We tested the efficiency of Leaf P-Ca in the field. Experimental tests have shown that its application produces fruits with greater size and average weight, and also more colored.
During 2023, a fertilization test was set up in collaboration with the Technology Transfer Center of the Edmund Mach Foundation in San Michele all'Adige (TN), on the cultivar Fuji/ M9 in Spagolle, in the municipality of Castelnuovo (TN), to test the performances of the Leaf P-Ca product by Fcp Cerea in comparison with the standard company thesis.
Leaf P-Ca is a synergistic formulation of phosphorus (23.6%) and calcium (6%) bound together, recommended to promote fruit development and increase its size, hardness and shelf life.
The test was carried out on a sandy-loam soil (48.5% sand, 46.5% silt and 5% clay), subalkaline (pH 7.6), extremely calcareous (total limestone 64.4%) but with low active limestone endowment (< 1%), with high organic matter endowment (7.6%), very rich in assimilable iron and copper (48.4 and 48.8 milligrams/kilo respectively) and with very high contents of exchangeable magnesium (1000 milligrams/kilo of MgO).
The plants, planted in 2019, are grafted on the M9 rootstock and bred with biaxial system (3.50 x 1.18), with planting density equal to 2414 plants per hectare (photo 1).
Figure 1. Plants in bloom on 19 April, before setting the test and particular operation of measuring the area of the trunk section of both axes for the selection of plants to be used for measurements during the growing season, as well as taking the entire unit production per plant. (Source: Fcp Cerea)
Each thesis was replicated four times within the plot in elementary plots of 12 homogeneous plants. Three representative plants were selected in each parcel, as they are homogeneous in the trunk section area, to carry out measurements of fruit growth during the growing season and for harvesting the entire unit production per plant.
The product Leaf P-Ca was used at a dose of 5 liters/hectare for three foliar applications, scheduled 20 days after flowering, 35 days after flowering and 50 days after flowering. The firm’s thesis was simultaneously treated with a concentrated solution that guaranteed the same calcium supply, which is the element that most affects the dynamics affected by the test.
All distributions were carried out with the same pump and with volumes ranging from one thousand to 1500 liters/ hectare in relation to the vegetative development of the plant.
From the three sample plants of each plot, 4 branches were chosen per plant, two on each side and placed at two different heights, for a total of 96 branches, to carry out diametric development and growth measurements of all fruits. These measurements were made with the gauge at the 2nd surgery, one week after the 3rd surgery (photos 2 and 3 on the left) and more than a month after the last surgery (photo 3 on the right).
Figure 2. Particular of fruits in growth in a branch of the replica 1 of the two monitored theses Leaf P-Ca (left) and company (right) to 20 June. (Source: Fcp Cerea)
Figure 3. Details of the fruit growth measures on 20 June (left) and 25 July (right) with caliber. (Source: Fcp Cerea)
Chemical thinning of the fruits was carried out on all the plants tested and after mid-June, two other calcium-based interventions were carried out with the same solution used previously in the company thesis.
It should also be borne in mind that in July there were hail events which partially affected commercial production but did not affect the test with regard to the results set.
The results showed no difference in the number of fruits per plant, whereas the fruit growth was significantly different (figure 1). At the end of July, plants treated with Leaf P-Ca had an average diameter of almost 3 millimeters higher with a daily growth statistically different from the company thesis.
Figure 1. Average diameters of the plants sampled in the two theses at the three survey dates. Significantly different values are indicated by different letters. Significance levels are reported for values of P < 0.05. (Source: Fcp Cerea)
This is confirmed by the result found at harvest with an average 3.6% more weight per fruit of the thesis treated with Leaf P-Ca (figure 2).
Figure 2. Average weight per fruit of the plants sampled in the two harvest theses. (Source: Fcp Cerea)
The distribution of fruits in the different size classes has also moved towards higher percentages in the upper classes, although statistical analysis does not detect statistically significant differences other than as trends.
Figure 3. Percentages of fruits in the different size classes in relation to the theses. (Source: Fcp Cerea)
Therefore, it is confirmed that Leaf P-Ca tends to increase the size at the same unit production per plant thanks to the synergy between phosphorus and calcium.
The analysis carried out with the spectrophotometer carried out on a sample of 40 fruits per parcel has also detected less yellow and more coloured fruits in the theses treated with Leaf P-Ca compared to those of the farm thesis.
Finally, an analysis of the main nutritional parameters was carried out, which revealed a substantial alignment of the two theses with significantly better performances than the untreated comparison test (Figure 4).
Figure 4. Comparison of some nutritional parameters in the three theses. Significantly different values are indicated with different letters. Significance levels are reported for values of P < 0.05. (Source: Fcp Cerea)