Abstract:【Objective】 This study aims to analyze the physicochemical properties of two natural humus-modified materials (M1 and M2) produced by different processing methods, compare the differences between the two materials, and investigate their effects at different concentrations on the growth of maize under drip irrigation conditions. The goal is to explore the most suitable application concentration and amount of humus under drip irrigation and provide new perspectives and practical bases for agricultural production. 【Method】 The content of humus and its components in M1 (natural humus sand grinding fluid) and M2 (fully water-soluble potassium nitrohumate) was determined and the physical and chemical properties of the materials were analyzed through elemental analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR). Then, field experiments were designed to evaluate the effects of applying different concentrations (0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0 g·L–1) and amounts (650, 1 300, 1 950 L·hm–2) of M1 and M2 on the height, biomass, and yield of maize. 【Result】 The results showed that: 1) There were significant differences in chemical composition between M1 and M2. M1 had a higher content of humus, larger molecular weight, more complex structure, and stronger stability in soil. On the other hand, M2 had a lower total content of humus, a high content of fulvic acid (FA), a smaller molecular weight, and a lower degree of humification. 2) The microstructure of M1 and M2 differed. M1 had a rough and complex particle surface with uneven particle size while M2 exhibited a smoother and looser sponge-like appearance with no chaotic structure on the particle surface. FTIR analysis showed that M1 may contain more aromatic structures or carboxylate salts and silicate impurities while M2 may contain more carboxyl groups. 3) Although the application of M1 and M2 had little effect on plant height, it significantly increased the biomass and yield of maize. Especially for M2, when its concentration was 1.0 g·L–1 and the amount was 1 300 or 1 950 L·hm–2, the biomass of maize plants increased significantly by 40.11% and 40.74% and the yield increased significantly by 25.75% and 27.45%, respectively. 【Conclusion】 The application of different concentrations and amounts of M1 and M2 effectively promoted the growth of maize, with M2 exhibiting greater growth potential under the same conditions. This may be attributed to the role of humus in improving soil structure, increasing and retaining soil moisture and nutrient content, activating specific biochemical pathways, and enhancing soil microbial activity, thereby improving the nutrient absorption efficiency and photosynthetic capacity of maize plants. Considering factors such as cost, it is recommended to apply M2 at a concentration of 1.0 g·L–1 and an amount of 1 300 L·hm–2 in the field to fully exploit its effects in promoting maize growth potential and increasing yield. This provides new perspectives and practical bases for the efficient utilization of humus in agriculture.

Abstract:【Objective】 Bentonite, as is widely used in industry and agriculture, has become an research hotspot in material science agricultural science and environmental science. Montmorillonite is the main mineral component of bentonite, and its content and unique mineralogical properties determine the economic and application values of bentonite. Bentonite ore is found widely distributed in Jiangsu Province. From the perspective of the current development and utilization of bentonite in China, the mineral is mined at a local small-scale to make low-level processing products. It is necessary to study how to further exploit the mineral resource. In this paper, based on the researches reported, the bentonites in South Jiangsu were chosen for analysis of their mineralogical properties, in an attempt to provide certain scientific basis for further development and reasonable utilization of the mineral. 【Method】To comprehensively explore mineralogical properties of the mineral, bentonite samples were collected from eight major bentonite mines in South Jiangsu and analyzed for pH, mineral composition, chemical composition, particle size distribution, cation exchange capacity and cation composition. 【Result】Results show that the natural bentonites in South Jiangsu tend to be high in pH, with an average being about 8.83 and are mainly composed of montmorillonite and a certain amount of associated minerals, which vary in type and content with origin of the samples. X-ray deflection analysis shows that the 8 samples are all calcium-based bentonites. Their chemical composition and cation composition varies somewhat in line with their metallogenic environments. Generally their CECs tend to be low. In the samples, CEC is found to be closely and positively related to the content of montmorillonite. All the findings in this study on physicochemical and mineralogical properties of the bentonite in South Jiangsu demonstrate that it has a good prospect in exploiting the resource.【Conclusion】The natural bentonites in South Jiangsu are all of the calcium-based type, and composed mainly of montmorillonite and certain associated minerals, which vary slightly with the origin of the samples. The samples also vary slightly in chemical composition due to their difference in metallogenic environment. The samples are generally basic in pH, which is mainly attributed to derivation of the mineral from its parent rock under an alkaline environment. The natural bentonite in South Jiangsu is generally low in cation exchange capacity, which is related to the content of montmorillonite in bentonite. The relationship is positive and significant. The content of montmorillonite decreases with increasing particle size, and montmorillonite exists mainly in particles <50 μm in size.

Abstract:With the aid of GIS(Geographical Information System),remote sensing technology,and the SWAT(Soil and Water Assessment Tool) model developed by the ARS(Agricultural Research Service) of the USDA(United States Department of Agriculture),relevant parameters essent ial to the SWAT model were extracted from Lianshui Basin,Xingguo County,Jiangxi Province,and computer simulation of chemical composition of the runoff in the study area was carried out,Twelve typical subbasins varying sharply in simulation value from 1993 to 2000 were selected for analysis of relationship between land use and simulated chemical composition,using the land use maps of the two time periods.Results show that land use was closely related to translocation rates of organic N,organic P,nitrate N,Soluble P and Mineral P.The findings of the study can be used as technical aid and basis for sustainable development of the agriculture,comprehensive administration and programming of the basin,and realization of agricultural BMPs(Best Management Practices).

Abstract:Authors systematically collected 147 samples(at last constituting 100 samples for analysis) of Malan Loess in Loess Plateau and 54 elements were analysed for each sample.Abundance of each element was calculated by means of weighted average method.The results showed that chemical compositions of loess were very similar to each other in all parts of Loess Plateau with a good characteristic of homogenity.Moreover,the average chemical compositions of loess were very close to Clark values of crust,which are used at present.Therefore,the average chemical compositions of loess may be used to represent average chemical constituents of comtinetal upper crust.From theoritical point of view,typical eolian loess has a very large area of material sources and was also mixed homogeneously.Consequently,using it to calculate Clark values of upper cmst should be more reasonable,more representative and more substantial than previous methods.it could be a new way for investigation of Clark values of crust and a new field of loess geochemistry study in future.