ENGLISH VERSION

ZESZYT 383

Zbigniew Jarosz
Effects of silicon nutrition on yield and chemical composition of cucumber (Cucumis sativus L.)and tomato (Lycopersicon esculentum Mill.) in greenhouse soilless cultivation
zeszyt 383, ss. 121

Silicon plays an important role in plant life, which mainly consists in the development of defence mechanisms against adverse environmental conditions. The effect of improved functioning of plant organisms fed with silicon is a quantitative increase in yield and improved quality of marketable plant parts. Despite undoubted benefits flowing from the application of silicon in plant nutrition, the use of this element in soilless culture is still marginal. The reason for this is the lack of a sufficiently stable fertilizer product that could be used in fertigation. Currently offered silicon supplements have a limited ability to mix with other fertilizers and they create a risk of blocking microcapillaries dispensing a liquid nutrient solution.

The aim of the present study was to determine the influence of root application of silicon in the form of colloidal silica solution and three types of growing media with different total silicon content on yield and chemical composition of cucumber (Cucumis sativus L.)cv. ‘Unicum’ and greenhouse tomato(Lycopersicon esculentum Mill.) cv. ‘Admiro F1’.

A three-factorial experiments were conducted using a drip irrigation and fertilization system with closed circulation, without recirculation. The nutrient solution was supplied to all plants in the same amount and with the same elemental composition, except for silicon. Silicon was added to the nutrient solution in the form of colloidal silica solution in the following amounts: 0 mg SiO2·dm3 (Si-0), 75 mg SiO2·dm3 (Si-1) and 100 mg SiO2·dm3 (Si-2) in the study on cucumber and 0 mg SiO2·dm3 (Si-0) and 100 mg SiO2·dm3 (Si-1) in the experiment with tomato. The study was carried out on rockwool (Grodan), large-grained river sand, and triticale straw.

In the conducted studies demonstrated that the use of colloidal silica along with fertigation at a concentration 75 and 100 mg SiO2∙dm-3 of nutrient solution in cultivation of cucumber cv. ’Unicum’ and 100 mg SiO2∙dm-3 in cultivation of tomato cv. ’Admiro F1’ significantly increases the yield of plants, compared to the control treatments. No statistical differences were found in the yield of the cucumber cultivar ’Unicum’ and of the tomato cultivar ’Admiro F1’ depending on the type of growing medium, except that the yield of early cucumber grown on straw was lower. The usage of the nutrient solution with the addition of colloidal silica in the tested concentrations increases the dry matter content in cucumber and tomato fruits as compared to the control plants. Enrichment of nutrient solution for fertigation at 100 mg SiO2·dm-3 in the form of colloidal silica has a positive influence on the content of L-ascorbic acid in cucumber fruit. Fertigation with nutrient solution supplemented in 100 mg SiO2·dm-3 in the form of colloidal silica increases the content of phosphorus, potassium and calcium in cucumber leaves as well as tomato leaves and fruits, compared to plants fed with a solution without silica. The use of nutrient solution with the addition of silicon in the form of colloidal silica positively affected the content of this component in leaves and fruit of the studied plants. The addition of colloidal silica in tested concentrations to nutrient solution significantly reduces the content of manganese in the leaves and fruits of cucumber and tomato. Fertigation with nutrient solution supplemented at 100 mg SiO2∙dm-3 in the form of colloidal silica, significantly reduces the copper content of the fruit and leaves of cucumber as well as tomato fruits, compared to the plants fertilized with nutrient solution without the addition of silica. Enrichment of nutrient solution in colloidal silica in the tested concentrations has no significant impact on the content of mineral nitrogen, phosphates, potassium, calcium, magnesium, iron, manganese, zinc and copper in extracts from the root environment of cucumber and tomato.

The results obtained in the present study confirm the beneficial effect of silicon in the form of colloidal silica used in fertigation at an amount of 75 and 100 mg SiO2∙dm-3 in the cultivation of the cucumber cultivar ’Unicum’ and at an amount of 100 mg SiO2∙dm-3 in the cultivation of the tomato cultivar ’Admiro F1’. These results prove that colloidal silica solution can be used at a concentration of 75–100 mg SiO2∙dm-3 in cucumber nutrition and at 100 mg SiO2∙dm-3 in tomato nutrition, using rockwool, sand or straw as growing media. Although in the cultivation of cucumber effect of silicon dose 100 mg SiO2∙dm-3 on the yield is similar to 75 mg SiO2∙dm-3, however benefit from a higher dose of silicon is significant increase in the yield of early fruit.