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Stable isotope technique is important for understanding the structure and function of soil food web, which is considered as a belowground black box. We reviewed typical application cases of stable isotope techniques in the research of soil food webs, including to determine food sources and feeding preferences of soil fauna by using isotopes, and to analyze the trophic structure of soil food webs through isotope fractionation effects during the process of feeding and nutrient sequestration by soil fauna. Additionally, stable isotope techniques could reveal the role of soil biota at different trophic levels within soil food web in ecosystem matter and energy flow, which favored to carry out accurate and efficient research on the contribution of soil food webs to soil carbon and nitrogen cycling process and the corresponding influence mechanism. We further put forward the limitations of current stable isotope techniques and the future development directions. [ABSTRACT FROM AUTHOR]

To understand the health status of aquatic ecosystem in Lake Erhai, the community structure of benthic animals was investigated based on 27 samples from 11 typical monitoring sections in March, June, September and December 2021, and the benthic index of biotic integrity (B-IBI) assessment system was also established. The results showed that Lake Erhai contains 56 genera and species of benthic animals, which refers to 4 phyla, 6 classes, 28 families and 54 genera. The assessment system of B-IBI for Lake Erhai consists mainly of the total number of classification units, proportion of chironomid individuals, and BMWP index, which obtained by range test, discriminatory power and Pearson correlation screen. The health status of aquatic ecosystem in Lake Erhai can divide into five grades according to ratio scoring method, i.e., >2.61, 2.10~2.61, 1.82~2.10, 1.42~1.82 and <1.42, representing health, sub-health, fair, poor and very poor health status, respectively. Based on above method and standard, the health of aquatic ecosystem for Lake Erhai in 2021 is fair status. Specifically, five, six, five, nine and two sampling sites were in health, sub-health, fair, poor and very poor health status, accounting for 18.5%, 22.2%, 18.5%, 33.3% and 7.4% of the total sites, respectively. [ABSTRACT FROM AUTHOR]

More and more projects in marine engineering use the inner spraying process to extend the service life of pipeline. At present, the application of pipeline inner wall spraying equipment in China is relatively mature, however, the shortage of data related to the moving speed of spraying equipment in the pipeline might cause some problems including uneven spraying and sagging defects. In this article, some sugesstions are presented accordingly with regard to the problems mentioned above. Experiments are made to examine the moving speed of spraying equipment in the pipeline and obtain the data which can be useful for improvement of the inner wall spraying process. [ABSTRACT FROM AUTHOR]

By using equal compartment agar method (ECAM), and through measuring the root length, shoot height, and root-and shoot dry weights of test ryegrass, this paper evaluated the allelopathic potentials of thirty-three wheat varieties with different origins in Northeast China against ryegrass. The results showed that different wheat varieties had significantly different allelopathic effects on ryegrass growth. With RI value as allelopathic index and through cluster analysis, these varieties could be divided into three groups, among which, four varieties (Longfu 9, Longfu 13, Jin 2003, and Xiaobing 33) were demonstrated to be obviously allelopathic, and inhibited the ryegrass growth strongly.

In this study, two kriging methods using an auxiliary variable, i. e., ordinary cokriging (OCK) and ordinary kriging combined with regression (OKR) were used for the interpolation of soil zinc (0.1 mol x L(-1) HCl extractable Zn) in a 17.6 hm2 field at the vicinity of a metal manufacturer in southern suburb of Shenyang, China. A total of 36 measured data of soil Zn content at the depth of 10 approximately 20 cm (subsoil Zn) was selected as target variable, 72 measured data at the depth of 0 approximately 10 cm (topsoil Zn) as auxiliary variable, while other 36 measured data of subsoil for validation. The two interpolation methods were evaluated for the suitability of estimating the spatial distribution of soil Zn by using an auxiliary variable. The results showed that OKR gave better results than OCK or ordinary kriging (OK). The theoretical model obtained from OKR exhibited higher coefficient of determination and lower residual sums of squares than that from OCK or OK. The prediction accuracy of soil Zn was increased by 4% with OKR than with OK. The map of soil Zn obtained with OKR was quite similar with that obtained with OK, by using 72 measured Zn data. However, no advantages were found between OCK and OK. It was suggested that OKR was an effective way to estimate the distribution of soil heavy metals by using auxiliary variables.

Wheat (Triticum aestivum) is the main food crop in the world, and plays an important role in agricultural production. In order to enhance wheat yield, herbicides and germicides were intensively applied and made negative effects on the environment. Wheat possesses allelopathic potential for weed suppression and disease control through the release of secondary metabolites from its living plants or residues, which could avoid the environment pollution brought by herbicides and germicides. This paper reviewed the research advances in wheat allelopathy. Hydroxamic acids and phenolic acids are the predominant allelochemicals frequently reported which could produce plant natural defense against weed, pest and disease. The allelopathic activity of allelochemicals is determined not only by the allelochemicals, but also by the factors of inheritance, environment and biology. The retention, transportation and transformation processes of allelochemicals, and the relationship between wheat allelopathy and soil biota and its mechanism were seldom studied and still needed to be researched profoundly. Utilizing wheat allelopathy in plant protection, environment protection and crop breeding would improve the stress-resistance, yield and quality of wheat in agricultural production.