Soil microbial activity and biomass is stimulated by leguminous cover crops     

R. Dinesh  S. Ghoshal Chaudhuri  T. E. Sheeja  K. N. Shiva 《植物养料与土壤学杂志》2009,172(2):288-296

The leguminous cover crops Atylosia scarabaeoides (L.) Benth., Centrosema pubescens Benth., and Pueraria phaseoloides (Roxb.) Benth., were grown in the interspaces of a 19 y–old coconut plantation and incorporated into the soil at the end of the monsoon season every year. At the end of the 12th year, soils from different depths were collected and analyzed for various microbial indices and their interrelationships. The objectives were to assess the effects of long‐term cover cropping on microbial biomass and microbial‐community structure successively down the soil profile. In general, total N (TN), organic C (OC), inorganic N, extractable P, and the levels of biological substrates viz., dissolved organic C (DOC) and N (DON), labile organic N (LON), and light‐fraction organic matter (LFOM) C and N decreased with depth at all the sites. Among sites, the cover‐cropped (CC) sites possessed significantly greater levels of TN, OC, DOC, DON, and LON compared to the control. Consequently, microbial biomass C (MBC), N (MBN), and P (MBP), CO₂ evolution, and ATP levels, in general, decreased with depth at all sites and were also significantly higher in the CC sites. Among the ratios of various microbial indices, the ratio of MBC to OC and metabolic quotient (qCO₂) declined with depth. Higher MBC‐to‐OC ratios and large qCO₂ levels in the surface soils could be ascribed to greater levels of readily degradable C content and indicated short turnover times of the microbial biomass. In contrast, the ratios of MBC to MBN and MBC to MBP increased with depth due to low N/P availability and relatively higher C availability in the subsoils. Cover cropping tended to enhance the ratios of MBC to OC, MBC to MBN, MBC to MBP, and ergosterol to MBC and decreased the ATP‐to‐MBC ratio at all depths. The relatively lower ATP‐to‐MBC ratios in the CC site, especially in the subsoil indicated microbial‐community structure possibly dominated by fungi. By converting the ergosterol content to fungal biomass, it was observed that fungi constituted 52%–63% of total biomass C at the CC site, but only 33%–40% of total biomass C at the control site. Overall, the study indicated that leguminous cover crops like P. phaseoloides or A. scarabaeoides significantly enhanced the levels of OC, N and microbial activity in the soils, even down to 50 cm soil depth.  相似文献   

施用味精废液对西瓜根际土壤微生物量碳、氮含量的影响   总被引：2，自引：0，他引：2  

臧传聪 《水土保持通报》2014,(4):99-103

通过大田试验,研究了N100(尿素提供100%的氮)、M10N90(味精废液和尿素分别提供10%和90%的氮)、M30N70(味精废液和尿素分别提供30%和70%的氮)和M50N50(味精废液和尿素各提供50%的氮)等处理对西瓜根际土壤微生物量碳(MBC)和微生物量氮(MBN)含量的影响。结果表明,施用味精废液使土壤生物过程活跃,有利于土壤有机物质的转化和西瓜正常生长所需的营养供应。在西瓜不同生育期,根际土壤MBC和MBN含量动态变化规律不同。与M30N70处理相比,M10N90和M50N50处理对西瓜根际土壤微生物量碳、氮的影响较小。分析可知,味精废液与化肥以3∶7比例配施对西瓜根际土壤微生态环境的作用效果最佳,更有利于平衡西瓜氮素营养。  相似文献   

Use of langbeinite to reclaim sodic and saline sodic soils     

《Communications in Soil Science and Plant Analysis》2012,43(17-18):2829-2842

Abstract

Langbeinite is a soluble potassium‐magnesium sulfate mineral (K₂SO₄2MgSO₄) found as an evaporite in many regions of the world. Langbeinite was used as a reclaiming material in a fine textured (clay loam) saline sodic soil (Grabe Series). This amendment can be dissolved and directly into the irrigation water, displacing sodium (Na) quickly with minimal water use. This amendment was superior over gypsum as a reclaiming material for a saline sodic soil in batch, column, and greenhouse studies. Langbeinite required 50% less irrigation water than gypsum to displace and leach exchangeable Na from soils. Langbeinite improved the infiltration rates of saline sodic soils, but not as effectively as gypsum. Significant increases in germination percent dry matter production mass of lima bean (Phaseolus lunatus L.) plants were observed when using langbeinite over the gypsum soil amendment.  相似文献   

Dynamics of soil labile carbon and nitrogen pools in riparian zone of Wyaralong Dam in Southeast Queensland,Australia     

Qi Jiang  Zhihong Xu  Yanbin Hao  Haibo Dong 《Journal of Soils and Sediments》2017,17(4):1030-1044

  相似文献   

IONIC DISPLACEMENT AND RECLAMATION OF SALINE‐SODIC SOILS USING CHEMICAL AMENDMENTS AND CROP ROTATION     

S. Ahmad  A. Ghafoor  M.E. Akhtar  M.Z. Khan 《Land Degradation \u0026amp; Development》2013,24(2):170-178

Biological, chemical and bio‐chemical strategies have been tested in the past for reclamation of saline‐sodic and sodic soils. The efficiency of two crop rotations (rice‐wheat and Sesbania‐wheat) alone or in combination with either gypsum (CaSO₄.2H₂O) or sulfuric acid (H₂SO₄) was tested for ionic displacement from four saline‐sodic soils. Pure gypsum was applied at 50 per cent of soil gypsum requirement at the time of planting rice and Sesbania, whereas 95 per cent pure sulfuric acid was added at 50 per cent soil gypsum requirement as one‐third applications by mixing with the first three irrigations. The rice crop biomass decreased at a soil saturation extract electrical conductivity (EC_e) of 8 dS m⁻¹, whereas wheat and Sesbania were influenced at a sodium adsorption ratio (SAR) of ≥40. Gypsum treatment helped the crops flourish well at these EC_e and SAR levels. The infiltrated volume of water dropped with decrease in EC_e : SAR ratio of soils and increase in crop biomass production. Crops rotation treatments alone helped leach sodium (Na⁺) and other ions successfully at SAR ≤ 21 but were less effective at SAR ≥ 40 at which point plants growth was also curtailed. Gypsum and H₂SO₄ treatments significantly aided leaching of Na⁺ and other ions with water at SAR ≥ 40 under both the crop rotations. Hence, crops effectively reclaimed soil at low sodicity level, whereas at high SAR, chemical amendments are obligatory in order to reclaim soils. This study also suggests that the required dose of H₂SO₄ should be applied with pre‐planting irrigation for better yield of the first crop. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Response of soil microbial community and diversity to increasing water salinity and nitrogen fertilization rate in an arid soil     

Wei Min  Huijuan Guo  Wen Zhang  Guangwei Zhou  Lijuan Ma  Jun Ye 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(2):117-126

The scarcity of fresh water has forced farmers to use saline water (SW) for irrigation. It is important to understand the response of the soil microbial community and diversity to saline irrigation water. The objective of this study was to determine the effects of irrigation water salinity and nitrogen fertilization rates on soil physicochemical properties, microbial activity, microbial biomass, and microbial functional diversity. The field experiment consisted of a factorial design with three levels of irrigation water salinity (electrical conductivities (ECs) of 0.35, 4.61 or 8.04?dS?m^?1) and two nitrogen rates (0 and 360?kg?N?ha^?1). The results showed that the 4.61 and 8.04?dS?m^?1 treatments both reduced soil microbial biomass C (MBC), microbial biomass N (MBN), basal respiration, total phospholipid fatty acid (PLFA), bacterial PLFA, fungal PLFA, and fungal:bacterial ratios. In contrast, the SW treatments increased the MBC:MBN ratio. Nitrogen fertilization increased soil MBC, MBN, basal respiration, total PLFA, bacterial PLFA, and gram-negative bacterial PLFA. In contrast, N fertilization decreased gram-positive bacterial PLFA, fungal PLFA, and fungal:bacterial ratios. Average well color development, Richness, and Shannon's Index were always lowest in the 8.04?dS?m^?1 treatment. Carbon utilization patterns in the 8.04?dS?m^?1 treatment were different from those in the 0.35?dS?m^?1 treatment. In conclusion, five years of irrigation with brackish or SW reduced the soil microbial biomass, activity, and functional diversity, which may cause the deterioration of soil quality. Thus, the high-salinity water (EC?>?4.61?dS?m^?1) is not appropriate as a single irrigation water resource. Proper N fertilizer input may overcome some of the negative effects of salinity on soil microbial.  相似文献   

“薄浅湿晒”灌溉稻田土壤微生物量碳、氮和酶活性研究   总被引：1，自引：0，他引：1  

梁燕菲  张潇潇  李伏生 《植物营养与肥料学报》2013,19(6):1403-1410

通过盆栽试验,研究了不同氮肥水平下薄、 浅、 湿、 晒灌溉对水稻拔节期、 孕穗期和乳熟期土壤微生物量碳（MBC）、 微生物量氮（MBN）、 硝化细菌和反硝化细菌数量和酶活性的影响,以探讨该灌溉方式下土壤微生物活性变化规律。试验设2 种灌水方式,即常规灌溉（CIR）和薄、 浅、 湿、 晒灌溉（TIR）; 3种氮肥水平,即低氮（N 0.10 g/kg）、 中氮（N 0.15 g/kg）和高氮（N 0.2 g/kg）。结果表明,与CIR处理相比,TIR处理土壤MBC增加13%~240%,而土壤MBN减少6.5%~47.3%;高氮水平时3个时期TIR处理土壤硝化细菌有所增加,反硝化细菌拔节期和孕穗期降低12.1%~61.2%,而乳熟期增加0.7~3.0倍;中、 低氮水平时孕穗期TIR处理土壤硝酸还原酶活性分别降低63.8%和43.3%。与低氮水平相比,中氮水平可以增加土壤MBC、 MBN、 硝化细菌和反硝化细菌数量以及过氧化氢酶、 脲酶和转化酶活性,而高氮水平则降低土壤MBN,以及过氧化氢酶、 脲酶和硝酸还原酶活性。可见,中等氮肥水平下薄、 浅、 湿、 晒灌溉方式能有效提高稻田土壤微生物量碳和过氧化氢酶、 脲酶、 转化酶活性。  相似文献   

Responses of microbial biomass and respiration of soil to topography,burning, and nitrogen fertilization in a temperate steppe     

Weixing Liu  Wenhua Xu  Yi Han  Changhui Wang  Shiqiang Wan 《Biology and Fertility of Soils》2007,44(2):259-268

Temporal dynamics of microbial biomass and respiration of soil and their responses to topography, burning, N fertilization, and their interactions were determined in a temperate steppe in northern China. Soil microbial indices showed strong temporal variability over the growing season. Soil microbial biomass C (MBC) and N (MBN) were 14.8 and 11.5% greater in the lower than upper slope, respectively. However, the percentage of organic C present as MBC and the percentage of total N present as MBN were 16.9 and 26.2% higher in the upper than lower slope, respectively. Neither microbial respiration (MR) nor metabolic quotient (qCO₂) was affected by topography. Both MBC and MBN were increased by burning, on average, by 29.8 and 14.2% over the growing season, and MR and qCO₂ tended to reduce depending on the sampling date, especially in August. Burning stimulated the percentage of organic C present as MBC and the percentage of total N present as MBN in the upper slope, but did not change these two parameters in the lower slope. No effects of N fertilization on soil microbial indices were observed in the first growing season after the treatment. Further research is needed to study the long-term relationships between changes in soil microbial diversity and activity and plant community in response to burning and N fertilization.  相似文献   

The microbial biomass and activity in soil with shrub (Caragana korshinskii K.) plantation in the semi-arid loess plateau in China     

Guo-Mei Jia  Bing-Ru Liu  Gang Wang  Baolin Zhang 《European Journal of Soil Biology》2010,46(1):6-10

Caragana korshinskii K. is a shrub species which is adapted to arid and semi-arid environments and plays an important role in soil protection. The objective of this study was to determine the influence of this shrub plantation on the soil ecosystem functions driven by microorganisms in the long-term. The changes in the size and activity of soil microbial biomass and the relationship between soil microbial biomass and chemical properties were investigated under shrub plantations aged 6, 18 and 26 years. The results showed that the pH value in the soil decreased gradually, while soil organic carbon (OC) and total nitrogen (TN) significantly increased with the age of C. korshinskii. Although microbial biomass carbon (MBC) and MBC/OC ratio gradually increased, the ratio of basal respiration to MBC (qCO₂) decreased with the age of C. korshinskii. The microbial biomass nitrogen (MBN) and MBC had a positive relationship with soil TN and OC, respectively. The flux of CO₂ decreased with the age of C. korshinskii which had a significant negative relationship with soil OC, TN, MBN and MBC. The results indicate that C. korshinskii plantations may help to improve microbially driven ecosystem functioning through long-term creation of resource-island.  相似文献   

黑河流域保护性耕作对农田土壤微生物量碳、氮和有机质的调控     

张凤云 《水土保持通报》2014,(1):93-97

为了探讨黑河流域保护性耕作对土壤生产力的影响,设计20cm留茬(NS20),20cm留茬压倒(NPS20),40cm留茬(NS40),40cm留茬压倒(NPS40)和传统耕作(CT)5个处理,研究了黑河流域保护性耕作对农田土壤有机质、土壤微生物量C、土壤微生物量N以及作物产量和水分利用效率的影响。结果表明,保护性耕作农田0—20cm土层土壤有机质、土壤微生物量C和N的含量均高于传统耕作,且其在剖面中的变化趋势基本一致,即随土层深度增加下降;土壤微生物量N有明显的"表聚现象";相关分析表明土壤有机质和土壤微生物量C之间显著正相关(r=0.85,p0.05),与土壤微生物量N之间无明显的相关关系(r=0.47,p0.05);保护性耕作提高了春小麦的产量,NPS20和NPS40增产效果最好,较CT分别增产53.08%和46.59%,与CT之间差异达到极显著水平;保护性耕作提高了春小麦的水分利用效率(WUE),NPS20,NS40,NPS40,NS20分别较CT的WUE提高了58.02%,43.40%,47.27%,23.78%。  相似文献   

山核桃集约经营过程中土壤微生物量碳氮的变化   总被引：1，自引：1，他引：1  

邵香君  徐建春  吴家森  沈振明 《水土保持通报》2016,36(2):72-75,81

[目的]研究不同集约经营历史山核桃林的土壤微生物量碳氮的演变规律,为山核桃林地土壤管理提供科学依据。[方法]在浙江省临安市分别采集并分析了经营历史为5,10,15,20a的山核桃林土壤样品,并与天然混交林(0a)进行比较。[结果]天然混交林改造为山核桃纯林并经集约经营后,林地土壤微生物量碳(MBC)、微生物量氮(MBN)、MBC/MBN,MBC/SOC均表现出先下降而后上升的趋势,经过10a经营后降到最低水平,与0a相比,0—10cm土层MBC,MBN和MBC/SOC分别降低了52.1%,32.0%和31.0%。经营10a的林地土壤MBC/MBN显著低于前期经营林地,而MBN/TN在经营过程中的差异并不显著。[结论]山核桃集约经营后,林地土壤微生物量碳氮含量显著下降。  相似文献   

间伐对杉木人工林土壤碳氮及其组分特征的影响     

王有良  宋重升  彭丽鸿  崔朝伟  郑鸣鸣  林开敏  任正标  谢汝根  胡永颜 《水土保持学报》2021,35(5):204-212

为探究不同间伐强度对杉木人工林土壤碳氮及其组分特征的影响,以福建省三明市官庄国有林场11年生杉木(Cunninghamia lanceolata)人工林为研究对象,采用弱度间伐(LIT)、中度间伐(MIT)、强度间伐(HIT)等3种间伐强度,研究不同间伐强度林分0—10,10—20,20—40,40—60,60—80,80—100 cm土层总有机碳(SOC)、全氮(TN)及易氧化有机碳(ROC)、硝态氮(NO_3~--N)、铵态氮(NH_4~+-N)、微生物量碳(MBC)、微生物量氮(MBN)、微生物熵碳(qMBC)、微生物熵氮(qMBN)的变化特征,以探讨不同间伐强度对杉木人工林土壤碳氮及其组分特征的影响。结果表明:间伐降低了土壤SOC和TN的含量,降低幅度分别为1.4%～36.9%,3.1%～45.7%。间伐增加了土壤MBC、NO_3~--N的含量,而对ROC、NH_4~+-N和MBN的程度在不同土层有差异,qMBC和qMBN随着间伐强度的增加而增大。相关性分析表明,土壤SOC分别与TN、qMBC、ROC、NH_4~+-N、MBC、MBN呈极显著正相关(P0.01);TN与qMBN、ROC、NH_4~+-N、MBC、MBN呈极显著正相关(P0.01)。杉木人工林间伐处理降低了土壤表层SOC和TN含量,增加了土壤SMBC和qMBC、qMBN,同时也增加了土壤表层(0—10 cm)SMBN。抚育间伐导致土壤SOC和TN含量降低主要是由于活性碳、氮含量的增加,提高土壤中有机质分解速率,最终导致土壤SOC和TN含量降低。  相似文献   

Effect of land management and soil texture on seasonal variations in soil microbial biomass in dry tropical agroecosystems in Tanzania     

Soh Sugihara  Shinya Funakawa  Method Kilasara  Takashi Kosaki 《Applied soil ecology》2010,44(1):80-88

Soil microbes are an essential component of most terrestrial ecosystems; as decomposers they are responsible for regulating nutrient dynamics, and they also serve as a highly labile nutrient pool. Here, we evaluated seasonal variations in microbial biomass carbon (MBC) and nitrogen (MBN) as well as microbial activity (as qCO₂) for 16 months with respect to several factors relating to soil moisture and nutrients under different land management practices (plant residue application, fertilizer application) in both clayey (38% clay) and sandy (4% clay) croplands in Tanzania. We observed that MBC and MBN tended to decrease during the rainy season whereas they tended to increase and remain at high levels during the dry season in all treatment plots at both of our test sites, although soil moisture did not correlate with MBC or MBN. qCO₂ correlated with soil moisture in all treatment plots at both sites, and hence soil microbes act as decomposers mainly during the rainy season. Although the effect of seasonal variation of soil moisture on the dynamics of MBC, MBN, and qCO₂ was certainly greater than that attributable to plant residue application, fertilizer application, or soil texture, plant residue application early in the rainy season clearly increased MBC and MBN in both clayey and sandy soils. This suggests that plant residue application can help to not only counter the N loss caused by leaching but also synchronize crop N uptake and N release from soil microbes by utilizing these microbes as an ephemeral nutrient pool during the early crop growth period. We also found substantially large seasonal variations in MBC and MBN, continuously high qCO₂, and rapid turnover of soil microbes in sandy soil compared to clayey soil. Taken together, our results indicate that soil microbes, acting as both a nutrient pool and decomposers, have a more substantial impact on tropical sandy soil than on clayey soil.  相似文献   

添加秸秆碳源对土壤微生物生物量和原生动物丰富度的影响   总被引：3，自引：1，他引：2  

张四海  曹志平  胡婵娟 《中国生态农业学报》2011,19(6):1283-1288

为了研究引入秸秆碳源对根结线虫(Meloidogyne spp.)病害严重土壤中微生物生物量和原生动物的影响, 以番茄为供试作物, 设置4个梯度的小麦秸秆添加量[CK(0 g·kg^-1), 1N(2.08 g·kg^-1)、2N(4.16 g·kg^-1)和4N(8.32 g·kg^-1)], 研究不同种植时间(6个月和4个月)下土壤微生物生物量碳、氮和原生动物丰度的变化。研究结果表明: 添加秸秆对微生物生物量碳、氮和原生动物丰富度有明显促进作用, 添加的秸秆量越多, 这种促进作用越明显。不同秸秆添加量处理中, 微生物生物量碳、氮和原生动物丰度为: 4N>2N>1N>CK。秸秆对原生动物的群落结构也有显著影响, 在各处理中, 鞭毛虫和肉足虫占有绝大比例, 分别占总丰度的29.44%和66.19%, 纤毛虫仅占4.37%。在相同添加秸秆量条件下, 土壤原生动物丰度随种植时间的延长而提高, 而微生物生物量碳、氮量随种植时间的延长而降低。而在种植时间相同条件下, 随着秸秆量的增加土壤微生物生物量碳、氮量和微生物生物量碳氮比和原生动物总丰度相应增加。  相似文献   

黄土高原半干旱地区撂荒地次生植被演替过程中土壤微生物活性研究   总被引：3，自引：0，他引：3  

JIANG Jin-Ping  XIONG You-Cai  JIANG Hong-Mei  YE De-You  SONG Ya-Jie  LI Feng-Min 《土壤圈》2009,19(6):735-747

To show the vegetation succession interaction with soil properties, microbial biomass, basal respiration, and enzyme activities in different soil layers (0--60 cm) were determined in six lands, i.e., 2-, 7-, 11-, 20-, 43-year-old abandoned lands and one native grassland, in a semiarid hilly area of the Loess Plateau. The results indicated that the successional time and soil depths affected soil microbiological parameters significantly. In 20-cm soil layer, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), MBC/MBN, MBC to soil organic carbon ratio (MBC/SOC), and soil basal respiration tended to increase with successional stages but decrease with soil depths. In contrast, metabolic quotient (qCO2) tended to decrease with successional stages but increase with soil depths. In addition, the activities of urease, catalase, neutral phosphatase, β-fructofuranosidase, and carboxymethyl cellulose (CMC) enzyme increased with successional stages and soil depths. They were significantly positively correlated with microbial biomass and SOC (P < 0.05), whereas no obvious trend was observed for the polyphenoloxidase activity. The results indicated that natural vegetation succession could improve soil quality and promote ecosystem restoration, but it needed a long time under local climate conditions.  相似文献   

不同栽培方式对温室连作黄瓜土壤微生物量碳氮和作物产量的影响     

张雪艳  曹云娥田蕾田永强  高丽红 《植物营养与肥料学报》2014,20(3):562-569

以连作8年温室连作黄瓜土壤为材料,试验设5个不同轮作方式处理, 1）早春茬黄瓜夏茬休闲秋冬茬黄瓜（CK）; 2）早春茬黄瓜夏茬休闲秋冬茬黄瓜间作大蒜（CS1）; 3）早春茬黄瓜夏茬茼蒿秋冬茬黄瓜（CS2）; 4）早春茬番茄夏茬菠菜秋冬茬黄瓜（CS3）; 5）早春茬黄瓜夏茬大蒜秋冬茬黄瓜(CS4),进行了5年的盆栽试验,采用后3年的数据,评价不同栽培方式对土壤微生物量碳氮和主栽作物产量的连年影响,探讨栽培方式对连作黄瓜土壤的修复效果。研究结果表明,相对CK,CS3在第三和四年早春茬显著增加微生物量碳、 氮以及碳/氮,CS2和CS3在三至五年夏茬显著增加微生物量碳和碳/氮, CS2显著增加三至五年早春茬、 早春茬+秋冬茬产量,CS4显著增加第3和4年早春茬、 早春茬+秋冬茬产量和第三至五年秋冬茬产量; 微生物量碳和碳/氮与秋冬茬产量呈显著正相关,与早春茬+秋冬茬产量呈极显著正相关; 处理与季节均对微生物量碳和碳/氮产生极显著影响,且两者有极显著交互作用; 季节、 处理季节对微生物量氮有显著影响,处理、 季节、 处理季节对作物产量有极显著影响。总之,CS2提高微生物量碳、 碳/氮、 作物产量效果最佳。  相似文献   

Effect of grazing intensity on protozoan community,microbial biomass,and enzyme activity in an alpine meadow on the Tibetan Plateau     

Bin Lin  Xiaorong Zhao  Yong Zheng  Sha Qi  Xingzhong Liu 《Journal of Soils and Sediments》2017,17(12):2752-2762

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苏打盐碱水灌溉的土壤添加石膏肥和有机肥后水溶性碳和微生物碳研究   总被引：1，自引：0，他引：1  

O. P. CHOUDHARY  J. K. GILL  BIJAY-SINGH 《土壤圈》2013,23(1):88-97

Microbial biomass carbon (MBC), a small fraction of soil organic matter, has a rapid turnover rate and is a reservoir of labile nutrients. The water-extractable carbon pools provide a fairly good estimate of labile C present in soil and can be easily quantified. Changes in soil MBC and water-extractable organic carbon pools were studied in a 14-year long-term experiment in plots of rice-wheat rotation irrigated with canal water (CW), sodic water (SW, 10-12.5 mmol c L-1 residual sodium carbonate), and SW amended with gypsum with or without application of organic amendments including farmyard manure (FYM), green manure (GM), and wheat straw (WS). Irrigation with SW increased soil exchangeable sodium percentage by more than 13 times compared to irrigation with CW. Sodic water irrigation significantly decreased hot water-extractable organic carbon (HWOC) from 330 to 286 mg kg-1 soil and cold water-extractable organic carbon (CWOC) from 53 to 22 mg kg-1 soil in the top 0-7.5 cm soil layer. In the lower soil layer (7.5-15 cm), reduction in HWOC was not significant. Application of gypsum alone resulted in a decrease in HWOC in the SW plots, whereas an increase was recorded in the SW plots with application of both gypsum and organic amendments in both the soil layers. Nevertheless, application of gypsum and organic amendments increased the mean CWOC as compared with application of gypsum alone. CWOC was significantly correlated with MBC but did not truly reflect the changes in MBC in the treatments with gypsum and organic amendments applied. For the treatments without organic amendments, HWOC was negatively correlated with MBC (r = 0.57*) in the 0-7.5 cm soil layer, whereas for the treatments with organic amendments, both were positively correlated. Irrigation with SW significantly reduced the rice yield by 3 t ha-1 and the yield of rice and wheat by 5 t ha-1 as compared to irrigation with canal water. Application of amendments significantly increased rice and wheat yields. Both the rice yield and the yield of rice and wheat were significantly correlated with MBC (r = 0.49**-0.56**, n = 60). HWOC did not exhibit any relation with the crop yields under the treatments without organic amendments; however, CWOC showed a positive but weak correlation with the crop yields. Therefore, we found that under sodic water irrigation, HWOC or CWOC in the soils was not related to MBC.  相似文献   

喀斯特峰丛洼地不同植被类型土壤微生物量碳氮磷和养分特征   总被引：1，自引：0，他引：1  

黄娟  邓羽松  韦慧  林立文  黄海梅  付智勇 《土壤通报》2022,53(3):605-612

  目的  探讨桂西北喀斯特峰丛洼地不同植被类型的土壤理化性质和微生物碳(MBC)、微生物氮（MBN）、微生物磷（MBP）含量的变化特征及它们之间的关系。  方法  利用生态化学计量方法和Pearson相关性分析方法研究不同植被类型和土层深度对土壤MBC、MBN、MBP含量和土壤养分含量分布特征的影响。  结果  （1）不同植被类型土壤养分含量和MBC、MBN、MBP含量依次为次生林 > 灌木 > 灌草 > 草地 > 耕地;土壤养分垂直分布表现为随着土层深度加深而下降,不同土层间土壤有机碳（SOC）、全氮（TN）、全磷（TP）含量差异显著,土壤MBC、MBN和MBP含量在不同植被类型和不同土层间差异显著,均表现为MBC > MBN > MBP。（2）不同植被类型土壤MBC/SOC和MBP/TP的值较小,MBN/TN的差异较大。不同植被类型的土壤MBC/MBN差异显著,MBC/MBP变化范围较大,MBN/MBP表现为次生林 > 灌草 > 灌木 > 草地 > 耕地。（3）土壤MBC和MBN与SOC、TN、速效氮和速效钾呈显著或极显著正相关,与土壤容重、pH值表现出不同程度的负相关,表明植被恢复过程中土壤MBC和MBN可作为衡量土壤养分的敏感性指标。  结论  不同植被类型的土壤微生物生物量碳氮磷、养分含量和化学计量特征有明显的表聚效应,随着植被的正向演替,土壤结构、养分和微生物群落功能得到显著提高。  相似文献   

退化马尾松林恢复过程中芒萁覆盖对土壤微生物生物量碳氮及其周转的影响     

苏浩浩  黄桥明  邓翠  吕茂奎  谢锦升 《水土保持学报》2023,37(3):336-344

为探究侵蚀退化红壤马尾松林恢复过程中林下芒萁对土壤微生物生物量碳氮月动态及其周转的影响,以不同恢复年限的马尾松林为研究对象,对比分析马尾松林恢复过程中林下保留芒萁、去除芒萁处理和林下裸地土壤中12个月的土壤微生物生物量碳(MBC)和微生物量氮(MBN)含量及其周转速率、周转时间和流通量,并分析其与土壤理化性状的关系。结果表明:(1)保留芒萁覆盖处理的MBC和MBN平均含量分布比林下裸地提高26.99%~277.31%和13.54%~173.39%,而去除芒萁处理分布比保留芒萁处理降低12.29%~27.01%和5.02%~28.45%,差异均随恢复年限呈先降低后增加的趋势。(2)所有处理的土壤微生物量碳氮季节动态均表现为春夏季较高,秋冬季较低的趋势,进入生长季前的土壤微生物量碳氮含量更能反映该地区的平均水平。(3)在退化马尾松林恢复过程中,芒萁覆盖降低土壤微生物生物量碳氮周转速率,增加周转时间,提高土壤微生物生物量碳氮含量和流通量,促进土壤有机质的积累和养分释放。相关分析和逐步回归分析表明,MBC、MBN流通量分别与DOC、DON呈显著正相关,周转速率分别与铵态氮(NH₄⁺-N)和TN呈显著负相关,表明土壤碳和氮及其有效性是影响土壤微生物量周转的关键因素。  相似文献