ISHS Acta Horticulturae 821: International Symposium on Tomato in the Tropics
REDUCING NEGATIVE EFFECTS OF SALINITY IN TOMATO (SOLANUM LYCOPERSICUM L.) PLANTS BY ADDING LEONARDITE TO SOIL |
| Authors: | F. Casierra-Posada , C.A. Rodríguez, G. Fischer |
| Keywords: | osmotic stress, NaCl, humic acid, fulvic acid |
| Abstract:
Fertigation is a great option for fertilizing under greenhouse conditions; however, it can bring soil salinity problems. Tomato plants of hybrids Astona and Gloria growing on pots with soil were exposed to 20, 40, 60 or 80 mmol NaCl under greenhouse conditions and the electrical conductivity values of treated soil were 2.95, 4.90, 6.56 and 7.70 dS m-1, respectively. NaCl was not added to soil of control plants and electrical conductivity was 1.42 dS m-1. To soil of some salt-stressed plants, Humitron® 60S (23.6% humic acid and 1.1% fulvic acid, from leonardite) was added 1.6 g per plant (40 kg ha-1, proportionally) at transplanting time to reduce the negative effect of salinity on plants. The study was carried out in greenhouse in Tunja, Colombia. Results showed statistical difference between hybrids. Salinity, in general, reduced the values of evaluated growth and yield parameters; however, leonardite ameliorated the negative effects of salinity on plants. The fruits of salt-stressed plants had higher specific leaf area, total soluble solids and titratable acidity in comparison with those of control plants, while total dry matter, yield, and leaf area were reduced. For most evaluated parameters, leonardite had poor effect on alleviation of salt-stress in plants of 20 mmol NaCl treatment, but in soils subjected to 40 to 80 mmol NaCl an increase of yield and dry matter production per plant as well as a reduction of total soluble solids and titratable acidity of fruits was observed. Results showed a possibility to reduce the negative effects of salinity on tomato plants growing under greenhouse conditions by adding leonardite to salinized soils. | |
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