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.

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.

Understanding the effects of different fertilization treatments on microbial functional diversity in loess tableland wheat soil in south Shanxi Province can provide the theoretical basis from the perspective of microbial functional diversity for chemical fertilizer reduction, wheat yield increase, and soil fertility improvement in dryland soil. We conducted a long-term field experiment with seven fertilization treatments in winter wheat cultivation area of loess tableland in south Shanxi Province, including straw charcoal fertilizer (SF), bacterial fertilizer (BF), organic fertilizer (OF), humic acid fertilizer (HF), monitoring fertilizer (MF), farmer fertilizer (FF) and no fertilizer (CK). We employed Biolog-ECO microplate technique to investigate the differences of carbon source utilization capacity and functional diversity of soil microorganisms. The results showed that all the fertilization treatments could improve the metabolic activity and functional diversity of soil microbial community. Carbon source utilization was the most efficient in SF, with the overall soil microbial utilization ability of the 31 carbon sources and the utilization ability of different guilds of carbon sources being improved. Functional diversity, richness, and dominance based on microbial carbon sources utilization were significantly higher in SF treatment than that under other five treatments, and the evenness was higher than BF. Results of principal component analysis (PCA) and biclustering heatmap analysis showed that different fertilization treatments had significant effects on the metabolic function of microbial community. SF treatment could promote the functional diversity of soil microbial community, especially for the utilization of carbohydrates, carboxylic acids and amino acids. In conclusion, straw charcoal fertilizer had positive effects on soil microbial activity in wheat soil of loess tableland in south Shanxi Province.

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.

Coal mining has caused a significant loss of nitrogen content of soil in mining areas. This article studies the effects of organic fertilizer, inorganic fertilizer, and combined application of Pseudomonas fluorescens with the ability of nitrogen fixation on soil nitrogen accumulation and composition in the reclamation area of Tunlan Coal Mine from 2016 to 2022 under the condition of equal nitrogen application, providing scientific basis for microbial fertilization and rapid increase of nitrogen content in the reclaimed soil of mining areas. The results showed that as the reclamation time increased, the nitrogen content and its composition structure of the soil treated with fertilization rapidly evolved towards normal farmland soil. The soil nitrogen content increased the fastest in the treatment of Pseudomonas fluorescens + organic fertilizer (MB), compared with inorganic fertilizer (CF), organic fertilizer (M), and Pseudomonas fluorescens + inorganic fertilizer (CFB) treatments, the treatment of Pseudomonas fluorescens + organic fertilizer (MB) can bring the total nitrogen (TN) content of the soil to normal farmland soil levels 1-3 years earlier. The comprehensive scores of Pseudomonas fluorescens + organic fertilizer (MB) and Pseudomonas fluorescens + inorganic fertilizer (CFB) on the two principal components were increased 1.58 and 0.79 than those of organic fertilizer (M) and inorganic fertilizer (CF) treatments, respectively. This further indicates that the combination of Pseudomonas fluorescens and organic fertilizer has a better effect on improving soil nitrogen accumulation than the combination of Pseudomonas fluorescens and inorganic fertilizer. At the same time, the application of Pseudomonas fluorescens will increase the content of unknown nitrogen (UN) in acid-hydrolysable nitrogen (AHN), and decrease the content of amino acid nitrogen (AAN) and ammonia nitrogen (AN), relatively. However, there was no significant effect on the content of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) in soil inorganic nitrogen (SMN). When combined with inorganic fertilizer, the contribution of soil mineralized nitrogen (SMN) to total nitrogen (TN) increased by 14.78%, while when combined with organic fertilizer, the contribution of acid-hydrolysable nitrogen (AHN) to total nitrogen (TN) increased by 44.77%. In summary, the use of Pseudomonas 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 Pseudomonas fluorescens and organic fertilizer.

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.

为筛选适宜改良生地土壤的绿肥品种,选取适应性较强的毛叶苕子、箭筈豌豆、草木樨、荞麦和春油菜5种不同绿肥品种进行试验,研究不同绿肥根际与非根际以及翻压后土壤养分及转化酶活性的变化趋势.结果表明:不同品种的绿肥作物根系活动导致根际与非根际生地土壤化学性状及土壤酶活性产生差异,各品种绿肥对土壤有机质和氮磷钾的富集活化作用有所不同.豆科绿肥箭筈豌豆和毛叶苕子对根际土壤脲酶的活化作用较好,其根际效应分别为3.99和4.41;春油菜、毛叶苕子对根际土壤蔗糖酶、碱性磷酸酶的活化效果好,根际效应分别为13.17、13.19和2.84、2.87;春油菜、毛叶苕子处理翻压后对土壤4种酶活性的提高效果显著.综合灰色关联法对复垦土壤化学性状及酶活性的变化分析,毛叶苕子和春油菜两种绿肥对生地土壤的改良效果较好.

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.

[目的]研究煤矿区不同复垦年限土壤中秸秆和生物炭的分解特征及其影响因素,为资源合理利用和矿区土壤培肥提供理论依据.[方法]依托山西煤矿复垦区试验基地,在复垦年限为1年(复垦初期阶段,R1)、10年(复垦中期阶段,R10)和30年(复垦长期阶段,R30)的土壤中进行了有机物料填埋试验.供试有机物料包括:玉米秸秆(MS)、小麦秸秆(WS)和生物炭(BC),以不添加有机物料为对照(CK).3种有机物料按土重(200 g)和有机碳比例为100:4混匀,装于尼龙网袋(孔径0.38μm)内,埋入试验基地15 cm深的土壤中.监测试验期内土壤积温,在埋入土壤后的第12、23、55、218、281、365天采集尼龙袋内土壤样品,分析有机物料残留量、土壤有机碳(SOC)、微生物量碳(SMBC)、微生物量氮(SMBN)、可溶性有机碳(DOC)和可溶性有机氮(DON)含量,分析各调查指标与有机物料分解残留率的关系.[结果]1)秸秆和生物炭的腐殖化系数分别为46.2％和86.6％,秸秆分解速率显著高于生物炭(P<0.05),有机物料的腐殖化系数在3种复垦年限土壤间无显著差异.秸秆分解速率在3种复垦土壤间表现出阶段性差异:分解0～12天,秸秆在R30中的分解速率显著高于R1;分解12天后,秸秆分解速率在3种复垦土壤之间无显著差异.2)由积温方程可知,秸秆和生物炭的易分解有机碳库占比分别为55％和12％,稳定有机碳库占比分别为43％和87％.3)添加秸秆显著提高了3种复垦土壤SMBC、SMBN、DOC和DON含量,其在R1的增长幅度显著高于R10和R30,后两者的增幅无显著差异;添加生物炭不影响复垦土壤的活性碳氮库.4)分解0～23天,秸秆分解速率与土壤活性碳氮含量、秸秆木质素含量显著相关;分解23天后,秸秆分解速率与土壤SMBN含量、秸秆木质素含量显著相关.土壤性质不影响生物炭的分解速率.整个分解时期复垦土壤中DOC增加量与秸秆分解速率呈极显著正相关(P<0.01).[结论]秸秆和生物炭的腐殖化系数与土壤复垦年限不相关,秸秆分解速率显著高于生物炭,主要是由于秸秆易分解有机碳库占比高于生物质炭.秸秆埋入复垦土壤后,在第12天分解速率达到最大值,土壤活性养分含量显著增加;生物炭性质稳定,分解缓慢,土壤活性养分含量无明显变化.综上,复垦土壤应加强秸秆还田以提高土壤活性碳氮含量,长期复垦土壤宜施用生物炭以稳定复垦土壤碳氮库.

Soil organic carbon (SOC) plays a key role in improving soil quality and optimizing crop yield. Yet little is known about the fate of macroaggregates (>0.25 mm) under long-term fertilization and their relative importance in SOC sequestration in reclaimed calcareous soil. Therefore, the effects of mineral fertilizers and organic manure on the mechanisms of organic carbon (OC) stabilization in macroaggregates were investigated in this study. Four treatments were used: unfertilized control (CK), mineral fertilizer (NPK), compost chicken manure alone (M), and mineral fertilizers plus manure (MNPK). Samples from the 0–20 cm layer of soil receiving 11-year-long fertilization were separated into four fractions based on the macroaggregates present (unprotected coarse and fine particulate organic matter, cPOM and fPOM; physically protected intra-microaggregate POM, iPOM; and biochemically protected mineral associated OM, MOM) by the physical fractionation method. Compared with the control, the long-term application of NPK had little effect on SOC content, total nitrogen (TN) content, and OC and TN contents of macroaggregate fractions. In contrast, incorporation of organic manure (MNPK) significantly increased SOC (45.7%) and TN (24.3%) contents. Application of MNPK increased OC contents within macroaggregate-extracted fractions of cPOM (292.2%), fPOM (136.0%) and iPOM (124.0%), and TN contents within cPOM (607.1%), fPOM (242.5%) and iPOM (127.6%), but not the mineral associated organic carbon (MOM-C) and nitrogen (MOM-N) contents. Unprotected C fractions were more strongly and positively correlated with SOC increase than protected C fractions, especially for cPOM-C, indicating that SOC sequestration mainly occurred via cPOM-C in the studied calcareous soil. In conclusion, MNPK increased the quantity and stability of SOC by increasing the contents of cPOM-C and cPOM-N, suggesting that this management practice (MNPK) is an effective strategy to develop sustainable agriculture.