Extracción de macronutrientes por el cultivo de tomate (Solanum lycopersicum Mill. Var. Alba) en casas de cultivo en Quíbor, Estado Lara

Macronutrient uptake for tomato crop (Solanum lycopersicum Mill var. Alba) under greenhouse conditions, at Quibor, Lara State, Venezuela The supply of plant nutrients in optimal amounts is a primary goal of fertilization programs. The objective of this research was to determine uptake levels of the macroelements N, P, K, Ca and Mg by tomato plant during its life cycle under glasshouse conditions. The research was carried out at Quibor experimental field of the INIA, Lara State, Venezuela. The tomato variety Alba was selected and planted at 30 cm between plants in the row and 80 cm between rows. A completely randomized design with four replications was used. Each plot consisted of 6 rows of 10 meters long each. Fertirrigation was supplied daily. Samples of plants were taken at 20, 40, 60, 75 and 125 days after transplanting (dat). It was found that in the early stages of the plant growth, the stem and leaves are the organs that accumulate more dry matter, and at the final stages the leaves and fruits have the greatest contributions. The leaf was the organ which showed the highest accumulation of calcium, while the fruit showed the highest potassium accumulation. Nitrogen was the third nutrient which presented a moderate level of extraction. The greater extraction of N, P and K corresponded to the fruit, while Ca and Mg were stored primarily by the leaves. The total removal of macronutrients for the tomato plants was 970, 358, 147, 2603 and 405 mg per plant for N, P, K, Ca, and Mg, respectively. Additional key words: Mineral nutrition, fertilization, macro element uptake, glasshouse