Lithovit Trials on Hayward Kiwifruit

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Alan J Thorn  B.Sc.(Waikato) MS (Georgia)  MBA (Massey)

L Maria Rogan  Dip Home Sci. (Otago)  Dip Dairy Tech. Distinction (Massey)


A replicated split-plot trial designed to assess the effects on crop production and fruit dry matter accumulation in a Hayward kiwifruit orchard, following the use of a calcium carbonate foliar fertiliser LithovitÒ, in association with and without girdling treatments was monitored over two growing seasons.

The increase in fruit production (trays/ha) was highly influenced by girdling P=.04. When LithovitÒ was applied in association with girdling an additional 606 trays/ha were produced. However, the effect of LithovitÒ without girdling was antagonistic reducing production by 230 trays/ha, but was not statistically significantly.

Fruit dry matter levels were elevated by LithovitÒ treatments, and consequently returns from ‘Taste’ payments increased.  The comparative increases from the addition of LithovitÒ were $625/ha for non-girdled treatments (9 cents per tray) and $1,542/ha (6 cents per tray) for girdled treatments.

Once product and girdling costs are subtracted, the Nett Return on Investment to the grower of $18,702 per hectare accrued with the use of LithovitÒ applications in association with girdling, compared with non-girdled, Control (no LithovitÒ) treatments.  Thirty two percent of this increased return was derived from the increased ‘Taste’ payment, resulting from higher dry matter accumulation.

If increased carbohydrate production is driving the observed productivity increases, then the additional benefits of general plant health which accrue from increased carbohydrate resources retained within the plant, then there is also an additional intangible benefit to the grower.


Enhancing the CO2 concentration in greenhouse environments is routinely used in production systems. Enhanced CO2 concentrations influence photosynthetic rates thereby increasing production of carbohydrates (COH) for plant use which in turn influence physiology, growth and general plant health.

However it is difficult to influence CO2 concentrations in open atmosphere situation such as an orchard, and this paper describes field testing the ability of LithovitÒ to improve fruit dry-matter content, deliver better fruit size and production (volume) in a Hayward kiwifruit orchard.

LithovitÒ is a natural calcium carbonate (CO2) foliar fertiliser supplemented with calcium, manganese, magnesium, copper, zinc  and cobalt micronutrients created by tribodynamic activation and micronization which delivers fine particles (<10mm) that can easily be adsorbed directly through the stomata of plant leaves.

The micronutrients supplied with LithovitÒ influence plant metabolism and cell wall formation (Ca), are central to chlorophyll (Mg), influence oxygen development via photosystem II functions (Mn), are a co-factor of enzymes (Zn), components of enzymes and a redox catalyst (Cu) and co-factor the symbiotic fixation of molecular nitrogen (Co), resulting in a product that has potential to increase and sustain improved plant metabolism.

Once inside the leaf intercellular spaces LithovitÒ particles break down and release gaseous CO2. enhancing the CO2 concentration at the photo-synthetically active area within the plant leaves. The normal  concentration of CO2 in the atmosphere is approximately 0.04 vol.%, which means that most cultivated plants fail to achieve the optimum level of photosynthetic rate, which is achieved at near to 0.1 vol.% CO2 .


Trial Design

A split-plot design experiment, with six replications was used to examine the impact of LithovitÒ over Control treatments in association with and without girdling -see Appendix I. The trial canopy area was approximately .67 hectares.

Control and LithovitÒ treatments were randomly allocated so that measurement bays (4.5 by 5m) were buffered by at least one bay (5m) from another treatment.  Girdled and non-girdled treatments were randomly allocated within the split-plots.

Year One

In Year One (2013) the trial received identical canopy management (all vines were girdled on 13 February). Insecticide, fungicide, foliar fertiliser applications and fertiliser inputs, were consistent across the trial.  Using an air-blast sprayer, treatment applications of LithovitÒ using 1.5 kg/ha LithovitÒ at a water rate of 1500 L/ha, were made on 9 April and 4 June.

Thirty fully expanded leaves were collected from each treatment, prior to LithovitÒ application and prior to harvest, measured for leaf area using an image processing technique and dried at 70oC to constant weight to measure leaf mass.

Fruit dry matter was assessed at trial initiation and again at harvest 2 April, following the procedures of the Zespri Quality Manual (2013).

Treatments Year Two

In Year Two (2014), the trial again received identical canopy management, pest control and fertiliser treatments. Girdling treatments were applied on 22 December 2013 and again on

1 March 2014. 

LithovitÒ (1.5 kg/ha) was applied using an air-blast sprayer at Green Leaf (18 Oct) and prior to flowering (29 Nov) at a water rate of 700 L/ha  and twice after Fruit Set (14 Jan & 13 Feb) at a water rate of 1500 L/ha.

At harvest, 8 April total fruit mass and dry matter (30 fruit sample) were assessed for each treatment, following Zespri Quality Manual (2013). Fruit mass was converted numerically to trays per hectare using a plot area conversion of 22.5 m2 and a standard tray weight of 3.542 kilograms.

Average Fruit Size Profile

Fruit profiles were constructed for Control and LithovitÒ treatments for both girdled and non-girdled (split plots) [by combining samples within Orchard Block 2 and within Orchard Block 3] to give 8 representative, 90 fruit sample profiles.


Returns were calculated on a per hectare basis, using the trays/ha production values multiplied by the submit tray value of $8.35 for Class 1 fruit (including service and loyalty payments) published in the Zespri August 2014 Forecast Fruit Payments (Kiwiflier 2014).

Taste payment components were calculated from the TZG value (Zespri Quality Manual 2013) derived for each treatment combination and the Maximum Taste Payment Value of $2.60 (Zespri August 2014 Forecast).


Year One

At harvest in year one, there was a slight (but not statistically significant) effect on the leaf area*mass measurement due to LithovitÒ application within girdled treatments only. If the

co-variate of leaf area*mass at trial initiation in year one is considered, then this effect remains but does not increase to a level that is statistically significant.

Fruit dry matter (DM) accumulations at harvest in year one were 18.52 (Control) and 18.96 (LithovitÒ). This difference between DM accumulation between the Control and LithovitÒ treatments (remembering all vines were girdled) was 0.44 percent, significant at P=.06 –see Appendix II.

Year Two

At harvest in year two, DM accumulation was strongly influenced by Girdling P=.0002, LithovitÒ added .27% to non-girdled treatments and .09% within the girdled treatments but these results were not statistically significant –see Appendix III.

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