高寒地区青稞配方专用肥对比试验

在门源县浩门镇头塘村的青稞进行配方专用肥对比试验，通过试验可以得出配方专用肥的产量比CK增产41．3％，比农民习惯施肥增产16．7％。     

喷施锌肥对渭北旱塬苹果生长及产量品质的影响

在陕西渭北旱塬果园,于苹果膨大期喷施不同浓度的锌肥,观测分析锌对果树生长和苹果品质的影响.结果表明,施锌可以抑制新梢生长速率,对果实直径生长速率、百叶干重、叶面积生长有显著的促进作用.其中,喷施0.5%浓度的锌肥,株产量比对照增加24.7%,可溶性固形物含量增加10.5%,还原糖增加27.5%,硬度提高了23.6%;喷施1%浓度的锌肥,株产量比对照增加40.2%,Vc含量提高了20.4%,可溶性糖增加了26.7%,花青苷含量提高了75%.综合考虑苹果生长与品质因素,该地区果园以喷施0.5%～1%浓度的锌为宜.     

渭北旱塬小麦玉米轮作区不同耕作方式 对土壤水分和作物产量的影响

【目的】陕西渭北旱塬属于暖温带半湿润易旱气候区,干旱对旱地农作物生产威胁严重,降水短缺及其季节分布不均制约着旱地冬小麦和春玉米生长发育,是导致作物产量低而不稳的主要因素。论文旨在探索渭北旱塬冬小麦-春玉米轮作区在不同轮耕措施下土壤蓄水保墒效果和作物增产增收效应。【方法】于2007-2013年在陕西合阳实施了免耕/深松、深松/翻耕、翻耕/免耕、连续翻耕等不同耕作处理田间定位试验,测定休闲期和作物生育期土壤水分及作物收获期土壤理化性状,分析各耕作处理作物产量和水分利用效率的变化规律。【结果】（1）3种耕作处理均能降低土壤容重,提高土壤孔隙度,增加田间持水量和土壤有机质,且以免耕/深松轮耕处理效果最佳,与连续翻耕相比,免耕/深松轮耕处理平均土壤容重较连续翻耕处理降低3.6%,平均土壤孔隙度、田间持水量和土壤有机质含量较连续翻耕处理分别增加4.4%、11.6%和6.9%。（2）在6个试验年度的3个休闲期间,平均土壤蓄墒率：免耕/深松＞翻耕/免耕＞深松/翻耕＞连续翻耕,免耕/深松、深松/翻耕和翻耕/免耕处理平均土壤蓄墒率较连续翻耕处理分别增加22.4个百分点、4.4个百分点和4.9个百分点,增墒效果显著;免耕/深松、深松/翻耕和翻耕/免耕处理0-200 cm土层平均土壤蓄水量较连续翻耕处理分别高18.2、1.3和11.8 mm。（3）在冬小麦生长期,免耕/深松、深松/翻耕和翻耕/免耕处理0-200 cm土层平均土壤蓄水量较连续翻耕处理分别增加13.2、1.7和14.6 mm;在春玉米生长期,免耕/深松和深松/翻耕处理0-200 cm土层平均土壤蓄水量较连续翻耕处理分别增加17.8和15.1 mm,深松/翻耕处理低于连续翻耕处理5.0 mm。（4）在冬小麦生产年度,免耕/深松、深松/翻耕和翻耕/免耕处理平均产量较连续翻耕处理分别增产8.1%、8.9%和4.9%,水分利用效率平均提高14.3%、13.8%和10.2%;在春玉米生产年度,免耕/深松和深松/翻耕处理平均产量较连续翻耕处理分别增产10.2%和6.4%,水分利用效率平均提高4.6%和8.2%,翻耕/免耕与连续翻耕处理平均产量接近,水分利用效率接近。【结论】综合可知,3种轮耕模式中,与连续翻耕处理相比,深松/翻耕轮耕模式土壤水分状况较差,但其作物产量和水分利用效率较高;翻耕/免耕轮耕模式土壤水分状况较好,但其作物产量和水分利用效率较差;而免耕/深松轮耕模式对于改善土壤耕层物理结构、提高土壤蓄水保墒效果和作物增产效应最佳,为渭北旱塬区麦玉轮作田较适宜的休闲轮耕模式。     

渭北旱塬区不同坡向土地利用类型对土壤性质的影响

为了研究不同坡向土地利用类型对土壤性质的影响,以渭北旱塬区5种土地利用类型(不同坡向)为研究对象,系统分析该区不同坡向土地利用类型剖面土壤物理、化学和生物性质的差异。结果表明:(1)除土壤pH和土壤颗粒组成外,5种土地利用类型土壤含水量、总孔隙度、有机质、全氮、微生物量碳和氮含量总体随土层加深呈下降趋势,土壤容重则相反。(2)0-30cm土层,阳坡农用地土壤含水量、黏粒含量和pH最高,粉粒和全氮含量最低;人工草地砂粒和全氮含量最高,黏粒含量最低;人工林地土壤总孔隙度、土壤有机质、微生物量碳和氮含量最高,土壤含水量、土壤容重和pH最低;天然草地土壤容重和粉粒含量最高,总孔隙度和砂粒含量最低;退耕地有机质、微生物量碳和氮含量最低。阴坡农用地土壤含水量、粉粒含量和pH最高,黏粒和全氮含量最低;人工草地土壤容重、黏粒和微生物量氮含量最高,土壤总孔隙度、粉粒、砂粒和有机质含量最低;人工林地有机质含量和微生物量碳含量最高;天然草地土壤总孔隙度、砂粒和全氮含量最高,土壤容重和pH最低;退耕地土壤含水量、微生物量碳和氮含量最低。(3)5种土地利用类型中,土壤容重、细黏粒、粗黏粒、细粉粒、粗砂粒、土壤pH和有机质(退耕地除外)表现为阳坡阴坡,土壤含水量(退耕地和农用地除外)、总孔隙度、粗粉粒、细砂粒、土壤质地粗化度、全氮(人工草地除外)、土壤微生物量碳和氮含量则为阴坡阳坡。     

Genetic structure of highland papayas (<Emphasis Type="Italic">Vasconcellea pubescens</Emphasis> (Lenné et C. Koch) Badillo) cultivated along a geographic gradient in Chile as revealed by Inter Simple Sequence Repeats (ISSR)

In Chile Vasconcellea pubescens is cropped to produce canned fruit, juice, jam and processed sweets. Additionally this species produces latex with a high level of papain, an important and valuable proteolytic enzyme with industrial applications. In this investigation seven ISSR primers were used to study the level and organization of genetic diversity in 333 samples of V. pubescens. Out of the 114 bands recorded, 63 proved to be polymorphic (P = 55.3%). At the species level, the genetic diversity was rather low (h = 0.01 ± 6,80188E-05, Shannon’s Index I = 0.16 ± 0,000148). The major portion of the genetic diversity was found within groups (65%). The genetic differentiation between the different groups was significant, as the AMOVA analysis suggested (Φ_pt = 0.35). When analysing the Northern area alone, the differentiation increased to Φ_pt = 0.40. When only the Southern area was analysed, Φ_pt decreased to 0.18, indicating greater genetic similarity among the samples. The results generated from Structure and Bayesian Analysis of Population Structure distinguished 8 genetically different groups, five of them located in the north and three in the south. The results are discussed in the light of the growers’ practices.     

An explorative study comparing skin surface lipids in the West Highland white terrier dog with and without atopic dermatitis

BackgroundThe skin barrier is important in the pathogenesis of atopic dermatitis and stratum corneum lipids have a critical role. Skin surface lipids have been largely overlooked but also contribute to barrier function. An untargeted approach was used to compare the skin surface lipids from atopic and non-atopic West Highland White terrier dogs (WHWT).ObjectivesThe primary hypothesis was that a difference in the lipidome would exist. The secondary hypothesis was that affected and unaffected skin lipids would differ.Animals and methodsThis prospective, cross-sectional, case-controlled study included thirty-nine privately owned WHWTs. Dogs were assigned to one of four disease status groups based on strict criteria. Samples for lipid analysis were collected from the skin surface of unaffected and affected sites. Lipid analysis was by untargeted liquid chromatography/mass spectrometry and utilised lipid identification software packages. Principle component analysis (PCA) and partial least-squares discriminant analysis (sPLS-DA) statistical methods analysed the association between the relative lipid abundance and disease status and affected and unaffected skin.ResultsSamples for lipid analysis found 421 lipid soluble features of which ten lipids were positively identified. Statistical analysis could not distinguish between non-atopic and atopic dogs but did reveal a statistically significant difference in the lipid profiles from affected and non-affected skin irrespective of disease status.ConclusionsA large array of unidentified lipids from the skin surface were found with a difference between affected and unaffected skin unrelated to disease status. Investigation into the lipidome of the skin surface is an emerging area of research with clinical and therapeutic applications.     

高原地区小牛肉生产试验

6头中国西门塔尔杂交二代公犊用于小牛肉生产试验。结果显示：经223d育肥,试验末期平均体重达到了221.58kg,日增重0.578kg,每头牛可获利365.36元。说明利用中国西门塔尔二代杂交牛和饲草料资源开展小牛肉生产在高原地区,能获得较好的经济效益。每头中国西门塔尔杂交育肥牛可获得18.07kg的高档牛肉,高档肉块重量占到活重的8.90%;优质牛肉22.95kg,优质肉块重量占到活重的11.31%。从牛肉产量上证明中国西门塔尔二代杂交牛可以作为高原地区生产高档优质牛肉的肉用牛种。     

陕西渭北旱塬区耕地时空格局变化分析

渭北旱塬区人地矛盾突出,准确认识该区耕地时空格局演变规律,有利于为耕地资源合理利用,粮食及生态安全保障提供决策依据.该研究基于1995—2020年耕地空间分布信息,采用重心模型、标准差椭圆、空间自相关和地学信息图谱等方法,从耕地总量变化特征、耕地空间变化特征和耕地LISA频率图谱特征3个方面开展,揭示陕西渭北旱塬区耕地...     

低温胁迫对青稞幼苗抗寒性生理指标的影响

［目的］研究低温胁迫下不同青稞品种幼苗抗寒性生理指标的变化规律,了解其抗寒机理。［方法］以青稞昆仑12号和肚里黄2个栽培品种为材料,测定了低温处理前、后和低温处理后恢复2d3个阶段的青稞幼苗叶片中超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）保护酶系活性的变化及脯氨酸（Pro）和丙二醛（MDA）含量的变化。［结果］2种青稞中的SOD、POD活性在低温处理后下降,恢复2d后上升,达到显著水平（P〈0.05）;CAT活性因品种不同而表现各异,肚里黄低温处理后活性下降,恢复后上升,昆仑12号低温处理后先升高恢复后再上升。2种青稞叶片中的Pro、MDA含量在低温处理后都增加,恢复2d后有所下降,均达到显著水平（P〈0.05）。［结论］昆仑12号耐低温胁迫的能力较强,肚里黄较弱。     

林木细根分布规律与土壤水分响应关系研究

通过野外调查和室内分析,对渭北黄土高原主要造林树种的根系分布特征和土壤水分的季节变化规律进行研究.结果表明:林地土壤水分可以划分为土壤水分活跃层、土壤水分稳定利用层和土壤水分稳定层3个层次,不同立地不同层次上的土壤含水量具有不同的时空分布特征.对不同立地条件上林木根系分布特征的研究结果表明,不同立地上刺槐根系的空间分布特征具有明显差异,阴坡立地上的刺槐根系具有更大的分布空间.进一步的分析结果表明,土壤水分的变化规律与根系的分布特征有密切的关系,适宜的水分环境可以保证根系得到充分的牛长发育,扩大水分养分的吸收空间,使林木的地上部分表现出更大的生产力,反之则降低林木生产力.