Background and aims: This research aimed to evaluate the effects of consecutive intercropping on soil phosphorus (P) partitioning, concentrations, and sensitivity to P fertilizer application, elucidating its impact on soil P bioavailability. Methods: A field experiment investigated soil P fractions and content under continuous wheat and faba bean intercropping. Three P levels (0, 45, and 90 kg P₂O₅ ha⁻¹ denoted as P0, P1, and P2, respectively) and three planting patterns (monocropped wheat (MW), monocropped faba bean (MF), and wheat and faba bean intercropping (W//F)) were established since 2014. Aboveground P uptake by wheat and faba bean was determined. The soil P fractions and content were analyzed after six-, seven-, and eight-year continuous field experiments. Results: Wheat and faba bean intercropping increased wheat aboveground P uptake by 28.3–42.7% compared to MW under P1 and P2 levels and presented a P uptake advantage (LER_Puptake > 1), although W//F had no impact on faba bean P uptake. Consequently, continuous intercropping for 8 years decreased soil available P reserves by 9.0–23.4% in comparison to the weighted average value of MW and MF (It). Faba bean consumed greater non-labile and labile P than wheat with low P input. W//F had nearly no impact on the labile P pool but reduced the non-labile P pool by 5.0–12.1% under all P levels and lowered the moderately labile P pool by 1.7–4.7% at P0 and P1 levels compared to It with consecutive intercropping for 8 years. Consecutive intercropping of wheat and faba bean primarily decreased the proportion of Resin-P in the labile P pool and the proportion of Residual-P in the non-labile P pool. According to the structural equation model, crop P uptake mainly originated from soil available P, which was directly affected by non-labile P (Residual-P and Conc. HCl-P). In addition, intercropping changed the contribution of each P faction to crop P uptake compared to MW and MF, and P uptake in intercropping primarily depended on Conc. HCl- P and Dil. HCl-P. Therefore, consecutive intercropping decreased soil non-labile P and drove soil available P depletion, and intercropping’s increase of P uptake was related to the non-labile P mobilized to moderately labile and labile P. Conclusions: Continuous wheat and faba bean intercropping reduced non-labile P and led to soil available P depletion under low P input. This practice stimulated non-labile P mobilization, enhancing soil P fraction effectiveness and facilitating P uptake in intercropping. Continuous intercropping of wheat and faba bean is as an effective method to maximize the biological availability of soil P and reduce P application rates.

Cereal and legume intercropping could improve cereal yield, but the role of intercropping in grain quality still lacks a full understanding. A two-year bi-factorial trial was conducted to investigate the role of two planting patterns (mono-cropped wheat (MW) and intercropped wheat+faba bean (IW)) and four nitrogen (N) fertilization levels (N0, no N fertilizer applied to both wheat and faba bean; N1, 90 and 45 kg N ha^–1 applied to wheat and faba bean; N2, 180 and 90 kg N ha^–1 applied to wheat and faba bean; N3, 270 and 135 kg N ha^–1 applied to wheat and faba bean), as well as their interaction on the productivity of wheat grain yield (GY) and quality. The results showed that intercropping increased both the yields of wheat grain protein and amino acids (AAs) relative to MW in both years. No difference in Aas content between IW and MW was found but the 9% grain protein content (GPC) of IW was higher than that of MW in 2020. By contrast, wheat gliadin content was increased by 8–14% when wheat was intercropped with faba bean in both years, and some AAs fractions including essential and non-essential AAs were increased under N0 and N1 levels but declined at the N3 level. This means that intercropping increased the grain quality either for protein and AAs content or for fractions. There was no negative relationship between GPC and GY in the present study, and intercropping tended to increase GPC with increasing GY. In conclusion, wheat and faba bean mainly affected GPC and fractions rather than AAs, and intercropping presented a potential to improve both wheat quality and yield concurrently. Modulated N rates benefitted the stimulation of intercropping advantages in terms of grain yield and quality in the southwest of China and similar regions.

The surrounding soil in mining areas generally suffers from severe pollution, characterized primarily by multi-metal contamination, and poses significant challenges in restoration and safe utilization. Therefore, it is urgent to explore low-cost restoration and safe utilization technologies that can achieve simultaneous treatment and utilization. This study selected a typical lead-zinc mining area in eastern Yunnan, China, where there is severe heavy metal pollution. It collected 15 common varieties of castor plants and systematically studied their absorption, accumulation, translocation, and removal characteristics of four heavy metal elements (Cd, Pb, Cu, Zn). The results showed that the heavy metal pollution in the mining area was extremely severe. Castor plants have a strong tolerance to heavy metal stress. There were significant differences in the absorption and accumulation of heavy metals among different castor varieties. The root parts mainly accumulated Pb, the stem parts mainly accumulated Cd, and the seeds had a higher ability to accumulate Cu. In terms of restoration potential, the Tong Castor No. 24, Fen Castor No. 10, and Zi Castor No. 3 plants had relatively large restoration potential. However, considering both biomass and heavy metal removal capacity, Dian Castor No, 2 Zi Castor No. 3, Dian Castor No. 5 plants were more ideal and could be applied in the restoration of heavy metal complex pollution soil in mining areas.

Addressing the environmental challenges posed by the massive stockpiling of phosphogypsum (PG) has become a global concern, highlighting the urgency of developing large-scale, low-cost and resource-efficient utilization approaches for PG. This study was conducted in the rocky desertification areas of southwestern China, where land and water resources are scarce. Two land creation techniques—layered reconstruction (GA) and integrated construction (GB)—were adopted with modified PG to systematically investigate their impacts on soil properties and potato growth, yield and quality. The results showed that both techniques significantly improved soil conditions and enhanced potato yield and quality, with each presenting distinct characteristics in soil improvement. Specifically, the GA technique showed relatively better performance in soil nutrient enrichment, while the GB technique was more conducive to enhancing soil enzyme activity. Compared with the local red soil control, both techniques reduced heavy metal accumulation in potato tubers; however, Pb and Cd contents still exceeded national food safety limits, indicating potential food safety risks. In summary, land creation using modified PG can effectively increase arable land area, improve soil quality in rocky desertification regions, and simultaneously promote potato yield and quality. Nevertheless, as the current results are based on a single-season field trial, they cannot reflect the long-term patterns of heavy metal migration and accumulation. Therefore, for large-scale application, it is necessary to strengthen the monitoring of heavy metal levels in imported soil and long-term regional environmental impacts so as to ensure the quality and safety of agricultural products from reclaimed land.