## 3 Results and Discussion
### Total Soil Phosphorus (P) Content
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**P-Fertiliser**} & \multirow{2}{*}{**P Dose (kg/ha)**} & \multirow{2}{*}{**Plant Protection**} & \multicolumn{2}{c}{**P Content (g/kg)**} \\ \cline{5-6}  & & & & **Start** & **End** \\ \hline I & No P & 0 & \(-\)PP & 0.566 & 0.511 \({}^{\text{a}}\)l \({}^{\text{1}}\)l \({}^{\text{1}}\) \\  & SP & 21 & & 0.579 & 0.579 \({}^{\text{a}}\) \\  & PR & 21 & & 0.549 & 0.570 \({}^{\text{a}}\) \\  & A + H\({}_{2}\)O & 21 & & 0.569 & 0.562 \({}^{\text{a}}\) \\  & A\({}_{\text{s}}\)_Bm_ & 21 & & 0.552 & 0.560 \({}^{\text{a}}\) \\  & B\({}_{\text{s}}\)_Bm_ & 21 & & 0.553 & 0.566 \({}^{\text{a}}\) \\ \hline II & No P & 0 & \(-\)PP & 0.585 & 0.569 \({}^{\text{th}}\) \\  & SP & 17.6 & & 0.561 & 0.584 \({}^{\text{efgh}}\) \\  & & 26.4 & & 0.550 & 0.624 \({}^{\text{bcd}}\) \\  & & 35.2 & & 0.590 & 0.649 \({}^{\text{ab}}\) \\  & PR & 17.6 & & 0.556 & 0.583 \({}^{\text{efgh}}\) \\  & & 26.4 & & 0.573 & 0.632 \({}^{\text{bc}}\) \\  & & 35.2 & & 0.571 & 0.672 \({}^{\text{a}}\)\(\uparrow\) \\  & & 17.6 & & 0.558 & 0.579 \({}^{\text{fgh}}\) \\  & & 26.4 & & 0.553 & 0.634 \({}^{\text{bc}}\) \\  & & 35.2 & & 0.571 & 0.677 \({}^{\text{a}}\)\(\uparrow\) \\  & & 35.2 & & 0.571 & 0.677 \({}^{\text{a}}\)\(\uparrow\) \\ \cline{5-6}  & & & & 0.571 & 0.677 \({}^{\text{a}}\)\(\uparrow\) \\ \cline{5-6}  & & & & 0.572 & 0.628 \({}^{\text{bc}}\) \\ PR & 17.6 & & & 0.577 & 0.579 \({}^{\text{fgh}}\) \\  & & 26.4 & & 0.553 & 0.591 \({}^{\text{defg}}\) \\  & & 35.2 & & 0.590 & 0.604 \({}^{\text{cdefg}}\) \\ A\({}_{\text{s}}\)_Bm_ & 17.6 & & & 0.563 & 0.576 \({}^{\text{fgh}}\) \\  & & 26.4 & & 0.547 & 0.609 \({}^{\text{cdef}}\) \\  & & 35.2 & & 0.554 & 0.615 \({}^{\text{cde}}\) \\  & & & & 0.554 & 0.615 \({}^{\text{cde}}\) \\ \cline{5-6}  & & & & & 0.569 & 0.594 \({}^{\text{B}}\) \\ \hline III & No P & 0 & \(+\)PP & 0.428 & 0.419 \({}^{\text{a}}\) \\  & SP & 17.6 & & 0.441 & 0.481 \({}^{\text{a}}\) \\  & & 26.4 & & 0.425 & 0.479 \({}^{\text{a}}\)\(\uparrow\) \\  & & 35.2 & & 0.432 & 0.497 \({}^{\text{a}}\)\(\uparrow\) \\  & A\({}_{\text{g}}\)_Af_ & 17.6 & & 0.456 & 0.499 \({}^{\text{a}}\) \\  & & 26.4 & & 0.417 & 0.478 \({}^{\text{a}}\)\(\uparrow\) \\  & & 35.2 & & 0.433 & 0.489 \({}^{\text{a}}\)\(\uparrow\) \\  & AB\({}_{\text{g}}\)_Af_ & 17.6 & & 0.449 & 0.476 \({}^{\text{a}}\) \\  & & 26.4 & & 0.429 & 0.479 \({}^{\text{a}}\) \\  & & 35.2 & & 0.420 & 0.483 \({}^{\text{a}}\)\(\uparrow\) \\ \hline IV & No P & 0 & \(+\)PP & 0.533 & 0.436 \({}^{\text{c}}\)\(\downarrow\) \\  & SP & 40 & & 0.557 & 0.479 \({}^{\text{abc}}\)\(\downarrow\) \\  & & 17.6 & & 0.593 & 0.497 \({}^{\text{abc}}\)\(\downarrow\) \\  & & 26.4 & & 0.552 & 0.501 \({}^{\text{abc}}\)\(\downarrow\) \\  & AB\({}_{\text{g}}\) & 35.2 & & 0.540 & 0.461 \({}^{\text{bc}}\)\(\downarrow\) \\  & & 17.6 & & 0.540 & 0.496 \({}^{\text{abc}}\)\(\downarrow\) \\  & & 26.4 & & 0.563 & 0.513 \({}^{\text{ab}}\)\(\downarrow\) \\  & AB\({}_{\text{g}}\)_Bm_ & 35.2 & & 0.542 & 0.488 \({}^{\text{abc}}\)\(\downarrow\) \\  & & 17.6 & & 0.529 & 0.511 \({}^{\text{abc}}\)\(\downarrow\) \\  & & 26.4 & & 0.505 & 0.541 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total P content in soil from wheat field. Compared with the starting situation, no P treatment resulted in a significant decrease of P content after wheat harvest in experiments I, IV and V, which was not proven in other experiments, although a clear tendency to decrease was observed. This decrease was undoubtedly due to the use of part of the soil P stock by plants and the P removal from the field during harvesting (Table 7). It cannot be ruled out that mobile P forms may be leaching from the soil [36]. According to [PERSON] et al. [40], the risk of the latter losses increases with increased P stocks in the soil. Studies by [PERSON] et al. [42] prove that the mere P uptake by crop plants without fertilisation leads to a negative P budget in the soil, which deepens over time.