The Influence of Heated Soil in Crop of “Tamaris” Tomato Plants on the Biological Activity of the Rhizosphere Soil

Tomato is a plant with high heat requirements and sensitive to cold weather and frost. The optimum temperature for the growth of tomato plants is between 21˚C and 27˚C during the day and between 17˚C and 21˚C at night. The soil temperature is also very important for plant growth. The optimum soil temperature for tomato cultivation should be within the range 15˚C - 18˚C. Besides, the proper development of the root system depends on the optimal temperature of the soil. A temperature below 14˚C reduces and inhibits the growth of the root system and encourages the development of fungal and bacterial diseases.

In this study, the authors aimed to evaluate the effect of heated soil on the population of bacteria, fungi and nematodes inhabiting the soil of tomato cultivar “Tamaris” growing in peat and coconut substrates. The experiment was carried out in 12 treatments and in 3 replications (one slab was one replication). The soils were tested in two different types of containers: cylinders (each of 5 L capacity) and slabs (each of 20 L capacity). The results were statistically evaluated (analyzed by) with multivariate analysis of variance verifying the hypothesis of equality of means (H0: x1 = x2 = x3) at significance level 0.05.

The results demonstrated that the total number of bacteria and fungi was significantly higher in the peat substrate than in the coconut substrate. A much higher number of beneficial bacteria producing spores were noted in the coconut soil. The total number of bacteria and fungi was modified by the heating levels. In all the experimental treatments, most of the identified individuals belonged to the group of nematodes that feed on bacteria and it was the most diverse group of species. The highest total number of nematodes was recorded for the second heating level, with the exception of cultivation carried out in peat slabs, where the most of nematodes were found at the control level. The highest first crop was produced by plants growing on the peat slabs supplied with the highest soil temperature. Tomato roots of all the control treatments showed the highest root morphological parameters.

In conclusion, the study has shown that heating the substrates limited the root growth of tomato plants.

Article by Lidia Sas Paszt, et al, from Research Institute of Horticulture, Skierniewice, Poland.

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