Conventional animal manure application based on crop nitrogen demand frequently induces phosphorus accumulation in soils, elevating non–point source phosphorus pollution risks. While phosphorus–based fertilization strategies have emerged as potential solutions, the differential impacts of manure types on nutrient cycling and microbial functionality at uniform phosphorus application levels remain poorly understood, particularly in reclaimed soils. This four–year field study conducted in a coal mining subsidence area systematically compared chicken, pig, and cow manures with chemical fertilizer. Under the uniform phosphorus application level, their effects on soil biochemistry and microbial ecology were evaluated. Key parameters analyzed included nutrient dynamics, microbial biomass, enzyme activities, and metabolic functional diversity indices assessed through the Biolog EcoPlates method. The results showed that: (1) animal manures decreased soil pH (0.06–0.13 units) and increased organic carbon (34.98

The chemical forms of nitrogen (N) are crucial to soil biogeochemical processes, with soil aggregates serving as the primary reservoirs for these N forms. However, the response of these N forms to different application rates remains inadequately understood in current N management strategies. A seven-year field experiment was conducted on reclaimed soil to evaluate effects on N forms in soil aggregates after application of four N rates (0 [CK], 100, 150, and 200 kg N ha(-1)) under two fertilization regimes: inorganic N fertilizer alone and a combined organic-inorganic fertilizer application (1:1 ratio). The results showed that combined fertilization significantly improved soil nutrient content, microbial biomass, and aggregate stability compared to single fertilizer treatments. At 200 kg N ha(-1), combined fertilization increased transformable N (TF-N) by 99.80 - 201.35% across all aggregate sizes, surpassing the 61.47 - 170.14% increase observed under equivalent sole fertilization treatments. Organic matter-sulfide-bound N (OSF-N) and ion-exchangeable N (IEF-N) were the dominant TF-N fractions, accounting for 62.47 - 70.85% and 10.23 - 20.28%, respectively. These forms exhibited distinct size-dependent distributions: OSF-N, IEF-N, and carbonate-bound N (CF-N) were mainly concentrated in aggregates < 0.25 mm, while iron-manganese-oxide-bound N (IMOF-N) was more abundant in aggregates > 0.25 mm. In addition, sole fertilization lowered soil pH (P < 0.01), suppressing enzymatic activity (P < 0.05) and indirectly limiting TF-N transformation. In contrast,combined fertilization directly enhanced TF-N transformation by improving nutrient availability and microbial biomass. This study highlights the effectiveness of organic-inorganic N application in enhancing N transformation in reclaimed soils, promoting agricultural waste recycling, and offering new insights into soil N cycling.

CO2-fixing bacteria are an important factor in restoring soil health in coal mining areas. The impact of crop rotation and fertilization on CO2-fixing bacteria in reclaimed mining soils remains unclear. To narrow this knowledge gap, in this study, maize (Zea mays L.) monoculture (M) and maize-soybean (Glycine max) rotation (R) cropping systems were set up in a coal-mining reclamation area with four fertilization treatments in each, namely, CK (without fertilization), inorganic fertilizer (F), organic fertilizer (O), and combined organic and inorganic fertilizer (OF). The abundance, diversity, community composition and RubisCO activity of CO2-fixing bacteria in topsoil under those treatments were investigated respectively using quantitative PCR, high-throughput sequencing based on the cbbL gene [that encodes ribulose-1,5-biphosphate carboxylase/oxygenase (RubisCO)] and enzyme-linked immunosorbent assay (ELISA). The results showed that R_O significantly increased easily oxidized organic carbon (EOC), total nitrogen (TN), and available nitrogen (AN) (P < 0.05). It also significantly increased the biomass of CO2-fixing bacteria (P < 0.05) and altered the CO2-fixing bacterial community. The CO2-fixing bacteria in R_OF, R_O and M_O exhibited comparable community structures and harbored a greater co-occurrence network complexity than other treatments. Several CO2-fixing bacteria associated with nitrogen cycling, such as Devosia, Nitrobacter, Hyphomicrobiales and Nitrosospira, were significantly enriched under the maize-soybean rotation system (P < 0.05). This study implied that crop rotation and organic fertilizer application could synergistically foster soil quality restoration in coal mining area by elevating soil nutrients and maintaining biomass, diversity and community structure of cbbL-carrying CO2-fixing bacteria, establishing a theoretical foundation for optimizing carbon sequestration strategies in post-mining ecological rehabilitation.

The initial variations in soil bacteria at the very beginning of reclamation still remains unclear. This study investigates the impact on bacterial communities of eight different treatments, including uncultivated land, unfertilized cultivation, chemical fertilizer, chemical fertilizer + bacterial fertilizer, manure, manure + bacterial fertilizer, manure + chemical fertilizer, and manure + chemical fertilizer + bacterial fertilizer, during the short-term reclamation of coal-mining soils. The results showed that total nitrogen, available phosphorus, soil organic carbon, microbial biomass carbon, and alkaline phosphatase activity were significantly increased in all fertilization treatments compared to uncultivated land (p < 0.05). All fertilization treatments other than chemical fertilizer harbored significantly higher activities of urease, catalase, and invertase than unfertilized cultivation (p < 0.05). The bacterial communities structures in manure-amended treatments significantly differed in uncultivated land and unfertilized cultivation and were phylotypically shifted from oligotrophic to Actinobacteria-dominant copiotrophic traits, accompanied with phenotypic succession of the enriching characteristics of Gram-positive, biofilms formation, and stress tolerance. The co-occurrence network in manure-amended treatments harbored a simple co-occurrence network, indicating more productive soils than in no-manure treatments. Manure amendment, total nitrogen, microbial biomass carbon, invertase, catalase, and soil moisture were the key driving factors. Our study underscores the bacterial initialization characteristics promoted by manure at the very beginning of coal-mining reclamation.

Fertilization is an effective measure to rapidly improve soil quality in reclaimed mining areas. However, the combined effects of fertilization regimes and reclamation age on phosphorus (P) fraction transformation and the pqqC-harboring microbial community in reclaimed soils remain unclear. In this study, we investigated the dynamics of inorganic P fractions and the pqqC-harboring bacterial community under different fertilization treatments (no fertilizer: CK; chemical fertilizer: CF; organic manure: M) and reclamation ages (1, 5, and 10 years) in a coal mining reclamation area of Shanxi Province, using long-term field experiments combined with high-throughput sequencing. Results showed that compared with the CF and CK treatments, the M treatment significantly increased soil organic matter (SOM), available P (AP), and total nitrogen (TN) content, and promoted the conversion of moderately labile P (NaOH-Pi) to labile P fractions (H2O-Pi, NaHCO3-Pi). Meanwhile, the pqqC gene abundance increased with reclamation age, with the M treatment maintaining the highest levels in all fertilization regimes. Co-occurrence network analysis of core species revealed that the number of connections gradually decreased and the network structure simplified with increasing reclamation age. Correspondingly, the microbial community transitioned from an initial stage characterized by rapid response and intense competition to a stable phase. Specifically, Pseudomonas spp. played a key role in P mobilization. Structural equation modeling (SEM) further demonstrated that reclamation age directly promoted the pqqC gene abundance and AP content, whereas fertilization indirectly influenced P transformation by regulating microbial diversity. Our findings reveal that reclamation age and fertilization synergistically shape the inorganic P profile and the associated bacterial community, providing insights for developing targeted P management strategies in reclaimed lands.

Coal mining has caused significant soil nitrogen loss in mining areas, limiting reclamation and reuse in agriculture. This article studies the effects of organic fertilizer, inorganic fertilizer, and the combined application of Pseudomonas fluorescens with the ability of nitrogen fixation on soil nitrogen accumulation and composition in the reclamation area of the Tunlan Coal Mine from 2016 to 2022 under the conditions of equal nitrogen application, providing a scientific basis for microbial fertilization and the rapid increase in nitrogen content in the reclaimed soil of mining areas. The results showed that as the reclamation time increased, the nitrogen content and the composition and structure of the soil treated with fertilization rapidly evolved toward normal farmland soil. The soil nitrogen content increased most rapidly in the presence of added P. fluorescens + organic fertilizer (MB). Compared to other treatments (inorganic fertilizer (CF), organic fertilizer (M), and P. fluorescens + inorganic fertilizer (CFB)), MB increased total nitrogen (TN) to normal farmland soil levels 1–3 years earlier. The comprehensive scores of MB and CFB on the two principal components increased by 1.58 and 0.79 compared to those of M and CF treatments, respectively. This indicates that the combination of P. fluorescens and organic fertilizer improves soil nitrogen accumulation more effectively than the combination of P. fluorescens and inorganic fertilizer. In addition, the application of P. fluorescens increases the content of unknown nitrogen (UN) in acid-hydrolysable nitrogen (AHN) and decreases the content of amino acid nitrogen (AAN) and ammonia nitrogen (AN). However, there was no significant effect on the content of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) in soil-mineralized nitrogen (SMN). When combined with inorganic fertilizer, the contribution of SMN to TN increased by 14.78%, while when combined with organic fertilizer, the contribution of AHN to TN increased by 44.77%. In summary, the use of P. fluorescens is beneficial for nitrogen recovery in the reclaimed soil of coal-mining areas. The optimal fertilization method under the experimental conditions is the combination of P. fluorescens and organic fertilizer.

We studied changes in the concentrations of aggregate -cementing agents after different reclamation times and with different fertilization regimes, as well as the formation mechanism of aggregates in reclaimed soil, to provide a theoretical basis for rapid reclamation of soil fertility in the subsidence area of coal mines in Shanxi Province, China. In this study, soil samples of 0-20 cm depth were collected from four fertilization treatments of a longterm experiment started in 2008: no fertilizer (CK), inorganic fertilizer (NPK), chicken manure compost (M), and 50% inorganic fertilizer plus 50% chicken manure compost (MNPK). The concentrations of cementing agents and changes in soil aggregate size distribution and stability were analysed. The results showed that the formation of >2 mm aggregates, the aggregate mean weight diameter (MWD), and the proportion of >0.25 mm water -stable aggregates ( WR 0.25 ) increased significantly after 6 and 11 years of reclamation. The concentration of organic cementing agents tended to increase with reclamation time, whereas free iron oxide (Fed) and free aluminium oxide (Ald) concentrations initially increased but then decreased. In general, the MNPK treatment significantly increased the concentrations of organic cementing agents and CaCO3 ,and CaCO3 increased by 60.4% at 11 years after reclamation. Additionally, CaCO3 had the greatest effect on the stability of aggregates, promoting the formation of >0.25 mm aggregates and accounting for 54.4% of the variance in the proportion and stability of the aggregates. It was concluded that long-term reclamation is beneficial for improving soil structure. The MNPK treatment was the most effective measure for increasing maize grain yield and concentration of organic cementing agents and CaCO3.

土壤团聚体作为土壤最重要的结构单元,储存着土壤中大多数的有机碳,对复垦土壤质量和肥力产生重要影响.为了研究不同有机肥对土壤团聚体活性有机碳的影响,依托山西省孝义市采煤塌陷区定位培肥试验平台,研究施用不同有机肥(鸡粪、猪粪、牛粪)和化肥对复垦土壤团聚体分布、活性有机碳含量的影响.结果表明,施肥处理和复垦年限影响着土壤团聚体的分布,随着复垦年限的增加,施肥处理提高了土壤>2.00 mm和0.25～2.00 mm团聚体数量,显著降低了<0.25 mm团聚体数量(36.34%～76.46%).施肥处理和复垦年限均影响土壤各粒径团聚体总有机碳、易氧化有机碳、可溶性有机碳、微生物量碳和轻组有机碳含量(<0.25 mm团聚体易氧化有机碳除外),而施肥处理和复垦年限互作仅影响 0.25～2.00 mm团聚体总有机碳含量、>2.00 mm和 0.25～2.00 mm团聚体微生物量碳及轻组有机碳含量;随着复垦年限的增加,有机肥均显著提高了各粒径团聚体活性有机碳含量,其中猪粪处理更显著,且在0.25～2.00 mm团聚体中活性有机碳含量最高.总之,随着复垦年限的增加,有机肥处理下>0.25 mm团聚体数量增加,并且提高了土壤团聚体活性有机碳含量.

[目的]石灰性复垦土壤磷素含量极低且易被其他离子吸附固定,严重影响作物的吸收与利用.研究不同有机肥对石灰性复垦土壤磷吸附解吸特征的影响,为加速培肥煤矿复垦土壤提供技术和理论依据.[方法]在山西省孝义市采煤塌陷区进行了4年的定位培肥试验,共设置了6个处理:不施肥、施鸡粪、施猪粪、施牛粪和氮钾肥、施氮磷钾肥.采集各处理土壤样品进行吸附动力学试验,测定复垦土壤磷最大吸附量、最大缓冲容量、吸附饱和度、解吸率,并分析影响磷吸附解吸的关键因素.[结果]采用Langmuir等温吸附方程可以极好地拟合复垦土壤对磷的吸附(R2=0.924～0.992).复垦年限和施肥处理以及二者的交互作用均对复垦土壤磷吸附解吸产生显著影响.随复垦年限的增加,土壤磷最大吸附量显著降低,而土壤磷吸附饱和度和解吸率显著增加.与复垦第1年相比,复垦第4年各施肥处理的土壤磷最大吸附量降低了12％～26％,土壤磷吸附饱和度增加了218％～885％,土壤磷解吸率增加了86％～118％.与两个化肥处理相比,3种有机肥处理下土壤磷最大吸附量显著降低了30％,最大缓冲容量降低了31％,土壤磷吸附饱和度增加了34％,磷解吸率增加了16％～24％.而且不同有机肥处理间也存在显著差异,有机肥对磷吸附的影响表现为猪粪>鸡粪>牛粪,对磷解吸的影响表现为鸡粪>猪粪>牛粪.冗余分析(RDA)结果表明,全磷和有机质是影响磷吸附-解吸的主要因素,贡献率分别为74％和13％ (P<0.01).[结论]施肥可以降低采煤塌陷复垦土壤对磷的吸附,增加磷的解吸能力,同一磷水平下有机肥的影响效果显著好于化肥.土壤对磷的吸附-解吸主要受土壤全磷和有机质含量的影响.在增加土壤磷有效性方面,鸡粪的效果优于猪粪和牛粪.随着施肥年限的增加磷吸附饱和度逐渐增加,建议持续监测土壤磷吸附-解吸特性,以警惕有机肥长期施用引起的环境磷流失风险.

The land damaged by coal mining can be recovered to healthy condition through various reclamation methods. Fertilization is one of the effective methods to improve soil fertility and microbial activity. However, the effects of coal-derived compound fertilizers (SH) on bacterial communities in coal mining subsidence areas still remain unclear. Here, we studied the effects on the nutrient characteristics and bacterial communities in fertilizer-reclaimed soil (CK, without fertilizer; CF, common compound fertilizers; SH, coal-derived compound fertilizers) in coal mining subsidence areas and we applied SH with four different nitrogen application rates (90, 135, 180, and 225 kg/hm(2)). The results showed that the application of SH significantly increased the contents of available nitrogen (AN), available phosphorus (AP), available potassium (AK), total phosphorus (TP) and soil organic matter (SOM) compared with CK, as well as the bacterial richness (Chao1) and diversity (Shannon) in reclaimed soil that increased first and then decreased with the increase of nitrogen application. Under the same nitrogen application rate (135 kg/hm(2)), the nutrient content, Chao1 and Shannon of SH2 treatments were higher than those of CF treatment. Meanwhile, SH increased the relative abundance of Proteobacteria, Actinobacteria and Gemmatimonadetes. LEfSe analysis indicated that the taxa of Acidobacteria and Actinobacteria were significantly improved under SH treatments. Canonical correspondence analysis (CCA) and Variance partitioning analysis (VPA) showed that SOM was the most important factor affecting the change of bacterial community structure in reclaimed soil. In conclusion, application of SH can not only increase nutrient content and bacterial diversity of reclaimed soil, but also improve bacterial community structure by increasing bacterial abundance.

Carbon-fixing microbes can potentially improve soil fertility. However, the potential and function of carbon-fixing microbes remains largely uninvestigated in reclaimed soil of coal-mining subsidence areas. In this study, treatments included UL (uncultivated land), CK (maize cultivation without fertilization), NPK (maize cultivation with chemical fertilizer), M (maize cultivation with manure), MNPK (maize cultivation with manure and chemical fertilizer) after 1-year reclamation in a typical coal mining subsidence area. Quantitative PCR, enzyme-linked immunosorbent assay (ELISA) and high-throughput sequencing were employed to investigate the topsoil carbon-fixing microbial biomass, RubisCO activity and community composition. The results showed that the dominant taxa (i.e., Proteobacteria, Cyanobacteria, Devosia and Marichromatium ) were significantly changed after reclamation ( P < 0.05). Carbon-fixing microbial community structure in fertilization treatments (NPK, M and MNPK) obviously differed from non-fertilizer treatments (UL and CK). Soil organic carbon and microbial biomass carbon were significantly higher in fertilization treatments than non-fertilizer treatments ( P < 0.05). M significantly increased RubisCO activity and cbbL gene abundance ( P < 0.05), MNPK significantly increased carbon-fixing microbial richness ( P < 0.05). Carbon-fixing microbial community structure was strongly influenced by soil moisture, catalase, total phosphorus and dissolved organic carbon. Some environmental factors indirectly influenced SOC by affecting carbon-fixing microbial biomass, diversity and community structure. Our study implies that even short-term (1-year) reclamation and fertilization could significantly influence carbon-fixing microbial community structure and promote soil carbon accumulation, and the fertilization treatments with manure (M and MNPK) were more conducive, which indicated that carbon-fixing microbes were greatly conducive to improve soil fertility in reclaimed mining areas and achieve carbon neutrality.

Phosphate-solubilizing bacteria (PSB) can alleviate available phosphorus deficiency without causing environmental pollution, unlike chemical phosphate fertilizers. However, the phosphate solubilization mechanisms of PSB are still unclear. Transcriptome sequencing was used to analyze the expression patterns of differential expressed genes (DEGs) of the phosphate-solubilizing bacterium W134 under the conditions of soluble phosphorus (group A), insoluble phosphorus (group B), and lacking phosphorus (group C). Nine DEGs in three different groups were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Then, high performance liquid chromatography (HPLC) was applied to detect the concentrations and composition of organic acids. Compared with group A, Gene Ontology (GO) annotation showed that the cluster of W134 DEGs in groups B and C were basically the same. Besides, the results of enrichment Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway indicated that genes in the Citrate cycle (TCA cycle) pathway closely related to organic acid production were significantly upregulated. The qRT-PCR results were almost consistent with the expression trends of the transcriptome data. The HPLC results showed that the formic acid, ascorbic acid, acetic acid, citric acid, and succinic acid concentrations were significantly increased in group B and C (p < 0.05), while the contents of lactic acid and malic acid were significantly increased in group B (p < 0.05). The above results provided further validation that the upregulated genes should be related to W134 secretion of organic acids. Our study revealed several potential candidate genes and tried to explain phosphate solubilization mechanisms. This provides a new insight for calcareous reclaimed soil, and it will reduce the need of chemical phosphate fertilizers to promote environmentally friendly agriculture.

Release of nanoceria (nCeO2) into the environment has caused much concern about its potential toxicity, which still remains poorly understood for soil microorganisms. In this study, nanoceria and cerium (III) nitrate at different doses (10, 100 and 500 mg/kg) were applied to bok choy (Brassica rapa subsp. chinensis), grown in potting soil, to investigate the responses of soil bacterial communities to nanoceria (NC) and ionic cerium (IC) applications. The results showed that bacterial richness was slightly increased in all cerium treatments relative to the negative control without cerium amendment (CK), but a significant increase was only found in IC500. The patterns of bacterial community composition, predicted functions and phenotypes of all NC treatments were significantly differentiated from IC and CK treatments, which was correlated with the contents of cerium, available potassium and phosphorus in soil. The co-occurrence network of bacterial taxa was more complex after exposure to ionic cerium than to nanoceria. The keystone taxa of the two networks were entirely different. Predicted functions analysis found that anaerobic and Gram-negative bacteria were enriched under nanoceria exposure. Our study implies that Proteobacteria and nitrifying bacteria were significantly enriched after exposure to nanoceria and could be potential biomarkers of soil environmental perturbation from nanoceria exposure.

为探究定位培肥矿区复垦土壤过程中不同有机肥对土壤磷素累积状况及环境流失风险的差异.以山西省孝义市采煤塌陷复垦土壤为研究对象,研究不同有机肥(鸡粪、猪粪、牛粪)和化肥在4个施磷水平下(0,25,50,100 kg/hm2)培肥4年后对矿区复垦土壤全磷、Olsen—P、Mehlich3—P、CaCl2—P以及磷饱和度(DPS)的影响及其之间的变化关系.结果表明:(1)施用有机肥增加土壤中磷素含量,且施磷量越大,对磷素含量的影响越明显,特别是土壤全磷、Olsen—P和Mehlic3—P,并使CaCl2—P呈增加的趋势;与不施磷处理和化肥相比,施用有机肥提高了土壤磷饱和度(DPS);总体来看,不同施肥处理对土壤磷素含量的影响均表现为鸡粪≥猪粪＞牛粪＞化肥.(2)各施肥处理土壤Olsen—P与Mehlich3—P、Olsen—P与CaCl2—P、Mehlich3—P与CaCl2—P之间存在显著的线性相关性.(3)与猪粪、牛粪和化肥处理相比,鸡粪处理对矿区复垦土壤磷素流失风险影响最大,当磷饱和度(DPS)≥39.31％、Olsen—P≥26.24 mg/kg、Meh-lich3—P≥49.06 mg/kg时,土壤CaCl2—P含量迅速增加.因此,可将上述指标作为矿区复垦土壤磷素流失的临界值,超过此值,土壤磷素流失风险加大,需要警惕对地表、地下水体的污染.

土壤团聚体的组成和稳定性是评价土壤质量的重要指标,土壤胶结物质是团聚体形成的物质基础,两者密切相关.通过研究不同施肥处理下团聚体胶结物质含量的变化,阐明采煤塌陷区复垦土壤团聚体的分布与形成机制.设不施肥(CK)、施化肥(NPK)、单施有机肥(M)和有机无机肥配施(MNPK)4个处理,另取未复垦生土(RS)和周边未破坏多年种植的熟土(US)作为参照.采集耕层(0-20 cm)非扰动的土样,利用干筛法分析团聚体(＞2、0.25-2、0.053-0.25 mm)和粉黏粒组分(＜0.053 mm)的分布比例,测定团聚体有机胶结物质(多糖、富里酸、胡敏酸和有机碳)和无机胶结物质(碳酸钙和颗粒组成)的含量.结果表明,同RS相比,各施肥处理均显著提高了＞0.25 mm机械稳定性团聚体的数量(R0.25),增幅为5.32％-5.94％,但是均显著降低了平均重量直径(mean weight diameter,MWD)(除M处理外),降幅为7.51％-9.83％,而M处理显著提高了几何平均直径(geometric mean diameter,GMD),增幅为5.65％.同CK相比,各施肥处理对大团聚体(＞0.25 mm)以及粉黏粒组分(＜0.053 mm)的分布比例无显著影响,仅M和MNPK处理显著降低了微团聚体(0.053-0.25 mm)的分布比例,降幅为49.45％-62.40％.各施肥处理对富里酸含量无显著影响.NPK处理仅显著降低了土壤有机碳含量.M处理显著提高了土壤有机碳和碳酸钙含量,却显著降低了土壤黏粒含量.而MNPK处理显著提高了土壤各胶结物质含量(除富里酸和黏粒外).胶结物质与机械稳定性团聚体的分布比例和稳定性的冗余分析结果表明,各胶结物质中,仅胡敏酸对机械稳定性团聚体的分布比例和稳定性变化的解释率达到了显著水平(P＜0.05),能够解释57.1％机械稳定性团聚体的分布比例和稳定性变化,并且其单独贡献率为75.9％.综上所述,经过6年培肥,同未复垦土壤相比,各施肥处理显著提高了大团聚体的数量,但同周边农田土壤相比,仍有待进一步培肥提高团聚体稳定性;MNPK处理是提高该复垦土壤有机胶结物质含量最有效的措施,胡敏酸是影响该复垦土壤机械稳定性团聚体的分布比例和稳定性变化的唯一显著的胶结物质.

【Objective】 Reclaimed soils are usually poor in nutrients and the aim of this paper is to investigate the efficacy of nitrogen-fixing bacteria combined with different nitrogen fertilizations in improving fertility of reclaimed soils. 【Method】 The experiments were conducted in pots filled with soil collected from a subsidized coal mining. The soil was incubated with nitrogen-fixing bacteria combined with different nitrogen fertilizers. In each treatment, we measured carbon and nitrogen in microbial biomass, enzymatic activity, total nitrogen, and ammonium and nitrate nitrogen in the soil. 【Result】 Combining nitrogen-fixing bacteria with ammonium or nitrate nitrogen fertilizer increases carbon and nitrogen in microbial biomass, total dissolved nitrogen, ammonium nitrogen in the soil. Compared with treatment with nitrate and ammonium nitrogen fertilization only, their combination with nitrogen-fixing bacteria increases the activity of catalase, sucrase, protease and urease by 4.96%, 17.85%, 12.53% and 6.12% respectively. Correlation analysis shows a close relationship between soil nutrients, enzymatic activity and carbon and nitrogen in microbial biomass; the activity of sucrase, protease and urease is positively correlated with total nitrogen, total dissolved nitrogen and ammonium nitrogen in the soil (P<0.01); the enzymatic activity is positively correlated with nitrate nitrogen (P<0.05); a positive correlation exists between carbon and nitrogen in microbial biomass and total dissolved nitrogen in the soil (P<0.05). Principal component analysis shows that ammonium nitrogen fertilization combined with nitrogen-fixing bacteria gives the best soil quality. 【Conclusion】 Combining nitrate and ammonium nitrogen fertilization with nitrogen-fixing bacteria can significantly increase soil microbial biomass and nitrogen content, and it can be used as an improved agricultural practice to improve quality of reclaimed soil from coal mining.

[目的]探明木醋液不同浓度处理土壤微生物量碳、微生物数量及土壤化学性状的变化规律,为木醋液更好地应用于植物生长、土壤改良及病虫害防治等农业生产提供参考.[方法]采用土柱模拟试验,研究木醋液处理(木醋液原液,木醋液1 ∶ 20稀释液,木醋液1 ∶ 60稀释液)对不同土层土壤生物化学性状的影响.[结果]与对照(蒸馏水)相比,土柱10 cm与20 cm处,木醋液原液对土壤微生物量碳转化产生抑制作用,微生物量碳含量较CK处理降低50％以上;浓度1 ∶ 20和1 ∶ 60木醋液较原液处理抑制作用逐渐减弱.经土柱渗透后的木醋液能促进土壤微生物量碳增加,土柱30 cm处,浓度1 ∶ 20木醋液处理的土壤微生物量碳含量较CK显著增加61％.不同浓度木醋液处理下,随着土层深度增加木醋液的杀菌效果降低.木醋液入土 2 h后,在土层10 cm处,原液处理对细菌、真菌和放线菌菌落数量杀菌率最大,杀菌率均在95％以上;在30 cm处,杀菌率降低,且处理菌落数大于CK,浓度1 ∶ 20和1 ∶ 60木醋液处理真菌数量分别较CK增加40.2％和26.8％.施用木醋液可增加土壤中有机质、碱解氮、有效磷和速效钾含量,有效磷含量的变化最显著,木醋液原液处理有效磷含量较CK增加70.2％.[结论]木醋液原液具有优异的杀菌和改良土壤的效果.

为探究假单胞菌与有机肥配施对复垦土壤的施用效果,以小白菜为供试材料,采用盆栽试验,通过不同浓度的假单胞菌菌剂与不同用量的鸡粪配施,研究其对小白菜产量、品质与养分的影响,并通过隶属函数法进行综合评价,确定最佳配施范围.结果表明,鸡Ⅱ(盆施腐熟鸡粪12.5 g/kg)+菌Ⅱ(10 mL有效活菌数≥1.0×108 cfu/g)处理与CK相比,小白菜产量、维生素C、还原糖、硝态氮、全氮含量分别显著提高65.97％、40.5％、33.71％、78.41％、62.69％;鸡Ⅱ+菌Ⅰ(10 mL有效活菌数≥0.5×108 cfu/g)处理叶绿素含量较CK显著提高50.6％;鸡Ⅱ+菌0(10 mL无菌的培养基)处理全钾含量较CK显著提高86.69％;菌剂配施鸡粪对增加小白菜产量与硝态氮含量大于单施菌剂,单施用菌剂大于不施用菌剂;菌剂配施鸡粪对增加小白菜Vc、还原糖、叶绿素及全氮、全钾的含量大于单施菌剂,单施用菌剂与不施用菌剂差异不显著.参考隶属函数法对假单胞菌配施鸡粪对小白菜产量及品质影响的综合效果进行评定,鸡Ⅱ+菌Ⅰ处理对小白菜影响的综合效果最佳,隶属度为0.5593,对提高小白菜产量、改善品质有重要的作用.综上所述,假单胞菌配施有机肥能够增加小白菜产量,改善小白菜的品质,对小白菜起到促生作用.

为阐明复垦土壤微团聚体对有机碳的固存机制,采集不同施肥措施下连续复垦6年的耕层(0-20 cm)土样,采用物理分组方法,分析微团聚体中各有机碳组分[未受保护的细颗粒有机碳(fPOC)、受物理保护的微团聚体内颗粒有机碳(iPOC)、受化学或生物化学保护的矿质结合态有机碳(MOC)]储量的变化,以及SOC含量、微团聚体中各有机碳组分储量与玉米籽粒产量之间的关系.设对照(CK)、施化肥(NPK)、单施有机肥(M)、有机无机肥配施(MNPK)4个处理,另取未复垦生土(RS)和周边未破坏多年种植熟土(US)作为参照.结果显示,同CK相比,各施肥处理均显著提高了玉米籽粒产量,且以M处理的提高效果最佳.NPK处理显著降低了SOC含量,达6.02％;M和MNPK处理均显著提高了SOC含量、fPOC和iPOC储量,增幅分别为20.74％-33.44％、64.44％-115.56％和110.98％-173.17％,且以MNPK处理增幅最大;但MNPK处理显著降低了MOC储量,达13.35％.微团聚体中各有机碳组分储量与SOC含量均呈显著正相关,尤其是fPOC储量,说明复垦土壤有机碳主要固存在fPOC组分中.SOC含量与玉米籽粒产量呈极显著相关,表明该区域复垦土壤有机碳库仍未达到饱和.本研究表明连续6年复垦显著提高了土壤肥力,但同周边农田土壤相比,仍有待继续培肥;MNPK处理对提高该复垦区SOC含量的效果最佳,且增加的有机碳首先累积在fPOC组分中,因此需要长时间持续投入才能恢复土壤有机碳的稳定性.

为研究从土壤中筛选的2株解磷菌w134和w137在复垦土壤中的存活能力与定殖特性,利用电击转化法将含绿色荧光蛋白(GFP)的质粒电转至解磷菌中,经荧光显微观察和质粒检测,获得发光稳定的标记菌株w134GFP和w137GFP.对标记菌和野生菌的生长曲线和解磷能力进行比较,结果发现,二者无明显差别.对标记菌在复垦土壤中的定殖动态观察结果表明,接种7 d时,w134GFP和w137GFP的菌量从初始的5.0×107 cfu/g分别增到7.6×108、9.8×109 cfu/g;之后定殖数量逐渐降低,35～42 d时,2株菌的数量在4.5×104 cfu/g;93 d降至10～20 cfu/g;在接菌的前28 d,灭菌土壤中标记菌的定殖数量高于未灭菌土壤,随后土壤灭菌和不灭菌对定殖的影响逐渐减小,到58 d时,定殖数量基本没有差别;此外,在接菌的0～58 d内,添加有机肥处理的标记菌定殖数量高于对应不施肥处理,添加有机肥促进了菌株的定殖.研究表明,解磷细菌w134和w137可以在复垦土壤中有效定殖,这为后期研究其在矿区复垦中的实际解磷效果提供了基础.