*4.4. Grain Quality*

Owing to the limited budget, we were able to analyze only three fertilization treatments in terms of quality (control, FYM, and FYM+N3PK). Our results are of limited value, ye<sup>t</sup> they can provide important information. The first important finding is that, as the FYM significantly affected grain yield (in comparison with the control), it wasnot able to provide a sufficient amount of nutrients, or beneficially affect the soil environment to produce quality grain. At least in the Czech Republic, where the minimum CPC content for bread-making "elite class" quality is 12.6%. The lower threshold is, for example, in France, where the CPC limit required for organic breadmaking wheat increased during the time from 9 to 10.5% [31]. However, even this value wasnot reached in our experiment. Manure is a valuable source of organic matter and nutrients that are released over time from the organic form to the inorganic form via the mineralization process. The released nutrients thus become accessible to plants. Most of the nutrients are released into the soil environment in the first year after application and, in subsequent years, this amount gradually decreases. The yearly rates of mineralization, expressed as decay series, vary significantly between the authors [32–34], but generally range (for nitrogen) from 40 to 60% in the first year, 10 to 25% in the second year, and 5 to 10% in the third year. The expected very low amount of available nutrients released from the manure during the third year after application could not meet the needs of wheat to produce higher amounts of protein. On the other hand, application of NPK significantly increased the CPC and ZST in all localities. Application of mineral N represents an effective way to increase grain's CPC [6,35,36]. Suitable soil-climate conditions in Ivanovice providedthe highest CPC and ZST, followed by Caslav, which offers similar soil-climate conditions. Both sites provided grain meetingthe requirements for category "E" (min. CPC 12.6%, min. ZST value 49 mL). On the other hand, even high doses of mineral fertilizers cannot break naturally createdsoil-climate barriers, such as in Lukavec (Table 7), where these requirements werenot met in the currently evaluated period, as well as in the previous years (2011–2013) [37]. The CPC in the wheat grain is significantly affected mainly by two factors: (1) N supply and (2) weather conditions. In Lukavec, N supply was at the same level as in Ivanovice and Caslav, but the results were not satisfying. According toBarneix [35], the CPC cannot be increased, despite the ample N supply, because two main regulatory points are active at the same time during the grain-filling period. This means that wheat (*Triticum aestivum*) has a ceiling in terms of protein content that cannot be exceeded. This can be seen in Ivanovice and Caslav. Ancient wheat species, such as *Triticum monococcum, Triticum dicoccum*, and *Triticum. spelt*, have the ability to produce higher CPC in comparison with *T. aestivum* [38], so the CPC is influenced by wheat species, too. The weather conditions are the second factor affecting the grain's CPC. Both yield creation (accumulation of starch) and grain's CPC (accumulation of proteins) are independent processes. Dry and hot conditions usually lead to high CPC, while wet and colder conditions lead to lower CPC [39], because dry conditions decrease starch synthesis and deposition, while proteosynthesis is not inhibited as much as starch synthesis by these environmental factors [40]. From this point of view, it is unlikely that, in Lukavec and other localities with comparable soil–climatic conditions, we will achieve a harvest of high–quality grain, at least via the fertilization. However, this could change with upcoming weather changes, as is expected for example in the UK [41], or generally in Europe [42].The direction of such changes can be seen in the results from Lukavec from 2018. This season was dry in Ivanovice and Caslav, with relatively low yields and high quality. However, in Lukavec, the year 2018 was characterized by relatively good yields and, at the same time, high quality. This means that the drought has acted here as a positive factor, smoothing the negative effect of the local soil–climate barriers.
