Leaf nitrogen (N), phosphorus (P), and potassium (K) stoichiometry can reflect plant strategies of nutrient allocation, which play key roles in ensuring food security and maintaining nutrient balance in the agroecosystem. Arbuscular mycorrhizal fungi (AMF) inoculation is an effective and green management measure affecting nutrient uptake and utilization strategies, especially in the agroecosystem. However, the interplay between AMF and leaf nutrient stoichiometry that is important for sustainable agriculture remain underexplored. Therefore, the efficacy of AMF in improving leaf nutrients of host plants in agricultural ecosystems were tested with meta-analysis by 1932 pairs of observations in research publications from 1995 to 2022. Overall analysis showed that AMF inoculation increases leaf N, P, and K by 8.75%, 24.61%, and 13.54%, respectively. Moreover, leaf P: K increased by 11.74% by AMF inocula, but leaf N: P and N: K of host plants decreased by 15.38% and 5.52%, respectively. Furthermore, the AMF effect on leaf nutrient stoichiometry was significantly regulated by species, life cycle, and growth habits of host plants. The prominent efficacy of AMF was higher for leaf P in fruit (30.06%), perennial (30.19%), and woody plants (31.6%) than other groups. Moreover, AMF effects on leaf N: P: K stoichiometry of inoculated crops varied depending on the identity of AMF. The Glomeraceae (especially Rhizophagus genera) increased more leaf P content than other AMF families. Thus, the leaf nutrient of host plants significantly increased by AMF inocula, especially leaf P content in the agroecosystem. The effect of AMF on leaf N: P: K stoichiometry was related to plant species, plant life cycle, plant growth habits, and the identity of AMF. These findings highlight the response of AMF to the strategies of nutrient in host plants and provide a theoretical and applicable way for better crop yield and sustainable agriculture.

The application of potassium fertilizer application and straw return are effective agronomic measures for increasing crop productivity; however, information on how straw return—when substituting potassium fertilizer—affects crop yield, efficiency, and quality in dryland remains limited. In this study, an experiment on a dryland summer maize and winter wheat rotation system was initiated in 2007. This study included four treatments: CK (no fertilizer and no straw return), NP (nitrogen and phosphorus fertilizer application without straw return), NPK (nitrogen, phosphorus, and potassium fertilizer application without straw return), and NPS (NP treatment with straw return, substituting potassium fertilizer as used in the NPK treatment). These treatments were employed to assess grain yield and fertilizer agronomic efficiency in 2015–2020. Additionally, we evaluated the content of nitrogen (N), phosphorus (P), and potassium (K), as well as the protein content and protein yield in maize and wheat grains and the protein components in wheat grains in 2019–2020. The results showed that compared to the CK treatment, NP, NPK, and NPS treatments not only significantly increased the yield, protein yield, and fertilizer agronomic efficiency in both maize and wheat but also increased the content of protein and protein components in wheat grains. Compared to the NP treatment, the NPK treatment significantly increased the contents of N, K, globulin, and gluten in wheat grains by 5.11%, 21.59%, 10.06%, and 15.14%. Compared to NPK treatment, NPS treatment significantly increased the average yield of summer maize by 21.33% and 20.91%, respectively, as well as the annual yield by 9.99% and 13.59%, the N fertilizer agronomic efficiency of summer maize by 132.47%, and the annual N and P fertilizer agronomic efficiency by 42.83% and 64.36%, over the five-year period. The NPS treatment also significantly increased the summer maize protein yield and annual protein yield by 10.43% and 23.08%, as well as the content of protein components, the protein content, and P content in wheat grains by 4.93–13.58%, 7.81%, and 28.89%, respectively. In conclusion, NPS treatment can not only enhance crop yield, protein yield, and fertilizer agronomic efficiency in summer maize annually but also has the advantage of promoting wheat quality. NPS is an efficient strategy to improve crop yield, efficiency, and quality in a dryland maize–wheat rotation system.

Senesced leaves play a vital role in nutrient cycles in the terrestrial ecosystem. The carbon (C), nitrogen (N) and phosphorus (P) stoichiometries in senesced leaves have been reported, which are influenced by biotic and abiotic factors, such as climate variables and plant functional groups. It is well known that mycorrhizal types are one of the most important functional characteristics of plants that affect leaf C:N:P stoichiometry. While green leaves’ traits have been widely reported based on the different mycorrhiza types, the senesced leaves’ C:N:P stoichiometries among mycorrhizal types are rarely investigated. Here, the patterns in senesced leaves’ C:N:P stoichiometry among plants associated with arbuscular mycorrhizal (AM), ectomycorrhizal (ECM), or AM + ECM fungi were explored. Overall, the senesced leaves’ C, with 446.8 mg/g in AM plants, was significantly lower than that in AM + ECM and ECM species, being 493.1 and 501.4 mg/g, respectively, which was mainly caused by boreal biomes. The 8.9 mg/g senesced leaves’ N in ECM plants was significantly lower than in AM (10.4 mg/g) or AM + ECM taxa (10.9 mg/g). Meanwhile, the senesced leaves’ P presented no difference in plant associations with AM, AM + ECM and ECM. The senesced leaves’ C and N presented contrary trends with the changes in mean annual temperature (MAT) and mean annual precipitation (MAP) in ECM or AM + ECM plants. The differences in senesced leaves’ C and N may be more easily influenced by the plant mycorrhizal types, but not P and stoichiometric ratios of C, N and P. Our results suggest that senesced leaves’ C:N:P stoichiometries depend on mycorrhizal types, which supports the hypothesis that mycorrhizal type is linked to the evolution of carbon–nutrient cycle interactions in the ecosystem.

Irrigation practice, tillage method, and nitrogen (N) management are the three most important agronomic measures for wheat (Triticum aestivum L.) production, but the combined effects on grain yield and wheat physiological characteristics are still poorly understood. We conducted a three-year split–split field experiment at the junction of the Loess Plateau and Huang-Huai-Hai Plain in China. The two irrigation practices (I0: non-irrigation and I1: one-off irrigation), three tillage methods (RT: rotary tillage, PT: plowing, and ST: subsoiling), and four N managements (N0, N120, N180, and N240) were assigned to the main plots, subplots, and sub-subplots, respectively. Irrigation practice, tillage method, N management, and most of their two-factor and three-factor interactions could significantly affect grain yield and the physiological characteristics of the leaves of winter wheat. One-off irrigation increased the grain yield by 46.9% by optimizing the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), the contents of proline (Pro) and soluble sugar (SS), and the net photosynthesis rate (Pn) in leaves during most growth stages of wheat. The improvement of grain yield and physiological characteristics under one-off irrigation was considerably affected by the tillage method and N management, and the effectiveness of one-off irrigation was improved under subsoiling and N180 or N240. One-off irrigation combining subsoiling and N180 had no significant difference relative to one-off irrigation combining subsoiling and N240, while it significantly increased grain yield by 47.1% over the three years, as well as increasing the activities of SOD, POD, and CAT, and Pn in wheat leaves by 23.2%, 41.2%, 26.1%, and 53.0%, respectively, and decreasing the contents of malondialdehyde (MDA), Pro, and SS by 29.2%, 65.4%, and 18.2% compared to non-irrigation rotary tillage combined with N240 across the two years and three stages. The wheat grain yield was significantly associated with the physiological characteristics in flag leaves, and the coefficient was greatest for POD activity, followed by SOD activity and Pn. Therefore, one-off irrigation combining subsoiling and N180 is an optimal strategy for the high-yield production of wheat in dryland regions where the one-off irrigation is assured.

Irrigation practices and nitrogen (N) addition play pivotal roles in wheat production, and their rational coordination can significantly enhance N, phosphorus (P), and potassium (K) use efficiency and yield of wheat. However, the comprehensive effects of irrigation practices and N addition rates on N, P, and K accumulation and utilization and yield of wheat in dryland remain unclear. A field experiment with two irrigation practices (W0, zero-irrigation and W1, one-off irrigation), and four N addition rates (0, 120, 180, and 240 kg N ha⁻¹, represented by N0, N120, N180, and N240, respectively) was conducted in 2021–2022 and 2023–2024. Compared to W0N0, W1N180 significantly increased wheat grain yield, spike number, and grains per spike by 46.4%, 35.9%, and 18.9%, respectively. Wheat yield and N, P, and K accumulation reached the maximum value at N180 or N240. One-off irrigation significantly improved the uptake efficiency and fertilizer partial factor productivity for N, P, and K, whereas increased N addition enhanced these parameters specifically for P and K. However, N180 treatment increased N uptake efficiency, N fertilizer partial factor productivity, P internal efficiency, and K internal efficiency by 22.2%, 31.1%, 9.4%, and 5.9%, respectively, compared to N240 under one-off irrigation. In addition, W1N180 significantly increased above-ground N, P, and K accumulation by 45.8%, 52.8%, and 51.8%, as well as pre-anthesis N and P translocation by 48.5% and 47.0%, respectively, compared to W0N120. Consequently, the W1N180 strategy not only improved wheat yield but also optimized N, P, and K accumulation, pre-anthesis N and P translocation, and nutrient use efficiency. Therefore, one-off irrigation combined with N180 can be recommended for enhancing wheat yield and nutrient use efficiency in dryland.