# Lawn Bonitation Value as a Function of Glycine-Complexed Iron Formulation Application
## 4 Discussion
This phenomenon has been described earlier in the studies of various authors who found that the concentration of chlorophyll can be used to quantify the color of turfgrasses [22; 25; 26]. As a result of such action, as expected, an increase in the values of the parameters (summer mainly) of the remaining visual values was noted, because high correlations between the individual components of the visual characteristics of the turfs were observed [19]. Additionally, iron significantly influences the proper development of plants and their growth [27], which is of great importance, especially in shaping the turf's compactness. It is also worth emphasizing that, according to [28], amino acids such as glycine and glutamic acid are essential metabolites in creating healthy leaf tissue and synthesizing chlorophyll. The complexation of iron with glycine could, therefore, significantly intensify the increase in chlorophyll concentration in plants, thanks to which photosynthesis could proceed more efficiently. The results of the visual value indicate that the use of this type of biostimulant can be helpful in the regeneration of lawns with a low functional value, for example, due to their intensive use or presence in environments and conditions where iron availability is low (high pH and no oxygen in the root zone). Using glycine-complexed iron fertilizer decreased susceptibility to snow mold and brown leaf spots. Indeed, statistically significant differences were not observed everywhere, but in both cases, there was a clear upward trend in resistance when increasing the dose of the biostimulator. Similar results were obtained in the experiment in [29], where a biostimulator reduced the susceptibility to fungal diseases of mixtures of perennial ryegrass and Kentucky Bluegrass. A reduction in the incidence of fungal diseases in grass mixtures was also noted in studies where the effect of using a biostimulator produced from brown algae (Phaeophyceae, containing various essential chemical compounds including amino acids, vitamins, alginic acid, and microelements) [30] and an amino acid biostimulator [19] was investigated. The results of this experiment and other studies indicate the synergistic effect of biostimulating preparations, which allow for the acquirement of high-quality turf with an increased resistance to fungal diseases. This is likely because the iron levels in a plant's nutritional profile can control the outcome of infection by affecting pathogen virulence and host defense [31]. However, on the basis of the obtained results, it is recommended that further research in this area should focus on: (1) determining the maximum dose of the biostimulant, beyond which the visual and functional value of the lawn is reduced; (2) the effect of combining the use of the biostimulator with other agrochemicals on the functional and visual value of lawn turfs. A positive effect of the foliar application of glycine-complexed iron fertilizer on the content of microelements and macroelements in plants was also noted. Although statistically significant differences were rarely observed, in almost all cases, an upward trend in the presence of these compounds was observed with the increasing fertilizer dose. First, between the variants, the iron level increased rapidly, confirming the validity of using this element as a fertilizer complex. Compared to conventional chelates, the glycine complex is lighter, which allows the grass mixture plants to absorb iron better. However, there is very little information in the literature related to the content of elements in grass plants due to their treatment with biostimulants, which significantly hinders their scientific interpretation. In a previous experiment, as a result of fertilization with a micronutrient fertilizer complexed with amino acids [19], a statistically significant increase in such elements as N, P, K, and Mg was obtained.