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.     

The Identification of QTL Associated with Cotton Fruit Branch Length Suitable for Mechanized Harvest Utilizing BSA-seq

[Objective] This study aims to identify quantitative trait loci (QTLs) associated with cotton fruit branch length by using the combination of bulked-segregant analysis (BSA) and next-generation sequencing (NGS) method. [Method] In this study, the cotton F₂ segregating population was developed with the short branch line Sujimian 125 and long-branch variety Sikang 1 as cross parents. According to the average internode length of fruit branches in middle, extreme individuals in F₂ population were divided into two groups to generate the bulked DNA samples. The whole-genome resequencing of two DNA bulks was applied to analyze the single nucleotide polymorphism (SNP) and insertion-deletion (InDel) between two groups, and the fruit branch internode length related QTLs were detected using Euclidean distance (ED). [Result] With SNP data obtained from sequencing, a 0.8 Mbp range associated region on chromosome A3 was identified; with InDel data obtained from sequencing, a 1.09 Mbp range associated region on chromosome A3 was identified. Two regions overlapped, and the overlapped range was 0.77 Mbp. [Conclusion] This result suggested that the difference between I-type fruit branch and zero-type was due to different genetic locus and pattern rather than dosage effect of the same gene.     

Nutrients in litterfall,forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ.     

入射角度对气力射播小麦种粒入土参数影响的试验研究

针对稻麦轮作区黏湿土壤条件下的小麦机械化播种,为避免传统接触式小麦播种技术存在的粘附堵塞严重和作业阻力、功耗大等问题,该文采用非接触式小麦气力射播技术理论,通过自制的小麦气力射播试验台,开展整洁种床土壤条件下入射角度对气力射播小麦种粒入土参数影响的试验研究。试验结果表明:随着入射角度的增加,相同加速气压下小麦种粒的射播速度垂直分量和射播深度不断增加,小麦种粒触土后产生水平滑移和弹跳的几率变小,且各入射角度下射播深度与射播速度呈正相关关系,不同入射角度下小麦种粒呈现出不同射播深度和土壤冲击效果,小麦种粒未产生损坏情况;当入射角度≥45°和射播速度垂直分量≥25 m/s时,小麦种粒可被完全射播入土壤中且出苗率大于86%,90°入射角度下的射播效果最好。同时,为实现田间作业时小麦种粒的垂直射播入土,应使射播速度水平分量与机具作业速度相等且射播速度垂直分量≥25m/s。试验结果可为非接触式小麦射播装备的研制提供基础数据和技术支撑。     

创意农业的生成机制及模式类型研究

当前，各界对创意农业的关注持续升温，经济发展推动我国各个产业不断向现代化迈进，在农业的产业现代化进程中，产业升级使传统农业产业结构不断调整；产业融合促进传统农业走向全新发展模式；农业产业链延伸有效提升农业生产各个环节的创新发展空间；创意产业为农业增加文化、创意附加值，创意农业应运而生。根据农业生产的不同产业链环节，创意农业划分为乡村及农业景观创意类、农业生产科技创意类、农产品及包装展示创意类、营销与服务创意类、农产品加工创意类、农业文化遗产创意类六大类型。     

寄主植物中抑制十字花科黑腐病菌Ⅲ型分泌系统小分子化合物的鉴定

 寻找抑制植物病原菌III型分泌系统的植物源活性小分子化合物,是研发生物安全农药的重要途径之一。本研究采用水煮提取法从十字花科黑腐病菌寄主植物满身红萝卜中提取分离活性小分子化合物,利用高效液相-质谱联用解析出活性物质的单体结构。然后用荧光素酶基因luxAB构建融合报告系统以及定量PCR检测活性物质对十字花科黑腐病菌III型分泌系统的抑制效果,最后采用剪叶接种和压渗接种的方法研究活性小分子物质对十字花科黑腐病菌的生防作用。研究表明,植物鞘氨醇和二氢鞘氨醇对十字花科黑腐病菌III型分泌系统基因的转录表达有一定程度的抑制作用,但是对I、II、IV型分泌系统基因的表达没有明显的抑制作用。植物鞘氨醇在XCM1上影响菌的生长,而二氢鞘氨醇不影响菌的生长。同时,还发现这两种物质能显著降低Xcc在寄主植株满身红萝卜上的病害症状以及能够使Xcc在非寄主植物辣椒上引起过敏反应的能力丧失。该研究结果为深入研究小分子化合物对十字花科黑腐病菌III型分泌系统的作用机制及后续开发植物源抑制剂提供了一定的理论依据。     

基于提等潜力和主导因素的耕地质量监测类型区划分及布点方法

以江西省南昌县为例,依托江西省耕地质量监测试点项目,依据耕地自然等指数提升潜力大小和对等级提升最大贡献值因子的组合类型来划分耕地质量监测类型区,并依据监测重点及监测类型区面积比例布设监测样点。实证分析表明,南昌县耕地质量等级监测共有14个组合类型,归并14个组合类型得到5个监测类型区:1个常规监测区和4个重点监测区。其中重点监测类型区包括易渍涝区、易干旱区、耕层瘠薄区和肥力缺乏区。依据监测重点和面积大小在各监测类型区内共布设监测样点70个。统计学检验结果证明,同其他常规布点方法对比,在相同监测样点情况下,依据耕地质量等级提升潜力及限制因子组合类型划分耕地质量监测类型区所布置的监测样点,监测的针对性更强,准确性更高。     

水果番茄新品种“晶杏”的选育

"晶杏"是由XS12为母本、CM14为父本杂交而成,为无限生长型,生长势旺盛,中熟,果实淡黄色,高圆形,单果质量约50 g。色泽亮丽,坐果率高,坐果整齐一致,果实大小均匀。丰产性好,口味佳,抗裂果,高抗叶枯病和枯萎病。产量约达97.5 t·hm^-2,是目前栽培的理想樱桃番茄品种,适合于内蒙古中部地区早秋、早春日光温室和大棚越夏栽培。     

Delayed-type hypersensitivity skin test against Neospora caninum in heifers with undetectable specific antibodies

Delayed-type hypersensitivity (DTH) has been used in human and veterinary medicine as a skin testing for evaluating in vivo cell-mediated immune responses (CMIR). Whereas CMIR is a key process to control intracellular pathogens, its value at identifying cattle exposed to the abortigenic intracellular coccidian parasite Neospora caninum is unknown. In this work, we have evaluated a DTH skin testing in cattle exposed to N. caninum and still seronegative. Female calves were experimentally sensitized by subcutaneous (SC) inoculation with live tachyzoites of N. caninum (NC-Argentina LP1) in sterile phosphate-buffered saline (PBS) (group A; n: 8) whereas other calveswere mock-sensitized with PBS (group B; n: 6). Two DTH skin tests were performed by intradermal inoculation with a soluble lysate of N. caninum tachyzoites (NC-Argentina LP1) in the neck region at 60d and 960 d after sensitization. Skinfold thickness at the intradermal inoculation site was measured at 0, 24, 48 h post each DTH skin test and skin biopsies taken for microscopic evaluation. Specific N. caninum antibodies kinetics was evaluated all throughthe experiment. We found that whereas N. caninum specific antibodies remained below the ELISA cut-off, a distinctive skinfold thickness increase was detected in sensitized animals (group A) at the DTH skin test site, showing induration, swelling and inflammatory infiltration. Mock sensitized animals (group B) showed no skinfold thickness growth and lacked specific antibody response. Thus, N. caninum DTH skin testing could be a useful diagnostic tool for the detection of CMIR during N. caninum infection in non-humoral responders.     

不同氮素水平下双季稻株型与冠层内光截获特征研究

本文旨在阐明双季稻株型与冠层内光合有效辐射截获的时空分布特征。选用4个不同株型早、晚稻品种,设置4个不同施氮水平,系统观测其植株形态和冠层内光合有效辐射截获率(IPAR)的时空分布状况。结果表明,施氮水平对早、晚稻株高、穗长、叶长和叶基角均有显著影响,均表现为随施氮水平的增加而增大;早、晚稻孕穗期的分层叶面积指数(LAI)和向上累积LAI大于抽穗后12 d,分层LAI呈冠层中部大于上部和下部的分布特征,最大分层LAI出现在0.58相对高度处;冠层上中部分层LAI和向上累积LAI随施氮水平的增加而增大;向上累积LAI随相对高度呈S型曲线分布,可用Logistic方程定量描述(R~2 0.99);早、晚稻孕穗期的冠层IPAR大于抽穗后12 d,且随施氮水平的增加而增大,其日变化表现为正午较小,早晚较大;株型紧凑的早、晚稻品种,冠层IPAR低;冠层IPAR与向下累积LAI之间的关系可用方程IPAR=a (1-e~(-b×LAI))定量描述(R~2 0.88);冠层内IPAR的三维空间分布表现为冠层上中部水平面上IPAR较低,光斑变化大,冠层下部水平面上IPAR较高,光斑变化较平缓,同一冠层高度水平面上的IPAR呈不均匀分布。研究结果可为双季稻高产栽培及理想株型的优化设计提供支撑。