Soil Microbial Biomass Nitrogen Contents Research Articles

Tillage with Crop Residue Returning Management Increases Soil Microbial Biomass Turnover in the Double-Cropping Rice Fields of Southern China

The variety of soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) content, and the flux turnover rate of SMBC and SMBN for 0–10 cm and 10–20 cm layers in a paddy field in southern China with different tillage practices were studied. The tillage experiment included conventional tillage and crop residue returning (CT), rotary tillage and crop residue returning (RT), no–tillage and crop residue returning (NT), and rotary tillage with all crop residues removed from the paddy field as a control (RTO). The result showed that the SMBC and SMBN contents at 0–10 cm and 10–20 cm layers in the paddy field with CT, RT, and NT treatments were significantly increased. This result indicates that the flux turnover rate of SMBC and SMBN for 0–10 cm and 10–20 cm layers in the paddy field with CT treatment were increased by 65.49%, 39.61%, and 114.91%, 119.35%, compared with the RTO treatment, respectively. SMBC and SMBN contents and the flux turnover rate of SMBC and SMBN for the 0–10 cm layer were higher than that of the 10–20 cm layer in paddy fields under the same tillage condition. Therefore, applying rotary tillage or conventional tillage and crop residue returning produced beneficial management for increasing soil microbial biomass content and its turnover under a double–cropping rice system in southern China.

Effects of Different Long-Term Fertilizer Management Systems on Soil Microbial Biomass Turnover in a Double-Cropping Rice Field in Southern China

Soil microbial biomass content is usually regarded as an early indicator of changes in soil quality and soil fertility in paddy fields. Soil microbial biomass turnover is mainly influenced by the application of different fertilizer management systems. However, there is still a need to further investigate the effects of different long-term fertilizer management systems on soil microbial biomass turnover in paddy fields under the double-cropping rice (Oryza sativa L.) system. Therefore, the effects of different long-term (36 years) fertilizer practices on soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) contents, and the flux turnover rates of SMBC and SMBN at the 0–10 cm and 10–20 cm layers in a double-cropping rice field in southern China were investigated in the present paper. The field experiment included four different fertilizer treatments: MF, RF, OM, and CK. The results showed that SMBC and SMBN contents at the 0–10 cm and 10–20 cm soil layers with RF and OM treatments were increased compared with the MF and CK treatments. Compared with the CK treatment, SMBC contents at the 0–10 cm and 10–20 cm soil layers with RF and OM treatments increased by 35.72% and 50.28%, and 32.29% and 42.77%, respectively. SMBN contents at the 0–10 cm and 10–20 cm soil layers with RF and OM treatments increased by 15.52% and 22.70%, and 16.32% and 21.49%, respectively. The fluxes of SMBC and SMBN at the 0–10 cm and 10–20 cm soil layers with RF and OM treatments were significantly higher than those of the CK treatment. This result indicated that the flux turnover rates of SMBC and SMBN at the 0–10 cm and 10–20 cm soil layers with the MF, RF, and OM treatments were significantly higher than those of the CK treatment. Compared with the CK treatment, the flux turnover rates of SMBC and SMBN at the 0–10 cm and 10–20 cm soil layers with OM treatment increased by 46.10% and 48.59%, and 73.39% and 116.67%, respectively. SMBC and SMBN contents, and the flux turnover rates of SMBC and SMBN at the 0–10 cm layer were higher than those of the 10–20 cm layer under the same fertilizer treatment condition. Early rice and later rice yields with RF and OM treatments were significantly higher than those of the MF and CK treatments. As a result, the combined application of crop residue and organic manure with inorganic fertilizer management is a beneficial practice for increasing soil nutrients and rice yield under the double-cropping rice system in southern Chin.

Response of Soil Microbial Biomass Carbon, Nitrogen and Enzyme Activity to Sophora Davidii Skeels and Pennisetum Sinese Roxb Intercropping Systems

To understand the response mechanism of soil microbial biomass carbon content, soil microbial biomass nitrogen content and soil enzyme activities to intercropping pattern, an experiment consisting of three cropping patterns: Sophora davidii Skeels monocropping pattern, Pennisetum sinese Roxb monocropping pattern and S. davidii and P. sinese intercropping pattern had established in the southern region of Guizhou Province, China. The results showed that soil microbial biomass carbon content, microbial biomass nitrogen content and enzyme activities were gradually reduced with the depth (0-30 cm) of the soil layer increased under the three cropping patterns. The microbial biomass carbon and nitrogen content of S. davidii and P. sinese intercropping pattern were significantly higher than those of S. davidii monocropping and P. sinese monocropping pattern in 0-20 cm soil layer (P <0.05). Five soil enzyme activities were ranked: P. sinese monocropping > S. davidii and P. sinese intercropping > S. davidii monocropping in most soil layers. The soil nutrient contents (soil organic matter, total nitrogen, total phosphorus, and total potassium) and soil microbial biomass content (microbial biomass carbon and nitrogen) were highly significant positive correlation (P <0.01), while five soil enzyme activities had a significant positive correlation with each other (P <0.05). However, there was no significant correlation between soil microbial biomass content and soil enzyme activities. Additionally, there was non-significant correlation between the activiies of nitric oxide synthetase, the activiies of β-N-acetylglucosidase and the activiies of leucine aminopeptidase (P> 0.05), but the activiies of β-N-acetylglucosidase, the activiies of soil nitrogenase, the activiies of soil Leucine aminopeptidase and the activiies of soil glutamine synthetase were showed a significant (P <0.05) or very significant positive correlation (P <0.01). In summary, the intercropping pattern of S. davidii and P. sinese has a significant effect on soil quality improvement in shallow soil (0-20cm), and the microbial biomass carbon, soil microbial biomass nitrogen and soil enzymes can be used as an important index for evaluating the changes of soil quality.

三峡库区消落带重建植被下土壤微生物生物量碳氮含量特征

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡库区消落带重建植被下土壤微生物生物量碳氮含量特征 DOI: 10.5846/stxb201610272191 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市林业重点科技攻关项目（渝林科研2016-8；2015-6）；国家国际科技合作专项（2015DFA90900）；中央财政林业科技推广示范项目（渝林科推[2014-10]）；重庆市研究生科研创新项目（CYS2015068）；重庆市研究生科研创新项目（CYB16066） Characteristics of soil microbial biomass C and N under revegetation in the hydro-fluctuation belt of the Three Gorges Reservoir Region Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究三峡库区消落带植被重建后，土壤微生物生物量含量特征及影响因素，对忠县消落带人工重建植被土壤及裸地土壤（作为对照）微生物生物量碳氮含量进行了调查研究。结果表明：（1）在消落带165-175 m高程土壤微生物生物量碳含量草地>林地>农耕地>裸地，微生物生物量氮含量规律与微生物生物量碳一致，农耕地明显提高；土壤微生物生物量总体呈现出草地最高、林地和农耕地次之，裸地最低的趋势，表明进行消落带植被恢复对土壤微生物生物量有显著的促进作用。（2）不同植被类型下，土壤微生物生物量碳氮比变化范围为8.02-10.25，土壤微生物生物量碳、氮占土壤有机碳、全氮的百分比范围分别是2.40%-4.60%和2.13%-3.58%，其中林地对土壤碳、氮库贡献显著高于裸地（P < 0.05）。（3）土壤微生物生物量碳、氮与土壤有机碳、全氮和pH值呈现显著相关性，与土壤含水量呈现极显著相关性，说明消落带重建植被土壤的这些理化性质对土壤微生物生物量碳、氮含量有强烈的影响。因此，在三峡库区消落带进行植被恢复重建能显著提高土壤微生物生物量及土壤质量，对加强三峡库岸生态系统的稳定性具有重要意义。 Abstract:Operation of the Three Gorges Dam Reservoir on the Yangtze River, China, has formed a hydro-fluctuation belt with an annual water level change of near 30 m spanning and an area of 350 km2. Such a change in water level has led to a direct shift in plant community composition within the hydro-fluctuation belt. Different vegetation types alter the riparian soil environment to varying extents, via their influence on the biogeochemical cycles of materials such as soil microbial biomass carbon and nitrogen. Accordingly, by determining the relationship between soil physicochemical properties and soil microbial biomass under different vegetation types, we can provide useful information for vegetation restoration in the hydro-fluctuation belt of the Three Gorges Reservoir Region. To explore the changes in re-vegetated soil quality in the hydro-fluctuation belt of the Three Gorges Reservoir, we examined the contents of soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) in this region. Soils under four typical vegetation types (natural grassland, artificial timber forest, crop land, and unplanted soil) were investigated in the reservoir riparian region of Zhong County (107°32'-108°14'E, 30°03'-30°35'N), located in the center of Chongqing Municipality. The results showed that both SMBC and SMBN content was the highest in natural grassland and the lowest in unplanted soil. Under different types of vegetation, the ratio of SMBC/SMBN ranged from 8.02 to 10.25, the ratio of SMBC/soil organic carbon (SOC) was 2.40%-4.60%, and the ratio of SMBN/total nitrogen (TN) was 2.13%-3.58%. The SMBC/SOC and SMBN/TN ratios of forest soils were significantly higher than those of the unplanted soil (both P < 0.05). Soil microbial biomass was significantly correlated with SOC, TN, and soil pH, and very significantly correlated with soil moisture. Our study showed that the physical and chemical properties of soil under revegetation had a significant impact on both SMBC and SMBN. Thus, revegetation facilitated an increase soil microbial biomass and enhanced soil quality in the hydro-fluctuation belt of the Three Gorges Reservoir Region. 参考文献 相似文献 引证文献

Soil-nitrogen net mineralization increased after nearly six years of continuous nitrogen additions in a subtropical bamboo ecosystem

In order to understand the effects of increasing atmospheric nitrogen (N) deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the rainy region of SW China, near the western edge of Sichuan Basin. Four N treatment levels—control (no N added), low-N (50 kg N ha−1 a−1), medium-N (150 kg N ha−1 a−1), and high-N (300 kg N ha−1 a−1)—were applied monthly in the P. amarus plantation starting in November 2007. In June 2012, we collected intact soil cores in the bamboo plantation and conducted a 30-day laboratory incubation experiment. The results showed that the soil N net mineralization rate was 0.96 ± 0.10 mg N kg−1 day−1, under control treatment. N additions stimulated the soil N net mineralization, and the high-N treatment significantly increased the soil N net mineralization rate compared with the control. Moreover, the soil N net mineralization rate was significantly and positively correlated with the fine root biomass, the soil microbial biomass nitrogen content and the soil initial inorganic N content, respectively, whereas it was negatively correlated with the soil pH value. There were no significant relationships between the soil N net mineralization rate and the soil total nitrogen (TN) content and the soil total organic carbon content and the soil C/N ratio and the soil microbial biomass carbon content, respectively. These results suggest that N additions would improve the mineral N availability in the topsoil of the P. amarus plantation through the effects of N additions on soil chemical and physical characteristics and fine-root biomass.

中国东部南北样带典型针叶林土壤酶活性分布格局研究

PDF HTML阅读 XML下载 导出引用 引用提醒 中国东部南北样带典型针叶林土壤酶活性分布格局 DOI: 10.5846/stxb201309272377 作者: 作者单位: 中国科学院地理科学与资源研究所生态网络观测与模拟重点实验室CERN综合研究中心,中国科学院地理科学与资源研究所生态网络观测与模拟重点实验室CERN综合研究中心,中国科学院大学,中国科学院地理科学与资源研究所生态网络观测与模拟重点实验室CERN综合研究中心,中国科学院地理科学与资源研究所生态网络观测与模拟重点实验室CERN综合研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31070435,31290222,31290221);国家重点基础研究发展计划项目(2012CB417103,2010CB833502);中国科学院地理科学与资源研究所"秉维"优秀青年人才基金(2011RC202);中国科学院战略性先导科技专项(XDA05050600) Pattern of enzyme activities of typical coniferous forest soils along the North-South Transect of Eastern China Author: Affiliation: Institute of Geographic Sciences and Natural Resources Research,,University of Chinese Academy of Sciences,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:选取中国东部南北样带不同气候区(寒温带、温带和亚热带)的针叶林作为研究对象,分析了多酚氧化酶、过氧化物酶、几丁质酶以及β-葡萄糖苷酶活性的变化。结果表明,土壤溶解性有机碳(DOC)、微生物生物量碳(MBC)、微生物生物量氮(MBN)含量从北到南依次减小,寒温带显著高于亚热带;土壤pH值在3个气候区差异显著,温带最高,亚热带最低。分解木质素的多酚氧化酶和过氧化物酶活性不存在显著性差异;而与氮循环密切相关的几丁质酶活性表现为温带显著高于寒温带和亚热带;与碳循环密切的β-葡萄糖苷酶活性在温带最高,并显著高于亚热带地区。逐步回归分析表明,土壤MBN与pH值影响土壤几丁质酶活性,而土壤β-葡萄糖苷酶活性主要受pH的控制。研究认为,在中国东部南北样带针叶林中,土壤几丁质酶和β-葡萄糖苷酶活性存在显著性差异,而pH与MBN可能是影响土壤酶活性的主要因素。 Abstract:Soil organic carbon (SOC) is the largest terrestrial pool of carbon, and the amount of carbon in soils represents about two thirds of total ecosystem. Therefore, any change in the size and turnover rate of SOC pools will potentially alter the atmospheric CO2 concentration and the subsequent global climate. Soil enzymes are involved in a series of catalyzing reactions and play pivotal roles in litter and soil organic matter decomposition as well as nutrient cycling in terrestrial ecosystems. Soil enzyme activity can be used as a proxy for plant and microbial substrate availability, the interference between soil ecosystem and external environment, and microbial community structure and metabolic capabilities. Therefore, the determination of soil enzyme activities is a powerful tool for understanding soil carbon and nitrogen biogeochemical processes and their responses to climate change. Soil enzyme activity has been a frontier of forest ecology research and has been widespread concern. Unfortunately, most of the studies to date have been limited to a single forest biome or a single forest site, and few studies concern the pattern and controlling factors of soil enzyme activity at a terrestrial transect scale. North-South Transect of Eastern China (NSTEC) is the fifteenth standard transect established by International Geosphere-Biosphere Program (IGBP) in 2005 and is mainly driven by heat, followed by precipitation. It covers almost all forest types from boreal forest to tropical rain forest, which provides an ideal tool to investigate the pattern and environmental control of soil enzyme activities in the boreal, temperate and tropical forest biomes. In the past decade, many studies were conducted to measure the main factors affecting the pattern of SOC storage and soil-atmosphere exchange of greenhouse gases in the typical forests along the NSTEC. However, little information is available on the pattern of soil enzyme activities involved in soil carbon and nitrogen cycles and they relate to soil microbial biomass at a large spatial scale. In this study, the typical coniferous forests distributed in the cold-temperate, temperate and subtropical climatic zones were selected along the NSTEC. The activities of polyphenol oxidase, peroxidase, chitinase and β-glucosaccharase, soil dissolved organic carbon (DOC), microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) as well as soil pH in the three coniferous forest soils were measured. The results showed that soil DOC, MBC, and MBN contents tended to decrease from north to south, and they were higher in the cold-temperate forest soils than in the subtropical forest soils. There was a significant difference in the soil pH values among the three coniferous forests, following the order cold-temperate > temperate > subtropical forests. Also, no significant differences were found in the soil polyphenol oxidase and peroxidase activities among the three typical coniferous forests. In contrast, the soil chitinase activity involved in soil nitrogen cycle was significantly higher in the temperate forest than in the cold-temperate and subtropical forests, and the soil β-glucosaccharase activity in the temperate forest was also significantly higher than that of the subtropical forest. Stepwise regression analysis showed that the soil chitinase activity was closely associated with soil MBN content and soil pH value, and the soil β-glucosaccharase activity was significantly and positively related to soil pH value. Our results suggest that soil cellulose- and chitin-degrading enzymes (i.e., chintinase and β-glucosaccharase) sensitively respond to climate zone. Soil MBN content and pH value are the main factors controlling soil enzyme activities of coniferous forests along the NSTEC. 参考文献 相似文献 引证文献

Productivity and soil response to plastic film mulching durations for spring wheat on entisols in the semiarid Loess Plateau of China

Plastic film mulching is an important agricultural practice in semiarid areas of the Loess Plateau in northwest China to improve crop productivity by changing soil properties. We conducted field experiments using spring wheat ( Triticum aestivum L. cv Longchun 8139-2) to examine the effect of film-mulching with varying durations on crop yield and soil properties in 1999 and 2000 on Loess Orthic Entisols in the semiarid Loess Plateau of China. The three mulching treatments with varying durations were applied: (1) M30: mulching for 30 days after sowing (DAS); (2) M60: mulching for 60 DAS; (3) Mw: mulching for the whole growth period, as well as the control; M0: without mulching. In 1999, seedlings from the three mulching treatments emerged 8 days earlier than those from unmulchingly treated. In 2000, a very dry year, emergence of seedlings in the mulching treatments occurred only 1–2 days earlier compared to control. Moreover, mulching treatments also significantly increased the total root biomass before 90 DAS in 1999 and before 30 DAS in 2000. There was a sharp increase in soil respiration in the mulching treatments. Soil microbial biomass nitrogen content in the Mw treatment was significantly lower at 43 DAS than that in control. Accumulation of total mineral nitrogen in the soil at harvest was clearly higher in Mw than in the other treatments and the control. Highest yields were recorded from wheat treated with M60 (3305 and 1203 kg ha −1 in 1999 and 2000, respectively). By contrast, no significant difference in yield was found among the three-mulched treatments in 1999. In 1999 the water use efficiency in all mulching treatments was significantly higher than in control, while in 2000 it was significantly higher in M60 and Mw than in M30 and control. These findings therefore suggest that mulching for 60 DAS increased grain yield by increasing the mineral nitrogen, soil water and the efficiency of water use and avoiding the over-decomposition of organic matter and over-mineralization of organic nitrogen.

Productivity and soil response to plastic film mulching durations for spring wheat on entisols in the semiarid Loess Plateau of China

Plastic film mulching is an important agricultural practice in semiarid areas of the Loess Plateau in northwest China to improve crop productivity by changing soil properties. We conducted field experiments using spring wheat ( Triticum aestivum L. cv Longchun 8139-2) to examine the effect of film-mulching with varying durations on crop yield and soil properties in 1999 and 2000 on Loess Orthic Entisols in the semiarid Loess Plateau of China. The three mulching treatments with varying durations were applied: (1) M30: mulching for 30 days after sowing (DAS); (2) M60: mulching for 60 DAS; (3) Mw: mulching for the whole growth period, as well as the control; M0: without mulching. In 1999, seedlings from the three mulching treatments emerged 8 days earlier than those from unmulchingly treated. In 2000, a very dry year, emergence of seedlings in the mulching treatments occurred only 1–2 days earlier compared to control. Moreover, mulching treatments also significantly increased the total root biomass before 90 DAS in 1999 and before 30 DAS in 2000. There was a sharp increase in soil respiration in the mulching treatments. Soil microbial biomass nitrogen content in the Mw treatment was significantly lower at 43 DAS than that in control. Accumulation of total mineral nitrogen in the soil at harvest was clearly higher in Mw than in the other treatments and the control. Highest yields were recorded from wheat treated with M60 (3305 and 1203 kg ha −1 in 1999 and 2000, respectively). By contrast, no significant difference in yield was found among the three-mulched treatments in 1999. In 1999 the water use efficiency in all mulching treatments was significantly higher than in control, while in 2000 it was significantly higher in M60 and Mw than in M30 and control. These findings therefore suggest that mulching for 60 DAS increased grain yield by increasing the mineral nitrogen, soil water and the efficiency of water use and avoiding the over-decomposition of organic matter and over-mineralization of organic nitrogen.