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Article

The Effects of Potassium on Plant Nutrient Concentration, Plant Development, and Rhizoctonia Rot (Rhizoctonia solani) in Pepper

by
Ümit Bayındır
and
Zeliha Küçükyumuk
*
Faculty of Agriculture, Department of Soil Science and Plant Nutrition, Isparta Applied Sciences University, Isparta 32000, Türkiye
*
Author to whom correspondence should be addressed.
Horticulturae 2025, 11(5), 516; https://doi.org/10.3390/horticulturae11050516 (registering DOI)
Submission received: 18 February 2025 / Revised: 3 May 2025 / Accepted: 5 May 2025 / Published: 10 May 2025
(This article belongs to the Special Issue Optimize Nutrient Cycling to Improve Soil Fertility and Plant Productivity)
Versions Notes

Abstract

:
Potassium has been identified as a vital nutrient for plant growth and functions. Studies have demonstrated its capacity to mitigate the severity of diseases by accelerating seed maturation and promoting robust root system development. In this study, we aimed to determine how increasing potassium doses affect the nutrient content, dry weight, root weight, and resistance to Rhizoctonia rot of the pepper plant. Pepper seedlings were used as plant material, and potassium sulfate was employed as the potassium fertilizer in this study. The experiment involved applying four different potassium doses (0, 50, 100, and 150 kg ha−1) to pepper seedlings, along with RS0 (control) and RS1 (diseased plant) in four replicates. At the end of the study, analyses of the plants’ nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and boron (B) content, dry weights, and root weights were performed, in addition to disease assessments. An increase in N, P, K, Fe, and B content was observed with applied potassium doses, while a decrease in Mg content was noted. No significant change was detected in Cu content in pepper leaves, and the change in Mn content was not found to be statistically significant. An increase in plant dry weights was determined based on the applied treatments. The results indicated that plants subjected to potassium exhibited resistance to disease, an increase in root weights, and overall better conditions compared to samples without potassium. The best results in the experiments were achieved with the application of 150 kg ha−1 K2SO4. It was observed that certain rates of potassium had positive effects on disease factors by suppressing Rhizoctonia rot and can be used for biological control.

1. Introduction

Plants with adequate and balanced nutrition tend to be more resilient than those with inadequate, excessive, or unbalanced nutrition. When plant nutrition is properly applied, plants are healthier, and the incidence of plant diseases decreases [1]. Deficiency in nutrients makes plants more susceptible to disease and paves the way for the development of diseases. The proper application of nutrients, in both adequate quantities and balanced proportions, is crucial for controlling plant diseases, as these diseases adversely impact plant health by interfering with the uptake of nutrients in multiple ways. Cultural practices, such as fertilization and changing conditions in the plant root zone, can play an important role in combating plant diseases [2].
Potassium plays an effective role in reducing disease severity; however, balanced fertilization is also necessary for the plant to be healthy and productive. In the case of potassium deficiency, problems such as thinning of the cell walls, weakening of the trunk and branches, sugar accumulation in the leaves, and an increase in the amount of unused nitrogen occur. These negative effects reduce plant resistance and may facilitate the entry of fungal and bacterial diseases into the plant. Nitrogen-containing fertilizers are often used to stimulate vegetative growth, but balanced fertilization between nitrogen and potassium is important for economical cultivation [3,4]. The effects of diseases or pests on plants only occur when plants provide a suitable environment for these organisms. The accumulation of some metabolic products, such as sugars and amino acids in plants, increases the risk of disease development [2]. Bergmann (1992) stated that when soluble sugar and amino acid levels are high in plants, that is, when nitrogen levels are high and potassium levels are low, pathogens are more prone to attack [1]. There are some reports on potassium’s effect in controlling plant disease. The potential of potassium in reducing disease severity has been signaled in various diseases, as is the case in charcoal rot disease of tomato, leaf spot on cotton, Alternaria leaf spot, Acidovorax citrulli on radish, fruit spot disease in melon and watermelon, and pith necrosis disease in tomato plants [5,6,7,8,9]. In a previous study, the use of potassium successfully controlled fungal diseases by 70%, bacterial diseases by 69%, insect damage by 63%, and viral diseases by 41%. The application of potassium led to a reduction in disease severity [10]. These treatments also led to an increase in plant yield and nutrient concentration. Amtmann (2008) determined the effect of K on disease occurrence and found it to be most beneficial for resistance against fungi, with 110 out of 155 cases showing a decrease in fungal disease with increasing K [11].
Pepper is a vegetable that originates from Central and South America and is widely consumed around the world. According to FAO data, approximately 36 million tons of pepper were produced worldwide in 2022 [12]. In the Western Mediterranean, F1 hybrid pepper varieties with the advantages offered by greenhouses are quite common. Breeding programs aim to increase the productivity of these varieties and provide them with qualities that meet the demands of consumers. However, in recent times, during which disease resistance has gained importance, resistance in pepper makes this variety more valuable and affects the preferences of producers [13].
One of the most dreaded diseases of vegetables is root rot caused by Rhizoctonia solani [14]. Potassium treatment could be a successful strategy for managing diseases and for feasible pepper production. In this study, the effect of applying increasing doses of potassium to pepper seedlings on the plant’s nutritional elements, dry weight (yield), and resistance to Rhizoctonia rot was determined.

2. Materials and Methods

This study was carried out as pot experiments in the greenhouse conditions of the Faculty of Agriculture of Isparta University of Applied Sciences. F1 Clarnet-type green pepper seedlings were used as plant material, and potassium sulfate (chemical) was used as a potassium fertilizer. The effect of potassium at increasing doses (0, 50, 100, and 150 kg ha−1) on the nutritional element contents of pepper plants, plant and root dry weights, and resistance to Rhizoctonia rot were determined. The experiment was carried out under greenhouse conditions in pots able to hold 1 kg of soil. The experimental soil was loam with a pH of 7.89 (1:2.5 water); CaCO3 18%; organic matter 1.5% [15]; 0.5 M NaHCO3-extractable P 14 kg ha-1; NH4OAC-exchangeable K 252 kg ha−1 [16,17]; and DTPA-extractable Zn 0.5 mg kg−1, Fe 5 mg kg−1, Mn 8 mg kg−1, and Cu 0.8 mg kg−1 [18]. The soil was autoclaved twice for one hour at 121 °C and 1.2 atmospheres of pressure.
The length of the pot was 15 cm, and its diameter was 14 cm. For basic fertilization, 100 mg N kg−1 and 100 mg P kg−1 were applied to the pots along with planting the seedlings. At the beginning of the experiment, one seedling was transplanted per pot. The experiment was carried out at four distinct potassium doses, 0, 50, 100, and 150 kg ha−1, along with control and diseased plants, with four replications. A total of 32 pots were used in the study. Disease inoculation was carried out four weeks after planting the seedlings. Rhizoctonia solani was incubated on PDA medium at 24 °C for 1 week. Rhizoctonia solani mycelial agar disks developed in PDA (5 pieces with a diameter of 1 cm in each pot) were applied to the soil. Until the end of the study, the plants were irrigated with tap water in equal amounts. At harvest, all green parts of the plant were cut from the root area, and the root part was removed from the soil. The wet weights of the samples washed with tap water and pure water were determined. The green parts of the plant were dried in an oven at 65 ± 5 °C and ground. At the end of the study, N, P, K, Mg, Ca, Fe, Mn, Cu, Zn, and B analyses were performed, the dry weight and root weight of the plants were determined, and disease evaluations were performed.
The plants were harvested nine weeks after transplantation by cutting them from the soil surface, and their dry weights were determined. The roots were separated from the soil. Root fresh weights were measured. Pepper leaf mineral concentrations were determined using the nitrogen (N) Kjeldahl method in dried and ground plant samples. In addition, the contents of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and boron (B) in the plant samples were determined using the wet digestion method using ICP [19].
Scale values were calculated according to the disease severity assessment 0–4 scale [20]. The disease evaluation is as follows: 0: Healthy plant,1: 1–25% disease in the root system, 2: 26–50% disease in the root system, 3: 51–75% disease in the root system, and 4: 76–100% disease in the root system.
The experiment and statistical model were a randomized complete block design (RCBD) with four replications. There are 8 different treatments in the study. A coding system of the notations employed in this study, K0, K1, K2, and K3, was used for the four distinct potassium doses (0, 50, 100, 150 kg ha−1), along with RS0 (control) and RS1 (diseased plant). There are four levels of potassium factor (0, 50, 100, and 150 kg ha−1) and two levels of disease factor (control and diseased plant). The total treatment number is 8.
Statistical analyses in factorial order as a result of the research were carried out in the MINITAB 16 package program. Duncan’s Multiple Comparison Test was used to determine the differences between group averages.

3. Results

The effect of different doses of potassium on pepper plant dry weight was statistically significant (Table 1). As can be seen in Table 1, the dry weight values of the R. solani inoculated plant (4.21 g) were found to be the lowest compared to the other plants. While the plant dry weight value was 6.79 g in the control application, it was 4.21 g in the diseased plant treated with R. solani, 7.03 g in the 50 kg ha−1 application of potassium, 6.97 g in the 100 kg ha−1 application, and 7.12 g in the 150 kg ha−1 application. With 50 kg ha−1, 100 kg ha−1, and 150 kg ha−1 potassium applications applied together with R. solani, dry weight values of 6.83, 6.71, and 7.45 g were determined from the pepper plants, respectively. It was determined that plant dry weights increased with potassium application compared to the control.
In this study, the effects of different potassium doses and disease (RS) applications on the root weight of pepper plants were investigated. When the analysis was performed in terms of root weight, no statistically significant difference was determined (ns). However, the highest root weight was observed in K3 RS0 application with 9.14 g, and the lowest root weight was observed in K0RS1 at 4.71 g. The combined use of high potassium doses and RS applications generally positively affected root development.
The effect of the application of different doses of potassium on the K content of pepper plants was found to be statistically significant (Table 2). The lowest K contents of pepper plant leaves were detected in the disease treatment (3.22%) and the control treatment (3.45%). With increasing potassium doses, the K contents in the leaves were determined to be 3.43%, 3.99%, and 3.92%, respectively. It was found that the combined applications of Rhizoctonia solani and potassium increased the K concentrations in the leaves compared to the control (3.45%), and this increase was 4.89%, 5.17%, and 5.89%, respectively. It was determined that, with potassium application, the K content of diseased plants was higher than that of disease-free plants. The effect of different doses of potassium and RS applications on pepper plant N contents was found to be statistically significant. While the N contents of control and disease-only plant samples were in the same statistical class, diseased or disease-free plants with different doses of K were in the same class. While the control application had 2.73% N content, the diseased plant’s N content was found to be 2.50%. The effect of different doses of potassium on the P content of pepper plants was found to be statistically significant. When the phosphorus contents of pepper plant leaves were examined, the P content of the control plant leaf was determined to be 0.39%, and the P content of the diseased plant leaf was determined to be 0.37%. An increase in leaf P contents was found in the untreated K1 and K2 doses compared to the control (0.47% and 0.41%), but there was no increase in the K3 dose (0.38%). In disease-treated plants, an increase was determined only in the K3 dose (0.45%) compared to the control.
The effects of different doses of potassium on plant Ca, Mg, and B contents are given in Table 3. For the control application, the Ca content of the pepper leaf was 2.50%, while the Ca content of the diseased plant was 2.69%. With the application of different doses of potassium, these values were determined to be 2.90%, 2.48%, and 2.49%, respectively. Regarding the Ca content of the plant leaf to which potassium was applied along with disease application, it was determined that the K3 dose resulted in the highest Ca content, at 2.99%. The leaf Mg content of the control plant (1.07%) and the leaf Mg content of the potassium applications were similar (1.18%, 1.07%, and 0.98%), while the disease and potassium-applied leaf Mg contents were 0.98%, 0.92%, and 0.96%. The effect of different doses of potassium on the B content of pepper plants was found to be statistically significant. While the control application was 61 mg kg−1, the K1 dose without disease application was 78 mg kg−1 B, while that of the K2 and K3 dose pepper plant leaves was 64 mg kg−1 B. Diseased K3 dose pepper plant leaves had the highest B content with 81 mg kg−1 B.
The effect of different doses of potassium on the Fe content of pepper plants was found to be statistically significant (Table 4). The lowest Fe contents of pepper plant leaves were observed in the control (158 mg kg−1), diseased plant (150 mg kg−1), and diseased plant K2 dose (177 mg kg−1). The highest Fe content (287 mg kg−1) was determined in the first dose of potassium application. The effect of different doses of potassium and RS applications on the Mn content of pepper plants was not found to be statistically significant. While the leaf Mn content of the control was the lowest (162 mg kg−1), the leaf of the pepper to which the K1 dose was applied had the highest Mn content (208 mg kg−1). The effect of different doses of potassium and RS applications on the Zn content of the pepper plants was found to be statistically significant. Compared to the control application (109 mg kg−1), an increase was determined in plant leaf Zn contents at K1 and K2 doses without disease application (151 mg kg−1 and 118 mg kg−1). K1 and K3 doses with disease application had 153 mg kg−1 and 150 mg kg−1 Zn contents.
The effect of different doses of potassium and RS applications on the Cu content of the pepper plants was found to be statistically significant. An increase was determined in K1 without disease application (47 mg kg−1) and the K3 dose with disease application (38 mg kg−1) compared to the leaf Cu contents in the control application (31 mg kg−1).

Disease Severity

Table 5 shows the assessment of disease severity induced by Rhizoctonia rot in pepper plants treated with potassium doses of 50, 100, and 150 kg ha−1 compared to the control (without potassium application).
The most severe disease was identified in the control inoculated with Rhizoctonia rot, and the severity of the disease decreased with increasing potassium doses applied to the plants.

4. Discussion

It was determined that plant dry weights increased with potassium application compared to the control. Kılıç (2010) found that there were significant differences (p < 0.001) in the dry matter yield of plants with the application of five different doses of potassium (0, 50, 100, 200, and 400 mg kg−1) in pepper varieties, and the results are consistent with those of our study [21].
In our study on pepper plants, in the sample (K0RS1) to which no potassium was applied, plant development was poor because the infection intensity in the root neck was high, and the nutrients synthesized in the root could not be transported to the above-ground part of the plant. The effect of potassium on root weight was consistent with the findings of previous studies. Güler Güney and Güldür (2018) found a decrease in the root and dry weight of pepper seedlings with R. solani [22]. Ismunadii (1976) reported that potassium widely reduces disease severity in diseases caused by biotrophic and necrotrophic pathogens due to its effect on the development of plant diseases [23]. In many cases, plants deficient in potassium are more prone to infection than plants supplied with adequate amounts of potassium. For example, in rice, the severity of infection caused by Helminthosporium sigmoideum was highest under a potassium-deficient supply but decreased rapidly as potassium content increased. The results of the above study were found to be comparable to the results of this study on pepper plants.
It was determined that, with potassium application, the K content of diseased plants was higher than that of disease-free plants. Pepper plant leaves’ K concentrations were higher when compared to adequate K concentrations [24]. The authors of previous studies have also concluded that potassium application increases N content. Çolpan et al. (2013) investigated the effect of potassium on the yield and fruit quality components of tomatoes [25]. K was used at doses of 0, 40, 80, 120, and 160 kg K2O/ha, and the nitrogen/potassium ratio in the leaves also affected tomato yield. They stated that the macronutrient elements of the leaf (N, P, K, and Ca) increased with potassium application and that the most appropriate dose in the study was 120 kg ha−1. Studies have shown that potassium facilitates the positive effect of nitrogen and supports this effect. If there is not enough potassium in the environment, the absorbed nitrogen is converted into independent amino acids. However, optimal protein synthesis can occur when there is sufficient potassium in the environment. This emphasizes that potassium supports protein synthesis by increasing the biological use of nitrogen [26]. When the limit values of pepper plant leaves in Jones et al.’s (1991) study were compared, the N results in our study were between 2.5% and 3.20% and were insufficient in terms of nitrogen content [24]. This situation is thought to be due to low nitrogen application. Peng et al. (2016) stated in their study on apple Valsa canker that the ratio of nitrogen (N) and potassium (K) plays a role in host–pathogen interactions [27]. An unbalanced N/K ratio causes the exacerbation of many plant diseases. Increasing the N/K ratio above 2.5 significantly increased the susceptibility of apple plants to Venturia inaequalis (apple scab). Potassium plays an important role in Valsa canker resistance, and improving K management in apple orchards is expected to reduce or control the occurrence of Valsa canker. This study in the literature is compatible with the results of experiments conducted on pepper.
The effect of different doses of potassium on the P content of pepper plants was found to be statistically significant. Baghour et al. (2001) reported that as the potassium doses applied to the pepper plant increased, the phosphorus (P) concentration in the pepper plant increased significantly, and potassium applications caused a significant increase in fruit yield [28]. In the research, it was stated that the highest yield and potassium concentration in pepper plants were obtained at a dose of 12 g/m2. Zengin et al. (2009) reported that sugar beet leaf P contents increased with potassium application [29]. Misra and Bhattacharyya (1999) observed in their study that the incidence of leaf spot increased with N application [30]. P did not affect disease development, but the combination of N, P, and K (20, 40, and 40 kg ha−1, respectively) revealed the lowest disease level and the highest yield. This demonstrated the effect of K in preventing the disease.
The effect of different doses of potassium on the Ca content of pepper plants was found to be statistically significant. Ersoy et al. (2023) concluded that different doses of potassium sulfate applied to the capia pepper variety had a significant effect on yield and quality and increased the calcium content in pepper compared to the control application [31]. The effect of potassium and RS applications on the Mg content of pepper plants was found to be statistically significant. Botella et al. (2016) determined significant differences in Mg concentrations with high K concentrations in pepper, and they determined a decrease in Mg content with increasing K application [32]. The effect of different doses of potassium applications on the Fe content of pepper plants was found to be statistically significant. In a study by Aksu and Atalay (2022), the authors found that potassium applications increased the Fe content of sugar beets [33]. The effect of different doses of potassium and RS applications on the Zn content of pepper plants was found to be statistically significant. It is thought that the increase in Fe, Zn, Mn, and Cu contents with increasing doses of potassium is due to the positive effect of K and these elements [25,26,27,28,29,30,31,32,33,34]. Küçükyumuk and Bayındır (2023) stated that a well-planned fertilization program is necessary to achieve healthy production, optimum yield, and maximum profit [35]. The availability of nutrients for plants is important in increasing productivity and providing resistance to diseases. It has been stated that improving nutritional concentrations helps prevent plant diseases.
While the average disease scale value is highest in plants without potassium and RS applied, it can be seen that the disease rate decreases in the different combinations of potassium at increasing doses. The reason for differences in disease severity in the different combinations of potassium applications may be due to disease resistance mechanisms in plants resulting from the applications. Sarker et al. (2022) carried out five different K applications to determine exactly how wheat yield losses due to leaf spot disease (Magnaporthe oryzae Triticum) occur in wheat and how this situation is affected by potassium fertilization [36]. It has been determined that wheat grown with K fertilizer is less affected by disease. Potassium has a significant effect on metabolic functions. Potassium deficiency results in a decrease in enzyme activity and the inability to synthesize organic compounds. This may reduce the resistance of plants to diseases and pests, especially fungal diseases [37]. K may promote the development of thicker outer walls in epidermal cells, thus preventing disease attacks. K can also influence plant metabolism, as K-deficient plants have impaired protein synthesis and accumulate simple N compounds, such as amides, which are used by invading plant pathogens. Tissue hardening and stomatal opening patterns are closely related to infestation intensity [38]. Application of K can decrease Helminthosporium leaf blight severity and increase grain yields in wheat [39,40].

5. Conclusions

It has been revealed that potassium-applied plants are resistant to disease, exhibit an increase in root weight, and are visually in a much better condition than samples not given potassium. It has been revealed that, in particular, potassium sulfate fertilization can indirectly increase a plant’s resistance to disease due to its positive effects on plant health, and it can be considered a new approach in the fight against R. solani disease in pepper. The best results were achieved with the application of potassium given as 150 kg ha−1 K2SO4 per hectare. The results may contribute to future studies and methods that can be applied to other vegetables. They will reduce pesticide applications and their negative effects on the environment, reveal the effect of plant nutrients on plant diseases, and be less expensive. This study can serve as an important resource in conducting studies on the effects of other plant nutrients on plant diseases.

Author Contributions

Methodology, Ü.B. and Z.K.; formal analysis, Ü.B. and Z.K.; investigation, Ü.B. and Z.K.; resources, Ü.B. and Z.K.; data curation, Ü.B. and Z.K.; writing—original draft preparation, Ü.B. and Z.K.; writing—review and editing, Z.K.; visualization, Ü.B. and Z.K.; project administration, Ü.B. and Z.K. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

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Table 1. The effect of different doses of potassium and RS applications on pepper plant dry weight and root weight.
Table 1. The effect of different doses of potassium and RS applications on pepper plant dry weight and root weight.
K Dose (kg ha−1)Dry Weight (g)Root Weight (g)
K0RSO:Control6.79 ± 0.08 AB *5.51 ± 0.70 ns
K0RS1:Diseased4.21 ± 0.29 B4.71 ± 1.99
K1RS0:Control7.03 ± 0.37 A8.73 ± 0.11
K2RS0:Control6.97 ± 0.44 AB7.68 ± 1.04
K3RS0:Control7.12 ± 0.73 A9.14 ± 0.49
K1RS1:Diseased6.83 ± 1.29 AB8.46 ± 0.35
K2RS1:Diseased6.71 ± 0.33 AB8.80 ± 2.49
K3RS1:Diseased7.45 ± 0.49 A8.99 ± 1.58
Capital letters indicate the difference between K doses and diseases. *: p < 0.05 ns = not significant.
Table 2. Effect of different doses of potassium and RS applications on the K, N, and P content of pepper leaves.
Table 2. Effect of different doses of potassium and RS applications on the K, N, and P content of pepper leaves.
K Dose (kg ha−1)K (%)N (%)P (%)
K0RSO:Control3.45 ± 0.21 CD **2.73 ± 0.07 B **0.39 ± 0.00 BC **
K0RS1:Diseased3.22 ± 0.21 D2.57 ± 0.08 B0.37 ± 0.00 BC
K1RS0:Control3.43 ± 0.26 CD3.13 ± 0.08 A0.47 ± 0.01 A
K2RS0:Control3.99 ± 0.08 BCD3.17 ± 0.02 A0.41 ± 0.00 ABC
K3RS0:Control3.92 ± 0.15 BCD3.19 ± 0.02 A0.38 ± 0.01 BC
K1RS1:Diseased4.89 ± 0.12 ABC3.20 ± 0.16 A0.36 ± 0.00 C
K2RS1:Diseased5.17 ± 0.25 AB3.05 ± 0.13 A0.38 ± 0.00 BC
K3RS1:Diseased5.89 ± 0.33 A3.20 ± 0.08 A0.45 ± 0.03 AB
Capital letters indicate the difference between K doses and diseases. **: p < 0.001.
Table 3. The effect of different doses of potassium and RS applications on the Ca, Mg, and B content of pepper plants.
Table 3. The effect of different doses of potassium and RS applications on the Ca, Mg, and B content of pepper plants.
K Dose (kg ha−1)Ca (%)Mg (%)B (mg kg−1)
K0RSO:Control2.50 ± 0.12 B **1.07 ± 0.02 ABC *61 ± 1.68 C **
K0RS1:Diseased2.69 ± 0.10 AB1.25 ± 0.02 A65 ± 2.53 BC
K1RS0:Control2.90 ± 0.26 AB1.18 ± 0.12 AB78 ± 7.5 AB
K2RS0:Control2.48 ± 0.02 B1.07 ± 0.02 ABC64 ± 2.70 BC
K3RS0:Control2.49 ± 0.03 B0.98 ± 0.00 ABC64 ± 1.49 BC
K1RS1:Diseased2.71 ± 0.05 AB0.98 ± 0.01 ABC69 ± 1.65 ABC
K2RS1:Diseased2.44 ± 0.03 B0.92 ± 0.02 C64 ± 2.29 BC
K3RS1:Diseased2.99 ± 0.08 A0.96 ± 0.02 BC81 ± 1.48 A
Capital letters indicate the difference between K doses and diseases, *: p < 0.05 **: p < 0.001.
Table 4. Effect of different doses of potassium and RS applications on the Fe, Mn, Zn, and Cu content of pepper plants.
Table 4. Effect of different doses of potassium and RS applications on the Fe, Mn, Zn, and Cu content of pepper plants.
K Dose (kg ha−1)Fe (mg kg−1)Mn (mg kg−1)Zn (mg kg−1)Cu (mg kg−1)
K0RSO:Control158 ± 3.0 CD **162 ± 8.9 ns109 ± 6.7 BC **31 ± 1.3 B **
K0RS1:Diseased150 ± 5.9 D187 ± 10.7 108 ± 7.7 C38 ± 1.5 AB
K1RS0:Control287 ± 7.1 A208 ± 17.5151 ± 7.0 AB47 ± 0.2 A
K2RS0:Control202 ± 7.0 BC171 ± 1.4 118 ± 2.6 ABC34 ± 1.9 B
K3RS0:Control199 ± 7.4 BCD167 ± 7.7 109 ± 8.6 BC32 ± 0.8 B
K1RS1:Diseased236 ± 2.5 AB184 ± 4.9 153 ± 18 A36 ± 1.6 B
K2RS1:Diseased177 ± 4.3 CD167 ± 14.2 107 ± 8.1 C30 ± 1.7 B
K3RS1:Diseased203 ± 6.8 BC203 ± 4.9150 ± 6.5 AB38 ± 4.5 AB
Capital letters indicate the difference between K doses and diseases, ns: not significant **: p < 0.001.
Table 5. Disease severity assessment.
Table 5. Disease severity assessment.
K Dose (kg ha−1)Average Disease Scale Values
K0RSO:Control0
K0RS1:Diseased4
K1RS0:Control0
K2RS0:Control0
K3RS0:Control0
K1RS1:Diseased3
K2RS1:Diseased2
K3RS1:Diseased1
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Bayındır, Ü.; Küçükyumuk, Z. The Effects of Potassium on Plant Nutrient Concentration, Plant Development, and Rhizoctonia Rot (Rhizoctonia solani) in Pepper. Horticulturae 2025, 11, 516. https://doi.org/10.3390/horticulturae11050516

AMA Style

Bayındır Ü, Küçükyumuk Z. The Effects of Potassium on Plant Nutrient Concentration, Plant Development, and Rhizoctonia Rot (Rhizoctonia solani) in Pepper. Horticulturae. 2025; 11(5):516. https://doi.org/10.3390/horticulturae11050516

Chicago/Turabian Style

Bayındır, Ümit, and Zeliha Küçükyumuk. 2025. "The Effects of Potassium on Plant Nutrient Concentration, Plant Development, and Rhizoctonia Rot (Rhizoctonia solani) in Pepper" Horticulturae 11, no. 5: 516. https://doi.org/10.3390/horticulturae11050516

APA Style

Bayındır, Ü., & Küçükyumuk, Z. (2025). The Effects of Potassium on Plant Nutrient Concentration, Plant Development, and Rhizoctonia Rot (Rhizoctonia solani) in Pepper. Horticulturae, 11(5), 516. https://doi.org/10.3390/horticulturae11050516

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