Growth, yield, and calcium and boron uptake of tomato (Lycopersicon esculentum L.) and cucumber (Cucumis sativus L.) as affected by calcium and boron humate application in greenhouse conditions

Abstract

The objective of this study was to examine the effect of calcium humate, boron humate, and humic acid solutions on growth, yield, quality, and calcium and boron uptake of tomato (Lycopersicon esculentum L.) and cucumber (Cucumis sativus L.), as well as changes in soil nutrient status after crop harvest. Four different concentrations (500, 1000, 3000, and 5000 mg kg(-1)) of calcium humate (12% CaO, 15% humic and fulvic acid), boron humate (10% BOH4, 15% humic and fulvic acid), and humic acid (15% humic and fulvic acid) were used in this research. The results revealed that Ca humate, B humate, and humic acid treatments applied at different rates positively affected the total marketable yield, average fruit weight, fruit diameter, fruit length, and leaf dry matter of tomato and cucumber plants. However, no statistically significant differences were observed among the treatments in terms of total soluble solids, fruit dry matter, chlorophyll, and plant length. The highest tomato yield (159,682 kg ha(-1)) was obtained from 2936 mg kg(-1) Ca humate application, while the highest cucumber yield (172,992 kg ha(-1)) was obtained from 2910 mg kg(-1) Ca humate application. In addition, the macro-and micronutrient concentration in leaves and fruits also increased significantly with these applications. Translocations of Ca and B from leaf to fruit were also affected positively by the Ca and B humate applications. Leaf Ca/fruit Ca ratio in tomato and cucumber decreased from 20.55 to 2.42 and from 10.70 to 1.37, respectively, while leaf B/fruit B ratio decreased from 15.80 to 1.82 in tomato and from 14.31 to 2.64 in cucumber. The applications also upgraded soil health by modifying the chemical characteristics of the soil and enhancing its nutrient status. The results showed that Ca and B humate nutrient sources should be used as an economical and simple application for tomato and cucumber plants without Ca and B deficiency during the plant growth period.