长武塬区苹果园和农田相互转换的深层土壤水环境效应

研究长武塬区苹果园和农田相互转换后0~1 000 cm土壤含水量特征，分析了苹果园土壤干燥化和苹果园转换为农田后土壤水分的恢复效应。结果表明：2、7、17、23、29 a苹果园200~1 000 cm的平均土壤含水量分别为22.8%、21.4%、16.8%、15.4%、14.9%。500~1 000 cm土层中，29 a苹果园平均土壤含水量（14.5%）高于23 a的果园（13.3%）；17~29 a的苹果园均表现为轻度干燥化；基于苹果园和农田转换后土壤水分变化情况估算，苹果园最大种植年限为21 a。苹果园转换为农田1、5、10 a后，农田200~1 000 cm土层土壤含水量分别为：15.3%、15.7%和16.2%，恢复到土壤稳定湿度以上的土层厚度分别为140 cm（1 a）、220 cm（5 a）和400 cm（10 a）。     

一例湖羊纤维素性肺炎的病理组织学观察

为探究四川省某养殖场湖羊患病情况,以1只发病湖羊为例,研究观察病羊临床症状、解剖变化,采用H.E.染色方法分析病羊实质器官病理组织学变化,并从病羊中分离出菌株Z-1,采用生理生化、16S rDNA基因测序对其鉴定,采用腹腔注射对菌株Z-1进行动物回感试验,纸片扩散法对菌株Z-1进行药敏分析。结果表明:患病羊病症有高热、剧烈咳嗽并伴有喘气,口鼻周围可见黄色浓稠分泌物;解剖变化为多个实质器官明显肿大、充血,肺脏充血、颜色暗红,切开有血样泡沫状液体流出;病理组织切片可见肺、肝、脾等组织细胞肿胀、充血、出血,肺泡腔和细支气管中有大量粉红色纤维素性渗出物,炎性细胞浸润;菌株Z-1为革兰氏阳性菌,乳糖、七叶苷和山梨醇等生化反应呈阳性反应,木糖醇、甘露糖和蜜二糖等生化反应呈阴性反应;16S rDNA基因目的片段长度为1 428bp,与菌株NR_026471的相似性达到98%,综合鉴定为链球菌;动物回感试验表明该菌株对小鼠具有很强的致病性;药敏试验表明该菌株对氧氟沙星、诺氟沙星、环丙沙星和庆大霉素等敏感,对氨苄西林、青霉素和拉氧头孢等耐药。综上,该病湖羊患链球菌感染的纤维素性肺炎。     

基于灰色-BP神经网络模型的多情景交通用地需求预测——以长江中游城市群为例

为探索科学预测区域交通用地需求的合理途径,指导国土空间规划编制中交通用地规模的划定,拟通过灰色-BP神经网络模型识别主要社会经济影响因素,以长江中游城市群为例,在预测其远景交通用地需求规模的同时,基于城市群发展的阶段特征选取典型城市群样本设置3类情景,对不同情景下的交通用地需求分别进行预测。结果表明:1)城镇化水平、产业结构高度化程度和劳动力资源禀赋是当前影响长江中游城市群交通用地需求的主要社会经济因素。2)通过系统仿真试验对比不同方法的交通用地需求预测结果,可以发现基于灰色-BP神经网络模型的预测方法精度较高,误差较小,该预测方法对于区域交通用地规模的预测具有一定的适用性。预测得到的长江中游城市群2020和2030年交通用地需求分别为31.22万和49.07万hm2。3)不同情景下长江中游城市群交通用地需求预测结果存在明显差异,底线情景可作为划定交通用地规模的底限,一般情景可作为基准,极限情景可作为红线,长江中游城市群交通用地合理规模应以基准为参考,介于底线和红线之间。     

Grain yield,nitrogen use efficiency and tillage intensity in wheat as affected by precision nutrient management

ABSTRACT

The present studies were conducted to evaluate the effect of different nutrient management practices under two tillage options in wheat. The experiments were laid out in split-plot design with a combination of two varieties (WH 1105 and HD 2967) and two tillage options (Conventional and No tillage) in the main plot and six precision nutrient management practices [absolute control, site-specific nutrient management with Nutrient Expert for wheat (SSNM-NE)(170 kg nitrogen (N)/ha), SSNM NE+GreenSeeker (GS)(153/158 N kg/ha), N₁₂₀ (120 kg N/ha) before irrigation, N₁₂₀ after irrigation and N Rich (180 kg N/ha)] in subplot replicated thrice. The grain yield and quality characters in no tillage (NT) and conventional tillage (CT) were similar but agronomic efficiency was higher in NT. Both the varieties (WH 1105 and HD 2967) gave similar grain yield and quality. Wheat variety WH 1105 recorded significantly higher sodium dodecyl sulfate sedimentation (SDS) and gluten index. The treatment SSNM NE+GS had resulted in 107.1% higher grain yield than no nitrogen control but similar to enriched N plot (180 kg N/ha). The grain protein, SDS and gluten index in need-based nutrient management (SSNM+GS) treatment were found to be similar as recorded in SSNM-NE (170 kgN/ha) and N enriched plot (180 kg N ha^?1). The agronomic efficiency and recovery efficiency in SSNM+GS were also better than SSNM NE.     

氮肥减量后移对喷灌玉米产量和水氮利用效率的影响

【目的】优化井灌区田间水肥管理。【方法】试验于2018年6—9月在河南省许昌灌溉试验站进行,以当地主栽玉米品种登海3737(P1)和豫单9953(P2)为试验材料,设置3种施肥调控方式,分别为当地传统施肥模式CK(N、P2O5、K2O施量分别为315、75、75 kg/hm^2,全部基施),优化模式F1(N、P2O5、K2O施量分别为225、75、75kg/hm^2,40%三叶期和60%拔节期追肥),优化模式F2(N、P2O5、K2O施量分别为225、75、75kg/hm^2,30%三叶期、30%拔节期和40%大喇叭口期追肥),研究了喷灌水肥一体化下氮肥减量后移对不同品种夏玉米生长发育、产量和水分利用效率的影响。【结果】增加施肥频次和施肥时间后移可提高玉米叶面积系数(LAI)和延缓叶片衰老,增加玉米干物质累积量以及最大生长速率。喷灌水肥一体化(F1、F2处理均值)较传统施肥籽粒产量提高7.8%,耗水量降低11.9%,水分利用效率(WUE)提高22.2%,籽粒氮肥偏生产力(PFPY)提高51.1%,生物量氮肥偏生产力提高49.2%。登海3737干物质累积、最大生长速率、WUE和PFPY的均值较豫单9953分别增加2.8%、7.7%、8.5%和8.6%,最大生长速率出现的时间没有差异。豫单9953干物质积累快增期持续时间比登海3737增加5.3 d。不同品种之间产量和构成要素差异极显著。登海3737平均产量为11 319 kg/hm^2,较豫单9953增产8.4%,其中穗长、百粒质量对产量贡献较大,分别提高22.5%和18.2%。【结论】本研究中,F2处理为最佳施肥模式,即N、P2O5、K2O施量分别为225、75、75 kg/hm^2,施肥配比为30%三叶期、30%拔节期、40%大喇叭口期。     

乌鲁木齐市冬春两季宠物源葡萄球菌的耐药性及耐药基因比较

采用琼脂稀释法,检测从乌鲁木齐市部分宠物医院冬季和春季分离鉴定的154株宠物源葡萄球菌(冬季75株、春季79株)对临床常用的12种抗菌药物(阿米卡星、克林霉素、硫酸庆大霉素、氟苯尼考、四环素、利福平、恩诺沙星、青霉素、苯唑西林、阿莫西林/克拉维酸、头孢噻呋、左氧氟沙星)的耐药性;通过卡方检验,比较供试菌耐药性差异;采用PCR方法,检测葡萄球菌的5类9种耐药基因。对抗菌药物的耐药结果显示:冬季葡萄球菌对苯唑西林和青霉素的耐药率高于90.0%,对头孢噻呋和四环素的耐药率高于50.0%;春季葡萄球菌对左氧氟沙星耐药率达92.4%,对苯唑西林和氟苯尼考耐药率高于80.0%。卡方检验结果显示:冬季葡萄球菌仅对苯唑西林的耐药率显著高于春季葡萄球菌(P0.05);春季葡萄球菌对氟苯尼考、利福平、左氧氟沙星、恩诺沙星和阿莫西林/克拉维酸的耐药率均显著高于冬季葡萄球菌(P0.05)。多药耐药差异性结果显示:冬季葡萄球菌多药耐药集中在1～3耐;春季葡萄球菌多药耐药集中在4、6、9耐。基因检测结果显示:冬季葡萄球菌主要检出的基因有ermB(40.0%,30/75)和fexA(22.7%,17/75);春季葡萄球菌主要检出的基因有fexA(39.3%,31/79)和femA(20.3%,16/79),冬、春季葡萄球菌均未检出cfr、fexB和tetA基因。     

水分与氮素及其互作对水稻产量和水肥利用效率的影响研究进展

了解水分、氮素及其互作对水稻产量与水、氮利用效率的影响,对协同提高水稻产量与水氮利用效率有重要意义。本文概述了水稻节水灌溉技术、氮肥利用效率与氮肥施用技术、水分与氮素对水稻产量及水氮利用效率的耦合效应、作物-土壤关系及水氮调控机制等方面取得的进展;讨论了存在的问题,这些问题包括:高产水稻作物与土壤的水氮互作效应尚不明确;高产水稻水氮耦合与高效利用的分子机理不清楚;协同提高水稻产量与水氮利用效率的调控途径尚未掌握。针对这些问题,建议今后重点研究:高产水稻作物与土壤的水氮互作效应及其机制;水氮互作调控水稻吸收利用水分和氮素的生理与分子机理;协同提高水稻产量和水氮利用效率的调控途径与关键技术。     

Cohort‐specific variation in juvenile coho salmon habitat use

In this study, we examined summer and fall freshwater rearing habitat use by juvenile coho salmon (Oncorhynchus kisutch) in the quickly urbanising Big Lake drainage in south‐central Alaska. Habitat use was assessed by regressing fish count data against habitat survey information across thirty study sites using generalised linear mixed models. Habitat associations were examined by age‐0 and age‐1+ cohorts separately, providing an opportunity to compare habitat use across different juvenile coho salmon life stages during freshwater rearing. Regression results indicated that the age‐0 cohorts were strongly associated with shallow, wide stream reaches with in‐stream vegetation, whereas age‐1+ cohorts were associated with deeper stream reaches. Furthermore, associations between fork length and habitat characteristics suggest cohort‐specific habitat use patterns are distinct from those attributable to fish size. Habitat use information generated from this study is being used to guide optimal fish passage restoration planning in the Big Lake drainage. Evidence for habitat use partitioning by age cohort during freshwater juvenile rearing indicates that pooling age cohorts into a single “juvenile” stage for the purposes of watershed management may mask important habitat use dynamics.     

The efficiency of nitrogen in cattle manures when applied to a double‐annual forage cropping system

The use of cattle manure (CM) for fertilization presents challenges for optimizing nitrogen (N) use. Our work aimed to assess N efficiencies, in a 6‐year experiment with three biennial rotations of four crops: oat–sorghum (first year) and ryegrass–maize (second year) in a rainfed humid Mediterranean area of Spain. Fertilization treatments included the following: control (no N), 250 kg mineral N ha^?1 year^?1 (250MN), three CM rates (supplying 170, 250 and 500 kg N ha^?1 year^?1) and four treatments where the two lowest CM rates were complemented with either 80 or 160 kg mineral N ha^?1 year^?1. Treatments were distributed randomly in each of three blocks. Maximum dry‐matter yield (~44–49 t ha^?1 rotation^?1) was achieved in the third rotation, and only the control and the 170CM yielded significantly less. Within the limitations of the EU Nitrate Directive, the N steady state supply of 170CM always requires a complement of mineral N (80 kg N ha^?1) to maximize N agronomic efficiency. The maximum N‐fertilizer replacement value (250CM vs. 250MN) was 0·67, without significant differences between the two treatments in other N‐related efficiency indexes, which indicates that plants took advantage of residual‐N effects. Nitrogen losses by leaching in the 250CM treatment were around 5–7% of the N applied. This reinforces the sustainability of manure recycling in long cropping seasons.