentrates the fertilizer effect on important stages through split application or top-dressing [3][2]
- It is extremely important in practical terms to increase field adaptability through field diagnosis, soil analysis, leaf analysis, etc.[2][4 ][5]
- Excessive N fertilization and late-season top dressing can cause fruit quality deterioration, disease induction, and material loss [3][5][22]
- Absorption dynamics and optimization strategies are different for characteristic cropping types such as organic cultivation and greenhouse cultivation [7][3]
6. Reference: Main documents/models as basis for estimation/distribution
- Japanese administrative materials/fertilization guidelines (MAFF, prefectural guidance) [3][4][5]
- Overseas absorption modeling research and branch plant design literature [13][8][19]
- Yield/Bio Estimation method based on mass accumulation and dry weight ratio for each growth stage [13][19]
- International knowledge of cultivation management policy and topdressing timing design based on absorption pattern [8][13][14]
Summary
Stage-wise NPK absorption (g/m²) for bell pepper, though direct data per stage is limited in Japan and internationally, can be logically estimated from yield benchmarks, biomass accumulation data, model distributions, and fertilization guidance. Absorption is very low in early stages, increases sharply from vegetative growth through flowering and fruit enlargement, and in the maturation stage contributes strongly to fruit quality formation. Field application should use these insights for regional and varietal diagnosis and fertilization design.
Although direct data on the amount of NPK absorbed (g/m²) at each growth stage of green peppers in Japan and abroad is scarce, logical estimation based on yield standards, biomass accumulation data, model distribution, and fertilization guidance revealed that it is very small in the early stages, rapidly increases from the vegetative growth period to the flowering/fruit enlargement stage, and has a strong contribution to fruit quality formation in the ripening stage. In the field, it is recommended to utilize this knowledge for diagnosis and fertilization design for each region and variety.
Sources
[1] How to grow the perfect peppers? Here are some tips! : https://www.goldenefertilizer.com/ja/news/how-to-grow-the-perfect-green-pepper-some-tips-to-share-with-you/
[2] Points of growing "green pepper" - Mirai-zou: https://mirai-zou.co.jp/advice/62/
[3] 4． Nutritional physiology and nutrient absorption of crops - MAFF: https://www.maff.go.jp/j/seisan/kankyo/hozen_type/h_sehi_kizyun/pdf/gum12.pdf
[4] Part 2 Basic and common techniques for organic cultivation of fruits and vegetables - Japan Soil Association: https://www.japan-soil.net/report/h25tebiki_02.pdf
[5] Soil fertilizer countermeasure guidelines - Wakayama Prefecture: https://www.mdpi.com/2311-7524/11/9/1066
[8] Crop Guide: Nutrients for Pepper - Haifa Group: https://www.haifa-group.com/articles/crop-guide-nutrients-pepper
[13] Growth stage wise fertigation scheduling improves nutrient uptake ...: https://www.fao.org/4/y5259e/y5259e07.htm
[19] Modeling Nutrient Uptake of Sweet Pepper - ResearchGate: https://www.researchgate.net/publication/40094508_Modelling_Nutrient_Uptake_of_Sweet_Pepper
[22] Growth and Yield Responses of Sweet Pepper (Capsicum annum L ...: https://jpp.journals.ekb.eg/article_35501_ba9a11dfdd2dd82e39d5005669c3a32a.pdf