Nitrogen concentration in dry matter of the fifth leaf during growth of greenhouse tomato plants

Abstract

The nitrogen concentration in dry matter of the fifth leaf during growth of a greenhouse tomato crop was determined. Plants of hybrid Monte Carlo were grown in 4.5 L bags, using a commercial substrate, in a plant density of 3.3 plants m-2. A nutrient solution containing, in mmol L-1: KNO3, 4.0; K2SO4, 0.9; Ca(NO3)2, 3.75; KH2PO4, 1.5; MgSO4, 1.0; iron chelate 19. 10³, was used as reference. Microelements were added by a commercial mixture. The T3 treatment was equal to the reference nutrient solution, whereas in treatments T1, T2, T4 and T5 quantities of all nutrients from T3 were multiplied by 0.25, 0.50, 1.25 and 1.50, respectively. In each treatment, the volume of 1 L of nutrient solution was supplied to each plant once a week by fertigation. Periodically destructive measurements were made from anthesis to ripening of the first truss, to determine dry matter and N concentration in shoot and in fifth leaf tissues, counted from the apex to the bottom of the plant. Five dilution curves were fitted from data of N concentration in the fifth leaf and shoot dry matter accumulation during growth of plants. A general relationship was adjusted between actual N concentration in shoot (Nt) and in the fifth leaf (Nf): Nt = 1.287 Nf (R² = 0.80). This relationship could be used to estimate the N status of plants by means of a nitrogen nutrition index (NNI), from analysis of the fifth leaf sap.

Role of biochar, compost and plant growth promoting rhizobacteria in the management of tomato early blight disease

“…To obtain the mean value of percent nitrogen content, five samples from each treatment were digested. For the purpose, 0.1 g of powdered sample was digested with 4 mL of H 2 SO 4 at 420 °C for 1 h. To attain optimum results, K 2 SO 4 and CuSO 4 were added as catalysts at a ratio of 9:1 97 , 127 .…”

Efectos de diferentes agroecosistemas en la dinámica de nitrógeno, fósforo y potasio en un cultivo de tomate

“…In the concentration of N leaf significant differences were detected (p≤ 0.01) between the agro-ecosystems (Table 5), with T 2and T 3 having higher concentrations of N leaf (Figure 3a). The curve of dilution of N plant has been proposed as an indicator of the nutritional state of the plant (Rattin et al, 2002). The curves of dilution that were obtained here through a logarithmic adjustment, allows us to estimate an initial value of 5.8%, very similar to all of the agro-ecosystems, even though the plants in T 3 were the ones that had the least decrease (Figure 2a).…”

“…En la concentración de N hoja se detectaron diferencias significativas (p≤ 0.01) entre los agroecosistemas (Cuadro 5), teniendo T 2 y T 3 las mayores concentraciones de N hoja (Figura 3a). La curva de dilución del N planta ha sido propuesta como un indicador del estado nutricional de la planta (Rattin et al, 2002). Las curvas de dilución obtenidas aquí mediante un ajuste logarítmico permiten apreciar un valor inicial de 5.8% muy similar en todos los agroecosistemas, aunque las plantas en T 3 fueron las que tuvieron la menor disminución (Figura 2a).…”

Bio-fertilizers issued from anaerobic digestion for growing tomatoes under irrigation by treated wastewater: targeting circular economy concept

“…These results can confirm the good physiological and biochemical processes during the crop season except PR's clay effect for some plants (20%). Total Carbone and Total N average values for all treatments are 41.85 g/100g and 4.23 g/100g respectively, according to commercial tomatoes instructions (Rattin, Andriolo and Witter, 2002).…”