Factors in the Success and Failure of Microbial Agents for Control of Migratory Pests

Microbial control agents generally kill insects more slowly than chemical pesticides, and fast-moving migratory pests may not at first sight appear to offer the most promising targets for microbial control. Operators responsible for control may need to have recourse to chemical control agents. Nevertheless, there are many occasions when pests breed and feed outside the crop and a microbial control agent can be used. Similarly, immature stages may cause little damage and early treatment in the crop can avoid damage. Microbial control agents are particularly likely to be favoured if the pest breeds in a conservation area, and if a publicly-accountable agency is responsible for control.Other key points of importance are the IPM context, in particular detection, planning and forecasting of outbreaks and the role of natural enemies.With these points in mind, we identify several locust and grasshopper systems where microbial control is becoming established; additionally, Sunn pest of wheat and Armyworm are identified as promising situations forbreak microbials.     

Influence of land management on soil nutrients and microbial biomass in the central loess plateau,northwest China

Loss of soil organic matter under cropping systems is often considered one of the most serious forms of agriculturally induced soil degradation. Therefore, understanding how to improve or maintain soil fertility is of importance for sustainable systems of agriculture. This study deals with the effects of succession fallow and fertilization combined with crop rotation on the chemical properties and microbial biomass of soil in the central Loess Plateau, China. In order to create a more uniform experimental environment and avoid the influence of different crop residues, wheat/potato (W/P) rotation was selected as a fertilization treatment. The results showed that with increasing fallow time organic carbon (Corg) and total nitrogen (TN) slightly increased, microbial biomass carbon (MBC) and MBC/Corg gradually decreased, and microbial biomass nitrogen (MBN) remained unchanged. However, only MBC/Corg among all the microbial parameters measured showed significant differences at various stages of fallow. Although there was a decrease in organic carbon and total nitrogen in the fertilized plots, MBC was not significantly different in the various fallow and fertilized plots except for one‐year‐old fallows, which had the highest MBC. MBN, MBC/Corg and MBN/TN in fertilized plots were higher than for plots at different stages of fallow. Fertilization can increase organic carbon, total nitrogen, MBC and MBN content (compared to the control). It was concluded that appropriate land management, such as fertilization combined with crop rotation and reducing one‐year‐old fallow, would be useful ways to improve or maintain soil fertility. Copyright © 2005 John Wiley & Sons, Ltd.     

长期定位施肥对旱作农田土壤有机碳及其组分的影响

基于田间定位试验,研究了长期施肥对旱作冬小麦农田土壤有机碳及其组分的影响,试验包括4个处理:不施肥(CK)、氮磷配施(NP)、化肥与有机肥配施(NPM)以及长期休闲地(BL)。结果表明:长期持续施肥30年后,在0~30 cm土层,NPM处理土壤有机碳、微生物量碳、潜在矿化碳以及碳库管理指数分别较CK提高了42.2%、55.9%、40.9%和40.0%(P0.05),NP处理土壤有机碳和微生物量碳与CK差异不显著,潜在矿化碳和碳库管理指数分别提高了29.1%和20.0%(P0.05),施肥对两种活性有机碳含量的影响在15~30 cm土层表现更加显著;与种植作物相比,长期休闲显著降低了土壤潜在矿化碳含量,BL处理较CK降低了20.5%(P0.05)。相关性分析表明,土壤有机碳、潜在矿化碳、微生物量碳以及碳库管理指数两两之间存在着显著的相关性,且有机碳组分含量与土壤有机碳含量在处理间变化具有一致性(除NP处理外),两种活性有机碳相对含量在各处理间差异均不显著。总的来说,长期持续施入有机肥能够有效地增加旱作农田土壤有机碳同时增加其活性组分,有助于培肥地力和土壤固碳。     

炬荣复合微生物肥料在蕹菜上的应用研究

院本实验通过在蕹菜上喷施炬荣复合微生物肥料,探讨了其对蕹菜产量、效益的影响。结果表明：喷施复合微生物肥料、减量施肥处理的蕹菜表现最好,产量比常规施肥和空白对照分别增加13.3%和31.3%,每667m2分别增收919.54元和1881.38元。     

以PLA、PHBV为碳源的生物絮团技术在海水养殖中的应用

本研究以聚乳酸(PLA)和3-羟基丁酸-co-3-羟基戊酸共聚(PHBV)作为外加碳源,探究在模拟海水生物絮团养殖中,高、中、低盐度下PLA与PHBV碳源释放规律以及对海水生物絮团养殖中水质、微生物多样性及其群落结构的影响.结果显示:PHBV碳源要优于PLA碳源,中盐度更有利于各种营养盐的转化,氨氮质量浓度最终保持在3...     

Effects of Microbial Phytase Supplementation in Corn Distiller's Dried Grain with Solubles on Nutrient Digestibility and Growth Performance of Rainbow Trout,Oncorhynchus mykiss

Abstract

Two experiments were conducted to evaluate the effects of microbial phytase in corn distiller's dried grain with solubles (DDGS) on apparent digestibility coefficients (ADCs) and growth performance of rainbow trout, Oncorhynchus mykiss. In experiment 1, DDGS was supplemented with phytase at 0,300,600,900, and 1200 FTU/kg diet. A total of 180 fish (129.1±9.3 g) were stocked into six 140-L tanks with 30 fish/tank. Fish were assigned randomly to a reference diet and each of the 5 diets containing DDGS. Yttrium oxide was used as an inert marker. Results showed that ADCs in DDGS supplemented with different dosages of phytase were: dry matter, 49.1-58.6%; crude fat, 78.9-88.9%; crude protein, 80.0-91.9%; gross energy, 50.5-66.6%; minerals, -7.3-99.7%; and amino acids: 73.9 to 96.8%. In experiment 2, abasal diet containing 15% DDGS supplemented with lysine and methionine was used to determine if trace mineral supplemental levels in rainbow trout diets could be reduced if microbial phytase was supplemented. Six diets were made with trace mineral premix supplementation at 0.1, 0.08, 0.06, 0.04, 0.02, and 0%. Phytase was not supplemented in the basal diet, but supplemented at 500 FTU/kg diet in all other diets. Ten-week results showed that there were no significant differences in fish weight gain, feed conversion ratio, and survival (P < 0.05). There were no significant differences in fish body composition and apparent nutrient retention among fish fed all diets, except that fish fed a diet without trace mineral supplementation had the lowest zinc level and the highest manganese retention. Results indicated that phytase was effective in releasing most of minerals, and that trace mineral supplementation level could be reduced when phytase was used in rainbow trout diets.     

人造林窗对粗枝云杉人工林土壤微生物量的影响

通过对川西亚高山云杉低效林不同大小林窗(面积50 m2、100 m2、150 m2)改造,以未处理作为对照,采用氯仿熏蒸浸提法研究了林窗改造对土壤微生物生物量碳、氮含量及其垂直分布特征的影响。结果表明:通过林窗改造,林下土壤微生物量碳、氮具有显著提升,其中,林窗面积越大,提升效果越显著。各土层土壤微生物量碳、氮含量均表现为:150 m2(L3)100 m2(L2)50 m2(L1)对照(CK);3种大小面积林窗和对照土壤微生物量碳、氮含量随着土层深度的增加而降低,均表现为上层(0~5 cm)中层(5 cm~10 cm)下层(10 cm~15 cm);且林窗改造降低了土壤微生物量碳、氮的表层富集特性,林窗面积越大,上层土壤微生物量碳、氮所占比例越低。     

High Throughput Sequencing to Study the Effect of Chronic Renal Failure on the Diversity and Gene Function Prediction of Gut Microbiota in Dogs

This study aimed to investigate the effect of chronic renal failure(CRF) on the gut microbiota diversity and predict the gene function of the flora. A total of 30 2-year-old dogs were selected and randomly divided into the chronic renal failure model group (CRF, established by renal artery ligation), sham operation control group (Sham) and healthy control group (HCG). All animals were fed normally during the 56 days of test period. The serum creatinine (Scr), blood urea nitrogen (BUN) and urine protein / creatinine ratio (UP/C) were detected regularly during the experiment. The effects of chronic renal failure on the structure, diversity and function of gut microbiota were analyzed according to the result of bacterial 16S rDNA sequencing from fresh feces collected without contamination. The flora markers index (FMI) was constructed based on the principal component Logistic regression analysis of different microbiota in CRF group to predict the development of chronic renal failure. The results showed that: 1) The levels of Scr, BUN and UP/C in CRF group from the start of the 28th day of the experiment were significantly higher than those of HCG group and Sham group (P<0.05), and significantly higher than that of the first day of CRF group (P<0.05). 2) Compared with those before chronic renal failure (CRF group at day 0 and 28), HCG group and Sham group, the Chao 1 diversity and Shannon diversity of gut microbiota in CRF group at day 56 were significantly lower (P<0.05), while the relative abundance of Bacteroidetes, Proteobacteria and Actinobacteria significantly increased and the number of Firmicutes significantly decreased (P<0.05). 3) LEfSe analysis showed that 20 species were enriched in CRF group, mainly including Pseudomonas, Escherichia, Proteus and so on, and most of them had negative correlation with other intestinal bacteria. Functional prediction revealed that genes of those different species were mainly enriched in amino acid metabolism, sugar biosynthesis and metabolism and carbohydrate metabolism in CRF group. The area under ROC curve (AUC) of the FMI constructed with those species enriched was 0.788, which could be used as the intestinal microbial marker for CRF in dogs. In summary, chronic renal failure can reduce the diversity of intestinal microbiota, lead to the imbalance of bacterial structure and change of bacterial function. Moreover, the enriched gut microbiota in CRF group can be used as the intestinal microbial marker of CRF in dogs, and the best prediction effect can be obtained by FMI.     

不同深度垫料对养猪土著微生物发酵床稳定期微生物菌群的影响

通过对养猪土著微生物发酵床稳定期时核心发酵层的判断以及对该发酵床土著微生物的分布进行分析,旨在探讨不同深度垫料对养猪土著微生物发酵床稳定期微生物菌群的影响。试验分别从发酵床的表层和深30、40、50、70cm处取垫料样品后测其温度、pH值、自由水、硝态氮和粗纤维,并从中分离纯化出22株菌,采用16SrDNA序列分析鉴定微生物种类。结果表明,表层垫料温度显著小于其他4层（P〈0.05）,并且随着深度加深垫料温度依次降低;表层垫料pH值显著高于其他4层（P〈0.05）,其中30、40cm处垫料pH值相等,50、70cm处垫料pH值相等,40、50cm处垫料差异显著,整体呈下降趋势;表层垫料自由水、硝态氮和粗纤维含量与30cm处垫料含量差异不显著,从整体上看,30、40、50、70cm深垫料的自由水和硝态氮含量呈下降趋势,而粗纤维含量呈上升趋势;表层活菌数显著（P〈0.05）小于30cm深处垫料活菌数,30、40、50、70cm深垫料的活菌数依次降低。结果表明,30cm深处为该发酵床的核心发酵层,地衣芽孢杆菌为该发酵床的主要土著菌种。表层垫料的各项指标受环境影响较大,其所存在的菌种主要为大肠埃希菌属。40cm深处所分离的菌种主要为乙酰微小杆菌。50、70cm深处除分离出地衣芽孢杆菌外还分离出其他多种微生物。稳定期土著微生物发酵床各层的菌种分布主要与外界环境的变化有关。