Copper-based foliar fertilizer and controlled release urea improved soil chemical properties, plant growth and yield of tomato

This experiment was carried out to determine the influence of copper-based foliar fertilizer and controlled release urea on soil chemical properties, plant growth and yield of tomato. Tomato plants were grown in pots under field condition. Controlled release urea (CRU), comparing with common urea, was placed into soil before transplanting seedlings. Plants were sprayed with copper-based foliar fertilizer with added zinc (CFF + Zn), a novel foliar formulation based on traditional Bordeaux mixture, at 43, 50, 70 and 97 days after transplanting (DAT) compared with plants sprayed with CFF and Kocide 2000 (KCD). Water-sprayed plants and no fertilized soil served as the controls. CRU provided the significantly higher NO3-N concentration in soil than common urea at the end of the experiment. Under the same placement of CRU, the application of CFF + Zn increased the available fraction of Cu in soil and thus made influence on soil pH and EC. At 89 DAT, plant height and leaf chlorophyll content were higher in plants sprayed with CFF + Zn compared with water-sprayed plants. Leaves from CFF, CFF + Zn and KCD treatments showed significantly higher total Cu concentration than control at 65 and 89 DAT. Without the placement of soil fertilizer, CFF treated plant increased the yield by 20.75% compared with water-sprayed plant. CRU treatment accompanied with water application significantly increased total yield by 28.58% compared with the Urea treatment. Accompanied with the same placement of CRU, yields of the plants sprayed with CFF + Zn were 27.07%, 20.73% and 20.46% more than the yields of water, CFF and KCD-sprayed plants, respectively. These results clearly indicate that the application of copper-based foliar fertilizer with added zinc and controlled release urea is favorable for tomato.

► A new type of copper-based foliar fertilizer can control fungal diseases and correct the zinc deficiency.
► Controlled release urea releases nitrogen slowly and thus reduces nitrogen loss through leaching and volatilization compared with common urea.
► The application of copper-based foliar fertilizer in conjunction with controlled release urea can improve soil chemical properties and increase both the plant growth and fruit yield of tomato.