多菌灵降解菌XJ-D的分离鉴定及特性研究

为了进行多菌灵污染土壤的生物修复,笔者从长期施用多菌灵农药的葡萄园中分离筛选得到1株多菌灵降解菌XJ-D,经Biolog微生物自动分析系统和16S rDNA序列比对,以及系统聚类分析等鉴定菌株XJ-D为红串红球菌（Rhodococcus erythropolis）。多菌灵降解菌XJ-D可利用多菌灵为唯一碳源、氮源进行生长,将其接种在600 mg/L多菌灵的无机盐培养基中,11天时多菌灵的降解率达99.0%,平均降解能力为52.87 mg/(L?d)。     

Soil Na+ concentration controls salt-affected soil organic matter components in Hetao region China

Purpose

There is little knowledge on the organic matter fractions of salt-affected soil aggregates. This study aimed at investigating characteristics of salt-affected soil organic carbon components and the relationships between soil salt concentration and soil organic carbon component content.

Materials and methods

Five typical salt-affected soils in Hetao region China were collected and analyzed for light (LF) and heavy fraction (HF) in different water-stable aggregates. And the soil organic carbon components were measured by Fourier transform infrared (FTIR) and pyrolysis-gas chromatography/mass spectrometer (Py–GC/MS).

Results and discussion

The results showed that the salt-affected soils were dominant in 53–10-μm water-stable aggregates, 61–80% in the bulk soil, and very low in >?250-μm macro-aggregates, less than 7.06% in the bulk soil. The proportions of >?250-μm macro-aggregates and the mean weight diameter (MWD) were negatively correlated to Na⁺ concentration (p?<?0.05). Furthermore, the macro-aggregates were generally higher in total organic carbon (TOC) and accordingly higher C/N ratio than those in micro-aggregates. Heavy fractions (HF) from both >?53 μm and <?53-μm soil aggregates accounted for 99.30–99.83% of the bulk soil and contained 89.6–98.5% lower TOC and accordingly 49.2–84.8% lower C/N ratio than those in light fractions (LF). The LFs were high in lignin (7.27–34.02% in total pyrolysis products, 19.89% on average) and alkane/alkene-derived compounds (9.51–37.21%, 23.18% on average), but low in N-containing compounds (0–3.64%, 1.71% on average), while HFs were high in both alkane/alkene (4.38–27.46%, 15.06% on average) and N-containing compounds (7.45–26.45%, 13.98% on average), but low in lignin-derived compounds (1.13–8.75%, 3.86% on average).

Conclusions

The tested salt-affected soils were predominant in 53–10-μm micro-aggregates, which was caused by the Na⁺ dispersion effect on soil aggregates. Most SOM was stored in HF that contained high N-containing compounds and low C/N ratios. Our results suggested that the components of SOM were mainly controlled by the soil Na⁺ concentration.

     

多菌灵降解菌XJ-D的分离鉴定及其特性研究(英文)

[目的]分离多菌灵降解菌XJ-D,并对其特性进行研究,以期用于多菌灵污染土壤的生物修复。[方法]从长期施用多菌灵农药的葡萄园中分离筛选1株多菌灵降解菌XJ-D,经Biolog微生物自动分析系统和16SrDNA聚类分析等对其进行鉴定。[结果]鉴定菌株XJ-D为红串红球菌(Rhodococcus erythropolis)。其可利用多菌灵为唯一碳源、氮源进行生长,将其接种在600mg/L多菌灵的无机盐培养基中,11天时多菌灵的降解率达99.0%,平均降解能力为52.87mg/(L·d)。[结论]该菌株在干旱区土壤农药污染修复方面具有较好的应用潜力和发展前景。     

燕麦与脱硫石膏对内蒙古河套地区盐渍化土壤肥力的影响

内蒙古河套地区土壤盐渍化格外严重,盐渍化土壤改良是农业生产及生态环境建设面临的主要问题。生物与化学技术结合是盐渍化土壤改良发展方向之一,为了探讨燕麦和施用脱硫石膏结合对本地区盐渍化土壤肥力的影响,采用田间试验方法,设置种植燕麦和施用脱硫石膏（30t／hm。）2个处理,在春季灌溉洗盐后采取土壤样品,在燕麦收获期采取植物和土壤样品,测定植物生物量和NPK含量,以及土壤pH、EC、盐分离子含量,有机质、全氮、有效氮磷钾等指标。结果表明：春季灌溉洗盐,能够大幅度降低土体各层土壤pH、EC和盐分离子含量,尤其是表层土壤降低的幅度更大,pH和EC分别降低了14％～17％和7％～69％。主要盐分离子Na‘和SO。。。分别降低了80％和39％,施用脱硫石膏对灌溉洗盐没有显著的影响。施用脱硫石膏对燕麦生长表现出一定的促进作用,但对其NPK营养有负面的影响。种植燕麦显著地降低了土壤盐分含量,但对土壤养分的影响比较小;同时施用脱硫石膏,对降低盐分没有显著的作用,但可提高有机质、有效氮磷钾含量,表现出一定的交互作用效应。     

8种耐盐植物与脱硫石膏对河套灌区盐碱土水稳定性团聚体的影响

为了探究种植不同耐盐植物配合施用脱硫石膏对河套灌区盐碱土水稳定性团聚体的影响,本研究在内蒙古河套灌区硫酸盐盐碱土上种植8种典型的耐盐植物,配合施用脱硫石膏,比较种植前后土壤水稳定性团聚体特征,以期筛选出适宜的耐盐植物。结果表明,种植耐盐植物后,<0.01 mm团聚体质量分数降低了44%~65%,而>0.25 mm和0.25~0.053 mm团聚体显著增加了95%~203%和21%~66%,0.053~0.01 mm团聚体质量分数没有发生显著的变化;各级团聚体有机碳和全氮显著提高,尤其是>0.25 mm水稳性团聚体,有机碳和全氮含量分别增加了13%~90%和75%~179%。不同耐盐植物存在明显的差异,其中多年生豆科植物的效果更为明显。>0.25 mm和0.25~0.053 mm团聚体质量分数与土壤pH、EC值、Na⁺、Mg²⁺、SO₄^2-和Cl^-含量呈显著的负相关关系,但与有机碳和全氮含量呈极显著的正相关关系,而<0.01 mm团聚体质量分数则与之相反。可见,盐分离子决定小团聚体,而大团聚体取决于有机质含量,种植耐盐植物由于降低盐分含量,同时提高有机质含量,从而促进盐碱土矿质土粒团聚作用,形成较大的水稳定性团聚体,多年生耐盐植物柳枝稷、紫花苜蓿、草木犀等效果更好,可有效地改良本地区盐碱土。