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Response of potatoes to nitrogen concentrations differ with nitrogen forms
1Key Laboratory of Crop Growth Regulation, Ministry of Agriculture Nanjing Agricultural University, People's Republic of China.
Journal of Plant Nutrition
|September 7, 2001
Summary
Potato plants grow best with nitrate (NO3-) nutrition compared to ammonium (NH4+). Higher nitrate concentrations support healthy growth, while ammonium can cause toxicity, especially at elevated levels.
Area of Science:
- Plant Physiology
- Agricultural Science
- Nutrient Management
Background:
- Nitrogen (N) is a crucial nutrient for plant growth, influencing crop yield and quality.
- Potatoes (Solanum tuberosum L.) have specific nitrogen requirements that can be met by different nitrogen forms, such as nitrate (NO3-) and ammonium (NH4+).
- Understanding the differential effects of nitrogen forms and concentrations is vital for optimizing potato cultivation.
Purpose of the Study:
- To investigate the impact of varying nitrate (NO3-) and ammonium (NH4+) concentrations on potato plant growth and mineral composition.
- To determine the optimal nitrogen (N) concentration ranges for potato plants under different nitrogen forms.
- To identify potential toxicity symptoms associated with ammonium nutrition in potatoes.
Main Methods:
- Two experiments were conducted using a non-recirculating nutrient film system in a controlled environment.
- Potato plantlets were subjected to five nitrogen (N) concentrations (0.5, 2, 4, 8, and 12 mM) of either nitrate (NO3-) or ammonium (NH4+).
- Growth parameters including leaf area, tuber number, and dry weights were measured, along with tissue mineral composition.
Main Results:
- Plant growth was greatest and similar at 2, 4, and 8 mM N with nitrate (NO3-), but optimal only at 2 and 4 mM N with ammonium (NH4+).
- Ammonium toxicity, characterized by interveinal symptoms, was observed at 12 mM NH4+, whereas plants showed healthy growth with 12 mM NO3-.
- Tissue phosphorus (P) concentrations decreased at lower N levels (0.5 and 2 mM), and mineral composition varied significantly between NO3- and NH4+ nutrition.
Conclusions:
- Optimal nitrogen (N) concentration ranges for potato plants are wider and higher with nitrate (NO3-) compared to ammonium (NH4+).
- Careful control of ammonium (NH4+) concentrations is essential to prevent toxicity and ensure healthy potato plant development.
- Nitrate (NO3-) appears to be a more favorable nitrogen source for potato growth and mineral balance than ammonium (NH4+) under the tested conditions.
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