Effects Of Fertilization Regimes Research Articles

Effects of Fertilization Regimes on Soil Organic Carbon Fractions and Its Mineralization in Tea Gardens

Changes in the organic carbon fraction and mineralization of soil aggregates play an important role in the improvement of soil quality by organic fertilization. Nevertheless, the effects of organic fertilizer application on the organic carbon fraction and mineralization characteristics of soil aggregates are still unclear. This study carried out a 6-year field trial with five different fertilization treatments, namely, no fertilization (CK), chemical fertilization (CF), rapeseed cake (CR), chicken manure (CM), and a combination of chicken manure with biochar (CMB). The distribution, organic carbon density, and carbon mineralization characteristics in soil aggregate fractions were tested. The results showed that CR significantly increased the contents of large soil macroaggregates and enhanced the stability of soil aggregates of all sizes. CM increased the contents of macroaggregates and microaggregates but decreased the stability of the soil aggregates. CR, CM, and CMB increased the content of soil organic carbon and its components in the tea garden, while the contribution rate of organic carbon to large aggregates was the highest under the CR treatment. Organic fertilizer treatments had a positive effect on enhancing soil microbial biomass and carbon and nitrogen contents. The mineralization rate and accumulation of organic carbon in tea garden soil aggregates were increased under organic fertilizer treatments, of which CMB was the most significant. There was a high increase in tea yield and bud density under the CR treatment. In short, the application of organic fertilizers in tea garden soil is helpful to improve soil nutrients and soil fertility; plant- and animal-derived organic fertilizers are recommended for corporate application in agricultural production.

Effect of fertilization regimes on continuous cropping growth constraints in watermelon is associated with abundance of key ecological clusters in the rhizosphere

The deterioration of the microbiome within the rhizosphere is the main reason behind continuous cropping obstacles and is affected by fertilization regimes. However, the potential associations among fertilization regimes, rhizosphere microbial communities, and the severity of continuous cropping obstacles are poorly understood. Here, we investigated how three-year fertilization regimes (including no fertilizer, chemical fertilizer, organic fertilizer, combination of chemical and organic fertilizer, and bio-organic fertilizer application) affect the rhizosphere microbiome and its associations with continuous cropping growth constraints during the whole growing period of watermelon, using a rhizobox system under greenhouse conditions. The results showed that different fertilization treatments induced drastic shifts in the richness, structure, and composition of rhizosphere microbial communities, whereas the growth stages induced few changes. Compared with no fertilizer treatment, the continuous application of chemical fertilizer inhibited the growth of watermelon. This was strongly associated with the reduced abundance of key ecological clusters within the bacterial co-occurrence network, which contains beneficial bacterial taxa, such as Lysobacter sp. and Haliangium sp. In contrast, continuous application of organic and bio-organic fertilizers promoted the growth of watermelon and was associated with the decreased abundance of key ecological clusters within the fungal co-occurrence network, which contains pathogenic fungal taxa, such as Fusarium sp., Cladosporium sp., and Acremonium sp. Overall, continuous chemical fertilizer application can induce severe continuous cropping obstacles by inhibiting the growth of beneficial bacteria. Continuous application of organic and bio-organic fertilizers can help alleviate such obstacles by suppressing pathogenic fungi. These findings reveal the microbial mechanisms underlying the effects of different fertilization regimes on continuous cropping growth constraints of watermelon.

Soil microbial communities response to different fertilization regimes in young Catalpa bungei plantation.

Fertilization is a fundamental aspect of global forest management that enhances forest productivity and drastically affects soil microbial communities. However, few studies have investigated the differences and similarities in the responses of below-ground microbial communities to different fertilization schemes. The effects of fertilization regimes on the composition and diversity of soil fungal and bacterial communities were investigated in a young Catalpa bungei plantation in Shandong Province, Eastern China. Soil microbial communities were assessed undergoing three types of fertilization: (i) no fertilization (CK), (ii) hole fertilization (HF), and (iii) the integration of water and fertilizer (WF). We further analyzed the effects of soil depth (i.e., 0–20 and 20–40 cm) on the structure of soil microbial communities. Our results indicated that the diversity of bacteria (e.g., Chao1 and Shannon indices) reduced undergoing fertilization, and WF had a higher negative impact on bacterial diversity than HF. A lower bacterial diversity was observed in the subsoil compared to the topsoil. In contrast to bacterial diversity, fungal diversity had a slightly increasing trend in the fertilized environments. The primary bacterial function was metabolism, which was independent of fertilization or soil depth. Among fungal functional guilds, symbiotic soil fungi decreased obviously in the fertilized stand, whereas saprotrophic fungi increased slowly. According to the structural equation models (SEM), the diversity and composition of bacterial and fungal communities were jointly regulated by soil nutrients (including N and P contents) directly affected by fertilization and soil layer. These findings could be used to develop management practices in temperate forests and help sustain soil microbial diversity to maintain long-term ecosystem function and services.

A meta-analysis of the effect of organic and mineral fertilizers on soil microbial diversity

Organic agriculture, employing manures or composts, has been proposed as a way of mitigating undesirable impacts of mineral fertilizer use. Of particular interest is the effect of fertilizer regime on soil microbes, which are key to nutrient cycling, plant health and soil structure. However, the effect of fertilizers on soil microbial diversity remains poorly understood. Since biological diversity is an important determinant of ecosystem function and a fundamental metric in community ecology, the effects of fertilizer regimes on soil microbial diversity are of theoretical and applied interest. Here, we conduct a meta-analysis of 37 studies reporting microbial diversity metrics in mineral fertilized (NPK), organically fertilized (ORG) and unfertilized control (CON) soils. Of these studies, 32 reported taxonomic diversity derived from sequencing, gradient gel electrophoresis, or RFLP. Functional diversity, derived from Biolog Ecoplate™ measures of carbon substrate metabolism, was reported in 8 studies, with 3 studies reporting both diversity metrics. Bacterial and archaeal diversity was reported in 28 taxonomic studies, and fungal diversity in 8 taxonomic studies. We found that functional diversity was 2.8% greater in NPK compared with CON, 7.0% greater in ORG vs. CON, and 3.8% greater in ORG vs. NPK. Bacterial and archaeal taxonomic diversity was not significantly different between NPK and CON, but on average 2.9% greater in ORG vs. CON, and 2.4% greater in ORG vs. NPK. Fungal taxonomic diversity was not significantly different between any treatment pairs. There was very high residual heterogeneity in all meta-analyses of soil diversity, suggesting that a large amount of further research is required to fully understand the influence of fertilizer regimes on microbial diversity and ecosystem function.

Long-term combined application of chemical fertilizers and organic manure shapes the gut microbial diversity and functional community structures of earthworms

Earthworms are crucial regulators of many soil ecosystem processes; however, the effects of fertilization regimes on earthworm gut microbiota remains poorly understood. Here, we investigated the effects of 10 years of fertilization on the gut microbiota of two different earthworm species, Metaphire californica and Amynthas phaselus, belonging to anecic and endogeic ecological groups, respectively. Five fertilization treatments were designed as follows: non-nitrogen fertilizer (CK), nitrogen fertilizer only (NPK), and the combined application of inorganic fertilizers and three different application rates of pig manure (NPKM1, NPKM2, NPKM3). We observed that, compared with the CK and NPK treatments, the organic manure treatments had strong effects on both earthworm gut microbial communities and the associated metabolic functions. The lower application rate of organic manure significantly increased the gut microbial diversity of both earthworm species, which may have further improved their gut microbial metabolic potential, especially for the metabolism of various carbon resources. With the increasing application of organic fertilizers, the abundance of several bacterial families, such as Comamonadaceae, Oxalobacteraceae, and Cytophagaceae, significantly increased in the gut of M. californica. These families have also been identified as the primary indicator taxa of high organic matter inputs and play a crucial role in regulating microbial community functionalities. However, a similar trend was not observed in the gut of A. phaselus, indicating that A. phaselus might be less sensitive to fertilization regimes because it lives deeper in the soil and has a long digestive tract compared with those of M. californica. Our results demonstrated that long-term organic amendment application significantly shapes earthworm gut microbial communities and results in greater decomposition potential of the earthworm gut. Furthermore, our study found that lower application rates of organic matter may be beneficial for earthworm gut microbial diversity and functional structures.

Effects of Fertilization Regimes on Grain Yields and Economic Returns of Pathum Thani 1 Rice Grown on Sapphaya Soil Series

Fertilizer has been considered as one of the most important inputs, driving productivity and economic returns of rice farming systems. This study aimed to determine an optimized fertilizer rate to maximize grain yields, economic returns over fertilizer cost, and agronomic fertilizer nutrient use efficiency (ANUE) of Pathum Thani 1 rice grown on Sapphaya soil series. A completely randomized design with 5 replications was used. The treatments involved 4 fertilizer regimes: 1) no fertilizer application (control, C), 2) fertilizer application based on soil analysis (SSF) at a rate of 4–4.4–4 kg N–P2O5–K2O/rai (1 rai = 0.16 hectare), 3) fertilizer application based on precision fertilizer management (PF) at a rate of 7.86–2.52–13.39 kg/rai and 4) fertilizer application based on traditional farmer practice (F) at a rate of 15.5–5–0 kg/rai. The results uncovered that grain yields (1,055 kg/rai) and economic return (7,724 Baht/rai) of rice received the PF treatment were significantly highest (P < 0.05), which were approximately 78, 37, and 27 % greater than those in the C, SSF, and F treatments, respectively. Similarly, the economic return of the PF was approximately 73, 46, and 35 % superior to those in the C, SSF, and F treatments, respectively. Moreover, ANUE (nitrogen and phosphorus) of rice received PF were greater (P < 0.05) than other treatments. These results suggest that productivity and economic returns of Pathum Thani 1 rice grown on Sapphaya soil series can be optimized by applying fertilizer at a rate of 7.86–2.52–13.39 kg N–P2O5–K2O/rai.

Changes in N supply pathways under different long-term fertilization regimes in Northeast China

Different long-term fertilization regimes probably influence N supplying capacity and N cycling processes in soils. However, the effects of fertilization regimes on the pathways of N retention and supply and the impacts of these pathways on crop N uptake remain undocumented. In this study, the contributions of different pathways to N retention and supply were investigated on the basis of a long-term experiment that began in 1990, including six treatments: no fertilizer (CK), recycled manure (M), N and P fertilizers (NP), P and K fertilizers (PK), N, P and K fertilizers (NPK), and NPK fertilizers with recycled manure (NPKM). In the maize growth season, soil microbial mineralization–immobilization turnover (MIT) was the primary driving force of N transformation under treatments without synthetic N. Conversely, NH4+ fixation and release by soil clay minerals prominently regulate N retention and supply under treatments with synthetic N. In general, soil microbial biomass N (SMBN) mineralization and fixed NH4+ release accounted for 51 % of the variation in crop N uptake and the contribution of the latter to crop N uptake was 2-fold greater than that of the former. The synchrony between crop N uptake and fixed NH4+release was higher than that between crop N uptake and SMBN mineralization. Therefore, the fixed NH4+ pool was important in synthetic N regulation at a short or medium temporal scale, especially for soils with high 2:1 clay mineral content. By contrast, MIT dominated N cycling at a long temporal scale. Clarification of the pathways of N retention and supply can provide helpful implications for optimizing N fertilizer management and enhancing the synchrony between crop N demand and soil N supply.

Effect of fertilization regime on Murraya exotica plants growth and bioactive compounds

Effect of fertilization regime on Murraya exotica plants growth and bioactive compounds

Nitrous oxide emission, global warming potential, and denitrifier abundances as affected by long-term fertilization on Mollisols of Northeastern China

ABSTRACTA long-term field experiment was performed to assess the effects of fertilization regimes on greenhouse gas emissions, soil properties, soil denitrifies, and maize (Zea mays) grain yield on Mollisols of Northeastern China. Chemical nitrogen (N), phosphorus (P), and potassium (K) fertilizers plus pig manure (MNPK) treatment significantly increased soil N2O emissions by 29.9–226.4% and global warming potential (GWP) by 29.8–230.7% compared to unfertilized control (CK), chemical N fertilizer only (N), chemical N, P, and K fertilizers (NPK) and chemical N, P, and K fertilizers plus corn straw (SNPK) treatments. However, the MNPK treatment yielded similar greenhouse gas intensity (GHGI) as compared with other treatments, mainly due to higher maize grain yield. There were also higher gene copy numbers of nirK, nirS, and nosZ in topsoil (0–20 cm depth) under MNPK treatment. Automatic linear modeling analysis indicated that main factors influencing soil N2O emissions were soil organic carbon (SOC), NO3− content, and nirK gene abundance. Although the application of chemical fertilizers plus organic manure increases N2O emissions due to higher N and C availability and nirK gene activity in the soil, this is still a promising fertilizer management due to its notable enhancement of maize grain yield and SOC content.

Effects of fertilizer regimes on greenhouse gas emissions in a Gray Luvisol from central Alberta, Canada

This study investigated how different fertilizer regimes with a long-term repeated N application experiment affected on the soil Greenhouse gases (GHGs) emissions in a Gray Luvisolic from central Alberta, Canada. The results showed fertilizer regimes significantly influenced on GHGs emissions. The higher emissions of N2O and CH4 induced by NPKS soils were due to the superior utilization rate of mineral N and organic N. The CO2 emission rates indicated that soil organic carbon (SOC) was upper after Manure application than that after NPKS and Lime applications. The lowest Global Warming Potential (GWP) and highest pH of Lime soils suggested that liming application cause a significant decrease of GHGs by changing soil properties, such as pH. As for CH4 emissions during the incubation period, NPKS soil acted as sources, whereas the Lime and Manure soils acted as CH4 sinks. In addition, the fertilization history with higher SOC stocks in the Manure soils did not affect higher N2O emissions. In conclusion, this research showed liming application could be a better policy for improving soil properties in the acid Gray Luvisol from central Alberta, but liming may result in lower emissions of N2O and CO2 than the treatment of mineral fertilizer or farmyard manure.

Coupling sugarcane yield to soil nematodes: Implications from different fertilization regimes and growth stages

Abstract Soil nematode communities provide important information for soil food web structure and function. Our study focused on the impacts of different fertilization regimes on sugarcane growth, while primarily considering their effects on soil nematode responses during different growth stages. The sugarcane yields were significantly increased in plots fertilized with functional biofertilizers (BIOs) compared with plots that received chemical fertilizers. Moreover, the BIO applications significantly ( P 0.01) decreased the relative abundance of plant parasite while significantly ( P 0.01) increased the relative abundance of beneficial nematodes: Cephalobus, Cervidellus, Acrobeles, Caenorhabditis in the group of bacteriores and Ditylenchus, Tylencholaimus in the group of fungivores. Nonmetric multidimensional scaling (NMDS) revealed that soil nematode communities were primarily separated by sampling time. A network analysis showed that BIO applications led to more simplified soil nematode community, which was possibly linked with the increased bacterivore abundance and improved soil fertility. The effects of fertilization regimes were significant ( P 0.05) and accounted for 3.35% of the total variation in soil nematode communities. Soil properties (e.g., pH, organic matter, total N, available K and available P) were influenced by the fertilization regimes and different sampling time, which significantly ( P 0.05) explained 14.53% of the soil nematode variation. In conclusion, BIOs applications might facilitate sugarcane yield by increasing the relative abundance of bacterivore while decreasing plant parasites. The changes in soil nematode communities may reflect the soil fertility and health and provide evidence for the benefits of BIO applications for sugarcane crops.

Effects of fertilization regimes on weed seed banks in a rice–wheat crop system

Effects of fertilization regimes on weed seed banks in a rice–wheat crop system

Effects of long-term fertilization on soil organic carbon content and aggregate composition under continuous maize cropping in Northeast China

SUMMARYFertilizer application can play an important role in soil organic carbon (SOC) retention and dynamics. The mechanisms underlying long-term accumulation and protection of SOC in intensive maize cropping systems, however, have not been well documented for cool high-latitude rainfed areas. Based on a 23-year fertilization experiment under a continuous maize cropping system at Gongzhuling, Jilin Province, China, the effects of fertilization regimes on SOC content and soil aggregate-associated carbon (C) composition were investigated. Results showed that, within the 0–1·0 m soil profile, SOC contents decreased significantly with soil depth in all treatments. In the topsoil layer (0–0·2 m), SOC concentrations in balanced inorganic fertilizers plus farmyard manure (MNPK), fallow system (FAL) and balanced inorganic fertilizers plus maize straw residue (SNPK) treatments were significantly greater than initial levels by 61·0, 34·1 and 20·1%, respectively. The MNPK and SNPK treatments increased SOC content by 50·7 and 12·4% compared to the unfertilized control in the topsoil layer, whereas no significant differences were found between balanced inorganic nitrogen, phosphorus and potassium fertilizers (NPK) and the unfertilized control treatment. There were no significant differences in aggregate-size distribution among the unfertilized control, NPK and MNPK treatments, whereas the SNPK treatment significantly enhanced the formation of micro-aggregates (53–250 μm) and decreased the formation of silt+clay aggregates (<53 μm) compared to the unfertilized control, NPK and MNPK treatments. Moreover, SOC concentrations in all aggregate fractions in the MNPK treatment were the highest among treatments. Furthermore, the MNPK treatment significantly increased SOC stock in micro- and silt+clay aggregates, which may slow down C decomposition in the soil. These results indicate that long-term manure amendment can benefit SOC sequestration and stability in the black soil of Northeast China.

Effect of fertilization regime on nutrient and plankton development in impounded run-off from a dystrophic reservoir

Plankton assemblage and productivity status of an artificial reservoir were studied. The overflow of the reservoir was impounded in earthen ponds of the Department of Fisheries and Aquatic Resources Management, Michael Okpara University of Agriculture, Umudike, Nigeria. Groups of three such ponds measuring 9 x4x1.5m each were fertilized with chicken droppings (to obtain higher quantities of phosphorus) (treatment 1) and organic matter (to obtain higher levels of organic matter) (treatment 2). Composite water and sediment samples were collected weekly from transects of the reservoir, and ponds, for 8 weeks. Triplicate samples were investigated for plankton species density in the water column; total phosphorus, total nitrogen, organic matter; and bacterial cell counts in the sediment. Data were analyzed using the ANOVA and means separated using Fisher’s LSD(0.05). Water column N and P were significantly higher in treatments 2 and 1 respectively (p<0.05). Sediment N followed the same trend. Sediment P was significantly higher in the reservoir p<0.05). Plankton densities were significantly higher in treatments 1 and 2 respectively (p<0.05). Protists excluded, zooplankton in treatment 2 was predominated 55% by cyclopoid copepods. Rotifers were the least encountered zooplankton in the three environments. The aquaculture significance of the findings is discussed.Key words: Dystrophic, impoundment, water column, bacteria, zooplankton, phytoplankton, fertilization.

长期施肥对紫色土农田土壤动物群落的影响

Soil fauna regulate processes affecting organic matter decomposition,mineralization and nutrient cycling,and play an important role in terrestrial ecosystem nutrient cycling and energy flow.Management of cropland,especially long-term fertilization,has considerable impacts on properties,and also affects the composition of faunal communities.The Sichuan Basin is an important agribusiness area in southwestern China which occupies 7% of the national cropland and supplies 10% of the agricultural products of China.The typical in the study area is highly productive and is called soil locally.It is classified as a Pup-Orthic Entisol in the Chinese Soil Taxonomy and an Entisol in the U.S.Taxonomy.However,the influence of long-term fertilization regimes on faunal communities and how indices of these faunal communities respond to changes in properties are poorly understood.To investigate the effects of long-term fertilization regimes on the faunal communities and their inter-relationships,seven fertilization regimes,a control with no fertilization(Control Check,CK),nitrogen fertilizer only(Nitrogen,N),a mixed synthetic fertilizer(Nitrogen Phosphorus Potassium,NPK),organic manure(Organic Manure,OM),organic manure plus synthetic fertilizer(Organic Manure Nitrogen Phosphorus Potassium,OMNPK),crop residues returned to the as fertilizer(Returning Straw Decomposition,RSD) and crop residues plus synthetic fertilizer(Returning Straw Decomposition Nitrogen Phosphorus Potassium,RSDNPK) were applied to the purple of the Sichuan Basin,China,and examined in May,July,September and November,2008 using modified Tullgren and Baermann funnels.A total of 9,454 individuals were collected,and classified into seven phyla,17 classes and 24 orders.Analysis of the data showed that the faunal communities were richer in the OM,OMNPK and RSDNPK plots,and that the greatest diversity of the faunal communities was found in the OM and RSDNPK plots,being significantly higher than those in the CK,N and NPK plots.Application of organic fertilizers promoted diversity and abundance of faunal communities,and was favorable for their survival and development.Analysis of variance indicated that different fertilization regimes had extremely significant impacts on the density of the main faunal groups(F=42.412,P=0.0001) and led to imbalances being present in the faunal groups.Analysis of the relationships between the fertilization regimes and the main groups of the faunal communities,using Principal Component Analysis,showed that the different fertilization regimes primarily affected six indices of fauna;individuals in the faunal population,individual nematodes,individual megadriles,individual Oribatidas,the DG index(density-group diversity index) and total groups in the faunal communities.Therefore,we consider that changes in the cropland faunal communities have a relationship with differences in long-term fertilization management.These six indices of the individual fauna population;individual Nematodes,individual Megadriles,individual Oribatidas,the DG index(density-group diversity index) and total groups in the faunal communities can be used to predict changes of fertility caused by long-term fertilization application,and have great potential as bio-indicators of changes in quality.

Effect of fertilization regime on tea yield, nutrient accumulation and soil fertility

Fertilization is an important agricultural measure that improves not only tea yield and quality,but also soil quality;all of which sustain tea garden utility.A 4-year field orientation experiment was conducted with 6 fertilization regimes to study the effects of fertilization regime on tea yield,nutrient accumulation and soil fertility.The fertilization regimes included none-fertilization,tea formula fertilizer,half tea formula fertilizer and half organic fertilizer,organic fertilizer,full tea formula fertilizer and legume green manure and half tea formula fertilizer plus half organic fertilizer with legume green manure.The tested nutrients included nitrogen,phosphorus,potassium,polyphenols and water extracts.The study was designed to facilitate the selection of reasonable tea fertiliza-tion models.Results showed that the fertilization regimes produced higher yields,accumulated nutrients and soil fertility than none-fertilization regime.Moreover,the regime of half tea formula fertilizer plus half organic fertilizer with legume green manure regime had the highest output of 5 929 kg·hm-2.Compared with the none-fertilization,it increased tea yield by 106.17%.Its accumu-lated nitrogen,phosphorus and potassium were 4.962 kg·hm-2,0.48 kg·hm-2,and 5.966 kg·hm-2,increased by 88.6%,57.41% and 98.87% over the none-fertilization regime respectively.The polyphenols and water extracts contents were 23.39 kg·hm-2 and 119.41 kg·hm-2,increased by 73.29% and 85.56%,respectively,compared with the none-fertilization regime.It also improved tea garden soil organic matter by 1.29 times,total nitrogen by 1.7 times,total phosphorus by 2.98 times,available nitrogen by 1.59 times,avail-able phosphorus by 34.3 times and available potassium by 3.3 times.It was therefore beneficial to adopt the fertilization regime of half tea formula fertilizer plus half organic fertilizer with legume green manure regime in tea production.

长期施肥对玉米生育期土壤微生物量碳氮及酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 长期施肥对玉米生育期土壤微生物量碳氮及酶活性的影响 DOI: 10.5846/stxb201110191555 作者: 作者单位: 西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌,西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌,陕西省土壤肥料工作站,西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌,西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌,西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌,西北农林科技大学/农业部西北植物营养与农业环境重点实验室,陕西杨凌 作者简介: 通讯作者: 中图分类号: 基金项目: 公益性行业(农业)科研专项(201203030)资助;西北农林科技大学创新团队项目资助 Effects of long-term fertilization on soil microbial biomass carbon and nitrogen and enzyme activities during maize growing season Author: Affiliation: Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling,,,,,,Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 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:以小麦-玉米轮作长期肥料定位试验为平台,探讨不同养分管理对玉米生育期塿土微生物量碳、氮和酶活性动态变化的影响。试验包括6个处理,分别为不施肥(CK)、单施氮肥(N)、氮磷配合(NP)、氮磷钾配合(NPK)、NPK+秸秆(SNPK)以及有机肥+NPK(MNPK)。结果表明玉米生育期土壤微生物量碳、氮变化显著。不同施肥管理下土壤微生物量碳、氮的高低显著性分别为MNPK > SNPK、NP、NPK > N、CK。玉米生育期内土壤酶活性也变化显著,蔗糖酶、脲酶和纤维素酶在玉米抽雄期达到活性高峰,而磷酸酶在玉米拔节期出现活性高峰。不同施肥管理对土壤酶活性的影响总体表现为MNPK处理最高,其次为SNPK处理,再次为NPK和NP处理,N和CK处理最低。不同施肥处理间土壤微生物量碳、氮以及酶活性与土壤有机碳、全氮、速效磷水平密切相关。塿土长期施用氮磷或氮磷钾化肥可以提高土壤微生物量碳、氮以及酶活性。一季作物秸秆还田配合氮磷钾化肥与氮磷钾相比有提高土壤微生物量碳、氮以及酶活性的趋势。在等氮量下,有机肥配合化肥与其他施肥模式相比,均显著提升土壤化学肥力因素、微生物量碳氮和酶活性。因此,塿土上建议进行有机无机肥配合以提高土壤肥力,保持土壤生物健康。 Abstract:This study was designed to examine the effects of continuous fertilization, straw incorporation, and manuring on the soil microbial biomass and activities of enzymes by a long-term fertilizer field trial with winter wheat and summer maize rotation system under temperate conditions in a loess soil in Shaanxi of China. Treatments at the site included application of recommended doses of nitrogen (N), nitrogen and phosphorus (NP), nitrogen, phosphorus and potassium (NPK), wheat/maize straw (S) with NPK (SNPK), dairy manure (M) with NPK (MNPK) and un-amended control (CK), totally six treatments. The results showed that soil microbial biomass carbon and nitrogen changed significantly during maize growing season. The effects of fertilization regimes on soil microbial biomass carbon and nitrogen can be arranged (based on statistical significance) in the following orders: MNPK > SNPK, NP, NPK > N, CK. Soil enzyme activities also significantly changed with maize development stage. Invertse, urease and cellulase activities reached the peak at the silk stage, but alkaline phosphatase activities was the highest at the jonting stage. The effects of fertilization regimes on soil enzyme activity generally followed the order: MNPK > SNPK > NPK, NP > N, CK. The difference in soil microbial biomass carbon, nitrogen and enzyme activity was related to the levels of organic carbon, total nitrogen and Olsen P in soils. Overall, long-term application of NP or NPK could significantly increase soil microbial biomass carbon, nitrogen and enzyme activity relative to CK. Compared with NPK, SNPK treated soil had a tendency to increase microbial biomass and enzyme activity. At the same N application rate, manure combined with chemical fertilizer significantly enhanced soil chemical and biochemical fertility compared with the other fertilization regimes. It is, therefore, recommended that NP application combined with crop straw could be a suitable way in the loess soil in order to improve soil fertility and maintain land productivity if organic manure were not applicable. 参考文献 相似文献 引证文献

The role of Variovorax and other Comamonadaceae in sulfur transformations by microbial wheat rhizosphere communities exposed to different sulfur fertilization regimes

Sulfonates are a key component of the sulfur present in agricultural soils. Their mobilization as part of the soil sulfur cycle is mediated by rhizobacteria, and involves the oxidoreductase AsfA. In this study, the effect of fertilization regime on rhizosphere bacterial asfA distribution was examined at the Broadbalk long-term wheat experiment, Rothamsted, UK, which was established in 1843, and has included a sulfur-free treatment since 2001. Direct isolation of desulfonating rhizobacteria from the wheat rhizospheres led to the identification of several Variovorax and Polaromonas strains, all of which contained the asfA gene. Rhizosphere DNA was isolated from wheat rhizospheres in plots fertilized with inorganic fertilizer with and without sulfur, with farmyard manure or from unfertilized plots. Genetic profiling of 16S rRNA gene fragments [denaturing gradient gel electrophoresis (DGGE)] from the wheat rhizospheres revealed that the level of inorganic sulfate in the inorganic fertilizer was correlated with changes in the general bacterial community structure and the betaproteobacterial community structure in particular. Community analysis at the functional gene level (asfA) showed that 40% of clones in asfAB clone libraries were affiliated to the genus Variovorax. Analysis of asfAB-based terminal restriction fragment length polymorphism (T-RFLP) fingerprints showed considerable differences between sulfate-free treatments and those where sulfate was applied. The results suggest the occurrence of desulfonating bacterial communities that are specific to the fertilization regime chosen and that arylsulfonates play an important role in rhizobacterial sulfur nutrition.

The effect of fertilization regime on juvenile walleye growth and prey utilization in rearing ponds

The effect of two contrasting fertilization regimes on juvenile walleye growth, survival and harvest was tested in six identical rearing ponds treated with fermented soybean meal at either a constant (36 g m−3week−1) or a progressively reduced (32 to 0 g m−3week−1) rate. Walleye length, percent survival and biomass harvest in constant fertilization ponds were 32, 83 and 294% greater, respectively, than those of reduced fertilization ponds. Chironomid larvae and pupae were the dominant prey (in terms of biomass) in juvenile walleye larger than 22 mm TL. Mean chironomid biomass was significantly higher in the constant fertilization ponds (5.1 vs. 1.7 g dry wt m−2), particularly after peak emergence around week 4. Zooplankton were less important prey after week 2, and mean zooplankton density was not significantly different between treatments. From these data we conclude that better walleye performance in the constant fertilization ponds was due to higher chironomid density during the last half of the experiment. Our findings are reviewed in light of current knowledge of juvenile walleye feeding ecology and contemporary pond culture procedures.