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Excessive or imbalanced fertilization has not only decreased nutrient use efficiency, but also degraded arable land and posed a great threat to the environment. In this study, the datasets were collected from field experiments for the period 1992 to 2017 in the main potato (Solanum tuberosum L.) production regions of China. We used the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model to estimate the soil‐plant balanced N, P, and K requirements for the potato in China. Our results revealed that there were great differences in the potato yield and nutrient uptake. The upper and lower 2.5th percentiles of N, P, and K internal efficiencies (IE, kg tuber per kg nutrient in the total plant) data were used as maximum accumulation (a) and maximum dilution (d) boundary parameters in the QUEFTS model, which were 133 and 463 kg kg–1 for N, 652 and 3030 kg kg–1 for P, and 119 and 790 kg kg–1 for K, respectively. The QUEFTS model predicted plant nutrient uptake of 4.0 kg N, 0.7 kg P, and 3.5 kg K to produce 1 Mg of tuber in the linearly distributed portion, and a corresponding tuber nutrient demand of 2.9 kg N, 0.5 kg P, and 2.3 kg K to produce 1 Mg of tuber. Field validation experiments confirmed that the QUEFTS model could be used to simulate optimum nutrient uptake and provide appropriate parameters in building fertilizer recommendation, which helps improve nutrient use efficiency for potato in China. Core Ideas This is the first report of QUEFTS model on estimating the optimum nutrient requirements for potato crops in China. The datasets used in this study were collected from multi‐year‐site field experiments. Multi‐site field validation experiments in potato‐producing areas confirmed the feasibility of QUEFTS model‐simulated nutrient uptake.

Salinity is a devastating problem of arid and semi-arid climatic regions with uneven salt accumulation which hinders growth and development of crops. The deleterious effects of salinity mainly depend on level and source of salinity. We hypothesized that types of sodium salt (NaCl and Na2SO4) might cause variable toxicity in maize (Zea mays L.) plants. The objective of the present study was to compare the effect of different types of sodium salt (NaCl and Na2SO4), each at EC 5 and 10 dS m–1 on growth, physiology and nutrient contents of maize plant grown in earthen pots under wire house conditions. Results revealed toxic effects of salt stress on seed germination, root and shoot growth and biomass. Maize physiology in terms of sub-stomatal CO2 index, chlorophyll and relative water contents, photosynthetic and transpiration rate also reduced under salt stress. Among the types of salt and levels of salinity, NaCl applied at the rate of 10 dS m–1 caused the highest reduction in seed germination, growth and physiology due to high accumulation of Na and Cl ions whereas low in K ion in maize plant tissues. Based on the findings, we do conclude that NaCl applied at the rate of 10 dS m–1 has more negative impact on maize growth and nutrient acquisition than Na2SO4 at same level of salinity.

Low phosphorus use efficiency (PUE) is one of the main problems of acidic soil that limit the crop growth. Therefore, in the present study, we investigated the response of crop yield and PUE to the long-term application of fertilizers and quicklime (CaO) in the acidic soil under wheat–maize rotation system. Treatments included, CK (no fertilization), NP (inorganic nitrogen and P fertilization), NPK (inorganic N, P and potassium fertilization), NPKS (NPK + straw return), NPCa (NP + lime), NPKCa (NPK + lime) and NPKSCa (NPKS + lime). Results showed that, fertilizer without lime treatments, significantly (p ≤ 0.05) decreased soil pH and crop yield, compared to the fertilizer with lime treatments during the period of 2012–2018. Average among years, compared to the CK treatment, wheat grain yield increased by 138%, 213%, 198%, 547%, 688% and 626%, respectively and maize yield increased by 687%, 1887%, 1651%, 2605%, 5047% and 5077%, respectively, under the NP, NPK, NPKS, NPCa, NPKCa and NPKSCa treatments. Lime application significantly increased soil exchangeable base cations (Ca2+ and Mg2+) and decreased Al3+ cation. Compared to the NP treatment, phosphorus use efficiency (PUE) increased by 220%, 212%, 409%, 807% and 795%, respectively, under the NPK, NPKS, NPCa, NPKCa and NPKSCa treatments. Soil pH showed significant negative relationship with exchangeable Al3+ and soil total N. While, soil pH showed significant (p ≤ 0.05) positive relationship with exchangeable Ca2+, PUE and annual crop yield. PUE was highly negatively correlated with soil exchangeable Al3+. In addition, soil exchangeable Ca2+, pH, exchangeable Al3+ and available N were the most influencing factors of crop yield. Therefore, we concluded that lime application is an effective strategy to mitigate soil acidification and to increase PUE through increasing exchangeable base cations and reducing the acidic cations for high crop yield in acidic soil.

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Core Ideas Nutrient Expert is a new nutrient management approach and is confirmed for use in north‐central China.The continual feasibility of Nutrient Expert was evaluated through multiple‐point field experiments.This is the first report of Nutrient Expert on improving environmental benefits of winter wheat. Over application of N and P and poor nutrient management have become a common practice on the North China Plain, and lead to low nutrient use efficiency (NUE) and serious environmental problems. Thus, nutrient management for crops must be improved. In this study, 315 field experiments were conducted from 2011 to 2014 in major winter wheat domains in north‐central China to validate the continual feasibility of the Nutrient Expert (NE) system for improving NUE and reducing greenhouse gas (GHG) emission. The NE system significantly increased grain yield, profitability, and NUE, and decreased GHG emission. Compared with farmers’ practice (FP), the NE treatment reduced N and P inputs by 41.4 and 30.1% (115 kg N ha−1 and 36 kg P2O5 ha−1), respectively, and increased K input by 51.5% (25 kg K2O ha−1). Compared with the FP and soil testing (ST) treatments, the NE treatment increased agronomic efficiency of nitrogen (AEN) by 70.0 and 13.3%, recovery efficiency of nitrogen (REN) by 73.8 and 13.3%, and partial factor productivity of nitrogen (PFPN) by 58.5 and 22.2%, respectively. Compared with the FP and ST treatments, the NE treatment reduced total N2O emissions by 54.8 and 26.3%, total GHG emissions by 44.8 and 22.9%, and GHG emission intensity by 45.8 and 22.0%, respectively. These results confirmed that NE is an effective method to make fertilizer recommendations for wheat in north‐central China and has the potential to improve yield, NUE, and profitability, with low environmental pollution.