Phosphorus (P) deficiencies are widespread in calcareous soils. The poor availability of nitrogen (N) and P in soils often restricts crop growth. However, the effects of P addition on plant growth and plant nutrient transport changes during the establishment of Leymus chinensis fields in Xinjiang are not clear. We investigated the responses of Leymus chinensis biomass and nutrient absorption and utilization to changes in soil N and P by adding P (0, 15.3, 30.6, and 45.9 kg P ha⁻¹ year⁻¹) with basally applied N fertilizer (150 kg N ha⁻¹ year⁻¹). The results showed that (a) Principal component analysis (PCA) of biomass, nutrient accumulation, soil available P, and soil available N during the different periods of Leymus chinensis growth showed that their cumulative contributions during the jointing and harvest periods reached 95.4% and 88%, respectively. (b) Phosphorus use efficiency (PUE) increased with the increase of P fertilizer gradient and then decreased and the maximum PUE was 13.14% under moderate P addition. The accumulation of biomass and nutrients in Leymus chinensis can be effectively improved by the addition of P fertilizer at 30.6 kg ha⁻¹. Different P additions either moderately promoted or excessively inhibited Leymus chinensis growth and nutrient utilization.

Introduction: Understanding the response of cross-domain co-occurrence networks of soil microorganisms to phosphorus stability and the resulting impacts is critical in ecosystems, but the underlying mechanism is unclear in artificial grassland ecosystems.Methods: In this study, the effects of four phosphorus concentrations, P0 (0 kg P ha⁻¹), P1 (15.3 kg P ha⁻¹), P2 (30.6 kg P ha⁻¹), and P3 (45.9 kg P ha⁻¹), on the cross-domain co-occurrence network of bacteria and fungi were investigated in an artificial Leymus chinensis grassland in an arid region.Results and discussion: The results of the present study showed that phosphorus addition significantly altered the stem number, biomass and plant height of the Leymus chinensis but had no significant effect on the soil bacterial or fungal alpha (ACE) diversity or beta diversity. The phosphorus treatments all increased the cross-domain co-occurrence network edge, node, proportion of positively correlated edges, edge density, average degree, proximity to centrality, and robustness and increased the complexity and stability of the bacterial-fungal cross-domain co-occurrence network after 3 years of continuous phosphorus addition. Among them, fungi (Ascomycota, Basidiomycota, Mortierellomycota and Glomeromycota) play important roles as keystone species in the co-occurrence network, and they are significantly associated with soil AN, AK and EC. Finally, the growth of Leymus chinensis was mainly due to the influence of the soil phosphorus content and AN. This study revealed the factors affecting the growth of Leymus chinense in artificial grasslands in arid areas and provided a theoretical basis for the construction of artificial grasslands.

The Tarim Basin is located in an arid inland area; the ecological environment is fragile, and it is extremely sensitive to climate change. For the purpose of studying dynamic changes in the vegetation response of vegetation in the Tarim Basin to extreme climate, this study used the Vegetation Ecological Quality Index (EQI) as a vegetation indicator and calculated 12 extreme climate indices using Rclimdex. Pearson correlation analysis was used to explore the relationship between EQI values and various extreme climate indices at both inter-annual and intra-annual scales. Additionally, geographic detector analysis was employed to examine the single and interactive effects of extreme climate on the EQI for different vegetation types. The following was found: (1) During 2000–2022, the EQI showed an upward trend in the Tarim Basin, and the increase in agricultural vegetation was the fastest. (2) Since 2000, the extreme warm temperature indices have risen, whereas the extreme cold temperature indices have declined. The warming rate of nighttime temperatures exceeds that of daytime, and the extreme precipitation rises intensively. Simultaneously, continuous dry days have also increased. (3) On an inter-annual scale, the EQI is primarily negatively correlated with the most extreme warm temperature indices, while it is positively correlated with extreme cold temperatures and extreme precipitation indices. On an intra-annual scale, there is an obvious regional concentration in the correlation between the EQI and extreme climate indices. The diurnal temperature range (DTR) and cold daytimes (TX10P) have inhibitory and promoting effects on areas with high and low EQI, respectively. The extremum indices, temperature warm indices, and precipitation intensity indices have a promoting effect on areas with a high EQI and an inhibiting effect on areas with a low EQI. The interaction between extreme climate indices has a greater impact on the EQI than the effect of a single extreme climate index, especially with a significant impact on forests and shrubs. This study provides a reference for the early warning of meteorological disasters, ecosystem protection, and sustainable management in the Tarim Basin.

Soil salinization poses a significant threat to agricultural sustainability. This study investigated the effects of different microbial fertilizers on the rhizosphere fungal community and physicochemical properties of saline–alkali soil cultivated with sunflower. Three microbial fertilizers were applied at three concentration gradients to two sunflower varieties with contrasting salt–alkali tolerance (salt-tolerant NX53177 and salt-sensitive NKY1502) to elucidate the mechanisms underlying microbial fertilizer-mediated amelioration of saline–alkali soils. Among all treatments, the application of Aikesa microbial fertilizer at 50 g per pot (treatments T8 and T17) demonstrated the most pronounced ameliorative effects. In the salt-tolerant variety NX53177, the 50 g/L Aikesa fertilizer treatment increased the relative abundance of the beneficial genus Mortierella by 46.2%. It decreased the potentially pathogenic genus Lophotrichus by 82.2% compared to the no-fertilizer control. Soil fungal diversity was significantly improved, with the Shannon index increasing by 9.86% and the Simpson index decreasing by 25.83%. Concurrently, critical soil properties were enhanced: soil pH decreased by 7.79%, salinity decreased by 3.13%, and the contents of organic matter, available nitrogen, available phosphorus, and available potassium increased by 42.13%, 49.96%, 12.34%, and 53.22%, respectively. In the salt-sensitive variety NKY1502, the 50 g/L Aikesa fertilizer treatment increased Mortierella abundance by 15.96% and decreased Lophotrichus by 73.6% compared to the no-fertilizer control. The ACE and Shannon diversity indices increased by 10.00% and 9.92%, respectively, while the Simpson index decreased by 12.17%. Soil health was also markedly improved, with pH decreasing by 7.47%, salinity by 2.95%, and substantial increases in organic matter (57.94%), available nitrogen (75.78%), available phosphorus (13.20%), and available potassium (52.97%). In conclusion, the 50 g/L Aikesa fertilizer treatment effectively improved the rhizosphere fungal community structure and significantly enhanced soil physicochemical properties under saline–alkali stress. These findings provide a theoretical foundation and practical guidance for utilizing microbial fertilizers in ecological restoration and sustainable agricultural development of saline–alkali lands.

Phosphorus (P) deficiencies are widespread in calcareous soils. The poor availability of nitrogen (N) and P in soils often restricts crop growth. However, the effects of P addition on plant growth and plant nutrient transport changes during the establishment of Leymus chinensis fields in Xinjiang are not clear. We investigated the responses of Leymus chinensis biomass and nutrient absorption and utilization to changes in soil N and P by adding P (0, 15.3, 30.6, and 45.9 kg ha^-1 year^-1) with basally applied N fertilizer (150 kg ha^-1 year^-1). The results showed that (a) Principal component analysis (PCA) of biomass, nutrient accumulation, soil available P, and soil available N during the different periods of Leymus chinensis growth showed that their cumulative contributions during the jointing and harvest periods reached 95.4% and 88%, respectively. (b) Phosphorus use efficiency (PUE) increased with the increase of P fertilizer gradient and then decreased and the maximum PUE was 13.14% under P2 treatment. The accumulation of biomass and nutrients in Leymus chinensis can be effectively improved by the addition of P fertilizer at P₂. Different P additions either moderately promoted or excessively inhibited Leymus chinensis growth and nutrient utilization.