Large areas of arable lands in China have been contaminated by heavy metals, in which cadmium (Cd) contamination was the most prevalent. Cd accumulation in main food crops and leafy vegetables grown in Cd-contaminated fields has aroused considerable attention in recent years. The present study investigated the Cd pollution of farmland soils and vegetables in Qujing city of Yunnan Province, China. By comparing the Cd uptake capacities of different crops, this study aimed to provide guidance for agricultural production in Cd-contaminated farmland, and clarify the influence of Cd bioavailability in soil and chemical forms of Cd in plant roots on its migration. Results showed that soil Cd concentration was up to 37 mg kg⁻¹, which was 61-fold higher than the soil environmental quality standard in China. Concentration of Cd in 73% of the investigated vegetable samples, with the mean value of 5.43 mg Cd kg⁻¹ (dry weight basis), exceeded the food safety standard of China. Leafy vegetables had the highest bioaccumulation factors (BF) and transfer factors (TF), with the mean values of 0.53 and 0.41, respectively. Water spinach (Ipomoea aquatica Forsk.), cole (Brassica campestris L.), and fennel (Foeniculum dulce Mill.) had the highest Cd TFs, with averages of 0.67, 0.66, and 0.64, respectively. On the contrary, garlic (Allium sativum L.), onions (Allium fistulosum L.), and pea (Lathyrus odoratus L.) had the lowest Cd TFs, with averages of 0.04, 0.03, and 0.04, respectively. The main chemical fraction of Cd in garlic root was insoluble phosphate (35–48%), whereas in water spinach root, it was pectate, protein binding or sorbed fraction (50–64%), resulting in a higher TF value of water spinach than garlic. These results indicate that there were significant differences in Cd uptake and accumulation between vegetables, and the Cd accumulation in leafy vegetable was significantly higher than that in alliums. Therefore, it is possible to reduce the uptake and accumulation of Cd in crop edible parts by the selection of vegetable species with low Cd accumulation capacity. The chemical fractions of Cd in crop roots, especially the proportions of more mobile fractions, might be an important reason for the root-to-shoot Cd transport and Cd accumulation in the aerial portions.

The application amount of fertilizer is believed to dramatically influence soil bacteria in paddy fields, and soil bacteria critically affect soil enzyme activities and the growth of rice in paddy fields. Thus, providing a suitable amount of fertilization to ensure rice yields is an important issue in field management. In this study, four treatments were carried out in a paddy field, including control (fertilization methods commonly used by farmers in the past), IT + RF 10, IT + RF 20, and IT + RF 30 (integrated technology and 10%, 20%, and 30% reduction in nitrogen fertilizer, respectively). Soil samples were collected in two periods, the rice booting stage and the harvest period. High-throughput sequencing was used for analysis of soil bacterial diversity and community composition across different fertilizer treatments, and clarified the effects of different fertilizer treatments on soil enzyme activities and bacterial community composition. This study showed that a reduction in chemical fertilizer application has a certain impact on the soil pH, total nitrogen (TN), total phosphorus (TP), soil organic matter (SOM) value, and bacterial community of the rice planting system, and that the IT + RF 10 treatment was the best way to reduce fertilizer application, which can reduce nutrient loss in the paddy soil. The application of organic fertilizer partially replaces chemical fertilizer, which not only effectively stimulates soil enzyme activity, but also enriches bacterial groups that may participate in complex organic matter decomposition and soil nutrient mobilization.

Vegetable contamination by cadmium (Cd) is of great concern. Water spinach (Ipomoea aquatica) is a common leafy vegetable in many countries and has a strong ability to accumulate Cd. The work was conducted to study the effects of sound wave, water management, and their combination on Cd accumulation and growth of water spinach, using the following three experiments: a hydroponic trial with the treatment of a plant acoustic frequency technology (PAFT) generator in test sheds, a hydroponic trial with three music treatments (electronic music (EM), rock music (RM), and classical music (CM)) in artificial climate boxes, and a soil pot trial with treatments of PAFT and EM under non-flooded and flooded conditions. The results showed that the hydroponic treatments of PAFT and EM significantly reduced the Cd concentrations in roots and shoots (edible parts) of water spinach by 22.01–36.50% compared with the control, possibly due to sound waves decreasing the root tip number per unit area and increasing average root diameter, root surface area, and total root length. Sound wave treatments clearly enhanced water spinach biomass by 28.27–38.32% in the hydroponic experiments. In the soil experiment, the flooded treatment significantly reduced the Cd concentrations in roots and shoots by 43.75–63.75%, compared with the non-flooded treatment. The Cd decrease and the biomass increase were further driven by the PAFT supplement under the flooding condition, likely related to the alteration in root porosity, rates of radial oxygen loss, extractable soil Cd, soil Eh, and soil pH. Our results indicate that the co-application of plant acoustic frequency technology and flooded management may be an effective approach to reduce Cd accumulation in water spinach.

Soundscape is an important part and one of the main factors of the underground space environment. Field surveys were conducted to evaluate the soundscape of underground commercial spaces and to compare it with the soundscape of the above-ground commercial spaces between two cities (Lu’an City and Hefei City) in China, consequently presenting the construction strategy of the soundscape of underground commercial spaces in urban areas. The results showed that the sound in the shopping center, which people found comfortable, was at the lower to intermediate level. The main sounds that people perceived as “general” sounds were environmental sounds such as music, the humming of the air conditioning, people talking, walking, and the hawking of the stores. Nevertheless, “very comfortable” sounds were background music and the sound of live performances, which were indicated in the majority of people’s opinions on evaluating a comfortable feeling, thus reflecting the impact of the sound of mall music on people’s cognitive psychology. Therefore, it is necessary to control the volume of environmental noise at a certain level so that people’s health is not adversely affected. It also helps shoppers to feel more comfortable psychologically and physiologically.

The excessive use of pesticides and fertilizers reduces the quality of crops, harms human health, and causes environmental pollution, thus hindering the sustainable development of agriculture. In the process of realizing ecological agricultural production, audio control technology has increasingly become an area of concern. As a physical agricultural technology, it has become a combination of music acoustics and agricultural science. However, the research on the ecological role and function of audio control technology is still relatively lacking. In view of this, the authors studied the effects of audio control technology (specific frequency sound wave and different types of music) on the growth of lettuce, and showed that the specific frequency sound wave treatment produced by the plant acoustic frequency technology generator significantly increased the growth of lettuce compared with the condition of silent environment processing. Treatments of different types of music (electronic music, rock music, and classical music) promoted lettuce growth, especially the significant increase in the output of edible parts under the influence of electronic music. The research results further showed that the specific frequency sound wave treatment produced by the plant acoustic frequency technology generator enhanced the chlorophyll content of lettuce leaves (1.98 ± 0.15 mg/g), thus promoting photosynthesis. Different types of music had different effects on the photosynthesis of lettuce leaves; electronic music treatment increased the chlorophyll content of lettuce (1.48 ± 0.07 mg/g), and had the greatest impact.