Physico-chemical characteristics and productivity of tomato plants in function of nitrogen sources and doses

Abstract

The objective of this study was to evaluate the effect of nitrogen sources and rates on the physicochemical characteristics and yield of tomato plants. Forty hybrids were cultivated at 100 and 400 kg ha-1 of N, combined with four sources (urea, ammonium sulfate, ammonium nitrate and calcium), plus a treatment without N application in a randomized complete block design four replicates. Size, stem diameter, number of leaves, SPAD (Soil Plant Analysis Development), leaf nitrogen, number of fruits / plants, fruit firmness, bark thickness and average fruit size, ° BRIX, pH, calcium, potassium and sodium in fruits. There was an increase in SPAD index, Brix and longitudinal diameter of fruits as a function of the N dose. The use of ammonium nitrate and calcium provided stronger fruits. Urea and ammonium nitrate provided the highest pH value in tomato fruits. The application of the 100 kg ha-1 dose of N resulted in the highest potassium content in fruits. The highest productivity was obtained with the application of sources containing ammonium and the lowest in the control treatment. Sources and doses of nitrogen fertilizers influenced growth, productivity and parameters related to tomato quality.

Opportunities of Reduced Nitrogen Supply for Productivity, Taste, Valuable Compounds and Storage Life of Cocktail Tomato

“…Overall, there were very small effects of the reduced N supply on tomato fruit yield and quality. Even the N content of the fruits (Table 4) was not affected by the N supply, in the same way as the other mineral elements (Table 4), which is in accordance with other studies with a comparable or even more severe N reduction than in our experiment [26,29,40,42,[53][54][55]. As proposed by Stefanelli et al [3], reduced N contents in plants would be expected if the N supply to plants was low.…”

“…As proposed by Stefanelli et al [3], reduced N contents in plants would be expected if the N supply to plants was low. However, the N content of the tomato leaves was not affected by the reduced N supply (data not shown), similarly to other reports of the N content in plants [40,53,54,56]. In other studies, there were no impacts of low N fertilizer levels on photosynthetic activity [57,58] and very little effects on the height and the aboveground biomass [27,40,53,56] of soil-grown tomato plants.…”

“…Albeit the fruit firmness decreased after storage in all varieties and treatments (as reported in other studies [35][36][37][38]), which-as consequence of decreased turgor and water loss by transpiration [39]-is a commonly known phenomenon of fruit ripening and senescence, there was no effect of the reduced N supply. This is surprising as N limitation is known to enhance the senescence processes of plants [1], but this is probably not true for fruit softening, as several other studies also report little effects on the firmness of tomato fruits [15,20,[40][41][42].…”

Fertigation Strategies to Alleviate Fertilizer Contamination Generated by Tomato Crops under Plastic Greenhouses

“…These authors suggest that fertilization practices using NO 3 − and NH 4 + are recommended in order to improve quality. Assunção et al [20] found an increase in • Brix and the longitudinal diameter of fruits as a function of the N dose. The objective of this research was the improvement of fertilizer use efficiency in greenhouse areas in the Mediterranean region, through the assessment of the effect of several fertigation strategies based on the reduction of the total nitrogen applied, as well as on the use of a percentage of NH 4 + as a nitrogen source, on the decrease in the environmental impacts caused by the traditional system, and if they are compatible with a high fruit yield (quantity and quality).…”