Potassium silicate and vinasse enhance biometric characteristics of perennial sweet pepper (Capsicum annuum) under greenhouse conditions

Abstract

An effective strategy for enhancing fruit production continuity during extended sweet pepper season involves adopting innovative biostimulants such as potassium silicate (PS) and vinasse. Adjusting PS and vinasse concentrations are crucial for maintaining the balance between vegetative and fruit growth, particularly in sweet pepper with a shallow root system, to sustain fruiting over prolonged season. However, the interaction between PS and vinasse and the underlying physiological mechanisms that extend the sweet pepper season under greenhouse conditions remain unclear. This study aimed to investigate the impact of PS and vinasse treatments on the yield and biochemical constituents of perennial pepper plants cultivated under greenhouse conditions. For two consecutive seasons [2018/2019 and 2019/2020], pepper plants were sprayed with PS (0, 0.5, and 1 g/l) and drenched with vinasse (0, 1, 2, and 3 l/m³). To estimate the impact of PS and vinasse on the growth, yield, and biochemical constituents of pepper plants, fresh and dry biomass, potential fruit yield, and some biochemical constituents were evaluated. Results revealed that PS (0.5 g/l) coupled with vinasse (3 l/m³) generated the most remarkable enhancement, in terms of plant biomass, total leaf area, total yield, and fruit weight during both growing seasons. The implementation of vinasse at 3 l/m³ with PS at 0.5 and 1 g/l demonstrated the most pronounced augmentation in leaf contents (chlorophyll index, nitrogen and potassium), alongside improved fruit quality, including total soluble solid and ascorbic acid contents, of extended sweet pepper season. By implementing the optimal combination of PS and vinasse, growers can significantly enhance the biomass production while maintaining a balance in fruiting, thereby maximizing the prolonged fruit production of superior sweet pepper under greenhouse conditions.

Keywords: Capsicum annuum; Condensed molasses soluble; Greenhouse; Potassium silicate; Sweet pepper; Vinasse.

Figure 1

The greenhouse microclimatic conditions, including minimum and maximum air temperature (°C) and relative humidity (RH%), during the 2018/2019 and 2019/2020 seasons.

Figure 2

Effects of potassium silicate (PS) and vinasse concentrations interactions on plant fresh biomass (a, b), plant dry biomass (c, d), and total leaf area per plant (e, f) of sweet pepper plants during the 2018/2019 and 2019/2020 seasons. Values are means ± standard error (SE) (n = 3). In the same season, means followed by the same alphabetic letter(s), do not differ significantly, according to the LSD test at a probability level of 0.05.

Figure 3

Effects of PS and vinasse concentrations interactions on the fruit weight of sweet pepper plants during the 2018/2019 and 2019/2020 seasons. Error bars showed standard error as the means ± SE (n = 3). In the same season, means followed by the same alphabetic letter(s), do not differ significantly, according to the LSD test at a probability level of 0.05.

Figure 4

Effects of PS and vinasse concentrations interactions on the total yield per m² of sweet pepper plants during the 2018/2019 and 2019/2020 seasons. Error bars showed standard error as the means ± SE (n = 3). In the same season, means followed by the same alphabetic letter(s), do not differ significantly, according to the LSD test at a probability level of 0.05.

Figure 5

Interaction effect between PS and vinasse concentrations on the relative yield of sweet pepper plants during the 2018/2019 (a) and 2019/2020 (b) seasons.

Figure 6

Effect of PS and vinasse concentrations interactions on leaves’ chlorophyll index (a), N (b), and K contents (c) of sweet pepper plants during the 2018/2019 and 2019/2020 seasons. Values are means ± (SE) (n = 3). In the same season, means followed by the same alphabetic letter(s), do not differ significantly, according to the LSD test at a probability level of 0.05.

Figure 7

Effect of PS and vinasse concentrations interactions on fruits’ TSS (a) and ascorbic acid contents (b) of sweet pepper plants during the 2018/2019 and 2019/2020 seasons. Values are means ± (SE) (n = 3). In the same season, means followed by the same alphabetic letter(s), do not differ significantly, according to the LSD test at a probability level of 0.05. F.W. means fresh weight of fruit.