糠醛渣改良土壤增强苕子对盐碱土的适应性

科学合理的盐碱土改良措施对植物在盐碱土上适应性栽培具有重要的科学意义与应用价值。该研究旨在通过施用糠醛渣探讨盐碱土土壤特性及植物生长适应性栽培研究,为糠醛渣在盐碱土的合理使用提供科学依据。试验按土壤质量为基数确定糠醛渣的用量,试验由添加量0、5%、10%糠醛渣的盐碱土3个处理组成,温室条件下进行盆栽试验。结果表明,施用糠醛渣不仅降低盐碱土pH和含盐量,而且显著提升了土壤微生物多样性Sobs和Shannon指数,降低了simpson指数降低。主要表现在变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)和绿弯菌门(Chloroflexi)成为优势菌门。施用糠醛渣增加了苕子叶片中叶绿素、可溶性糖含量和脯氨酸含量。显著增强了过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性。施用糠醛渣明显促进苕子生长发育,增加了苕子苗期生物量,5%糠醛渣用量处理改良盐碱土效果较优。研究表明糠醛渣通过改善盐碱土的其理化特性及生物多样性分布,促进苕子的生长发育,研究为糠醛渣在盐碱地土壤改良及植物适应性栽培的合理应用提供了科学依据与参考。     

TRMM在海河流域南系的降水估算精度评价及其对SWAT模型的适用性

准确估算区域降水对水文过程评价和水资源管理意义重大。为评估TRMM 3B42V7降水产品在海河流域南系的估算精度及其在土壤和水评估模型(Soil and Water Assessment Tool,SWAT)中的适用性,利用28个气象站降水观测数据(2007-2016年)和101个雨量站观测数据(2010-2016年)开展研究。研究表明:站点尺度上,3B42V7降水产品对月降水估算的均方根误差小于15 mm,平均误差小于8.5 mm;在湿润季节的估算精度更好。流域尺度上,日降水估算精度较差,相关系数小于0.6。分区尺度上,3B42V7能够很好地捕捉到不同等级降水强度,但对微量降雨有所低估;山区和平原的年降水量均出现高估现象,平原区较为突出;此外,3B42V7能够较好地捕捉到研究区内极端降水的时间和空间分布。分2种情景进行水文模拟,利用月平均流量对模型进行校准和验证,在情景Ⅰ中,验证期模拟结果较好,决定系数在0.56~0.96之间,纳什效率系数在-11.09~0.94之间。TRMM 3B42V7可为海河流域及其类似区域的水资源管理提供参考。     

缓释肥侧位深施及用量对油菜产量和肥料利用率的影响

为明确红壤稻田直播油菜缓释肥（N-P2O5-K2O:25-7-8）侧位深施效果及适宜用量，该研究连续2 a在两熟制和三熟制2种种植模式下开展缓释肥侧位深施效果对比试验（设置不施肥、土表撒施和侧位深施3个施肥方式）和施用量试验（设置0、300、450、600、750和900 kg/hm2 共6个施肥水平），研究缓释肥侧位深施及不同用量对油菜产量形成和肥料利用率的影响。结果表明，施肥方式对红壤稻田油菜产量形成和肥料利用率均有显著影响，且对两熟制油菜影响更为显著。相比传统土表撒施，侧位深施显著促进了油菜产量和肥料利用率的提高。缓释肥侧位深施明显提高了各时期油菜干物质量，尤其是显著增加了初花期至成熟期的干物质积累量，促进了花后根部与地上部干物质同步增长；促进了根系对N、P、K的吸收，提高了油菜产量和肥料利用率。菜籽产量与缓释肥用量呈线性加平台关系，适宜施肥量可保证较大的收获密度，并协同产生较多的每株角果数和每角粒数，从而提高籽粒产量、肥料利用率和经济效益。两熟制和三熟制油菜缓释肥侧位深施的适宜用量分别为715和585 kg/hm2，产量潜力可分别达2 450和1 700 kg/hm2。研究表明，侧位深施适量缓释肥可显著提高红壤稻田直播油菜生产力，建议结合机械化种植因地制宜推广应用。     

Arbuscular mycorrhizal-like fungi and glomalin-related soil protein drive the distributions of carbon and nitrogen in a large scale

Purpose

Arbuscular mycorrhizal-like fungi (AM-like fungi) are crucial for ecosystem functioning and soil organic matter (SOM) is an indicator of soil quality. However, the spatial distribution of arbuscular mycorrhizal-like fungi, glomalin-related soil protein (GRSP) and SOM in a large scale is still unclear. The objectives of this study were to investigate the spatial distribution of SOM, arbuscular mycorrhizal-like fungi and GRSP, and reveal the potential relationship among them in a large scale across China.

Materials and methods

Soil samples (different in vegetation type, climate, and soil variables) were collected from 26 sites in a large scale across China. The soil properties including pH, total carbon (TC), total nitrogen (TN), and SOM were determined. Quantitative PCR amplification of the 18S rRNA gene was conducted to evaluate the abundance of arbuscular mycorrhizal-like fungi. The contents of easily extractable GRSP (EE-GRSP), difficultly extractable GRSP (DE-GRSP), and total GRSP (T-GRSP) were measured.

Results and discussion

Arbuscular mycorrhizal-like fungi abundance was significantly affected by the vegetation type and dramatically correlated with the soil TN and mean annual precipitation (MAP). EE-GRSP and DE-GRSP were more associated with the TC and TN content, respectively. The abundance of arbuscular mycorrhizal-like fungi significantly but weakly correlated with the T-GRSP and EE-GRSP. The SOM content positively correlated with the DE-GRSP and T-GRSP. Those results suggested that the arbuscular mycorrhizal-like fungi are a larger contributor to regulating the content of GRSP, which is an important indicator of the soil organic carbon pool.

Conclusions

Our results indicated that arbuscular mycorrhizal-like fungi abundance has a greater contribution to driving the distribution of soil C and N in a large scale by affecting the content of glomalin-related soil protein.

     

A chronosequence study of purple paddy soils with respect to improving ammonium and potassium fertilization management

Journal of Soils and Sediments - Purple paddy soils cover about 66% of the paddy soils in Sichuan Basin. Complex interactions made the effects of potassium fertilizer application on NH4+ adsorption...     

Variation in soil bulk density and hydraulic conductivity within a quasi-circular vegetation patch and bare soil area

Journal of Soils and Sediments - Soil bulk density and hydraulic conductivity are two of many key factors for vegetation establishment and the other way around. Variations in them may cause patchy...     

间作对红壤旱地棉花农艺性状、产量及品质的影响

为探讨红壤旱地棉花适宜的耕作方式，增加棉花产量、改善品质以获得更高的经济效益，以棉花单作为对照，分别比较了棉花与大豆、玉米和甘薯间作对棉花株高、果枝数等农艺性状以及产量、纤维品质的影响。结果表明，间作较单作可提高棉花第一果枝高度和第一果枝节位；促进棉花株高、果枝数、真叶数的增加；可增加棉花成铃数，特别是提高伏桃比例从而提高棉花产量；可降低马克隆值和提高断裂比强度从而改善棉花纤维品质。综合分析认为，棉花间作甘薯的优势较为明显。     

江苏省4个太湖新银鱼种群遗传多样性和遗传结构分析

太湖新银鱼(Neosalanx taihuensis)是我国特有的银鱼种类，主要分布在长江和淮河中下游及其附属湖泊，近年来其资源量呈明显下降趋势。为了解太湖新银鱼遗传背景，本研究采用线粒体细胞色素b (Cytochrome b, Cyt b)基因序列，分析了江苏省太湖、高邮湖、洪泽湖和骆马湖4个太湖新银鱼野生群体共144尾样本的遗传多样性及遗传结构。结果显示，太湖新银鱼Cyt b基因序列共发现29个变异位点，定义25个单倍型；平均单倍型多样性(Hd)为0.682±0.037，核苷酸多样性(π)为0.00231±0.00021；4个群体中，高邮湖群体的遗传多样性最高(Hd: 0.609±0.078; π: 0.00094± 0.00027)，太湖群体的遗传多样性最低(Hd: 0.343±0.107; π: 0.00075±0.00033)。分子方差分析(AMOVA)显示，太湖新银鱼群体间遗传差异(71.53%)大于群体内遗传差异(28.47%)，遗传变异主要来自于群体间。遗传分化指数Fst值统计检验表明，骆马湖群体与太湖、高邮湖和洪泽湖群体之间有显著性差异。分子系统树和单倍型网络进化图分析显示，25个单倍型形成2个明显的地理分支，一支由太湖群体、高邮湖群体和洪泽湖群体组成，另一支由骆马湖群体组成。中性检验和错配分布图分析表明，太湖新银鱼历史上发生过群体扩张。整体来看，太湖新银鱼野生种群遗传多样性较低，应加强种质资源保护。建议将太湖、高邮湖群体和洪泽湖群体作为整体进行管理和保护，骆马湖群体单独管理和保护。     

Bilateral apex pubis distance：a novel index for follicular development and egg laying status in domestic hens (Gallus gallus domesticus)

ABSTRACT

1. Measures of the bilateral apex pubis (BAP) in White Leghorn (WLH) hens aged from 16 to 64 weeks (from the time ovaries were completely undeveloped to senility) were ranked into various groups so the relationship between external traits (BAP distance, comb length, comb height, wattle length, wattle height, body weight) and internal traits (largest ovarian follicle diameter (LFD) and oviduct weight and length) could be determined.

2. Using correlation and regression analysis with data from 16 weeks of age to the onset of lay, measurements of the apex pubis showed a strong correlation with LFD (r = 0.80, P < 0.01) and oviduct weight (r = 0.80, P < 0.01).

3. Multiple comparisons among WLH hens from 16 to 43 weeks of age showed that the BAP distance increased in all groups ranked by LFD or by laying period.

4. In the late laying period (>60 weeks of age), BAP distance showed a significant decrease (P < 0.01) in long-term non-laying hens compared to laying hens.

5. These findings suggest BAP distance can serve as an index for evaluating the onset and probable stages of follicular development during sexual maturation and/or aid in the identification and selection of non-laying hens during reproduction.     

高邮湖大银鱼、太湖新银鱼Cytb和COⅠ 基因序列多态性分析

为探明高邮湖大银鱼、太湖新银鱼野生资源状况,利用线粒体DNA Cytb和COⅠ基因序列,对高邮湖大银鱼、太湖新银鱼的遗传多样性水平及遗传结构进行分析。试验结果显示,大银鱼Cytb基因序列全长1141 bp,其中多态性位点14个,共定义12个单倍型,单倍型多样性和核苷酸多样性分别为0.871±0.031和0.00172±0.00019,具有高单倍型多样性和低核苷酸多样性特征。COⅠ基因片段长度为630 bp,其中多态位点5个,共定义6个单倍型,单倍型多样性和核苷酸多样性分别为0.747±0.041和0.00202±0.00019,具有高单倍型多样性和低核苷酸多样性特征;太湖新银鱼Cytb基因序列全长1141 bp,其中多态性位点13个,共定义9个单倍型,单倍型多样性和核苷酸多样性分别为0.609±0.078和0.00094±0.00027,具有高单倍型多样性和低核苷酸多样性特征。COⅠ基因片段长度为630 bp,其中多态位点2个,共定义3个单倍型,单倍型多样性和核苷酸多样性分别为0.232±0.085和0.00038±0.00014,呈现低单倍型多样性和低核苷酸多样性。大银鱼和太湖新银鱼Tajima′s D和Fu′Fs中性检验值为负值,且歧点分布曲线呈单峰型,表明历史上经历过种群扩张。研究结果表明,应通过多种措施加强高邮湖银鱼种质资源保护。