## 4 Discussion
### Soc, TN, TP, N-NO\({}_{3}\)\({}^{-}\), and N-NH\({}_{4}\)\({}^{+}\)
The effects of tillage strategies (e.g., NT and CT) and N fertilization on soil nutrient accumulation is still a matter of debate, since research in different climatic conditions and soil types have led to varying results [57]. Furthermore, NT benefits perhaps sustained by numerous variables counting the climatic conditions, soil types, and soil management strategies (e.g., tillage duration, type of crop, and application of fertilizer). Soil NO3-N and NH4+-N are water-soluble forms of inorganic N that can be directly absorbed and utilized by plants. Plant species differ with respect to the uptake, utilization, and physiological regulation of NO3-N and NH4+-N [58]. The results showed that the content of NO3-N in the soil of each soil layer was higher in CTN, CTM, CTNM, NTN, NTM, and NTNM, over the CT and NT treatment. Moreover, the maximum NO3-N was observed in CTN treatment, and the lowest was noted in CT treatment, and it also increased first and then decreased with the deepening of soil layer, reaching a maximum in the 20-40 cm soil layer. This is because the fertilization treatment transports a large amount of N to the soil, which increases the content of NO3-N in the soil through mineralization. In addition, the application of N fertilizer treatments makes a large amount of N enter the soil, resulting in excess soil N, aggravating soil acidification and salinization, and limiting the ability of crop roots to absorb nutrients, resulting in the increase of NO3-N residue. In addition, NO3-N is the largest under CTN treatment because CT changes the distribution of surface soil, resulting in reduced SWC, enhanced soil aeration, easier conversion of NH4+-N to NO3-N, and a large amount of N fertilizer application, which further increases the residue of soil NO3-N [59]. At the same time, no-till farming and the combined application of organic and inorganic N fertilizer with a NT system was found to effectively reduce NO3-N leaching, which reduces N loss and environmental pollution, and can thus be used as an ideal tillage practice and fertilizer ratio. In this study, the soil NO3-N increased at top soil layers as a result of soil amendments presented in Figure 4. This concurs with results reported by [PERSON] et al. [17] and [PERSON] et al. [59]. Nevertheless, the soil NO3-N was noticeably lower at deep soil layers, maybe because the N fertilizers (organic and inorganic) was mostly incorporated into the topsoil, which kept the soil NO3-N from leaching. Among them, rainfall and other climatic factors play a decisive role, but due to the relatively low annual precipitation in the study area, consequently, NO3-N in the soil cannot be leached into the deeper soil layer, so it is the largest in the 20-40 cm layer. The soil NH4+-N content trend was consistent with that of TN, but was the opposite to that of NO3-N content. On the one hand, this can be explained by the fact that NH4+-N mainly comes from the mineralization of soil TN, while on the other hand, it may be because the soil under traditional tillage is loose, with a high porosity and strong aeration, and NH4+-N is readily converted into NO3-N, resulting in leaching and the loss of N [60]. In addition, NH4+-N content is also affected by N mineralization, soil microbial activities, and aboveground vegetation absorption. Under CT conditions with no N fertilization application, the growth of the wheat plants was negatively affected, and the root absorption rate decreased, as did organic N mineralization, vegetation absorption, and utilization efficiency, resulting in a decrease in the NH\({}_{4}\)+-N content. These results are consistent with those of [17; 42; 45].