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4582716 
Journal Article 
Phosphorus toxicity in tomato plants: When and how does it occur? 
Jones, JB 
1998 
Yes 
Communications in Soil Science and Plant Analysis
ISSN: 0010-3624
EISSN: 1532-2416 
29 
11-14 
1779-1784 
For many years and in most agricultural production systems, phosphorus (P) has been identified as the most frequently occurring essential element deficiency limiting crop yields, and it is still an element that continues to receive considerable research attention. However, little has been researched or written about the effects of high P on plants other than that associated mainly with zinc (Zn) nutrition, and iron (Fe) to some degree, as high P levels are known to interfere with their normal metabolism. Also, P is known to promote manganese (Mn) uptake. At what levels P would be considered toxic has not been clearly defined for most crops. The author has observed the occurrence of nutritional stress in tomato plants when the P level in leaves exceeds 1.00% of its dry matter, mainly occurring for container-grown plants and those being grown hydroponically. This and other data will be presented that suggests that 1.00% P may indeed be the critical level between sufficiency and toxicity for tomato plants. Visual symptoms of P toxicity will also be described.