Shunjiang Li

Inversion tillage is recognized as an effective agronomic measure for mitigating cadmium contamination in agricultural soils. However, its ecological impacts in intensive greenhouse vegetable systems remain poorly understood. A field experiment was performed in a solar greenhouse in Beijing, China, to compare no tillage (CK) with inversion tillage at depths of 30 cm (F30) and 40 cm (F40). The results showed that inversion tillage significantly decreased total Cd (38.89-57.41%) and available Cd (43.90-65.85%) concentrations in the topsoil (0–20 cm), thereby reducing Cd accumulation in crop tissues by 10.87-60.42%. These reductions were primarily attributed to the redistribution of contaminated topsoil with significantly less polluted subsoil soil along the soil profile. Nevertheless, inversion tillage notably decreased soil organic carbon and total nitrogen concentrations in the topsoil, especially under the F40 treatment. Despite the decline in soil fertility, crop biomass and nutrient uptake exhibited no significant differences in the first year, owing to the sufficiently high initial soil nutrients level. At the phylum level, the dominant soil microbial communities remained stable, whereas moderate restructuring occurred at the genus level, indicating functional resilience of soil microbes to tillage disturbance. Furthermore, the abundances of several key taxa (e.g. decreased Microvirga , Planifilum , Subgroup_10 , Bryobacter , and increased Nitrospira ) changed, indicating adaptive responses to alleviated Cd stress and modified soil nutrient conditions. Overall, inversion tillage efficiently lowered the short-term Cd exposure risk in greenhouse soils but might impair soil fertility and organic carbon sequestration. Integrating inversion tillage with organic amendments is thus recommended to maintain food safety, soil nutrient availability and microbial ecological functions in Cd-contaminated agricultural soils.

To examine the safety of producing edible rapeseed in heavy-metal-contaminated farmland, field experiments were performed with 25 varieties of edible rapeseed on farmland lightly polluted with Cd in the central southern part of Hunan Province. Growing characteristics and Cd contents in rapeseed tissues were measured, and Cd uptake, translocation and removal potential were calculated. The results showed that the growth of 25 rapeseed varieties was not inhibited without withering or inconsistent changes in the shoot. The shoot and root Cd contents of rapeseed varieties ranged from 0.05 to 0.26 mg·kg⁻¹ and 0.04 to 0.26 mg·kg⁻¹, respectively. The bioaccumulation factor (BCF) showed that the shoot had a greater capacity for Cd transport than roots. The total Cd removed by rapeseed varieties ranged from 1.606 to 16.159 μg·plant⁻¹. There were significant differences in plant height, BCF of soil available Cd in the shoot, translocation factor (TCF) of Cd from root to shoot and Cd intake by rapeseed among the edible rapeseed varieties. Cluster analysis of Cd accumulation in the 25 rapeseed varieties indicated that Lvjin 1, Guanyou Qingjing and Guanyou brassica not only reduced soil pollution but also allowed for the production of safe leafy rapeseed, although Cd contents in the shoot of 25 rapeseed varieties did not exceed the national safety standards of China.

The utilization of crop straw resources has been highly emphasized by governments and academia in recent decades. The growing importance of straw decomposition in the wheat-maize rotation system and the remarkable diversity of accumulated information on this topic inspired us to quantitatively explore variations in the outcomes of individual studies. We conducted a data analysis of 46 experimental studies reporting the effects of agronomic measures on the straw decomposition rates of wheat (14 studies) and maize (38 studies). Statistical results showed that maize straw crushed and buried in soil with turn-over or rotary tillage can significantly increase straw decomposition rates. Further, with the increase in nitrogen input and straw burial depth in the soil, the maize straw decomposition rate increased significantly, while the amount of straw return showed the opposite trend. Among all agronomic measures in this research, burial depth has demonstrated a significant positive effect on the wheat straw decomposition rate. The random forest analysis identified decomposition time as the most important predictor of straw decomposition rates for wheat and maize. In addition, some agronomic measures and straw decomposition time jointly affect the decomposition rate of straw. In general, agronomic measures are effective factors in controlling straw decomposition in a wheat-maize rotation system.

Trace elements (Cu, Zn, Fe, Ca, Mg, Mn, Al, K, Ba, P, Sr, Cd, V, Cr, Ni, Pb and Co) concentrations in the drinking water of KBD-affected and non-affected areas were measured using ICP-AES. The RSD of this method was between 0.80% and 2.83%, and the analytical results of the reference samples were consistent with the certified values. The method was simple and accurate. The results indicated that there is an obvious difference in trace elements concentrations between KBD-affected areas and non-afffected areas. The results provided a scientific theoretical basis to improve the conditions of drinking water in KBD-affected areas in Tibet.