To explore the growth differences among different green manure varieties and their effects on rice yield, nutrient accumulation and soil properties after turning over, the winter fallow field (CK) was used as the control, three common green manures (Astragalus sinicus L., Vicia villosa var. and Vicia sativa L.) were selected to conduct field experiments to analyze the differences in the characteristics of green manures during the growth period and their effects on rice yield, nutrient accumulation and soil properties after turning over. The results showed that the performance of plant height and biomass in the three types of green manure was as followed: Vicia villosa var. > Vicia sativa L. > Astragalus sinicus L., with Vicia villosa var. being the best and suitable for planting in the region. After turning over green manures, the rice yield significantly increased compared to CK, with the yield under Vicia villosa var. reached 10.47 t/hm², which was 58.88% higher than that of CK. Green manure turning over could improve the taste value and nutrient accumulation of rice. Compared with CK, the taste value of rice treated with Astragalus sinicus L., Vicia villosa var. and Vicia sativa L. increased by 5.58%, 9.46% and 11.16%, respectively, and total potassium accumulation in rice straw increased by 50.88%, 42.87% and 67.70%, respectively, the total nitrogen accumulation in rice grains increased by 17.25%, 45.62% and 47.74%, respectively and the total potassium accumulation in rice seeds increased by 17.96%, 54.28%, and 48.88%, respectively, the total phosphorus accumulation in rice shoots increased by 11.32%, 62.16% and 27.41%, respectively, the total accumulation of total potassium increased by 45.53%, 44.73% and 64.64%, respectively, with the best comprehensive effect being the Vicia villosa var. and Vicia sativa L.. Green manure could improve soil properties and had the potential to improve soil fertility. Among them, the treatment of Vicia sativa L. had a pH increase of 2.96%, organic matter increased by 10.05%, and total nitrogen content increased by 4.41% compared to CK. The treatment of Astragalus sinicus L. had an organic matter increase of 1.43%, total nitrogen content increase of 24.25%, total phosphorus content increase of 9.20%, and available phosphorus content increase of 10.95% compared to CK. In summary, the biomass and nutrient accumulation of Vicia villosa var. and Vicia sativa L. were both high, and their flipping could improve the yield, taste value and nutrient accumulation of rice. Therefore, they were recommended as green manure varieties for planting in this region; Astragalus sinicus L. and Vicia sativa L. had the potential to increase soil fertility through tillage, while Vicia sativa L. had a better effect. This study could provide a theoretical basis for the utilization of green manure and sustainable agricultural production in the northern Jiangsu region.

In order to mitigate the adverse effects of drought on the development of summer maize seedlings caused by climate change, using ‘Zhengdan 958’ as experimental material, the effects of different treatment combinations on soil moisture and growth of maize seedling were studied. The results showed that the soil moisture content increased with the depth of the soil layer, and the pattern was moist soil, wheat straw returning to the field>normal moisture content, wheat straw returning to the field>moist soil, wheat straw not returning to the field>dry soil, wheat straw returning to the field>normal moisture content, wheat straw not returning to the field>dry soil, wheat straw not returning to the field. SPAD value, photosynthetic rate and yield showed the same trend, normal moisture content, wheat straw returning to the field>moist soil, wheat straw returning to the field>moist soil, wheat straw not returning to the field>normal moisture content, wheat straw not returning to the field>dry soil, wheat straw returning to the field>dry soil, wheat straw not returning to the field. Therefore, compared with the removal of stubble, plain stubble can better improve the soil water environment, increase the emergence rate and photosynthetic rate of maize, and increase the yield, which can be widely applied in production.

To solve the problems of excessive application of chemical fertilizer, low crop nutrient utilization efficiency and high risks of non-point source pollution in rice production, the impacts of chemical fertilizer reduction combined with organic fertilizer on nutrient absorption, partial productivity of fertilizer, nutrient balance and rice yield were studied. The optimum management practices were identified in this study, which provided a theoretical basis for reducing fertilizer use, increasing use efficiency and improving soil fertility. A field experiment was carried out in the early rice growing season of western Guangdong in 2021. Four local recommended fertilization methods were tested, including optimized fertilization treatment (OPT), and reducing the rate of farmers’ conventional fertilizer application by 10%, 20% and 30% while applying organic fertilizer denote as OM1, OM2, and OM3 treatment, respectively. The results showed that the grain yield and grain-to-straw ratio varied from 5667-5967 kg/hm² and 1.09-1.31, respectively. The partial factor productivity of nitrogen (N), phosphorus (P) and potassium (K) fertilizer were 30.4-47.2, 96.0-122.1 and 47.2-105.9 kg/kg, respectively. The apparent balance of N, P and K were 54.2-115.3, 17.1-29.8 and 1.2-67.0 kg/hm², respectively. All of them were in a surplus state. In the treatments of organic fertilizer application, the rice grain yields, ratios of grain to stem, N, P, K fertilizer partial productivity, P absorption rate and K absorption rate increased along with the decrease of synthetic fertilizer application rate, while the apparent balance of N, P and K decreased. The straw K content and K partial factor productivity of each organic fertilizer substitution treatment were significantly higher than those of OPT treatment (P<0.05). Compared with farmers’ conventional fertilizer application, OPT, OM1, OM2 and OM3 treatments could maintain the paddy yield, and improve the ratio of grain to stem, the P content and K contents of grain and straw. Considering the ratio of grain to stem, P and K partial productivity, OM3 treatment was identified as optimum management practice. While considering the partial productivity of N fertilizer, N absorption rate, N surplus rate in soil and output-input ratio, OPT treatment was identified as optimum management practice.

Microbial exopolysaccharides have important characteristics such as renewability, biodegradability, strong adsorption, anti-inflammatory, antioxidant, and antiviral properties. They have multiple applications in fields of food, pharmaceuticals, cosmetics, and environmental protection. Previous studies mainly focused on the isolation, purification and structure of microbial exopolysaccharides, but there were few reports on the relationship between the structure and function of microbial exopolysaccharides and the role of exopolysaccharides in environmental protection. In order to elucidate the structure-function relationship of microbial exopolysaccharides and expand their applications, this article reviews the impacts of monosaccharide composition, molecular mass, functional groups, glycosidic linkages, and surface morphology on their functions. Furthermore, potential applications of microbial exopolysaccharides in wastewater treatment, soil remediation, and antibiotic elimination for environmental protection are summarized. Due to the low yield and biological activity of microbial exopolysaccharides, their extensive industrial application is limited. It is expected that the yield of microbial exopolysaccharides can be enhanced through genetic engineering techniques, structural modification, and optimization of fermentation conditions and promote their development and application in environmental protection.

To screen new introduced table grape varieties with saline-alkali tolerance, 10 grape varieties were used as materials to study the variation characteristics of physiological and biochemical indexes of grapes after 30 days of compound saline-alkali stress of different concentrations (0.29%, 0.58%, and 0.87% of the dry weight of pot soil). The correlation analysis of all indexes was carried out, and the principal component analysis was used to comprehensively evaluate the saline-alkali tolerance of the grape varieties. The results showed that with the increase of saline-alkali concentration, the root activity and leaf relative water content decreased gradually, the relative conductivity and the content of malondialdehyde and proline increased gradually, and the superoxide dismutase activity showed two trends of first increase then decrease or continuous increase. Correlation analysis showed that malondialdehyde content in leaves, malondialdehyde content in roots and proline content in leaves had extremely significantly and positively pairwise correlation. Superoxide dismutase activity in roots was significantly and negatively correlated with malondialdehyde content and superoxide dismutase activity in leaves. Three principal components with eigenvalues greater than 1 were extracted by principal component analysis, and the cumulative contribution rate was 77.99%. Finally, the order of saline-alkali tolerance of the 10 grape varieties from strong to weak was determined as ‘Zitianwuhe’, ‘Blackcrunchy Seedless’, ‘Hutai 8’, ‘Zaoxiawuhe’, ‘Silk Road Red Rose’, ‘Shine Muscat’, ‘Crimson Rose’, ‘Summer Black’, ‘Sweet Sapphire’, and ‘Wagamichi’.

By exploring the changes in the research field of fresh-eating corn in China, grasping the research status and hot topics, and discussing the research frontiers and development trends, the study aims to provide theoretical reference for the research of fresh-eating corn. The research team used 1588 fresh-eating corn research literature in the CNKI database from 2010 to 2021 as the research objects, and carried out visual quantitative analysis based on CiteSpace software. In the past 10 years, the research development in the field of fresh-eating corn was stable, and the number of core papers published per year remained above 100. The high-yield authors were represented by LU Weiping, LIU Chunquan, LI Dajing, LU Dalei, etc., presenting single-line or radial team cooperation. The institutions to which the authors belong were mainly agricultural colleges and universities and scientific research institutes. Agricultural colleges and universities achieved more significant results in terms of the number of publications, and scientific research institutes had more advantages in the research and development of new varieties, and scientific research institutions and universities had close team cooperation. The analysis of emerging words indicates that haploid, super sweet corn, seed germination, genetic diversity, nutritional quality, flavor, folic acid, soluble sugar, etc. are the research trends. The core task of future fresh-eating corn research will be expanding the research coverage, breaking through the traditional limitations, exploring gene editing technology, transgenic technology, gene sequencing, single-celled sequencing, genome, proteins, transcription and other cutting-edge biotechnologies which are auxiliary means for traditional fresh-eating corn breeding research, and the focus will be on sweet and waxy corn and super sweet corn research. The future research should also highlight the quality and nutrition of fresh-eating corn varieties, and improve their resistance to diseases and insects, lodging, drought and other stresses. In the fields of food processing and feed research, more attention should be paid to the technology development of new processing equipment for extending the harvesting period and storage period of fresh-eating corn and maintaining the nutrition of corn during storage.

Phosphorus in soil directly determines plant growth and crop yields, but phosphorus existing forms in soil are very complex, and those phosphorus forms that can be absorbed and utilized by plants account for only a small part of total phosphorus. Therefore, it is important to study the existing forms and classification methods of phosphorus in soil to improve the phosphorus use efficiency of crops, explore ways to enhance phosphorus availability, and reduce phosphorus loss. In this paper, the existing forms of phosphorus in soil, influencing factors of soil phosphorus availability and phosphorus classification methods were reviewed. The results show that the forms of phosphorus in soil consist of two major categories: inorganic phosphorus and organophosphorus, phosphorus absorbed by plants is mainly water soluble inorganic phosphorus, and other forms of phosphorus are difficult to be absorbed by plants, causing low utilization efficiency of phosphorus in soil. There are many factors that lead to low phosphorus use efficiency, mainly ions like calcium, iron and aluminum, and organic matter, pH, temperature, moisture etc. To study and improve the mechanism of the influencing factors could effectively enhance phosphorus utilization efficiency. At the same time, with the continuous improvement of phosphorus classification methods by domestic and foreign scholars, the effective forms of phosphorus have been studied more in-depth and accurately. Bowman-Cole organophosphorus classification method and Hedley’s phosphorus classification method are the two most widely used methods at present.