**1. Introduction**

Farmers have recently been exposed to many pressures and challenges that a ffect their decisions and activities. These pressures and challenges arise from currently changing climatic conditions, increased public awareness of the environment, the development on the market with meat and dairy products, new technologies, and financial possibilities of farmers themselves. As a reaction, we can see a huge shift from the traditional approaches of farmers, who are responsible for food and feedingstu ff production and maintaining the function of the landscape. Such examples in the Czech Republic are a two-thirds decline in numbers of animals over the last two decades and changes in crop rotations connected with increased biogas production [1], a decline in production of organic manures, decline in doses of applied mineral phosphorus and potassium (Figure 1), and worsening of the soil organic matter quality in Chernozems [2].

**Figure 1.** The mean doses of mineral N, P, and K applied on arable land in the Czech Republic.

The source of organic manures is significantly limited, because animal husbandry production decreased significantly since 1989 (the Velvet revolution, the transformation of the society from centrally planned economy into the market economy), and this trend continued when the Czech Republic joined the European Union (EU) [3]. Mineral P and K fertilizers are not applied in a sufficient amount owing to the high purchase prices, and crop rotations were adjusted to supply agricultural biogas stations. Moreover, with reduced animal husbandry, the need for clover and other grasses decreased, so their position in crop rotation was replaced.

Another challenge significantly affecting the behaviour and decision making of farmers representsupcoming weather change and weather instability. According to Olesen et al. [4], the farmers in Europe adapt to climate change by changing the timing of cultivation, and by selecting other crop species and cultivars.

In workshops with farmers, we often encounter questions about wheat fertilization and current weather changes. What are the benefits of organic manure? What will be the result of omitting P and K fertilizers? What dose of nitrogen should we choose? From the literature, we know that nitrogen is the most crucial element for wheat [5,6] and addition of mineral N was and is a standard way for securing high yields and grain quality of wheat. In the past, "the more fertilizer, the higher yield" strategy [7], which is characteristic by application of N doses greater than the crops need, led to the inefficiency and environmental problems and farmers and scientists focused on optimization of mineral fertilizer inputs. This optimizations depend on many factors, mainly on soil-climate conditions, so such optimization differs site by site [7,8]. Another issue represents the application of P and K fertilizers. Is it necessary? According to Duncan et al. [6], the co-application of P, K, and sulfur fertilizers increases the N efficiency and helps to achieve higher yields with higher protein content via "protection against protein dilution as yields increase". These questions are based on the above-mentioned issues. To answer some of these questions, we analysed suitable fertilizer treatments and the 4-year sequence (2015–2018) from the three long-term field experiments, established in the Czech Republic in 1955. In this paper, we evaluated the effect of seven different fertilizer treatments (control, farmyard manure—FYM, FYM+N1, FYM+N2, FYM+N1PK, FYM+N2PK, FYM+N3PK) and soil-climate conditions on the winter wheat grain yield and quality. The effect of different fertilization regimes on soil nutrient content and soil properties was also analysed in this study.
