Phosphorus (P) fertilizer use efficiency in potato production is relatively low in semi-arid regions, wasting P resources and increasing environmental risks. Therefore, improving P use efficiency (PUE) is critical for sustainable potato production. The critical P dilution curve (CPDC) and P nutrition index (PNI) have proven to be robust diagnostic tools for assessing crop P status and aiding in improving P fertilizer management. Several potato CPDCs have been established, however, few studies have been conducted to establish a CPDC for potato (Solanum tuberosum L.) under ridge planting with drip irrigation, a planting pattern that has been increasingly adopted in semi-arid regions. In addition, the different CPDCs established using the conventional Jestus statistical model cannot discriminate the true variability across scenarios or have become linked to estimation errors. Therefore, the objectives of this study were to (1) establish a potato CPDC based on a Bayesian statistical method and (2) evaluate the relationship between potato yield and PNI. Three years of field experiments with five levels of P₂O₅ application (0, 80, 160, 240, 320 kg ha⁻¹) were conducted in Inner Mongolia, China. No significant differences were found between CPDCs across the year × site for the assessed scenarios, and thus, a generic CPDC for potatoes in the region was derived as Pc = 0.616 DM^−0.296, and it can be used to calculate the PNI. Further analysis showed that at each growth stage, the PNI exhibits a significant plateauing linear relationship with relative potato tuber yield. Thus, it provides a standard for diagnosing the P nutritional status in potatoes and lays a robust foundation for precise P recommendations in the region.

The preference of potato plants for specific nitrogen (N) form changes with growth stage. Potato plants prefer nitrate N before tuber formation, while they favor ammonium N after tuber formation. However, few studies have focused on N species management in potato production. In this study, 2-year field experiments were conducted from 2020 to 2021 in Inner Mongolia, China, under drip irrigation with four N treatments: (1) CK (no N was used), (2) conventional farming practices (F) (urea was the only N source applied for potato growth), (3) nitrate N supplied before tuber formation and ammonium N with nitrification inhibitor supplied after tuber formation (N-NI), and (4) nitrate N supplied before tuber formation and frequent, low-dose ammonium N applied after tuber formation (Opt). The results demonstrated that, compared with the F, the Opt treatment facilitated potato N uptake, with a 33–40% increase in plant N accumulation, and significantly increased potato growth, which ultimately resulted in a yield increase of 12–20% and an increase of 11–22 percentage units in NUE. In addition, the Opt treatment reduced the soil N residual by ~14% after harvest. Compared with the N-NI, the Opt treatment did not result in a decrease in tuber yield or NUE. Therefore, supplying nitrate N before tuber formation and frequent, low-dose ammonium N after tuber formation can result in a better match between the supply and demand of potato plants for N forms without the use of nitrification inhibitors, improving both potato yield and NUE, which is of substantial agronomic and environmental value.

In potato production, relatively low phosphorus use efficiency (PUE) leads to excessive phosphorus (P) fertilizer application in many regions, resulting in increasingly environmental risks. Consequently, an increasing number of researchers have started to explore the ways to improve the PUE. The symbiosis between arbuscular mycorrhizal fungi (AMF) and crop roots enhances P uptake. However, the effectiveness of AMF inoculation under field conditions depends on the environment and agronomic managements. In Inner Mongolia, China, few field experiments have been conducted on AMF inoculation in potato production. This is mainly due to low estimates of AMF colonization attributed to fungicide use in seed tuber treatments and soil mechanical disturbance caused by ridging. This study aimed to test whether inoculation with AMF after ridging at the seedling stage could improve AMF colonization in potatoes, thereby enhancing P uptake and tuber yield. Field experiments were conducted in Inner Mongolia to compare the effects of AMF inoculation after ridging at seedling stage versus inoculating seed potato with AMF during sowing, and to investigate the potential of reducing the P application rate through inoculation with AMF in potato production. The AMF colonization rate, soil hyphal density, P uptake, plant growth and tuber yield of potatoes under different treatments were measured. The results showed that compared with AMF inoculation at sowing, inoculation after ridging at the seedling stage significantly increased AMF colonization by 8 percentage points. This led to a significant improvement in P uptake and potato growth, ultimately resulting in a yield increase of approximately 6%. Further findings showed that reducing P application by 25% from the conventional rate (160 kg P₂O₅ ha⁻¹) led to significant yield loss. Whereas with AMF inoculation at the seedling stage, yield levels were maintained and the partial factor productivity of P fertilizer (PFP) was increased by an average of 39%. In conclusion, this study reveals that AMF inoculation after ridging can mitigate the negative impacts of fungicides in seed tuber treatment and ridging-caused soil disturbance on AMF colonization. It highlights importance of inoculation timing for achieving higher AMF population density. Moreover, the study demonstrates that the developed AMF inoculation enables a reduction of P fertilizer application in potato production. This provides a viable approach to enhance PUE and promote sustainable potato production in areas such as Inner Mongolia. It carries significant agronomic and environmental implications.

Fertigating with phosphorus (P) through drip irrigation has recently emerged as a promising strategy to enhance phosphorus use efficiency (PUE) in potato production. However, due to P’s limited mobility in soil—particularly in the lateral direction—and the relatively sparse root system of potatoes, its uptake remains suboptimal under conventional practices. This study, conducted from 2021 to 2022 in Inner Mongolia, China, investigated whether modifying drip tape depth and emitter spacing could improve the spatial alignment between soil-applied P and potato roots, thereby boosting PUE. Two variables were tested: the depth of drip tape placement and the distance between emitters. Key parameters measured included plant dry weight, leaf area index (LAI), soil Olsen P concentration, root distribution, tuber yield, and partial factor productivity of fertilizer P (PFP _P ). Results showed that subsurface drip tape placement at a 10 cm depth or reducing emitter spacing to 15 cm significantly improved root-P alignment. These adjustments led to increased P uptake, higher LAI, greater biomass accumulation, and improved tuber yield and PFP _P compared to the conventional setup (surface drip tape with 30-cm emitter spacing). The findings underscore the importance of optimizing drip tape configuration to synchronize P availability with crop demand. Deep placement and closer emitter spacing can significantly enhance PUE and yield in drip-fertigated potato systems, offering valuable guidance for more efficient P management in potato production.