Impact of Microbial Inoculants on Microbial Quantity, Enzyme Activity and Available Nutrient Content in Paddy Soil

The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg hm-2.

Effects of butachlor on microbial enzyme activities in paddy soil

This paper reports the influences of the herbicide butachlor( n butoxymethl chloro 2', 6' diethylacetnilide) on microbial respiration, nitrogen fixation and nitrification, and on the activities of dehydrogenase and hydrogen peroxidase in paddy soil. The results showed that after application of butachlor with concentrations of 5.5 μg/g dried soil, 11.0 μg/g dried soil and 22.0 μg/g dried soil, the application of butachlor enhanced the activity of dehydrogenase at increasing concentrations. The soil dehydrogenase showed the highest activity on the 16th day after application of 22.0 μg/g dried soil of butachlor. The hydrogen peroxidase could be stimulated by butachlor. The soil respiration was depressed within a period from several days to more than 20 days, depending on concentrations of butachlor applied. Both the nitrogen fixation and nitrification were stimulated in the beginning but reduced greatly afterwards in paddy soil.

Effects of Long-Term Combined Application of Organic and Mineral Fertilizers on Microbial Biomass,Soil Enzyme Activities and Soil Fertility

Soil health is important for the sustainable development of terrestrial ecosystem. In this paper, we studied the relationship between soil quality and soil microbial properties such as soil microbial biomass and soil enzyme activities in order to illustrate the function of soil microbial properties as bio-indicators of soil health. In this study, microbial biomass C and N contents （Cmic ＆ Nmic）, soil enzyme activities, and soil fertility with different fertilizer regimes were carried out based on a 15-year long-term fertilizer experiment in Drab Fluvo-aquic soil in Changping County, Beijing, China. At this site, 7 different treatments were established in 1991. They were in a wheat-maize rotation receiving either no fertilizer （CK）, mineral fertilizers （NPK）, mineral fertilizers with wheat straw incorporated （NPKW）, mineral fertilizers with incremental wheat straw incorporated （NPKW＋）, mineral fertilizers plus swine manure （NPKM）, mineral fertilizers plus incremental swine manure （NPKM＋） or mineral fertilizers with maize straw incorporated （NPKS）. In different fertilization treatments Cmic changed from 96.49 to 500.12 mg kg^-1, and Nmic changed from 35.89 to 101.82 mg kg^-1. Compared with CK, the other treatments increased Cmic ＆ Nmic, Cmic/Corg （organic C） ratios, Cmic/Nmic, urease activity, soil organic matter （SOM）, soil total nitrogen （STN）, and soil total phosphorus （STP）. All these properties in treatment with fertilizers input NPKM＋ were the highest. Meantime, long-term combined application of mineral fertilizers with organic manure or crop straw could significantly decrease the soil pH in Fluvo-aquic soil （the pH around 8.00 in this experimental soil）. Some of soil microbial properties （Cmic/Nmic, urease activity） were positively correlated with soil nutrients. Cmic/Nmic was significantly correlated with SOM and STN contents. The correlation between catalase activity and soil nutrients was not significant. In addition, except of catalase activity, the soil pH in this experiment was negatively correlated with soil microbial properties. In conclusion, soil microbial properties reflect changes of soil quality and thus can be used as bio-indicators of soil health.

Effects of Long-term Fertilization on Soil M icrobial Com m unity Structure,Labile Organic Carbon and Nitrogen and Enzym e Activity in Paddy Field and Upland

To investigate the effects of long-term fertilization systems on soil microbial community structure,labile organic carbon and nitrogen and enzyme activity in yellow sand paddy field and upland,a field experiment was conducted at the experimental station of Dongyang Institute of Maize Research in Zhejiang Province,China in 2009.The experiment consisted of six treatments with three replicates,and they were arranged in a completely randomized design,including no fertilization in paddy field (PCK),conventional fertilization in paddy field (PCF),formulated fertilization by soil testing in paddy field (PSTF),formulated fertilization by soil testing with organic manure in paddy field (PSTF+OF),conventional fertilization on upland (DCF),and formulated fertilization by soil testing with organic manure on upland (DSTF+OF).Soil nutrients,enzyme activity,microbial biomass and community structure were determined in 2015.The results showed that compared with no fertilization in paddy field (PCK),fertilization increased soil phosphorus and potassium content,and decreased pH value.No fertilization in paddy field (PCK) had no significant effect on soil culturable microorganisms in paddy field and upland,but formulated fertilization by soil testing with organic manure on upland (DSTF+OF) significantly increased the number of fungi.Formula fertilization by soil testing with organic manure (PSTF+OF) also significantly increased soil microbial biomass carbon and nitrogen in paddy field and upland.Moreover,fertilization had no significant effect on soil cellulase activity,but formula fertilization by soil testing with organic manure (PSTF+OF) significantly increased soil dehydrogenase and catalase activity.Therefore,long-term application of chemical fertilizer with organic fertilizer can effectively improve soil fertility.

Response of Soil Microbial Properties to Long-Term Application of Organic and Inorganic Amendments in a Tropical Soil (Saria, Burkina Faso)

Soil microbial biomass carbon (MBC), β-glucosidase, acid phosphatase and fluorescein diacetate (FDA) activities and bacterial community structure were assessed in a long-term (26 years) experiment, at physiological stages of sorghum growth, comparing different management methods for organic (manure, straw residues) and inorganic (urea) amendments at the INERA field station in Saria (Burkina Faso). Annual application of manure led to the highest soil microbial biomass and enzyme activities. Investigations indicated that only microbial biomass and β-glucosidase activities were affected during the cropping season. Phosphatase and FDA enzyme activities did not depend on the crop development stages. The application of N fertilizer modified phosphatase and FDA enzyme activities, the activities being higher in soils amended with N fertilizer. The bacterial community structure was analyzed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the eubacterial 16S rRNA gene. Cluster analysis of PCR-DGGE patterns showed two major clusters, the first containing the mineral fertilization and straw treatments and the second, the straw + urea, manure and manure + urea treatments. Sorghum grain yields were the highest for manure treatments. In this long-term experiment, applying straw did not produce a better grain yield than that obtained in the un-amended plot.

A Field Study on Effects of Nitrogen Fertilization Modes on Nutrient Uptake,Crop Yield and Soil Biological Properties in Rice-Wheat Rotation System

Rational application of nitrogen （N） fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of microbes.The result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes （bacteria,actinomycetes,and fungi）.On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,respectively.Further,organic fertilizer replacement had a Shannon＇s diversity index （H） of 2.18,which was higher than that of other modes of single N fertilizer application.The results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.

不同施肥处理对‘渝城1号’核桃产量、品质和土壤肥力的影响

以‘渝城1号’核桃为研究对象,设置单施复合肥、单施有机肥、施用核桃配方肥及不施肥4个处理,测定不同施肥处理时核桃产量、品质及核桃园土壤理化性质、微生物数量等,对核桃配方肥的应用效果进行评价。结果表明:施复合肥、有机肥及核桃配方肥均能提高核桃产量,其中,施用核桃配方肥的增产效果最好,经济效益最高,该施肥处理比不施肥的收益提高88.1%。相比于不施肥,施用核桃配方肥时核桃果实的蛋白质及脂肪总量显著提高,油酸、亚油酸、α-亚麻酸等不饱和脂肪酸占比增加,硬脂酸、棕榈酸等饱和脂肪酸占比下降。施用复合肥能促进核桃园土壤有效氮、磷、钾质量分数的增加,但会引起土壤pH及有机质质量分数下降。施用有机肥和核桃配方肥均能促进土壤有机质和有效养分质量分数增加。施用核桃配方肥后,土壤总微生物量增加,固氮菌、解磷菌、解钾菌、纤维降解菌等功能微生物数量均显著增多,土壤脲酶、磷酸酶、蔗糖酶、过氧化氢酶等活性大幅升高。施用核桃配方肥能显著提升核桃的产量和品质,更利于土壤养分转化和果园可持续经营。

水稻土微生物群落、酶活性及理化性质对有机肥、石灰连续施用的响应

【目的】探究水稻土微生物群落、酶活性及理化性质对有机肥、石灰连续施用的响应规律,为培育健康水稻土提供理论依据。【方法】于2014年冬季,选取湘东双季稻区典型酸紫泥田,分别进行了连续施用鸡粪发酵商品有机肥、生石灰的大田试验。每年早、晚稻翻耕前各撒施一次有机肥、石灰,施用量均为2.25 t/hm^(2),分别以不施有机肥、石灰的处理为对照。在处理后第3年(2017年)和第7年(2021年)晚稻黄熟期,采集表层(0—15 cm)混合土壤样品,测定土壤微生物磷脂脂肪酸(PLFAs)含量、酶活性及理化性质,筛选指示性强、响应敏感的土壤指标。基于土壤理化性质与生物学性质间的相互关系,构建结构方程模型,解析土壤PLFAs含量与酶活性对有机肥、石灰处理的响应机理。【结果】与对照相比,有机肥连施3年后,土壤革兰氏阴性菌(G^(-))PLFAs含量提高23%,革兰氏阳性菌/革兰氏阴性菌值(G^(+)/G^(-))因而降低29%;连施7年后,总PLFAs、细菌、革兰氏阳性菌(G^(+))和放线菌PLFAs含量分别提高16%、13%、28%和38%,腐生真菌PLFAs含量降低19%,而G^(-)菌PLFAs含量、G^(+)/G^(-)均与对照无显著差异。石灰连施3年后,土壤微生物类群PLFAs含量平均降低30%,连施7年后,平均降幅增至36%。有机肥施用3年后,土壤脲酶活性提高了29%;施用7年后,土壤过氧化氢酶、蔗糖酶和脲酶活性分别显著提高了63%、82%和39%。连施石灰3年,脲酶活性显著提高25%,连续施用7年则显著降低39%,对其他酶活性无显著影响。有机肥连施3、7年,土壤通气孔隙度分别增加了14%、33%,有机质总量分别增加了12%、7%,3个活性有机碳组分平均分别提高29%、69%;pH和碱解氮、有效磷、速效钾含量无显著变化;连续施用石灰3、7年,土壤pH分别提高0.6、0.6个单位,而通气孔隙度分别显著降低了47%、28%,总有机质和易氧化有机碳含量无显著变化,细颗粒有机碳含量分别提高了24%、9%,粗颗粒有机碳含量分别提高了100%、21%,施用石灰3年对速效养分含量无显著影响,施用石灰7年土壤碱解氮含量显著降低而有效磷含量显著增加。土壤物理、化学、生物学指标对连续施用有机肥的响应比值以正值为主,对连续施用石灰的响应比值以负值为主,土壤生物、化学指标对连续施用有机肥7年的响应比值较3年趋向更高正值,而对施用石灰趋向更高负值,达到17%~149%。结构方程分析结果表明,连续施用有机肥主要通过增加粗颗粒有机碳含量提升土壤易氧化有机碳,提升微生物总PLFAs含量和脲酶活性,而随着石灰累积用量的增加,降低土壤通气孔隙度、粗颗粒有机碳和碱解氮含量,降低土壤微生物总PLFAs、脲酶活性。【结论】长期连续施用有机肥可持续改善土壤通气性,增加有机质积累,提高土壤物理、化学和生物学性质,短期施用石灰有利于改善土壤物理、化学和生物学性状,但长期连续施用则降低石灰的正向效果。粗颗粒有机碳对土壤生物和化学性状响应有机肥、石灰连续施用的影响最为关键,具有预测土壤健康的潜能。

沼液配施化肥对大葱产量和土壤养分、微生物及酶活性的影响

明确沼液替代化肥的合适比例以及沼液对大葱产量和土壤养分、微生物含量以及酶活性的影响,可为沼液的合理施用提供理论依据。试验设计了不施肥(CK)、化肥(CF)、沼液替代25%化肥氮(25BS)、沼液替代50%化肥氮(50BS)、沼液替代75%化肥氮(75BS)、沼液替代100%化肥氮(100BS)6个处理,分析了大葱产量及土壤养分含量、磷脂脂肪酸含量和碳氮磷循环相关酶活性,并通过偏最小二乘法路径模型(PLS-PM)探究上述指标的因果关系。结果表明,与CK相比,CF和各沼液处理(25BS、50BS、75BS和100BS)均能显著提高大葱产量(P<0.05),并且大葱产量随沼液替代化肥比例的增加呈先增加后降低趋势,其中50BS处理的大葱产量最高,达59.9 t·hm^(−2)。施用沼液可有效改善土壤养分状况,与CK相比,施用沼液显著提高土壤有机碳(SOC,19.5%~65.8%)、全氮(TN,40.5%~69.6%)、铵态氮(NH_(4)^(+),26.8%~77.4%)、硝态氮(NO_(3)^(−),30.1%~41.9%)、速效磷(AP,10.5%~40.6%)、速效钾(AK,5.4%~8.5%)含量。施用沼液可有效提高土壤微生物含量以及土壤酶活性,与CK相比,施用沼液显著提高细菌、真菌、放线菌等微生物的磷脂脂肪酸含量(P<0.05),降低了革兰氏阳性细菌∶革兰氏阴性细菌的比例(P<0.05),有助于提高土壤碳、氮、磷相关循环酶活性(P<0.05);但是,随着沼液替代比例的增加,细菌、革兰氏阳性细菌、真菌、总磷脂脂肪酸含量以及碳、氮、磷相关循环酶活性均呈先增加后降低的趋势(P<0.05)。PLS-PM分析表明,沼液通过增加SOC、TN、NH_(4)^(+)、NO_(3)^(−)、AP含量,进而提高土壤微生物含量以及碳、氮循环酶活性,并提升大葱产量,但是过量的沼液可导致土壤电导率升高,并对土壤微生物活性和大葱生长产生抑制效果。本研究表明,短期施用沼液可显著提高大葱产量,有效改善土壤养分状况,并有利于土壤微生物含量以及酶活性提高,其中以沼液替代50%化肥氮的处理效果最优,但是沼液并不能完全替代化肥,施用过量的沼液容易造成土壤盐分累积,不利于大葱和土壤微生物的生长。

蔬菜废弃物堆肥对设施蔬菜连作土壤生态质量的改良效果

为了探究利用蔬菜废弃物堆肥制备的生物有机肥对设施蔬菜连作土壤的改良效果,将芹菜、白菜、胡萝卜、花椰菜等蔬菜废弃物与玉米秸秆进行堆肥,并施用于不同连作年限的设施小白菜土壤。研究表明,受试的4种土壤中细菌、放线菌及真菌数量,土壤酶活性及小白菜品质均随着堆肥添加量的增加而提高;而土壤尖孢镰刀菌数量则随着堆肥添加量的增加而降低。在连作5年的土壤中,高剂量施肥处理与未施肥对照相比,土壤细菌、放线菌及真菌数量,土壤蔗糖酶、过氧化氢酶、脲酶及磷酸酶活性分别提高0.77、1.63、1.53、3.50、1.66、0.99及1.65倍;小白菜维生素C与可溶性糖含量分别提高了88.56%和50.42%;土壤尖孢镰刀菌数量减少了94.55%。结果表明,利用蔬菜废弃物堆肥制备的生物有机肥能够显著改善连作土壤的生态质量,并且对连作年限长的土壤有着更显著的效果。

菌解小分子鱼肽肥对毛竹鞭笋生长及竹林土壤生态的影响

毛竹林经营过程中为提高鞭笋产量而重施化肥造成竹林生态退化和竹笋品质降低,引进菌解小分子鱼肽肥,通过研究不同肥料配施方式对毛竹鞭笋产量及竹林土壤生态因子的影响,探明菌解小分子鱼肽肥对毛竹生理生态的作用机制。以相同经营现状的毛竹笋用林为研究对象,设置4个肥料配施处理(CK为750 kg·hm^(-2)复合肥、T1为375 kg·hm^(-2)复合肥、T2为“375 kg·hm^(-2)复合肥+150 kg·hm^(-2)菌解小分子鱼肽肥”、T3为“375 kg·hm^(-2)复合肥+300 kg·hm^(-2)菌解小分子鱼肽肥”)进行施肥,于鞭笋笋期统计鞭笋产量,测定土壤养分元素质量分数、土壤酶活性、叶片叶绿素以及叶片养分元素质量分数等指标,分析各指标在不同施肥处理之间的差异显著性和不同指标之间的相关性。结果表明:与750 kg·hm^(-2)复合肥处理相比,“375 kg·hm^(-2)复合肥+150 kg·hm^(-2)菌解小分子鱼肽肥”和“375 kg·hm^(-2)复合肥+300 kg·hm^(-2)菌解小分子鱼肽肥”处理时的鞭笋产量分别提高39.39%、29.09%。比较于750 kg·hm^(-2)复合肥处理和375 kg·hm^(-2)复合肥处理,“375 kg·hm^(-2)复合肥+150 kg·hm^(-2)菌解小分子鱼肽肥”处理显著提高了土壤p H以及有机碳、全氮、全钾、水解性氮、速效钾等土壤养分元素质量分数,显著提升了土壤脲酶、蔗糖酶、酸性磷酸酶活性,同时增加了叶片叶绿素以及碳、氮、钾等元素质量分数。相关性分析结果表明:鞭笋产量与土壤p H、有机碳、全氮、水解性氮、全钾、速效钾质量分数、蔗糖酶活性以及竹叶叶绿素、有机碳、氮、钾质量分数呈极显著正相关。菌解小分子鱼肽肥和复合肥合理配施可通过提高土壤肥力和土壤酶活性,促进毛竹养分元素吸收,从而提高鞭笋产量,减少化肥施用量。

减施化肥增施有机肥和菌肥对番茄产量及土壤微生物和酶活性的影响

通过研究不同化肥减量配施有机肥和菌肥对设施番茄产量及土壤微生物和酶活性的影响,为化肥减量配施有机肥和菌肥的可行性和设施番茄种植中减肥增效提供科学依据。试验设置6个处理,CK:空白对照(不施肥);CF:单施化肥;RF_(1):化肥减施20%配施有机肥20%;RF_(2):化肥减施40%配施有机肥40%;RFM1:化肥减施20%配施有机肥20%+菌肥;RFM2:化肥减施40%配施有机肥40%+菌肥。结果表明:化肥减量配施有机肥和菌肥番茄根际土壤细菌数量提高了53.05%~134.15%,放线菌数量提高13.94%~26.55%,真菌数量降低了20.32%~37.92%,并随有机肥施入量的增加而增加。化肥减量增加菌肥能有效提高土壤细菌/真菌和放线菌/真菌的值。化肥减量配施有机肥和菌剂提高了脲酶、蔗糖酶和过氧化氢酶活性,且随有机肥施入量的增加而增加。减施化肥处理对应增加菌肥处理显著减少了番茄有机酸含量,提高了可溶性固形物、Vc和番茄红素含量。RF_(1)、RF_(2)、RFM_(1)和RFM_(2)产量较CF增产4.40%、-6.55%、8.13%和0.81%。单株结果数、单果重和产量以RFM1较高。综上所述,化肥减量增加有机肥和菌肥能改善根际土壤微生物群落的结构和数量,增加土壤有效养分含量和酶活性,促进植株生长发育,达到增产提质的目的。从土壤微生物数量和结构、酶活性、产量、品质的综合考虑,设施番茄栽培减少20%的化肥用量配施有机肥和菌肥更适宜。

Effect of Groundwater Irrigation on Soil PAHs Pollution Abatement and Soil Microbial Characteristics:A Case Study in Northeast China

To evaluate the effect of groundwater irrigation on the polycyclic aromatic hydrocarbons(PAHs) pollution abatement and soil microbial characteristics,a case study was performed in the Shenfu irrigation area of Shenyang,Northeast China,where the irrigation with petroleum wastewater had lasted for more than fifty years,and then groundwater irrigation instead of wastewater irrigation was applied due to the gradually serious PAHs pollution in soil.Soil chemical properties,including PAHs and nutrients contents,and soil microbial characteristics,including microbial biomass carbon,substrateinduced respiration,microbial quotient(qM),metabolic quotient(qCO2),dehydrogenase(DH),polyphenol oxidase(PO),urease(UR) and cellulase(CE) in surface and subsurface were determined.Total organic C,total N,total P,and available K were significantly different between the sites studied.The PAHs concentrations ranged from 610.9 to 6362.8 μg kg-1 in the surface layers(0-20 cm) and from 404.6 to 4318.5 μg kg-1 in the subsurface layers(20-40 cm).From the principal component analysis,the first principal component was primarily weighed by total PAHs,total organic C,total N,total P and available K,and it was the main factor that influencing the soil microbial characteristics.Among the tested microbial characteristics,DH,PO,UR,CE,qM and qCO2 were more sensitive to the PAHs stress than the others,thus they could serve as useful ecological assessment indicators for soil PAHs pollution.

Effect of Rhizobacterium Rhodopseudomonas palustris Inoculation on Stevia rebaudiana Plant Growth and Soil Microbial Community

There is an increasing concern that the continuous use of chemical fertilizers might lead to harmful effects on soil ecosystem.Accordingly, a biocompatible approach involving inoculation of beneficial microorganisms is presented to promote plant growth and simultaneously minimize the negative effect of chemical fertilizers. In this study, Rhodopseudomonas palustris, a plant growth-promoting rhizobacterium(PGPR), was inoculated into both fertilized and unfertilized soils to assess its influence on Stevia rebaudiana plant growth and microbial community in rhizosphere soils in a 122-d field experiment. Soil enzyme assays(dehydrogenase, urease, invertase, and phosphomonoesterase), real-time quantitative polymerase chain reaction(RT-_qPCR), and a high-throughput sequencing technique were employed to determine the microbial activity and characterize the bacterial community. Results showed that the R.palustris inoculation did not significantly influence Stevia yields and root biomass in either the fertilized or unfertilized soil. Chemical fertilization had strong negative effects on soil bacterial community properties, especially on dehydrogenase and urease activities.However, R. palustris inoculation counteracted the effect of chemical fertilizer on dehydrogenase and urease activities, and increased the abundances of some bacterial lineages(including Bacteroidia, Nitrospirae, Planctomycetacia, Myxococcales, and Legionellales). In contrast, inoculation into the unfertilized soil did not significantly change the soil enzyme activities or the soil bacterial community structure. For both the fertilized and unfertilized soils, R. palustris inoculation decreased the relative abundances of some bacterial lineages possessing photosynthetic ability, such as Cyanobacteria, Rhodobacter, Sphingomonadales, and Burkholderiales. Taken together, our observations stress the potential utilization of R. palustris as PGPR in agriculture, which might further ameliorate the soil microbial properties in the long run.

有机无机氮肥比例对稻田土壤肥力和作物产量的短期效应

【目的】研究短期内(<5年)有机无机氮配施比例对土壤肥力以及水稻产量的影响,以明确提升地力与兼顾产量的养分管理措施。【方法】田间定位试验于2017—2021年在长江中下游的红壤双季稻田进行。共设6个处理:不施肥(CK),单施化肥(CF),有机氮比例分别为25%、50%、75%与100%的有机无机肥配施处理(25%ON,50%ON,75%ON,100%ON)。2021年,早、晚稻成熟后测产;晚稻收获后采集耕层土壤样品,分析土壤物理性状(容重与大团聚体含量)、化学性状(pH、有机质、全氮、全磷、全钾、有效氮、有效磷、速效钾、有效锌、有效硅)与生物学性状(脲酶、酸性磷酸酶、β-葡糖苷酶、微生物生物量碳、微生物生物量氮),采用土壤肥力综合指数(IFI)评价不同比例有机肥料的培肥效果,运用偏最小二乘路径模型(PLS-PM)分析有机无机肥配合比例对IFI以及产量的影响。【结果】随着有机肥比例的提高,有机无机肥配施提升土壤物理、化学、生物学性状的效果也随之提升。土壤有机质含量和β-葡糖苷酶活性与其它所有指标的相关关系均达显著水平,有机碳含量与碳循环过程对土壤物理结构、养分以及微生物活性均有较强影响。相对于其他指标,土壤全磷与有效磷的变异系数较大,受有机肥投入的影响较大。施肥显著提高了土壤IFI,有机无机肥配施的肥力指数显著高于单施化肥,且随着有机肥配施比例升高而递增,而双季稻产量则随着有机肥配施比例升高而递减,有机肥配施比例≤50%时,产量与单施化肥持平,>50%时表现为减产。PLS-PM分析结果显示,有机肥和无机肥投入对IFI均有显著影响,有机肥的效应大于无机肥;有机肥对产量无显著影响,而无机肥投入量对产量影响显著。【结论】有机无机肥配施可以全面改善土壤环境,提高土壤肥力,且有机肥配施比例越高效果越好。但如果培肥时间较短(5年以内),化肥氮对产量的贡献占绝对优势,有机氮的投入比例应控制在50%以下,才能兼顾地力提升与产量的维持。

不同施肥措施对重庆茶园土壤微生物学特性的影响

为探讨长期不同施肥措施对茶园土壤微生物学特性的影响,通过定位施肥试验,于春茶、夏茶、秋茶和冬管期,采集施用菌渣、生物炭+复合肥、有机肥、生物炭有机肥和复合肥(对照)为基肥,脲甲醛缓释肥为追肥的茶园土壤,研究不同施肥措施对重庆茶园土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)含量和β-葡萄糖苷酶(BG)、β-纤维二糖苷酶(CBH)、蔗糖酶(INV)和脲酶(URE)4种碳氮转化酶活性的影响。结果表明:土壤MBC、MBN含量和酶活性均随茶叶不同生长期表现出明显的动态变化,与对照相比,有机肥配施缓释肥显著提高了春茶期土壤MBC含量,提高幅度为50.34%;生物炭有机肥配施缓释肥处理显著提高了春茶期和夏茶期土壤MBN含量,提高幅度分别为61.16%和25.27%;菌渣配施缓释肥对春茶期BG、URE活性提升效果最佳,较对照提升幅度分别为45.56%、44.32%,而CBH活性受到抑制,不同施肥措施INV活性在茶叶不同生长期均受到抑制。通径分析表明,土壤有效磷、NO_(3)^(-)-N直接影响土壤MBC、MBN含量,同时土壤可溶性有机氮还直接影响土壤BG活性,土壤NO_(3)^(-)-N则直接影响土壤CBH、URE和INV活性。因此,重庆地区茶园追肥施用脲甲醛缓释肥时,基肥选用商品有机肥或菌渣有利于提升土壤MBC、MBN含量,并维持相关转化酶活性。

包膜与稳定性氮肥改善棕壤理化和生物学肥力并延缓酸化的效应

【目的】包膜和稳定性尿素肥料的氮素释放及其在土壤中的转化、残留特征不同于普通尿素,本研究评价了长期施用包膜和稳定性尿素肥料对土壤相关性质的影响。【方法】不同包膜和稳定性尿素肥料的定位试验始于2007年。将脲酶抑制剂[N-丁基硫代磷酰三胺(N)、氢醌(H)]和硝化抑制剂[3,4-二甲基吡唑磷酸盐(DM)、双氰胺(D)]按常用添加量添加到大颗粒尿素中制备6种稳定性尿素,供试包膜尿素肥料包括树脂包膜尿素(PCU)和硫包衣尿素(SCU)。试验共9个处理,具体为普通大颗粒尿素(U)、H+U、N+U、D+U、DM+U、H+D+U、N+DM+U、SCU和PCU。于2021年收获期采集0—20 cm耕层土样,分析了土壤基本理化性质指标及与氮转化相关的酶活性及土壤微生物量碳、氮含量。【结果】与试验前(2007年)土壤相比,施用包膜和稳定性尿素增加了棕壤有机质、全氮、全磷、全钾、有效磷以及速效钾含量,有机质增幅达34%~48%,以SCU和U处理的全氮含量最高,为1.26 g/kg,增幅为88%。稳定性尿素处理的土壤pH较常规尿素处理有所提高,其中DM+U处理的土壤pH最高(5.83),较U处理升高了10%,以SCU处理的pH最低(4.87),较U处理的降幅为8%,土壤酸化严重。长期施用包膜与稳定性尿素不同程度地提高了土壤微生物量碳含量,DM+U处理还显著提高了土壤微生物量氮含量。H+U处理抑制了棕壤脲酶活性,硫包衣与树脂包膜尿素则显著激发了脲酶活性。施用包膜与稳定性尿素均增强了棕壤硝化作用潜势与硝化作用,除N+DM+U处理外,包膜与稳定性尿素肥料提高了硝酸还原酶活性。【结论】长期施用包膜与稳定性尿素不同程度地提高了棕壤微生物量,稳定性尿素肥料的长期施用能够有效延缓棕壤酸化,包膜尿素则显著增加了棕壤中全氮和速效氮含量,减少了尿素氮素损失,但硫包衣尿素会导致棕壤pH下降迅速,酸化严重。因此,硫包衣尿素不宜长期在旱田棕壤中施用,而树脂包膜尿素与稳定性尿素均可长期用于棕壤的玉米栽培。

减氮配施生物有机肥对植烟土壤特性及烟草青枯病的防效研究

为解析植烟土壤质量与烟草青枯病发生发展的关系以及减氮配施生物有机肥对烟草青枯病的防控效果,以常规施氮为对照,设置4个减氮水平(5%、10%、15%和20%)+生物有机肥处理的田间小区试验,研究了减氮配施生物有机肥模式对土壤主要理化性质、烟叶产量和质量的影响,并进一步考察了对烟草青枯病的田间防效,基于相关性分析解析土壤理化因子与病情指数间的关系。结果表明,减氮配施生物有机肥各处理的土壤容重、pH下降,土壤碳氮比、有机碳含量、碳储量、氮储量、土壤蔗糖酶活性、脲酶活性、微生物量碳、微生物量氮均不同程度增加,烟叶产量、上等烟比例、中上等烟比例均显著提升。烟草青枯病病情指数显著降低70.32%~75.31%,平均防治效果为69.64%~75.97%。其中,减氮15%配施生物有机肥处理为最佳模式。相关性分析结果表明,病情指数与土壤碳氮比、有机碳、碳储量、氮储量、蔗糖酶活性、脲酶活性、微生物量碳和生物量碳氮比呈极显著负相关(P<0.01),与pH呈极显著正相关(P<0.01),与微生物量氮呈负相关(P<0.05),与土壤容重、碱解氮、有效磷和速效钾呈正相关(P<0.05)。在试验条件下,适当减氮并配施生物有机肥能有效改善土壤质量,提高烟叶产量和质量,降低烟草青枯病的发生。

地膜覆盖及不同施肥处理对根际土壤微生物数量和酶活性的影响

通过室内分析和田间裂区试验相结合的方法,研究地膜覆盖和不同施肥处理对玉米不同生育期土壤微生物数量和土壤酶活性的影响。结果表明:(1)对于根际土壤而言,覆膜条件下各施肥处理的脲酶活性、蔗糖酶活性均高于不施肥处理;无膜条件下各施肥处理的碱性磷酸酶活性均高于不施肥处理。其中脲酶活性在大喇叭口期最高,NPK-C(氮磷钾配施-覆膜)、NPKO-C(氮磷钾配施有机肥-覆膜)、NPKB-C(氮磷钾配施生物炭-覆膜)分别较CK-C(对照-覆膜)高31.03%、66.01%、49.26%;蔗糖酶活性也是大喇叭口期最高,NPK-C、NPKO-C、NPKB-C分别较CK-C高38.43%、117.53%、64.94%;碱性磷酸酶活性在乳熟期最高,NPK(氮磷钾配施)、NPKO(氮磷钾配施有机肥)、NPKB(氮磷钾配施生物炭)分别较CK(对照)高43.84%、30.38%、31.53%。(2)覆膜条件下各施肥处理细菌、真菌、放线菌数量均高于不施肥处理。其中乳熟期细菌数量最大,NPK-C、NPKO-C分别较CK-C高19.74%、26.26%;放线菌数量也是乳熟期最大,NPK-C、NPKO-C、NPKB-C分别较CK-C增加了23.49%、62.94%、46.97%;真菌数量在大喇叭口期最大,NPK-C、NPKO-C分别较CK-C高120.30%、60.89%。综合比较,覆膜条件下化肥配施有机肥(NPKO-C)对于增加土壤酶活性和微生物数量效果最佳。

对比不同微生物肥料与化肥对茶园土壤肥力和茶叶品质的影响

为探究微生物肥料对茶园土壤肥力及茶叶产量与品质的影响,以茶树“龙井43”品种为材料,通过田间试验,研究了不施肥(CK)、常规化肥(TF)、多菌种复合微生物肥料(BCF1)、豆粕发酵类微生物肥料(BCF2)、黄腐酸类微生物肥料(BCF3)对茶园土壤养分含量与碳、氮、磷转化酶活性及绿茶产量与品质的影响。结果表明,与常规化肥相比,3种微生物肥料使土壤pH平均提升0.27个单位、容重显著降低9.73%,土壤速效钾、有效磷、有机质和碱解氮含量平均提升9.72%、6.25%、9.19%和5.40%;与常规化肥相比,3种微生物肥料使土壤β-葡萄糖苷酶、β-N-乙酰氨基葡萄糖酶活性分别增加11.61%、20.13%,且黄腐酸类微生物肥料使亮氨酸氨基肽酶、纤维二糖苷酶和β-木聚糖酶活性分别显著增加97.70%、66.44%和71.62%。与常规化肥相比,3种微生物肥料处理使茶叶磷积累量上升10.08%;铁、钙、锰和镍分别增加19.63%、7.56%、12.06%和24.14%。与常规化肥相比,黄腐酸类微生物肥料显著提高了百芽重、发芽密度、鲜叶产量和游离氨基酸总量。相关性分析表明鲜叶产量与土壤速效钾、碱解氮、有机质含量及纤维二糖苷酶、酸性磷酸酶和β-木聚糖酶活性显著正相关(P<0.05)。综上所述,3种微生物肥料相比化肥可以更好地提高茶园土壤肥力,提高茶叶产量和品质,其中黄腐酸类微生物肥料效果最好。