_applied sciences_  
_Article_  
**Effect of Amino Acid and Titanium Foliar Application on Smooth-Stalked Meadow Grass (_Poa pratensis_ L.)**  
**Macronutrient Content**  
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applied to leaves, and according to many studies, the latter type of treatment can be used for stimulant application [1; 2]. Substances supplied to leaves are quickly absorbed, with nutrients readily available to plants. Additionally, foliar application of plant nutrients has economic benefits, which is why it is becoming increasingly popular [3]. Stimulants can act directly on plant physiology and metabolism or indirectly by modifying environmental conditions [4], among others, due to their beneficial effects on the soil microbiological activity. These products are usually used as an additive to standard fertilizers to improve nutrient efficiency and product quality [5].  
The timing of stimulant application is very important. They should be used at plant development stages crucial for yield quality and quantity, e.g., during sowing, applied to the soil, and in the tillering or flowering stages, applied to the leaves. Stimulants are also recommended as an intervention method to help plants respond to stressful conditions such as frost, drought, hail, strong wind, and chemical contamination with pesticides. They can be used before expected stress or during adverse conditions, as well as after stress for better plant growth [6].  
Many studies have reported on the ability of amino acids to reduce abiotic stress and on their beneficial effect on plant growth and yield [7]. The importance of amino acids is due to their role in the biosynthesis of many different organic compounds [8]. According to [PERSON] et al. [9], apart from increasing the yield and its quality, they also shorten the productive cycle. Amino acids are the building blocks of proteins, and [PERSON] et al. [10] confirm that they are involved in the growth and development of plants. In addition, they are part of enzymes, nucleic acids, antioxidants, and other secondary compounds. However, for the biosynthesis of amino acids, plants require significant energy for nitrogen uptake and assimilation [11] since nitrate must be reduced to nitrite and then to ammonium, with the latter being included in the biosynthesis of amino acids [12]. Amino acids are easily absorbed and moved in plant tissues [2; 13].  
As growth stimulants, amino acids are mainly used in the cultivation of vegetables and fodder crops on arable land, but in recent years various biostimulants and similar products have been developed also to use on grassland [14; 15]. Some of such biostimulants contain amino acids as essential ingredients [16; 17].  
As a microelement, Ti is also used on crops as a stimulant, which is why it was also tested in the present experiment. It has a beneficial effect on biochemical processes occurring in plants, leading to growth acceleration and an increase of their yield [18]. Ti stimulates the activity of many enzymes, e.g., catalase, peroxidase, lipoxygenase, or nitrate reductase. In addition, it accelerates metabolic processes, facilitates pollination, fertilization in flowering plants, and the setting of fruit and seeds. It increases chlorophyll content in leaves, accelerating their growth and development, and reduces the sensitivity of plants to adverse environmental conditions, increasing their resistance to fungal and bacterial diseases. In addition, it has been found that Ti has a beneficial effect on the uptake of components both from the soil and from fertilizers [19].  
The aim of the study was to determine the effect of the combined foliar application of amino acids and Ti on the dry matter yield and macronutrient content in _Poa pratensis_ harvested three times a year.