Responses of Tomato to Potassium Rates in a Calcareous Soil

Abstract

<jats:p>Florida produces the most vegetables in the United States during the winter season with favorable weather conditions. However, vegetables grown on calcareous soils in Florida have no potassium (K) fertilizer recommendation. The objective of this study was to evaluate the effects of K rates on leaf tissue K concentration (LTKC), plant biomass, fruit yield, and postharvest quality of tomatoes (<jats:italic>Solanum lycopersicum</jats:italic> L.) grown on a calcareous soil. The experiment was conducted during the winter seasons of 2014 and 2015 in Homestead, FL. Potassium fertilizers were applied at rates of 0, 56, 93, 149, 186, and 223 kg·ha<jats:sup>−1</jats:sup> of K and divided into preplant dry fertilizer and fertigation during the season. No deficiency of LTKC was found at 30 days after transplanting (DAT) in both years. Potassium rates lower than 149 kg·ha<jats:sup>−1</jats:sup> resulted in deficient LTKC at 95 DAT in 2014. No significant responses to K rates were observed in plant (leaf, stem, and root combined) dry weight biomass at all the sampling dates in both years. However, at 95 DAT, fruit dry weight biomass increased with increasing K rates to 130 and 147 kg·ha<jats:sup>−1</jats:sup>, reaching a plateau thereafter indicated by the linear-plateau models in 2014 and 2015, respectively. Predicted from quadratic and linear-plateau models, K rates of 173 and 178 kg·ha<jats:sup>−1</jats:sup> were considered as the optimum rates for total season marketable yields in 2014 and 2015, respectively. Postharvest qualities, including fruit firmness, pH, and total soluble solids (TSS) content, were not significantly affected by K rates in both years. Overall, K rate of 178 kg·ha<jats:sup>−1</jats:sup> was sufficient to grow tomato during the winter season in calcareous soils with 78 to 82 mg·kg<jats:sup>−1</jats:sup> of ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extracted K in Florida.</jats:p>

Effect of Organic Phosphorus on Pre-Harvest and Post-Harvest Traits of Tomato (Lycopersicon Esculentum) Grown Under Field Conditions

“…The present results are in accordance with the findings of Melendez (2012) that phosphorus helped in early flowering and fruiting. Zhu et al (2017) reported that phosphorus application to tomato plants showed increase in number of pickings plot-1. The obtained findings are in agreement with the results of Dabire et al (2016) who described that phosphorus applied to tomato plants showed more no of fruits plot-1 and no of pickings plot -1 .…”

“…Zekri and Obreza (2002) stated that the process of photosynthesis of the plant dropped severely that resulted in smaller fruit when provided with low concentrations of NPK therefore, the growth of plant was stunted and reduced fruits were formed. Zhu et al (2017) revealed that with the application of higher rates of NP fertilizers, maximum average tomato fruit weight can be achieved. In contradiction, Majanbu et al (1985) found no response due to phosphorus fertilization to pod weight of okra.…”