## 2 Materials and Methods
The soil water content can change the P availability for plants and P uptake by plants [35], and abundant precipitation can be conducive to P leaching from the soil tillage layer into groundwater or water ecosystems [36]. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**Soil Type**} & \multirow{2}{*}{**Soil Texture**} & \multirow{2}{*}{**pH (in KCl)**} & \multicolumn{5}{c}{**Total (g/kg)**} \\ \cline{5-10}  & & & & & **C** & **N** & **K** & **Mg** \\ \hline I & Luvisols & sandy clay loam & 6.23 & 8.31 & 1.30 & 2.98 & 2.07 \\ II & Luvisols & sandy loam & 5.32 & 8.90 & 1.35 & 2.90 & 2.01 \\ III & Luvisols & sandy loam & 5.51 & 8.87 & 1.36 & 3.21 & 2.25 \\ IV & Luvisols & sandy loam & 5.23 & 7.15 & 1.09 & 3.30 & 2.20 \\ V & Luvisols & sandy clay loam & 6.28 & 8.53 & 1.42 & 2.98 & 2.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Basic agricultural data for the experiments. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Item**} & \multicolumn{5}{c}{**Experiment**} \\ \cline{2-7}  & **I** & **II** & **III** & **IV** & **V** \\ \hline Wheat cultivar & Trappe & Monsun & Julius & Julius & Monsun \\ Previous crop & spring barley & cereal-legume mixture & winter rape & winter rape & winter rape & winter rape \\ Soil tillage system & plough tillage & plough tillage & plough tillage & plough tillage & plough tillage \\ Fertilisation & & & & & & \\ K\({}_{2}\)O \({}^{1}\), kg/ha & 120 & 100 & 100 & 100 & 100 \\ N \({}^{2}\), kg/ha & 100 & 110 & 130 & 120 & 130 \\ Plant protection & \(-\)PP & \(-\)PP \(+\)PP & \(+\)PP & \(+\)PP & \(+\)PP \\ \(-\) herbicides & \(-\) & \(-\)/\(+\) & \(+\) & \(+\) & \(+\) \\ \(-\) fungicides & \(-\) & \(-\)/\(+\) & \(+\) & \(+\) & \(+\) \\ \(-\) insecticides & \(-\) & \(-\)/\(+\) & \(+\) & \(+\) & \(+\) \\ \(-\) growth regulators & \(-\) & \(-\) & \(+\) & \(+\) & \(-\) \\ Sowing date & 25.04.2014 & 9.04.2015 & 2.10.2014 & 15.10.2015 & 21.04.2016 \\ Harvest date & 11.08.2014 & 11.08.2015 & 5.08.2015 & 9.08.2016 & 12.08.2016 \\ \hline \hline \end{tabular} \({}^{1}\) potassium chloride, \({}^{2}\) ammonium sulphate, \(+\)applied, \(-\)not applied.  
\end{table} 
Table 5: Atmospheric precipitation and air temperature during the study period according to the Meteorological Station in Balcyny. Experiments I and III-V were established in a randomised block design and experiment II in a parallel strip design. In each experiment, particular experimental variants were performed in four replications (plots). The area of a single experimental plot was 20 m\({}^{2}\). Soil samples were taken from the 0-30 cm soil layer twice: before the start of the experiment and after wheat harvest. They were collected from each plot separately at evenly distributed points using a hand-held twisting probe (Egner's stick). A total of about 1 kg of soil was taken from a single plot. The collected soil material was dried at room temperature for several days, then thoroughly mixed and sieved. Afterwards, the separated portions of about 300 g each were forwarded for chemical analyses. Grain samples of approximately 1 kg from each plot were taken from the volumes obtained after combine harvesting. From these samples, portions of about 200 g of grain were weighed and forwarded to chemical analyses after previous cleaning from impurities and weed seeds. Shortly before harvest, the samples of straw (i.e., wheat stems with leaves) and weeds were collected. Wheat plants were collected manually from two 1-metre-long rows of each plot. The spikes were removed and the roots were cut off at a level equal of the harvester's moving height. Straw was cut into pieces of about 10 cm in length. Weeds were taken from a randomly determined area of 0.25 m\({}^{2}\) (0.5 m \(\times\) 0.5 m frame) from each plot. Weed roots were separated from the aboveground parts and removed.