Siliceous natural nanomaterials (SNNMs), i.e., diatomaceous earth and natural zeolites, have a nanoporous structure with large active surfaces that adsorb cations or polarized molecules. Such nanoporous feature determines the effects related to SNNM utilization as low-risk plant protectants and soil improvers. This work used SNNMs from Romanian quarries as carriers for foliar fertilizers applied to stone-fruit trees, apricot and peach. We determined the effects of SNNMs on the physiology, yield and fruit quality of the treated stone-fruit trees. SNNM application determined impacts specific to the formation of particle films on leaves: reduced leaf temperature (up to 4.5 °C) and enhanced water use efficiency (up to 30%). Foliar fertilizers’ effects on yield are amplified by their application with SNNMs. Yield is increased up to 8.1% by the utilization of SNNMs with foliar fertilizers, compared to applying foliar fertilizer alone. Diatomaceous earth and natural zeolites promote the accumulation of polyphenols in apricot and peach fruits. The combined application of SNNMs and foliar fertilizer enhance the performance of peach and apricot trees.

Iron chlorosis represents a physiological phenomenon with negative impact on the quality and quantity of grape production in the vineyards. The bicarbonates are considered to be the main group of compounds which immobilize the iron in the soil in forms not assimilable by the plants. The grape production in conditions of iron deficiency can be improved significantly by applying foliar fertilizers. The best result in mitigating the effects of iron deficiency were obtained by the application of the fertilizers which, in addition to a complex mineral composition, also have a content of organic matter in the form of humic substances or protein hydrolysate.

Particle film forming materials were introduced as a solution to reduce the effects of excessive solar irradiation on plant photosynthesis. Covering plant leaves with particle films leads to plant bio-stimulant-like effects: increased protection against abiotic stress and increased fruit quality. We used zeolites and diatomaceous earth carriers for foliar fertilizer, known for their application as particle film-forming material. The aim of this paper was to investigate the plant bio-stimulant-like effects of this combined two-in-one product on the yield of apple trees and their photosynthetic pigments and fruit quality. The experiments were conducted for two years, 2021 and 2022, which had different agroclimatic patterns: 2021 had a deficit of precipitation, whereas 2022 was warmer by more than +4.8 °C compared to the recorded average temperature. Applying particle film-forming material and foliar fertilizer reduces the degradation of the photosynthetic pigments by drought and excessive solar radiation by 25–30%. In the year with a deficit of precipitation there was an increased yield by an additional 11.56–12.38% and the fruit quality similarly increased. Such effects of these combined two-in-one products were limited in 2022 as the temperature was higher than normal by several degrees.

In recent years, plant biostimulants have been increasingly used in agriculture The paper focuses on a new plant biostimulant with a complex matrix of organic substances based on protein hydrolysates (a mixture of peptides and free amino acids), algae extract (Ascophyllum nodosum) and secondary nutrients, used in viticulture. The experimental biostimulante was tested in the vineyard (Chasselas dore) by foliar application, in a concentration of 0.5%, three treatments in the vegetative phase. The trials were performed in comparison to a non-fertilized control. The use of foliar biostimulant led to yield increases of 29.1% compared to the control. The application of the three foliar treatments with the experimental plant biostimulant increased by 25 -36% the process of photosynthetic assimilation to the vineyard, cultivated on the Hortic Antrosols.

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