Effect of farm management on topsoil organic carbon and aggregate stability in water: A case study from Southwest England,UK

There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content (F = 8.500, p < .0001) or not (F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC_adj R² = .571, p < .0001) or not (SOC_unadj R² = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.     

河南油田注聚井聚合物堵塞机理及防治技术

为解决河南油田聚合物驱油注聚井堵塞导致采收率严重下降的问题,采用物理模型试验及扫描电镜(SEM)的方法对堵塞位置、堵塞因素进行研究.聚合物注入性试验结果表明,注入阻力越大,注入压力就越高,确定堵塞位置为近井地带,结果与实际矿场结果相符;扫描电镜结果表明,高渗岩心以吸附堵塞为主,低渗岩心以机械捕集为主;静态吸附试验显示防吸附剂质量分数、聚合物相对分子质量、矿化度、温度均对聚合物吸附有不同程度影响,为此研制出一种使砂岩表面润湿反转以减少吸附的防吸附剂(代号5807),并对注入参数进行优化:防吸附剂最优注入质量分数为0.5％;该防吸附剂耐盐性较好,不同矿化度(1500～10000mg/L)对该防吸附剂体系的防吸附率影响不大;防吸附剂注入体积数越大,聚合物防吸附率越高,最佳注入体积为0.6PV;防吸附剂处理地层的时间越长,聚合物防吸附率越高,处理时间在12h以上防吸附率大于70％;防吸附剂的最佳注入方式为:顶替液+0.6 PV防吸附剂段塞+1PV清洗剂.该研究对油田后续现场施工及动态调整具有重要指导意义,同时也可为河南油田提高聚合物驱技术应用效果提供理论支持.     

圈养林麝秋季日常行为研究

为探索圈养林麝的秋季日常行为,2020年8—9月,每月定期10 d,采用行为取样法和全事件记录法在云南昆明麝达林业科技发展有限公司林麝养殖基地观察并记录9只林麝(6只成体雌麝,3只成体雄麝)的日常行为.共记录林麝24种行为,可归纳成7种行为型,即摄食、运动、反刍、卧息、站立、排遗及嗅闻行为.通过对秋季林麝各行为类型的统计与比较发现,雄性林麝的活跃度高于雌麝,不同性别间卧息、嗅闻行为存在显著差异(P<0.05),排遗和站立行为存在极显著差异(P<0.01).这可能与性别、圈养方式和雄性林麝刚结束产麝周期等因素有关.     

Projecting future habitat quality of three midwestern reservoir fishes under warming conditions

Rising temperatures caused by climate change are likely to affect cool‐water and warm‐water fishes differently. Yet, forecasts of anticipated temperature effects on fishes of different thermal guilds are lacking, especially in freshwater ecosystems. Towards this end, we used spatially explicit, growth rate potential (GRP) models to project changes in seasonal habitat quality for a warm‐water piscivore (largemouth bass Micropterus salmoides), a cool‐water piscivore (walleye Sander vitreus) and a hybrid piscivore (saugeye S. vitreus × S. canadensis) in two Midwestern reservoirs. We assessed habitat quality for two periods (early and middle 21st century) under two realistic greenhouse gas emission scenarios (a mid‐century emissions peak and a rapid continuous increase in emissions). Largemouth bass were projected to experience enhanced or slightly reduced habitat during all seasons, and throughout the mid‐21st century. By contrast, walleye habitat was projected to decline with anticipated warming, except during the spring in the smaller of our two study reservoirs and during the fall in the larger of our two study reservoirs. Saugeye habitat was projected to either increase modestly or decline slightly during the spring and fall and declines in habitat quality and quantity that were smaller than those for walleye were identified during summer. Collectively, our findings indicate that climate warming will differentially alter habitat suitability for reservoir piscivores, favouring warm‐water species over cool‐water species. We expect these changes in habitat quality to impact the dynamics of reservoir fish populations to varying degrees necessitating the consideration of climate when making future management decisions.     

采食后奶牛瘤胃短链脂肪酸及其吸收相关蛋白表达的研究

本试验旨在研究奶牛采食前后瘤胃中短链脂肪酸(SCFA)浓度的变化及其吸收相关蛋白表达量的差异。试验选用3头体重(720±30)kg且装有瘘管的健康荷斯坦牛(动物伦理审查编号为SXAU-EAW-2019-C002013),采食精粗比为40:60的日粮(10kg),试验预试期10d,于第11天饲喂前开始取样,采用气相色谱法检测奶牛采食前(0 h)和采食后(1、2、3、4、5、6、7、8 h)瘤胃液中SCFA浓度;并采用荧光定量PCR方法检测瘤胃上皮组织中与SCFA吸收相关的蛋白表达量。结果表明:在采食后1 h奶牛瘤胃中SCFA浓度最高(P<0.05);在采食后一段时间内(2~5h)与SCFA吸收相关蛋白表达量上调(P<0.05),AE2、MCT1基因表达量均在5 h最高,PAT1、NHE3基因表达量均在4 h最高,MCT4基因表达量在4、5、6h均较高,NHE1基因表达量在2h达到最高;AE2、MCT1、MCT4、NHE1基因表达量与SCFA浓度负相关或正相关(P<0.05),AE2、MCT1、MCT4基因表达量与瘤胃内pH正相关(P<0.05)。以上结果初步揭示,在采食后一定时间内,瘤胃中与SCFA吸收相关蛋白表达受SCFA浓度和pH的调节。     

胡杨河市棉铃虫理化诱控集成技术研究

为践行绿色植保理念,推动胡杨河市农药减量控害,研究棉铃虫在新型种植模式(稀-早-优)下的诱控技术.以性诱、灯诱、食诱为主体,以化学防治技术为辅助,开展棉铃虫的理化诱控集成技术研究.结果显示,理化防控区棉田落卵量较对照区降低,新增蕾铃被害率降低,防治成本较常规化学防治区降低909元/hm2.然而,理化诱控技术单一使用较为容易,如何与化学防治集成需进一步探索.因此,在新型种植模式下,理化诱控集成技术可以更好地防治棉铃虫,保护天敌,调控生态平衡,经济效益及生态效益显著.     

农林高校工商管理专业校外实践教学基地建设探索

当前校外实践教学基地建设已成为各高校本科教学的重要环节.农林高校工商管理专业校外实践教学基地建设具有一定的难度.为了提升农林高校工商管理专业校外实践教学基地的运行质量,在分析农林高校工商管理专业校外实践教学基地建设难点、必要性及存在问题的基础上,提出了加强其校外实践教学基地管理体系及运行机制建设的具体思路.     

Bilateral intracorporeally sutured inguinal herniorrhaphy using 3-dimensional laparoscopy in a dog

A 7-month-old, intact male, mixed breed dog with bilateral inguinal hernias underwent general anesthesia for laparoscopic bilateral inguinal herniorrhaphy via a 3-port approach. A 3-dimensional laparoscopic system was used to perform the procedure immediately following prescrotal open castration. Intracorporeal suturing with polypropylene was performed, and 2 cruciate sutures were placed to close each inguinal ring. The caudal aspect of each inguinal ring was left slightly open so as not to disrupt the passage or patency of vessels and nerves. No intra- or post-operative complications occurred. One year after surgery, the dog has no evidence of recurrence of the inguinal hernias.Key clinical message:This case report demonstrates a novel minimally invasive approach to inguinal herniorrhaphy in a dog with no reported complications and a good long-term outcome. Intracorporeally sutured inguinal herniorrhaphy is feasible in dogs with good results, although additional cases are needed to gain experience with this technique in dogs with varying presentations of inguinal hernias.     

Performance of pyrazosulfuron-ethyl in non-puddled transplanted rainy season rice and its residual effect on growth of the succeeding crop in rice-wheat cropping pattern

Abstract

A study was carried out in sandy clay loam textured soil of Mymensingh, Bangladesh to evaluate weed control efficiency of pre-emergence herbicide pyrazosulfuron-ethyl either alone or in sequential application with post-emergence herbicide in transplanted rainy season rice under non-puddled strip-tilled (NPST) field condition and also to examine the residual effect of those herbicides on germination and growth of the subsequently grown wheat crop. Five treatment combinations of pyrazosulfuron-ethyl were tested against one weedy check and one weed-free check. The study revealed that NPST rice field was mostly infested by grass and sedge weeds and herbicide treatments offered a wide range of control (above 50% to 95%) on all types of weeds. Application of pyrazosulfuron-ethyl followed by (fb) orthosulfamuron fb butachlor plus propanil provided the most effective and economic weed control over two years of the study. Moreover, micro-plot bioassay study claimed germination and growth of subsequently grown wheat were not adversely affected by herbicides that were applied in rice. Therefore, application of pyrazosulfuron-ethyl followed by post-emergence herbicide could be effective and economic to control weeds in NPST rice under rice-wheat system, but proper rate and time of application should strictly be followed.