A pot experiment with rice cultivation was conducted to investigate the effects and mechanisms of liming materials（m（quicklime）：m（dolomite）：m（limestone）=1:3:6）combined with rice husk ash-derived silicon（Si）on arsenic（As）uptake by rice in acidic soils.Three treatments were designed including a control （CK）,root application of rice husk ash combined with foliarSispraying at critical growth stages（R-S）,and the combination of liming materials with R-S（L-R-S）.The results showed that compared with CK,the L-R-S treatment significantly increased the pore waterSiconcentration by 58.3% ,enhanced theAssequestration in the root surface iron plaque（DCB-As content）by 21.7%,and reduced theAscontent in white roots by 19.4%.Furthermore,the translocation ability ofAsfrom roots to above-ground tissues decreased,ultimately leading to a 19% reduction in the inorganic As（i As）content in milled rice.Fourier-transform infrared spectroscopy（FTIR）analysis revealed that liming materials promoted the attack of OH^- as a nucleophile toward the Si-O-Si bond,thus accelerating its cleavage followed by the formation of water-soluble silicic acid with increasing pH during flooding and thereby driving the efficient dissolution ofSifrom rice husk ash.The study demonstrates that the combined application of liming materials and rice husk ash effectively improve theSirelease efficiency of rice husk ash,and reduce the grainAsaccumulation by strengtheningAsretention in root surface iron plaque and competitively inhibitingAsuptake in roots. This strategy offers a practical approach for the safe production in acidic paddy soils.

This study aims to develop and optimize a novel biochar-based fertilizer composed of rice straw biochar loaded with potassium dihydrogen phosphate and urea solution,featuring high-performance nutrient slowrelease capability.Response surface methodology（RSM）was employed to optimize the fertilizer formulation for maximum nutrient loading at minimal cost.Fundamental physicochemical analyses and scanning electron microscope （SEM）images confirmed the successful attachment of phosphate and urea onto the porous structure of the biochar, significantly enhancing the nutrient loading capacity.The results of the pot experiment indicated that this fertilizer significantly increased the chlorophyll content in wheat.This study provides a reference for developing novel biochar-based fertilizers that combine yield-enhancing potential with reduced environmental risks.

To investigate the impact of large-scale citrus cultivation on nitrogen pollution in the catchment, this study selected the Baishe catchment in Nanfeng,Jiangxi as the research area.Water samples from ponds,tributaries,and main streams were collected across different dry and wet seasons.Utilizing nitrogen isotope source analysis,the spatial-temporal distribution and source composition of nitrogen pollution were revealed,with key nodes in nitrogen transport processes being identified in the catchment.Results showed that the mean TN concentrations were higher in dry season（1.75±1.47mg/L）than wet season(1.38±0.60mg/L). NO₃^--N concentrations were elevated during wet season（0.16~2.55mg/L）,whereas those of NH₄⁺-N were higher in dry season（0.05-3.76mg/L）.Nitrogen sources varied seasonally.In wet season,manure/sewage（38.2%）and nitrogen fertilizer（34.5%）domina-ted,followed by soil nitrogen（21.1%）.In dry season,manure/sewage（50.8%）accounted for the largest,with nitrogen fertilizer（26.6%）and soil nitrogen（18.0%）as secondary contributors.This study revealed that agricultural activities and hydrological connectivity severed as key driving forces for regulating the spatiotemporal differentiation of nitrogen.This led to the formation of critical nitrogen transport nodes during wet season,primarily located in downstream tributaries and pond systems near citrus orchards,where nitrogen sources were manure/sewage and nitrogen fertilizer.In contrast,paddy fields near the main stream were the most polluted nodes in dry season,with manure/sewage as the main nitrogen source.To mitigate the nitrogen pollution,corresponding nitrogen control strategies were proposed.Identification of the variation in nitrogen pollution processes provides a scientific basis for the development of large-scale orchards and the effective control of non-point source pollution in the catchment.

To analyze soil water storage and moisture retention effects of different soil textures and their impacts on crop yield,this study used field experiment data in 2023 and 2024 to examine the differences in soil bulk weight,soil porosity,saturated hydraulic conductivity,and field capacity of silty loam,silty sand,and sandy loam at soil depths of [0,20],(20,40],(40,60],(60,80],and (80,100]cm.The characteristics of soil water content,water storage,and water consumption in the 0-100cm soil layer were investigated to clarify the effects of these three soil types on maize yield and water use efficiency（WUE）.The results showed that the sandy loam had lower average soil bulk density and field water-holding capacity but higher soil porosity and saturated hydraulic conductivity in the 0-100cm soil layer as compared with the other two soil types.Over two years,the average water content and water storage in the 0-100cm soil layer decreased in the order of silty loam,silty sand,and sandy loam at maize seedling,jointing,and flowering stages.In addition,the three soil textures had no significant effect on the maize plant height,ear position,and leaf number（P>0.5）.However,compared with sandy loam,silty loam and silty sand treatments increased maize yield for two consecutive years,with silty loam and silty sand boosting yields by 24.9% and 13.6%,respectively,in 2023.The water use efficiency of the three soil textures over two years decreased in the order of silty loam,silty sand,and sandy loam.In conclusion,silty loam significantly outperformed silty sand and sandy loam in the soil water storage and moisture retention as well as the increment of maize yield.

To conduct ecological restoration on high-steep rocky slopes in western China,this study takes the Xiaowanzi Quarry in Pingliang city as an example to prove that the plant habitat reconstruction technology is feasible for the ecological restoration of such slopes in the region.Field surveys and sample tests show that the eco-geological indicators and their thresholds are as follows.（1）The rock mass fracture rate around approximately 2%;（2）The depth of planting holes is greater than or equal to 70 cm;（3）The habitat temperature ranging from 3 to 33°C; （4）The planting density of about 2 plants /m²;（5）The soil fertility indicators of organic matter 25mg/g,total salt content 1.0mg/g,alkaline nitrogen 60μ g/g,available phosphorus 15μ g/g,and available potassium 150μ g/g.These can serve as technical parameters for the greening restoration of rocky slopes in western China.