Clay minerals are the main cementing substances for sandy soils to form aggregates. The clay mineral attapulgite clay is abundant in Northwest China, and its special colloidal properties and crystal structure make it excellent in improving soil physicochemical properties. Using attapulgite as soil conditioner, the effects of different application rates of attapulgite on the formation and stability of sandy soil aggregates were studied through field experiments for two consecutive years. The results showed that the application of 6000 kg·hm⁻² attapulgite soil in sandy soil farmland for two consecutive years reduced the soil bulk density by 0–20 cm, from 1.55 g·cm⁻³ to 1.47 g·cm⁻³, a decrease of 3.6%; the soil pH was increased by 3.7% from 8.59 to 8.84. The soil organic carbon, inorganic carbon and total nitrogen in the whole soil increased by 4.52%, 5.23% and 6.22%, respectively. The mass fraction of macro-aggregates of 2–0.25 mm and micro-aggregates of 0.25–0.053 mm as well as the contents of organic carbon, inorganic carbon and total nitrogen increased by 3.5%, 5.2%, 8.7%, 5.6% and 6.7%, respectively, thus improving the stability of aggregates. However, low application rates (1500 kg·hm⁻² and 3000 kg·hm⁻²) of attapulgite had no significant effect on soil physical and chemical properties. Attapulgite, as a kind of highly adsorptive clay mineral, can be directly applied to sandy soil to increase soil cementitious substances, promote the formation of soil aggregates and increase the carbon and nitrogen fixation capacity of sandy soil. The improvement effect on the formation and stability of aggregates will gradually accumulate with the years of application. Therefore, in the future, the effects of adding attapulgite on the growth of various crops under various types of soil and climatic conditions should be carried out to obtain more systematic conclusions.

Industrial agglomeration in a region changes the economic structure, strategic layout and resource status of a city, and has an important impact on sustainable economic development. The relationship between industrial agglomeration, air pollution and economic sustainability is a key issue concerning the high-quality development of national economy. China is a developing country that once experienced severe air pollution. Now, the Chinese government is aiming to achieve the goal of sustainable and high-quality economic development in China. In this paper, a spatial Dubin model was developed to study the relationship between industry, environment and the economy. The statistical analysis used the air pollutant data of 273 prefecture-level cities in China from 2015 to 2018. The results showed that: (1) there was a positive U-shaped nonlinear relationship between industrial agglomeration and sustainable economic development, and there was a spatial spillover effect. (2) There was a positive U-shaped nonlinear relationship between air pollution and sustainable economic development, and there was a spatial spillover effect between them. (3) The effect of industrial agglomeration on sustainable economic development was influenced by air pollution, an intermediary variable. The existence of air pollution weakens the promoting effect of industrial agglomeration on sustainable economic development.

Exploring the impact of different tillage practices on soil moisture retention and crop yield in dryland winter wheat- spring maize rotation on the Loess Plateau is crucial for enhancing rainfall utilization and advancing tillage systems in arid agricultural regions. A long-term field experiment was conducted from 2019 to 2021 in the Weibei dryland area of the Loess Plateau to investigate the effects of conservation tillage. Continuous tillage (CC) was used as the control, with three alternative methods: no-tillage (NN), subsoiling (SS), and a combination of no-tillage and subsoiling (NS). The study assessed the impact of these tillage practices on soil water retention, bulk density, relative chlorophyll content, crop yield, and water use efficiency during both the fallow period and the growing seasons of winter wheat and spring maize. The results revealed the following: (1) All treatments effectively reduced soil bulk density in the 0–60 cm soil layer relative to pre-experiment levels and increased soil porosity. Among the treatments, NS was the most effective, reducing the average bulk density in the 0–60 cm layer by 0.1–0.2 g cm⁻³ and increasing porosity by 2.0-5.5% compared to the other treatments. (2) During the fallow period, tillage treatments significantly enhanced soil water content and storage compared to CC, with NN and NS treatments showing superior water retention effects. (3) In the winter wheat growing season, the average soil water content in the 0–200 cm layer for the NN, SS, and NS treatments was 4.8%, 5.4%, and 3.5% higher than that of CC, respectively. During the spring maize growing season, the increases were 49.3 mm, 17.7 mm, and 36.3 mm, respectively. All tillage treatments resulted in higher soil water storage in the 0–200 cm layer compared to CC, with NN being the most effective during the winter wheat season and SS during the spring maize season. (4) Compared to CC, all tillage treatments improved SPAD values, with NS showing the most significant effect. (5) All treatments increased the yields of both winter wheat and spring maize compared to the control, with increases of 5.4-10.0% for winter wheat and 7.3-18.7% for spring maize. Notably, NS significantly boosted crop yields. Water use efficiency improved by 1.2-6.0% for winter wheat and 5.5-31.3% for spring maize, with SS improving water use efficiency for winter wheat and NS for spring maize. In conclusion, the combination of no-tillage and subsoiling significantly improves soil quality, crop yield, and water use efficiency in the drylands of the Loess Plateau. This makes it a promising tillage practice for the sustainable development of dryland agriculture.

This study aimed at exploring the effects of γ-polyglutamic acid on the growth of desert alfalfa and the soil microorganisms in the rhizosphere. The study examined the effects of varying concentrations of γ-polyglutamic acid (0%-CK, 2%-G1, 4%-G2, 6%-G3) on sandy soil, the research investigated its impact on the growth characteristics of alfalfa, nutrient content in the rhizosphere soil, and the composition of bacterial communities. The results indicated that there were no significant differences in soil organic matter, total nitrogen, total phosphorus, total potassium, and available phosphorus content among the G1, G2, and G3 treatments. Compared to CK, the soil nutrient content in the G2 treatment increased by 14.81–186.67%, showing the highest enhancement. In terms of alfalfa growth, the G2 treatment demonstrated the best performance, significantly increasing plant height, chlorophyll content, above-ground biomass, and underground biomass by 54.91–154.84%. Compared to the CK treatment, the number of OTUs (operational taxonomic units) in the G1, G2, and G3 treatments increased by 14.54%, 8.27%, and 6.84%, respectively. The application of γ-polyglutamic acid altered the composition and structure of the bacterial community, with Actinobacteriota, Proteobacteria, Chloroflexi, Acidobacteriota, and Gemmatimonadota accounting for 84.14–87.89% of the total bacterial community. The G2 treatment significantly enhanced the diversity and evenness of soil bacteria in the rhizosphere. Redundancy analysis revealed that organic matter, total nitrogen, total potassium, moisture content, and pH were the primary factors influencing the structure of bacterial phyla. At the genus level, moisture content emerged as the most influential factor on the bacterial community. Notably, moisture content exhibited a strong positive correlation with Acidobacteriota, which in turn was positively associated with indicators of alfalfa growth. In summary, the application of γ-polyglutamic acid at a 4% ratio has the potential for improving sandy soil quality, promoting plant growth, and regulating the rhizosphere microbial community.

With the rapid development of industry, heavy metal pollution has seriously damaged the health of soil, and heavy metals spread through the food chain, posing a threat to human health. The firm existence of heavy metals in soil under earthy conditions is a center trouble faced by soil dense metal pollution solidification and correction technology. However, the existing investigation results are mostly controlled to soil passivation experiments using various materials. Macroscopically, heavy metal passivation materials have been selected, but the intrinsic mechanisms of different compound functional groups in soil passivation have been ignored. With the common heavy metal ion Pb²⁺ as an example, the stability of the combination of heavy metal ions and common ion groups in soil was analyzed in this study by using quantum chemical calculation as the theoretical guidance. The results show that SO₄²⁻ and PO₄³⁻, as functional groups of passivating agents, are used to control lead pollution and have been verified to have good effects. When the pollution is particularly serious and not easy to passivation and precipitation, Fe³⁺ can be considered to enhance the passivation effect.

The Mu Us Sandy Land is a region characterized by wind-blown sand and soil erosion in northern China. To enhance the soil quality of this area, various organic materials were incorporated into the mixed soil at a volume ratio of 1:2 for feldspathic sandstone to sand. Culture was conducted in the field and under constant temperature conditions in laboratory culture chambers. Four treatments were established in the experiment, each calculated based on weight ratio and controlled (with no organic material added, CK); single application of straw (5% straw, P1); single application of biochar (5% biochar, P2); combined application of biochar and straw (5% biochar + 5% straw, P3). After 90 days of culture, soil samples were collected for analysis of various indicators such as soil aggregate particle size distribution, water stability of soil aggregates, mean weight diameter, mean geometric diameter, and fractal dimension using dry sieving and wet sieving methods. The objective is to establish a scientific basis and provide technical support for addressing the challenges associated with compound soil and implementing rational fertilization measures. The research results indicate that: (1) The quantity of aggregates > 0.25 mm under different treatments follows the order CK < P1 < P2 < P3, and the differences between treatments are significant (P < 0.05); (2) Soil water stability, mean weight diameter (MWD), mean geometric diameter (GMD), and fractal dimension of soil aggregates in compound soil with different organic material additions are superior to the control, and the effect of biochar on improving soil aggregates is better than that of corn straw. The combined application of both significantly improves the effect compared to single applications. In both culture modes, under wet sieving, the P3 treatment shows the highest MWD and GMD of soil aggregates, with an increase ranging from 3.45% to 85% and 4.55% to 38.46%, respectively, compared to other treatments. (3) The trend of fractal dimension among treatments is consistent: P3 < P2 < P1 < CK, and the differences between treatments are significant (P < 0.05). Moreover, there is a good negative correlation linear equation relationship between the fractal dimension (y) and WR > 0.25 (x) of compound soil, with a correlation coefficient of up to 0.9851. In conclusion, the incorporation of organic materials can effectively enhance the proportion of macroaggregates in compound soil consisting of Feldspathic sandstone and sand, thereby improving soil stability and erosion resistance. The optimal outcome is achieved through the combined application of biochar and straw. Indoor culture proves to be more effective than field culture, while wet sieving accurately reflects the structural characteristics of compound soil under both dry and wet sieving treatments.