Fertilization with Silicon in Sweet Pepper Improved Plants Grown under Salt Stress

Aims: The objective of this research was to investigate the effect of calcium silicate on gaseous exchanges and production factors in the sweet pepper, cultivated under conditions of soil salinity induced by potassium fertilization, in protected cultivation.

Study Design: The experiment was arranged in a randomized complete block design in a 2 × 5 factorial scheme with five replications.

Place and Duration of Study: The experiment was conducted in the sector of Olericultura and Experimentation of the course of Agronomy from October 12, 2018 to February 2019.

Methodology: The experiment was arranged in a randomized complete block design in a 2 × 5 factorial scheme (two sources of correction: calcareous and silicon and five increasing rates of KCl equivalent to 150, 300, 450, 600 and 700 kg ha-1 of K2O). Ten treatments with five replicates where each experimental unit consisted of a polyethylene pot, with a volume of 19 dm3. The electrical conductivity, the determination and quantification of silicon in soil and plant, liquid photosynthesis, stomatal conductance, intercellular CO2 concentration, transpiration, water use efficiency and instantaneous carboxylation efficiency were analyzed.

Results: With the increase of K2O in the soil there was a tendency of reduction in liquid photosynthesis, transpiration, stomatal conductance, intercellular CO2 concentration, water use efficiency and instantaneous carboxylation efficiency in the presence and absence of calcium silicate. Higher rates of K2O (300, 450 and 600 kg ha-1) reduced the length and yield of sweet pepper fruits in the presence and absence of calcium silicate. The rate of 150 Kg K2O favored the growth of sweet pepper plants in the presence of calcium silicate.

Conclusion: It is concluded from the research that the dose of 300 kg ha-1 of K2O, in the presence of calcium silicate, provided the best results for the electrical conductivity of 2.76 dS m-1, silicon content in the soil of 5.70 mg kg-1, 14% silicon leaf content, improving photosynthetic rates, transpiration, water use efficiency and fruit production. The increase in salinity reduced fruit yield, in the presence and absence of Si.