Effect of Nutri-Vant-PeaK foliar spray on plant development, yield, and fruit quality in greenhouse tomatoes

Fruit development in tomato is often accompanied by the depletion of foliar potassium to the detriment of both the plant and the fruit quality. In an attempt to restore high foliar levels of potassium in the greenhouse tomato Lycopersicon esculentum Mill cv. Durinta, the leaves were sprayed with Nutri-Vant-PeaK, a novel foliar nutritive formulation based on monopotassium phosphate (MKP) and designed to provide controlled and lasting penetration of potassium and phosphorus into leaves. Nutri-Vant-PeaK contains 95% MKP and 5% Ferti-Vant, a non-destructive and long-lasting adjuvant delivery system. The findings were compared with those for plants sprayed with MPK. The two types of foliar fertilizer were administered at 1% (w/v) concentrations on days 40, 70 and 100 after planting. Nonsprayed plants served as the controls. Plant height, leaf chlorophyll and mineral contents, and fruit maturity were monitored during plant development. Total and marketable yields and fruit number and size distribution were measured after the harvest. Fruit appearance and quality were scored following cold storage under conditions simulating export. Plants sprayed with Nutri-Vant-PeaK were taller than the plants in the other two groups. Chlorophyll, potassium, phosphate, magnesium and iron contents in the leaves were significantly higher in plants sprayed with Nutri-Vant-PeaK or MKP than in nonsprayed plants. Fruit matured significantly earlier in plants sprayed with MKP or Nutri-Vant-PeaK. Marketable yield was significantly higher in the Nutri-Vant-PeaK treatment group than in the other two groups. Fruit quality of plants spray with Nutri-Vant-PeaK was superior: there was a higher percentage of firm fruit and a lower percentage of blotchiness and rotten fruits than in the control plants. Glucose content and dry matter after storage were higher for fruit from both groups of sprayed plants than for control plants, whereas fruit potassium, phosphorus and magnesium contents were higher only for the Nutri-Vant-PeaK group. Fruit total nitrogen, nitrate, calcium, iron and zinc contents were not affected by the spraying treatments. The results clearly show that application of foliar potassium and phosphorus nutrition via Nutri-Vant-PeaK is beneficial for greenhouse tomato production.