Influence of Potassium Doses on the Development of Chrysanthemum Plants

Background: The chrysanthemum is one of the main flowers cultivated in the world, comprises the main merchandise of all floriculture. The difficulty in expanding the crop is related to the lack of technical information about its cultivation, mainly on the nutritional needs.

Aims: Evaluate the influence of potassium doses on the development of cutting chrysanthemum plants.

Place and Duration of Study: Horticulture Sector of the Federal Institute of Education, Science and Technology of Espírito Santo - Campus Itapina, between May 2017 and August 2017.

Methodology: The experimental design was DIC (completely randomized design) with four treatments and twenty four replications considered useful plants within each plot. The treatments consisted of three diferent doses of potassium fertilization and one control: 0 kg.ha-1 of K2O (without any application of potassium); 60 kg.ha-1 of K2O (fertilizer used by producers in the region); 120 kg.ha-1 of K2O (recommended according to the amount of potassium in the soil analysis) and 240 kg.ha-1 of K2O (double the dose recommended by the soil analysis), being used as source potassium chloride.

Results: The height of the plant presented an increasing linear, the results show that the dose of 240 kg.ha-1 of K2O was adequate in order to supply potassium in the ideal amount for the growth of chrysanthemum plants. When the diameter of the stem was evaluated, a quadratic model was generated with a maximum of 7.05 mm diameter of the stem when applied 179 kg.ha-1 of K2O. An increase in the number of leaves per plant was observed, from 27 at 0 kg.ha-1 dose of K2O to 51.75 at 240 kg.ha-1 dose of K2O. When estimating the ideal dose with the equation Ŷ = 277.7146 + 4.1805*x -0.0136*x², the dose of 153.69 kg.ha-1 of K2O provided the largest leaf area, reaching the value of 598.97 cm². The SPAD (Chlorophyll content) the linear model better explained the data with coefficient of determination (R²) of 0.79. The highest volume of fresh matter found was 81.56 grams with the dose of 203.22 kg.ha-1 of K2O. Through the adjusted model was verified that the dose that maximized the dry matter of the plant with 16.17 grams, was the dose of 161.66 kg.ha-1 of K2O.

Conclusion: Doses between 150 and 240 kg.ha-1 of K2O provided positive results for the development of the plant, while doses under 150 kg.ha-1 presented unsatisfactory results.