Cover crops are an interesting option for designing biodiversity-based cropping systems and moving toward agroecological systems. However, the influence of different biodiversity-based cropping systems on the cover crop biomass, nitrogen and carbon storage and soil nutrient is still unclear. In this four-year field experiments, two cropping systems (sweet corn monocropping+ryegrass, MC; sweet corn-soybean intercropping+ryegrass, CS) and three nitrogen rates for sweet corn (N0, 0 kg N ha- 1, N1, 150 kg N ha- 1, N2, 300 kg N ha- 1) were designed to investigate the effects of different cropping systems and N rates of the preceding crops (sweet corn) on biomass production, carbon and nitrogen accumulation of ryegrass and soil nutrients. The results indicated that the cumulative dry matter yields of ryegrass were significantly higher in the preceding intercropping system than that in the preceding monocropping system under N2. However, the preceding intercropping system suppressed the ryegrass biomass production under N0 and N1. Compared to N0, N2 increased ryegrass yield and carbon accumulation across all four years in both cropping systems (CS and MC), with the exception of the MC in 2021. Additionally, N2 increased ryegrass N accumulation across all four years in both cropping systems. However, N2 reduced the C/N ratio across all four years in the CS. Moreover, under N2, the soil nitrate was reduced in CS compared to MC in 2021 and 2022. The preceding intercropping had a significant negative correlation between soil nitrate-N and biomass, carbon and nitrogen accumulation of ryegrass under N2. In MC, ryegrass biomass, carbon and nitrogen accumulation, and C/N ratio were positive correlated with soil Olsen phosphorus with N application increasing, but had a contrary result in CS. In conclusion, the preceding cropping system and nitrogen rate for the preceding crop could affect the biomass production, and carbon and nitrogen accumulation of cover crop (ryegrass). Therefore, in order to increasing the biomass of cover crop and reducing soil residual nitrogen loss, the reasonable preceding cropping system and nitrogen application should be considered.

[Objective]This study aims to determine the suitable sowing date for the cultivation of ordinary maize in red soil dryland of Jiangxi Province.[Method]The experimental materials used in this study were Zhengdan 958 and Xianyu 335 maize varieties.The sowing date treatments were set between May and July in 2021 and 2022.The study investigated the changes of maize yield and its contributing factors under different sowing date.The aim of this study was to provide theoretical reference for high-yield maize cultivation in Jiangxi Province.[Result]The adjustment of the sowing date significantly impacted the growth process,pre-and post-silking material accumulation,and the final yield of maize.Planting maize in early May yielded the highest(5529.99 kg/hm2),with a downward trend observed with delayed sowing dates.Ear grain number emerged as the primary factor influencing production with changes in sowing dates.Furthermore,grain weight was notably affected by adjustments in the sowing date and exhibited a significant positive correlation with grain weight during the maximum grain filling rate.In terms of hybrid comparison,Zhengdan 958 showed a higher overall yield than that of Xianyu 335.[Conclusion]In order to achieve a higher yield in common maize cultivation in the red soil dryland of Jiangxi,it is recommended to select suitable varieties and sow them before early/mid-May,while ensuring that it does not interfere with the cultivation of winter crops such as rapeseed.

Catalysts created by loading FeOx and AgOx on SBA-15 surfaces via wet impregnation were used to remove toluene with the assistance of non-thermal plasma (NTP). The catalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and H2 temperature-programmed reduction (H2-TPR). The results showed that incorporating the SBA-15, 3

Their unique layered structure, large specific surface area, good stability, high negative charge density between layers, and customizable composition give layered double hydroxides (LDHs) excellent adsorption and detection performance for heavy metal ions (HMIs). However, their easy aggregation and low electrical conductivity limit the practical application of untreated LDHs. In this work, a ternary MgZnFe-LDHs engineered porous biochar (MgZnFe-LDHs/PBC) heterojunction was proposed as a sensing and adsorption material for the effective detection and removal of Cd2+ from wastewater. The growth of MgZnFe-LDHs in the PBC pores not only reduces the accumulation of MgZnFe-LDHs, but also improves the electrical conductivity of the composite. The synergistic effect between MgZnFe-LDHs and PBC enables the composite to achieve a maximum adsorption capacity of up to 293.4 mg/g for Cd2+ in wastewater. Meanwhile, the MgZnFe-LDHs/PBC-based electrochemical sensor shows excellent detection performance for Cd2+, presenting a wide linear range (0.01 ng/L–1 mg/L), low detection limit (3.0 pg/L), good selectivity, and stability. The results indicate that MgZnFe-LDHs/PBC would be a potential material for detecting and removing Cd2+ from wastewater.

Catalytic oxidation technology is one of the most widely used for VOCs elimination because of its scientific and industrial applications. In this study, MnO 2 nanotube and a series of Fe dopped-MnO 2 nano-material(0.6% Fe-MnO 2 , 1% Fe-MnO 2, and 5% Fe-MnO 2 ) were prepared via a hydrothermal method, and these nano-materials utilized for the 2 053 mg/m~3 toluene elimination in the flow of dry air at the condition of different temperatures. The morphology and the structural properties of nano-materials were characterized by scanning electron microscope（SEM）, X-ray diffraction（XRD）, N 2 gas adsorption-desorption, and Raman spectroscopy. The characterization results indicate that the Fe ions can enter the skeleton structure of the MnO 2 nanotube, rather than exist on the surface of the MnO 2 nanotube as FeO x particles. But the Fe ions doping does not affect the MnO 2 nanotube morphology and crystal. The morphologies of these catalysts are still nanotube and α-MnO 2 crystals are also presented. While the specific surface area, pore-volume, and the most probable pore size of the nano-materials significantly reduced after the Fe doping, and that decreased with the increase of Fe doping. For the series of Fe dopped-MnO 2 nano-materials, their catalytic conversion activity for toluene increased with the temperature rise. The temperature of 100 % toluene conversion followed the sequence: MnO 2 ,1% Fe-MnO 2 （225 ℃）＜0.6% Fe-MnO 2 （235 ℃）＜5% Fe-MnO 2 （245 ℃）. In addition, the temperature of T 90 with the 1% Fe-MnO 2 shows lower than MnO 2 nanotube, and the CO 2 selectivity also follows the same sequence. This demonstrates that the 1%Fe-MnO 2 nanotube has the best catalytic performance for toluene. For these reasons, it may be ascribed to the fact that the chemical environment of Mn—O and the bond energy between Mn—O change over the 1% Fe dopped MnO 2 catalyst, resulting in the generation of lattice defect, promoting the formation of oxygen vacancy, which improves the catalytic activity of 1% Fe-MnO 2 catalyst.

生物多样性是生态防控杂草的重要措施之一.本研究通过两年(2019-2020年)田间定位试验,对春季和秋季甜玉米苗期、孕穗期和收获期田间杂草的种类及密度进行了监测,探讨不同种植模式(甜玉米-大豆,CS;甜玉米单作,MC;大豆单作,MS)和施氮水平(0 kg·hm-2,N0;150 kg·hm-2,N1;300 kg·hm-2,N2)对田间杂草种群和群落结构的影响.结果表明:两年共收集杂草15科34种.马唐(Digitaria sanguinalis)是所有处理中的优势种,在不同种植模式中占所有杂草密度的34.60％～54.95％.稗草(Echinochloa crusgalli)在CSN0中是优势种,占比24.52％.马松子(Melochia corchorifolia)在MCN1中是优势种,占比13.96％.狗尾草(Setaria viridis)在CSN1、MCN0和MCN2处理下为优势种,占比为11.26％、13.76％和17.27％.牛筋草(Eleusine indica)在CSN2、MCN1和MCN2处理下为优势种,占比为10.72％、10.81％和16.40％.相比不施氮,施氮降低了2019年春季CS及春季和秋季MC模式下杂草平均密度.多因素方差分析表明,甜玉米生育期对两年的杂草平均密度、2020年种类数、2019年密度-种类指数及2020年Simpson指数、Shannon指数和丰富度指数有显著影响;施氮显著影响了2019年的杂草密度-种类指数.去趋势排序分析表明,杂草群落组成的变化与甜玉米生长季节及生育期密切相关,而种植模式及施氮对杂草群落组成的影响规律不一致.综合来看,施氮降低了甜玉米田间杂草密度,间作种植能够部分抑制作物苗期杂草丰富度,施氮条件下的甜玉米间作大豆种植模式有利于防控杂草.

Corn (Zea mays L.)–soybean (Glycine max (L.) Merr.) intercropping is one of the main traditional intercropping systems used. We hypothesized that sweet corn–soybean intercropping with reduced nitrogen application could improve the crops’ fresh grain yield and nitrogen acquisition. We clarified whether sweet corn intercropped with soybean has the advantages of improved crop yield and carbon and nitrogen accumulation and assessed interspecific competition in the intercropping systems. A four-year (2017–2020) field experiment was conducted with three nitrogen application levels (0, 150, and 300 kg∙ha−1) and three planting patterns (monocropped sweet corn, monocropped soybean, sweet corn–soybean intercropping) at Jiangxi Agricultural University, Nanchang, China. The LER (land equivalent ratio), AG (aggressivity), and CR (competitive ratio) were calculated using the fresh grain yield and nitrogen and carbon accumulation of sweet corn and soybean. The LER values were greater than 1.0 in most of the intercropped patterns, except for the value based on the crops’ fresh grain yield without nitrogen application in 2020. Sweet corn had greater values of CR and AG than soybean in the intercropping system. Compared with common nitrogen application (300 kg∙ha−1), reduced nitrogen application (150 kg∙ha−1) did not significantly reduce the LER or the average CR and AG values. Under reduced nitrogen application, the values of LER, CR, and AG, based on the crops’ fresh grain yield and nitrogen acquisition, were not significantly different between the four years. In conclusion, based on the LER, CR, and AG, sweet corn–soybean intercropping had the advantage of crop yield and nitrogen acquisition, and sweet corn was the superior competitor. Sweet corn–soybean intercropping with nitrogen application (150 kg N ha−1) showed good inter-annual stability of crop productivity and competitiveness of the sweet corn.

Antimony (Sb) is a serious toxic and non-essential metalloid for animals, humans, and plants. The rapid increase in anthropogenic inputs from mining and industrial activities, vehicle emissions, and shoot activity increased the Sb concentration in the environment, which has become a serious concern across the globe. Hence, remediation of Sb-contaminated soils needs serious attention to provide safe and healthy foods to humans. Different techniques, including biochar (BC), compost, manures, plant additives, phyto-hormones, nano-particles (NPs), organic acids (OA), silicon (Si), microbial remediation techniques, and phytoremediation are being used globally to remediate the Sb polluted soils. In the present review, we described sources of soil Sb pollution, the environmental impact of antimony pollution, the multi-faceted nature of antimony pollution, recent progress in remediation techniques, and recommendations for the remediation of soil Sb-pollution. We also discussed the success stories and potential of different practices to remediate Sb-polluted soils. In particular, we discussed the various mechanisms, including bio-sorption, bio-accumulation, complexation, and electrostatic attraction, that can reduce the toxicity of Sb by converting Sb-V into Sb-III. Additionally, we also identified the research gaps that need to be filled in future studies. Therefore, the current review will help to develop appropriate and innovative strategies to limit Sb bioavailability and toxicity and sustainably manage Sb polluted soils hence reducing the toxic effects of Sb on the environment and human health.

为探讨种植模式和施氮水平对甜玉米(Zea mays L.var.Rugosa Bonaf.)和大豆[Glycine max(L.)Merr.]产量和农艺性状的影响,于2017-2021年连续5年在江西农业大学农业科技园开展大田定位试验,设置3个施氮量(N0,0 kg·hm-2;N1,150 kg·hm-2;N2,300 kg.hm-2)和3种种植模式(MC,甜玉米单作;MS,大豆单作;CS,甜玉米间作大豆),分别在甜玉米和大豆的成熟期测定产量和农艺性状.结果表明,5年施氮(N1和N2)都显著增加了甜玉米鲜穗产量,但N1和N2处理间5年都无显著差异.相同施氮下间作较单作模式下的甜玉米鲜穗产量5年都无显著差异.随着种植年份的增加,不施氮的间作模式下甜玉米鲜穗产量在2020和2021年较2017年显著降低.甜玉米间作大豆模式中,甜玉米施氮(N1和N2)对大豆鲜荚产量5年都无显著影响.施氮显著增加了甜玉米株高、茎粗和穗位高.相对N2,N1仅在2017和2020年分别显著降低了单作甜玉米的茎粗和间作甜玉米的穗位高.5年数据相关性分析表明,间作模式下的甜玉米鲜穗产量与株高相关性更强,单作模式下的甜玉米鲜穗产量与茎粗相关性更强.大豆鲜荚产量主要与单株总荚数、多荚数和单荚数呈显著正相关.综合来看,施氮能显著改善甜玉米间作大豆种植模式中的甜玉米鲜穗产量和农艺性状.过量施氮(300 kg·hm-2)未显著增加甜玉米鲜穗和大豆鲜荚产量.从节约成本和保护农田环境考虑,施氮量为150 kg·hm-2的甜玉米间作大豆种植模式有利于甜玉米和大豆的可持续发展.本研究结果为进一步优化甜玉米间作大豆种植模式提供了理论依据.

Crop rotation has widely contributed to increasing farmland biodiversity as well as to improving soil carbon pools and microbial diversity. However, there is a weak understanding of the suitability of winter crop rotation intensification in double rice fields, especially rotation with various winter crops. For this task, a long-term field experiment based on one from 2012 was conducted with five winter crop systems for double rice: winter fallow (T0), winter milk vetch (T1), winter rape (T2), winter garlic (T3), winter rotation intensification with potato, milk vetch, and rape (T4). Parameters such as crop yield, soil carbon, nitrogen, and soil microorganism were measured. It was found that compared to winter fallow, winter milk vetch, rape, garlic, and crop rotation intensification practices increased the late rice yield by 2.5%, 2.3%, 4.5%, and 3.7%, respectively; winter garlic and crop rotation intensification also increased the early rice yield by 4.6% and 3.5%, respectively. This is associated with the promotion of rice tillering. At the same time, for winter crop rotation, compared to winter fallow, the soil organic carbon increased by 21%. With the input of diversified crop residues, winter crops were effective in soil carbon sequestration, improving soil microbial structure, and increasing soil microbial diversity. The Shannon diversity index of winter crops ranged from 9.75 to 9.91, while winter fallow was 9.38. The Simpson's diversity index of winter crops ranged from 0.997 to 0.998, while winter fallow was 0.996. In conclusion, winter crop practices, especially winter crop rotation intensification, can enhance soil health and sustainability in double rice fields through its positive feedback on crop yield, soil carbon sequestration, and microorganisms.

In order to explore the effects of biochar and cropping systems on soil copper (Cu) speciation and copper accumulation in sweet corn (Zea mays L. var. Rugosa Bonaf.) and soybean (Glycine max (L.) Merr.), three ratios of biochar (C0, 0%, C1, 2%, C2, 5% by mass ratio, (w/w)) and three cropping systems (monocropped sweet corn, MC; monocropped soybean, MS; sweet corn–soybean intercropping, CS) were studied under three Cu levels (Cu0, 0 mg·kg−1, Cu1, 200 mg·kg−1, and Cu2, 400 mg·kg−1) in a pot experiment. The following results were obtained: (1) Compared with C0, adding biochar (C1, C2) could significantly reduce the Cu concentration in sweet corn, and C2 significantly reduced the Cu concentration in soybean under Cu1 and Cu2; the Cu concentrations in sweet corn and soybeans under Cu1 were lower than 10 mg·kg−1. (2) Compared with MC or MS, C2 significantly reduced the Cu concentration (below the detection limit) in sweet corn and the Cu concentration (1.65 mg·kg−1) in soybean straw in CS under Cu1. The Cu concentration in sweet corn ears and soybean straw in CS under Cu2 also decreased significantly, reaching 1.84 and 10.36 mg·kg−1, respectively. (3) Compared with C0, C2 significantly reduced the soil acid-soluble Cu concentration under Cu1 and Cu2, but significantly increased soil oxidated Cu concentration. (4) Compared with MC, the concentration of soil acid-soluble Cu was significantly decreased in CSC1 under Cu2. Under Cu1, the concentrations of reducible Cu were significantly increased in CSC1 and CSC2, and the oxidizable Cu concentration was increased in CSC2. In conclusion, sweet corn–soybean intercropping combined with biochar 5% (w/w) is beneficial to reducing the concentration of acid-soluble Cu, and increases the concentration of oxidizable Cu in copper-contaminated soil. Under Cu1 (200 mg·kg−1), the Cu concentrations in sweet corn and soybean were lower than 10 mg·kg−1, which meets the national food safety standard of China. Under Cu2 (400 mg·kg−1), the Cu concentration in sweet corn was lower than 10 mg·kg−1, but it was higher than 10 mg·kg−1 in soybean.

Agricultural soils are major sources of greenhouse gases (GHGs) that related with intensive fertilizer input. Biochar is widely used to mitigate GHGs, which may interact with soil water content impacting GHG emissions. Camellia oleifera fruit shell (FS) and spent mushroom substrate (MS) are ideal biochar feedstocks. However, the impact of water content and biochar on soil GHG emissions has not been thoroughly understood. Here, we examined CH4 and N2O emissions from C. oleifera plantation soils as affected by biochar (derived from MS or FS, 1 g 25 g(-1) soil), water content (60%, 120%, 240% or 360% water holding capacity, WHC), and fertilization (control or chicken manure, CM 2.5 g 25 g(-1) soil). We determined the abundance of related microbial functional genes to obtain the underlining mechanisms. The results showed that higher N2O emissions occurred in soils with 120%WHC, due to increased abundance of AOA, AOB and nirS. MS or FS biochar differed in their effects on soil GHG emissions with different WHC. MS biochar was higher in pH, C/N and specific surface area, and mitigated more N2O emissions from soils with CM and 120%WHC relative to FS biochar (by 92.9% and 34.6%, respec-tively). MS biochar significantly decreased abundance of nitrification related functional genes (AOA, AOB) in soils with 120%WHC and CM, which explained the decrease in N2O emissions. However, MS biochar increased cumulative CH4 emissions from flooded soils via increase in mcrA abundance. Thereby, biochar feedstocks should be considered in CH4 and N2O mitigations from soils with different water contents.

Intercropping plays an indispensable role in sustainable agriculture. The response of bandwidth row ratio configuration to crop interspecific relationships and land productivity in the maize–soybean intercropping system (MSI) is still unclear. A 2-year field experiment was conducted with sole maize (SM) and sole soybean (SS), two different bandwidths (2.4 m (B1), 2.8 m (B2)), two different maize and soybean row ratios (2:3 (R1), and 2:4 (R2)) for MSI. The results showed that intercropping had advantages for land productivity compared with sole planting. Intercropping cropping had significant differences on crop yield under different intercropping treatments. The 2-yr average land equivalent ratio (LER, 1.59) and group yield under the intercropping patterns of B1R2 were significantly higher than other intercropping treatments (p < 0.05). With a bandwidth of 2.4 m and planting four rows of intercropped soybean, the total LER and group yield increased by 7.57% and 10.42%, respectively, compared to planting three rows of soybean. Intercropped maize was the dominant species and also had a higher nutrient aggressivity than intercropped soybean. The complementarity effect was higher than the select effect in the MSI system, and intercropping advantage was mainly derived from the complementarity effect, which was significantly correlated with intercropped maize yield. Nitrogen and phosphorus nutrient aggressivity in intercropped maize showed significant correlations with group yield and intercropped maize yield. In conclusion, bandwidth 2.4 m, row ratio 2:4 was a reasonable planting pattern because of its superior land productivity, crop nutrients uptake advantage, and harmonious interspecific relationship, which could provide a reference for MSI promotion and application research.

Cover crop has been widely contributed to increasing farmland biodiversity, as well as to improving soil carbon pools and microbial diversity. However, a weak understanding is what cover crop in the double rice field, especially rotation with various cover crops, is suitable for this task. A long-term field experiment from 2012 was conducted with five cover crop systems based on double rice: winter fallow (T0), winter milk vetch (T1), winter rape (T2), winter garlic (T3), winter rotation with potato, milk vetch and rape (T4). Parameters such as crop yield, soil carbon, nitrogen, and soil microorganism were measured. It was found that, compared to winter fallow, winter milk vetch, rape, garlic and crop rotation practice increased the late rice yield by 2.5%, 2.3%, 4.5% and 3.7%, and winter garlic and crop rotation also increased the early rice yield by 4.6% and 3.5%, which is associated with promoting rice tillering. At the same time, cover crop rotation, compared to winter fallow, the soil organic carbon increased by 21%. With the input of diversified crop residues, winter cover crops are effective in soil carbon sequestration and contribute to improving soil microbial structure and increasing soil microbial diversity. Shannon diversity index of winter cover crops ranged from 9.75 to 9.91, while winter fallow was 9.38. Simpson diversity index of winter cover crops ranged from 0.997 to 0.998, while winter fallow was 0.996. In conclusion, winter cover crop practices, especially winter cover crop rotation, can largely keep soil healthy and sustainable of double rice field through its positive plant-soil feedback in crop yield, soil carbon and microorganism.

Planting cover crop has been suggested as a way of increasing soil organic carbon in agricultural land. Ryegrass (Lolium multiflorum L.), as a cover crop, could improve soil fertility and lower soil CO2 emission. However, effects of soil water content and nitrogen on soil carbon mineralization after ryegrass incorporation are not fully understood. The present study was to investigate the effect of soil water content and nitrogen rate on soil carbon mineralization after ryegrass incorporated into upland red soil (Ferralsols). A laboratory experiment was established, including soil water contents [15% (W1), 30% (W2), 45% (W3)] and nitrogen rates [0 (N1), 60 mg/kg(N2), 120 mg/kg(N3)]. The results showed that the highest soil carbon mineralization accumulation was observed in W3N3. Nitrogen application inhibited carbon mineralization rate and accumulation in the late stage of ryegrass incorporation at W1, but increased carbon mineralization rate and accumulation at W2. With increasing soil water content, nitrogen application could improve soil carbon mineralization at the early stage of ryegrass incorporation. In conclusion, soil nitrogen and water content could regulate soil carbon mineralization. Considering to reduce the soil CO2 emissions, rational nitrogen application should be taken seriously during cover crop (ryegrass) incorporated into the upland red soil.

MnOx was one of the important catalysts for the degradation of organic compounds. MnO2 with different morphology (nanotube, nanowire, nanocubic and nanoflower) were synthesized by hydrothermal method using KMnO4 and MnSO4 as precursors. Firstly, their structures were studied by X-ray diffraction (XRD), N2 adsorption desorption curve, H2 temperature programmed reduction (H2-TPR) and X-ray electron spectroscopy (XPS). Next, their catalytic conversion test for toluene was carried out under the condition of toluene concentration of 500 ppm and gas flow rate of 200 mL min–1. The results showed that the crystal structure of nanotube and nanowire were α-MnO2, nanoflower was α-MnO2 phase and other crystalline, the nanocube was β-MnO2. For the different morphology MnO2, their catalytic conversion activity for toluene were increased with the rise of temperature. Nanotube, nanowire, nanoflower and nanocube reached 100% toluene conversion at 225°C, 250°C, 275°C and 325°C, respectively. MnO2 nanotube showed the highest activity for toluene among all the samples, which attribute to the larger specific surface area, better low-temperature reduction performance and higher the Mn4+ content.

为探讨不同氮肥种类和油菜秆还田对水稻苗期碳氮累积的影响,设置了氮肥种类(尿素、碳酸氢铵和硫酸铵)和秸秆还田的双因素的盆栽试验,测定了移栽后水稻苗期碳氮累积量和碳氮比.结果表明,相比施用尿素,硫酸铵显著提高了水稻地上部氮素累积量,显著降低了不添加油菜秸秆条件下的水稻地上部和根碳氮比.添加油菜秆条件下,施用硫酸铵较尿素显著提高了播后57 d时水稻地上部和根部碳素累积量.相比不添加油菜秆,油菜秆还田显著抑制了播后57 d时水稻地上部和根氮吸收累积,显著增加了播后71 d时水稻根部氮碳素累积和57 d时碳酸氢铵和硫酸铵处理下的水稻地上部和根部碳氮比.综合来看,稻油轮作系统中油菜秆还田时配施硫酸铵能更好的促进水稻苗期碳氮的吸收累积.研究结果为南方稻油轮作系统中氮素养分管理提供了一定的技术支持.

Herein, MnMgFe-layered double hydroxides/biochar (MnMgFe-LDHs/BC) composite was fabricated by immobilizing MnMgFe-LDHs on BC via the coprecipitation method, which was employed as an effective material for the detection and removal of Cd2+ from aqueous media. A lamellar structure of MnMgFe-LDHs with abundant surface-hydroxyl groups and various interlayer anions inside present a greater chance of trapping Cd2+. Meanwhile, the conductive BC with a porous structure provides numerous channels for the adsorption of Cd2+. Using the MnMgFe-LDHs/BC-based sensor, Cd2+ can be detected with a low limit of detection down to 0.03 ng/L. The feasibility of detecting Cd2+ in paddy water was also carried out, with satisfactory recoveries ranging from 97.3 to 102.3%. In addition, the MnMgFe-LDHs/BC material as an adsorbent was applied to remove Cd2+ from water with adsorption capacity of 118 mg/g, and the removal efficiency can reach 91%. These results suggest that the as-prepared MnMgFe-LDHs/BC can serve as a favorable platform for efficient determination and removal of Cd2+ in water.

长江中游地区是我国重要的水稻生产基地,为全国粮食安全和生态系统安全健康作出了重要贡献.科学合理评估稻田生态系统服务功能价值,可为其服务功能价值演变、改善和推广稻田绿色可持续发展模式提供重要依据.本文在梳理稻田生态系统服务功能内涵和服务功能价值评估体系、方法的基础上,对评估长江中游地区不同稻田生态系统服务功能的方法进行了分类对比,并归纳总结了该区稻田生态系统服务功能价值评估研究框架和研究思路.因稻田类型、稻区分布区域和价值评估指标体系不同,各稻田生态系统服务功能价值评估的方法和单位面积服务功能价值量存在一定差异,认为未来研究需要不断完善不同稻田生态系统服务功能价值评估指标体系,改进评估方法,提高评估准确性;同时本文还对长江中游地区部分稻田的服务功能进行了分析,发现研究主要集中在稻田微观试验和省市县区域宏观测算2个维度上,对稻田生态系统某一部分服务功能或系统整体服务功能价值进行了静态评估,而对其价值评估的长期动态跟踪研究不足,对稻田生态系统服务功能净价值研究也有待于进一步深入.

为探讨油菜秆还田和施用不同种类氮肥对水稻生育前期土壤养分的影响,设置油菜秸秆还田(还田、不还田)和氮肥种类(尿素、碳酸氢铵、硫酸铵)两因素的盆栽试验,测定油菜秆翻压后15、29、43、57、71 d时水稻生长过程中的土壤养分指标.结果表明,相比施用尿素,碳酸氢铵、硫酸铵处理下的土壤pH值在油菜秆翻压15 d时(水稻移栽日)明显降低.施用硫酸铵有利于油菜秆翻压15～43 d时保持较高的土壤全氮、碱解氮、铵态氮含量,但降低了土壤硝态氮含量.相比不添加油菜秆,添加油菜秆有利于提高土壤有机质和速效钾含量,还有利于保持57、71 d时硫酸铵处理下的土壤全氮和硝态氮含量.综合来看,添加油菜秆可以改善土壤肥力;与施用尿素、碳酸氢铵相比,施用硫酸铵更有利于维持土壤氮素养分含量.