Ruolo del potassio nel terreno e nelle piante, in particolare influenza sulla pianta di mais (Zea Mais L.)

Potassium (K) is one of the many minerals that influences the growth, development, production and quality of the production of plants. Potassium is located in the ground in different forms, affecting its absorption rate by plants. Unlike nitrogen (N), potassium is a more manageable element because it is less subjected to losses for evaporation in the atmosphere or leaching, but favourable conditions for its uptake should be created. This element is present in the soil within the Michees, which have a particular internal structure called Otthedrica. In presence of other stronger cations able to substitute it, potassium became freely available in the form of K+. However, if the soil is poor in potassium, the best choice is to fertilize with products such as potassium chloride (KCl) and potassium sulphate (KSO4). The study of the yucle of K+ and of the mechanisms governing its assimilation by plants, is essential to improve the efficiency of potassium utilization. To highlight the importance of potassium in corn its cycle and the needs of the plant were described and examined in terms of crop characteristics, pedological environment, climatic environment, necessary crop rotations, soil management, required treatments, period of use of the herbicide and all the elements to understand the circulation of potassium. Potassium strongly affects quality for agricultural production, in fact it positively influences the specific weight, and the dry weight that are fundamental requirements that can increase the gain of the crop. K is also important because it improves the efficiency of water use, which is fundamental in response to the climate change, leading to more and more frequent occurrence of drought events. In this thesis an in-depth analysis of corn fertilization, with particular attention to the types of fertilizers that are used and that are present on the market, distinguishing the type of action they have on the soil and on the plant has also been conducted. . The main aim is to provide farmers an overview of the principal factors affecting potassium availability and of its effects on plant development, to help them in the early identification of potassium deficiency symptoms. To give them a more complete picture, the description was focused on both the potassium deficiency visible symptoms and thenon-visible ones.