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1. chinaXiv:202205.00116 [pdf]

基于通径分析的低营养水体环境中芽孢杆菌生长与氮转化影响因素研究

黄海洪; 李朝云; 类延菊; 邹万生; 杨品红; 武孟祥
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Fisheries

[目的] 芽孢杆菌在养殖水体等低营养水环境中氮的转化治理方面具有较高的应用价值,但受很多因素的影响,其中又数菌株特性和环境条件较为重要,然而目前对这两种因素的综合研究尚少,基于通径分析的低营养水体环境中芽孢杆菌生长与氮转化影响因素进行分析研究。

[方法] 为此,选取2株芽孢杆菌NT9和YB3作为研究对象,通过平板法测定其水解酶活性和抑菌活性等特性,然后模拟配置了4种低营养水体环境,并应用通径分析方法研究菌株特性和环境条件对芽孢杆菌生长和氮转化作用的影响,如直接效应、间接效应和综合效应等。

[结果] 结果显示,菌株NT9为枯草芽孢杆菌(Bacullis subtilis),与蜡样芽孢杆菌(B. cereus)YB3不同,具有较强的蛋白酶、淀粉酶活性以及抑菌活性,而纤维素酶活性较弱。同时又与菌株YB3相似,在低营养条件下菌株NT9也仅具有有机氮和氨氮降解作用,其中氨氮降解率可达89.3%。通径分析显示,模型的决定系数为0.55-0.95,其它主要的适配度指标也均符合判定标准。菌株的纤维素酶活性(cel)对大多数环境中菌株的生长(gro)以及有机氮、氨氮的降解(dtan)均具有显著的直接促进效应(P<0.001)。水体起始的菌量(iod)、有机氮含量(ion)、氨氮含量(itann)以及时间阶段(stage)等环境因素对grodtan也具有显著的直接影响(P<0.05),但仅限于某些特定的环境。菌株活性与环境因素之间也具有交互作用(P<0.05),对grodtan产生间接效应,增强或抵消直接效应,使某些因素表现出显著的总效应(P<0.05),但也导致其它因素的总效应不显著(P>0.05)。grodtan在某些环境中相互之间也具有直接的促进效应(P<0.001),并且也相互间接影响。研究表明,菌株特性和环境因素的综合作用对低营养水体中芽孢杆菌的生长和氮转化作用具有重要影响,但是在不同的环境中作用的方式不同。

[结论] 因此,在实际应用中,可能需要结合菌株特性和环境条件拟定具体方案,如菌株、氮源的投加量和投加方式等,以达到更好的使用效果。

submitted time 2022-05-18 Hits92Downloads46 Comment 0

2. chinaXiv:202205.00115 [pdf]

淡化条件下生物絮团技术对凡纳滨对虾生长与水质的影响.pdf

黄海洪; 李朝云; 类延菊; 邹万生; 杨品红; 武孟祥
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Fisheries

[目的]为研究淡化条件下生物絮团技术对凡纳滨对虾成虾养殖的影响。

[方法]在5‰盐度条件下,应用200L水体进行普通养殖(对照组)与生物絮团养殖(BFT组),放养密度90尾/m3,并测定两种养殖方式对虾生长指标与水质指标,以及分析养殖经济效益和污染物减排效果。

[结果]结果显示,经过63d的养殖,BFT组对虾成活率(100%)和生产力(1.32 kg/m3)显著高于对照组(P<0.05),同时的对虾平均体重(13.20±1.64 g)、特定生长速率(4.26±0.20%/d)和饵料系数(1.09±0.14)等也均优于对照(P>0.05)。

[结论]研究表明,淡化条件下采用BFT养殖凡纳滨对虾能够保持良好的水质,提高成活率,促进生长,降低饵料系数。

submitted time 2022-05-18 Hits101Downloads45 Comment 0

3. chinaXiv:202205.00108 [pdf]

芽孢杆菌特性对养殖水体氮转化作用的影响

黄海洪; 李朝云; 类延菊; 邹万生; 杨品红; 武孟祥
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Fisheries

[目的]研究养殖条件下菌株特性及水体环境对芽孢杆菌氮转化作用的影响。

[方法] 测定了2株芽孢杆菌NT9和YB3的水解酶活性、抑菌活性和生长能力等特性,并对模拟养殖过程中的氮转化作用进行了通径分析。

[结果] 结果显示,菌株NT9属于枯草芽孢杆菌(Bacullis subtilis),在低营养条件下也具有氨氮转化功能,去除率达89.3%,与菌株YB3相比,具有较强的蛋白酶、淀粉酶活性以及抑菌活性,但是生长能力较差。在模拟养殖水体中,2株菌对硝酸氮、亚硝酸氮、溶解氧、pH、碱度等水质条件影响不大,均能够促进有机氮降解,但氨氮转化效果较差,导致水体氨氮显著积累(P< 0.05)。通径分析显示,水体总菌量(cfu)是促进有机氮降解的主要因素,通径系数(直接作用)0.550(P< 0.01),菌株的纤维素酶活性(cel)和生长能力(gro)等都通过cfu对有机氮降解产生较大的间接作用;而微生物的生长增殖活动(总菌增量,dcfu)则是促进氨氮转化的主要因素,通径系数为-0.112(P< 0.01)。

[结论] 研究表明,2株芽孢杆菌在养殖条件下均能够促进饲料蛋白的降解,但是氨氮转化效果不明显,根据通径分析结果,可以通过促进芽孢杆菌生长,对同步转化氨氮进行研究。

submitted time 2022-05-17 Hits157Downloads66 Comment 0

4. chinaXiv:202205.00022 [pdf]

Effects of mixed-based biochar on water infiltration and evaporation in aeolian sand soil

ZOU Yiping; ZHANG Shuyue; SHI Ziyue; ZHOU Huixin; ZHENG Haowei; HU Jiahui; MEI Jing; BAI Lu; JIA Jianli
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

Abstract: Aeolian sandy soil in mining areas exhibits intense evaporation and poor water retention capacity. This study was designed to find a suitable biochar application method to improve soil water infiltration and minimize soil water evaporation for aeolian sand soil. Using the indoor soil column method, we studied the effects of three application patterns (A (0–20 cm was a mixed sample of mixed-based biochar and soil), B (0–10 cm was a mixed sample of mixed-based biochar and soil and 10–20 cm was soil), and C (0–10 cm was soil and 10–20 cm was a mixed sample of mixed-based biochar and soil)), four application amounts (0% (control, CK), 1%, 2%, and 4% of mixed-based biochar in dry soil), and two particle sizes (0.05–0.25 mm (S1) and <0.05 mm (S2)) of mixed-based biochar on water infiltration and evaporation of aeolian sandy soil. We separately used five infiltration models (the Philip, Kostiakov, Horton, USDA-NRCS (United States Department of Agriculture-Natural Resources Conservation Service), and Kostiakov-Lewis models) to fit cumulative infiltration and time. Compared with CK, the application of mixed-based biochar significantly reduced cumulative soil water infiltration. Under application patterns A, B, and C, the higher the application amount and the finer the particle size were, the lower the migration speed of the wetting front. With the same application amount, cumulative soil water infiltration under application pattern A was the lowest. Taking infiltration for 10 min as an example, the reductions of cumulative soil water infiltration under the treatments of A2%(S2), A4%(S1), A4%(S2), A1%(S1), C2%(S1), and B1%(S1) were higher than 30%, which met the requirements of loess soil hydraulic parameters suitable for plant growth. The five infiltration models well fitted the effects of the treatments of application pattern C and S1 particle size (R2>0.980), but the R2 values of the Horton model exceeded 0.990 for all treatments (except for the treatment B2%(S2)). Compared with CK, all other treatments reduced cumulative soil water infiltration, except for B4%(S2). With the same application amount, cumulative soil water evaporation difference between application patterns A and B was small. Treatments of application pattern C and S1 particle size caused a larger reduction in cumulative soil water evaporation. The reductions in cumulative soil water evaporation under the treatments of C4%(S1), C4%(S2), C2%(S1), and C2%(S2) were over 15.00%. Therefore, applying 2% of mixed-based biochar with S1 particle size to the underlying layer (10–20 cm) could improve soil water infiltration while minimizing soil water evaporation. Moreover, application pattern was the main factor affecting soil water infiltration and evaporation. Further, there were interactions among the three influencing factors in the infiltration process (application amount×particle size with the most important interaction), while there were no interactions among them in the evaporation process. The results of this study could contribute to the rational application of mixed-based biochar in aeolian sandy soil and the resource utilization of urban and agricultural wastes in mining areas.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits383Downloads50 Comment 0

5. chinaXiv:202205.00023 [pdf]

Impact of rainfed and irrigated agriculture systems on soil carbon stock under different climate scenarios in the semi-arid region of Brazil

André L CARVALHO; Renato A ARA?JO-NETO; Guilherme B LYRA; Carlos E P CERRI; Stoécio M F MAIA
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture

Abstract: Understanding the dynamics of soil organic carbon (SOC) is of fundamental importance in land use and management, whether in the current researches or in future scenarios of agriculture systems considering climate change. In order to evaluate SOC stock of the three districts (Delmiro Gouveia, Pariconha, and Inhapi districts) in the semi-arid region of Brazil in rainfed and irrigated agriculture systems under different climate scenarios using the Century model, we obtained RCP4.5 and RCP8.5 climate scenarios derived from the Eta Regional Climate Model (Eta-HadGEM2-ES and Eta-MIROC5) from the National Institute for Space Research, and then input the data of bulk density, pH, soil texture, maximum temperature, minimum temperature, and rainfall into the soil and climate files of the Century model. The results of this study showed that the Eta-HadGEM2-ES model was effective in estimating air temperature in the future period. In rainfed agriculture system, SOC stock under the baseline scenario was lower than that under RCP4.5 and RCP8.5 climate scenarios, while in irrigated agriculture system, SOC stock in the almost all climate scenarios (RCP4.5 and RCP8.5) and models (Eta-HadGEM2-ES and Eta-MIROC5) will increase by 2100. The results of this study will help producers in the semi-arid region of Brazil adopt specific agriculture systems aimed at mitigating greenhouse gas emissions.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits106Downloads53 Comment 0

6. chinaXiv:202205.00037 [pdf]

Soil carbon mineralization as affected by water content and nitrogen rate after ryegrass incorporated into soil

Meijuan Lu; Jiancheng Xu; Xiaowei Wang; Wenting Yang
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Agronomy

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.

submitted time 2022-05-08 Hits86Downloads46 Comment 0

7. chinaXiv:202203.00074 [pdf]

Variation of soil physical-chemical characteristics in salt-affected soil in the Qarhan Salt Lake, Qaidam Basin

HUI Rong; TAN Huijuan; LI Xinrong; WANG bingyao
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

Soil salinization has adverse effects on the soil physical-chemical characteristics. However, little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas. Here, we selected five sampling sites (S1, S2, S3, S4, and S5) alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations, soil physical-chemical characteristics, and environmental variables in April 2019. The results indicated that most sites had strongly saline and very strongly saline conditions. The main salt ions present in the soil were Na+, K+, and Cl–. Soil nutrients and soil microbial biomass (SMB) were significantly affected by the salinity (P<0.05). Moreover, soil salt ions (Na+, K+, Ca2+, Mg2+, Cl–, CO32–, SO42–, and HCO3–) were positively correlated with electrical conductivity (EC) and soil water content (SWC), but negatively related to altitude and soil depth. Unlike soil salt ions, soil nutrients and SMB were positively correlated with altitude, but negatively related to EC and SWC. Moreover, soil nutrients and SMB were negatively correlated with soil salt ions. In conclusion, soil nutrients and SMB were mainly influenced by salinity, and were related to altitude, soil depth, and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment. These results imply that the soil quality (mainly evaluated by soil physical-chemical characteristics) is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake. Our results provide an accurate prediction of how the soil salt ions, soil nutrients, and SMB respond to the changes along a salt gradient. The underlying mechanisms controlling the soil salt ion distribution, soil nutrients, and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.

submitted time 2022-03-24 Cooperative journals:《Journal of Arid Land》 Hits355Downloads210 Comment 0

8. chinaXiv:202203.00037 [pdf]

Integrating multiple electromagnetic data to map spatiotemporal variability of soil salinity in Kairouan region, Central Tunisia

Besma ZARAI; Christian WALTER; Didier MICHOT; Jean P MONTOROI; Mohamed HACHICHA
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions, which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it. Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil. To develop suitable management strategies for salty soil reclamation, it is essential to improve soil salinity assessment process/mechanism and to adopt new approaches and techniques. This study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in Kairouan region in Central Tunisia, taking into account the thickness of soil materials. Two electromagnetic conductivity meters (EM38 and EM31) were used to measure the electrical conductivity of saturated soil-paste extract (ECe) and apparent electrical conductivity (ECa). Multiple linear regression was established between ECe and ECa, and it was revealed that ECa-EM38 is optimal for ECe prediction in the surface soils. Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally. Variation in salinity at the soil surface was greater than that at a depth. These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity, thus improving the efficiency of soil management.

submitted time 2022-03-15 Cooperative journals:《Journal of Arid Land》 Hits1201Downloads255 Comment 0

9. chinaXiv:202202.00026 [pdf]

努尔苏丹樟子松人工林土壤粒度组成特征研究

娄泊远
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

为了揭示努尔苏丹不同林龄樟子松人工林对土壤粒度组成的影响,通过野外采样与室内分析相结合,分析了努尔苏丹周边不同林龄樟子松人工林土壤粒度与分形维数特征,研究了分形维数与土壤特性之间的关系。结果表明:(1)研究区土壤粒度组成以粉粒为主,砂粒次之,黏粒最少, 樟子松人工林的种植能够显著提升土壤表层细颗粒物质含量。不同林龄人工林深层土壤颗粒量差异不显著。种植樟子松人工林对土壤粒度的影响主要在表层区域。(2)土壤分形维数变化在 2.059~2.569之间,在人工林生长过程中分形维数呈现先增大后减小的趋势,并在种植年限为15 a 时达到最大。土壤分形维数与黏粒、粉粒具有正相关性,20 μm粒径是反映研究区人工林土壤分形维数的临界粒径。(3)研究区土壤分形维数与土壤有机质、全氮含量呈极显著正相关关系,土壤分形维数可以用来评价土壤的养分状况。研究结果可以为努尔苏丹人工林建设和生态恢复提供理
论依据。

submitted time 2022-02-11 Cooperative journals:《干旱区地理》 Hits872Downloads172 Comment 0

10. chinaXiv:202109.00035 [pdf]

亚寒带荒漠草原不同树种人工林土壤生态化学计量特征

娄泊远
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

为了阐明亚寒带荒漠草原不同树种人工林间土壤养分含量及生态化学计量特征的差异,通过野外调查与室内分析相结合的方法,在哈萨克斯坦首都努尔苏丹选取种植白桦、樟子松、梣叶槭3种不同树种,林龄为11 a的亚寒带荒漠草原人工林为研究对象,以裸地为对照,对其土壤养分含量及其生态化学计量特征进行了分析。结果表明:(1)土壤养分含量受树种的影响,但不同树种间生态化学计量特征差异不显著。(2)种植人工林后,不同树种人工林土壤有机碳与全氮含量均显著增加,针叶林与阔叶林土壤表层有机C、全N含量差异显著。(3)土壤C、N、P含量呈极显著正相关关系,C含量是C:N、C:P的控制因子,N含量是N:P的控制因子。研究区种植人工林后,虽然土壤养分含量显著增加,但是总体含量仍小于全球平均水平,当地土壤养分仍处于匮乏状态。N是该地区养分循环和植物生长的限制性因素,在人工林生长过程中适当施用氮肥,可加快人工林生长和生态恢复进程。本研究可为哈萨克斯坦首都努尔苏丹的人工林建设和持续经营管理提供科学依据。

submitted time 2021-09-14 Cooperative journals:《干旱区研究》 Hits1302Downloads386 Comment 0

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