转盘式全自动红枣去核机的设计

为解决目前红枣人工去核过程中劳动强度大、工作效率低、卫生条件差、安全隐患多以及加工的产品质量难以控制等问题,设计了一种多工位转盘式全自动红枣去核机。该装置采用电动机输出的动力经减速器减速后带动两个弧面分度凸轮机构同时进行间歇转位运动和提升运动,使转盘的转位及滑板的上下运动相配合,加上新型扶正去核杆的使用,一次性完成红枣的扶正、定位、去核三道工序,完成红枣的去核任务。同时,对全自动红枣去核机的整机结构在Pro/E软件中进行三维实体建模,并且设计加工出了试验装置。结果证明,该装置各部件组装合理,去核效果理想,可以进行后续的物理样机制作。     

黄土高原晋南旱塬长时间序列冬小麦产量与水量平衡要素动态变化

为揭示黄土高原旱地冬小麦田长期产量及水文变化,以山西省万荣县连作冬小麦为研究对象,分析了冬小麦产量1951—2020年变化趋势及气候年际波动对产量的影响,同时利用Hydrus-1D模型和标定的模型参数模拟了1965—2020年田间水量平衡要素各分量的变化过程。结果表明：试验地冬小麦产量多年平均增产率是31.9 kg/(hm²·a),年际气候变化对冬小麦产量的影响达到±22.4%,其中影响最为显著的气象要素是生育期平均相对湿度和全年降水量;标定期和验证期Hydrus-1D模型的决定系数分别为0.65～0.68,0.57～0.65;近56 a冬小麦平均蒸腾量为(176±29) mm,土壤蒸发量为(296±28) mm占降水量的60%～80%,渗漏量一般小于40 mm,土壤含水量变化为(-2±45) mm。综上,研究地70 a冬小麦产量呈上升趋势,且受年际气候变化的影响其产量波动较大。Hydrus-1D模型能够较好地模拟晋南旱塬冬小麦田的水文变化情况,多年来研究地冬小麦田土壤含水量呈下降趋势。     

基于HYDRUS-1D的城市草地土壤水分模拟——以扬州市人工草地为例

[目的] 研究城市化背景下草地土壤水分运动规律,为提升海绵城市建设水平提供科学依据和技术支撑。[方法] 以江苏省扬州大学扬子津校区农水与水文生态试验场的人工草地为研究区,利用实测降雨和同期土壤含水量数据对不同降雨事件下的雨水入渗深度进行分析。通过HYDRUS-1D模型对研究区土壤含水量变化过程进行模拟。[结果] 在小雨（<10 mm）和中雨（10~25 mm）事件中,研究区草地的雨水入渗深度分别小于15 cm和30 cm;在大雨（25~50 mm）到暴雨（>50 mm）事件中,雨水入渗深度通常超过30 cm,或可达60 cm以上;土壤含水量模拟值与实测值的均方根误差范围为0.012～0.034 cm³/cm³。[结论] 不同等级降雨事件下的草地雨水入渗深度存在明显差异,入渗深度总体上随着降雨量的增加而增加;HYDRUS-1D模型能够准确模拟不同等级降雨事件下的城市人工草地区雨水入渗深度。     

切割处理和2,4-D对多棱裸大麦离体成熟胚出愈率的影响

为了筛选适宜成熟胚离体培养的多棱裸大麦材料,并建立其成熟胚愈伤组织的高效诱导培养技术体系,采用3次重复的L25(56)正交设计,探究成熟胚基因型、切割处理、外源生长素(2,4-D)、萘乙酸(NAA)、6-苄基嘌呤(6-BA)和矮壮素(CCC)对多棱裸大麦成熟胚出愈率的影响。结果表明,成熟胚基因型、不同浓度的2,4-D和切割处理均可影响多棱裸大麦成熟胚出愈率,且成熟胚基因型、2,4-D和切割处理间具有一定的组合效应;但不同浓度的NAA、6-BA和CCC对多棱裸大麦成熟胚出愈率没有显著影响。添加0.5~2.0mg·L-1的2,4-D可有效提高多棱裸大麦成熟胚出愈率,但诱导不同基因型的成熟胚愈伤组织所需2,4-D浓度不同。横向切割部分胚芽、横向切割部分胚根-胚芽和纵向切割部分胚均可提高多棱裸大麦成熟胚的出愈率,但横向切割部分胚根对成熟胚的出愈率没有明显影响。在25个处理中,处理Ⅱ、XX和XXV中成熟胚的出愈率分别达到了72.00%±1.91%、70.67%±2.66%、70.00%±1.25%,3个处理的大麦品种ZJ49、D4和ZJ46可用作多棱裸大麦成熟胚培养的候选材料。在25℃、光照16h、光强1 200lx条件下,以添加40g·L-1蔗糖和0.5mg·L-12,4-D的MS培养基培养纵向部分切割的ZJ49成熟胚、添加40g·L-1蔗糖和2.00mg·L-12,4-D的MS培养基培养横切部分胚芽的D4成熟胚或横切部分胚根-胚芽的ZJ46成熟胚,可高效诱导成熟胚愈伤组织。     

Stable isotope labelling of earthworms can help deciphering belowground–aboveground interactions involving earthworms,mycorrhizal fungi,plants and aphids

Functional relationships between belowground detritivores and/or symbionts and aboveground primary producers and their herbivores are not well studied. In a factorial greenhouse experiment we studied interactions between earthworms (addition/no addition of Lumbricus terrestris; Clitellata: Lumbricidae) and arbuscular-mycorrhizal fungi (AMF; with/without inoculation of Glomus mosseae; Glomerales: Glomeraceae) on the leguminous herb Trifolium repens (Fabales: Fabaceae) and associated plant aphids (Aphis gossypii, A. craccivora; Hemiptera: Aphidoidea). In order to be able to trace organismic interactions, earthworms were dual-labelled with stable isotopes (¹⁵N-ammonium nitrate and ¹³C-glucose). We specifically wanted to investigate whether (i) isotopic signals can be traced from the labelled earthworms via surface castings, plant roots and leaves to plant aphids and (ii) these compartments differ in their incorporation of stable isotopes. Our results show that the tested organismic compartments differed significantly in their ¹⁵N isotope enrichments measured seven days after the introduction of earthworms. ¹⁵N isotope incorporation was highest in casts followed by earthworm tissue, roots and leaves, with lowest ¹⁵N signature in aphids. The ¹³C signal in roots, leaves and aphids was similar across all treatments and is for this reason not recommendable for tracing short-term interactions over multitrophic levels. AMF symbiosis affected stable isotope incorporation differently in different subsystems: the ¹⁵N isotope signature was higher below ground (in roots) but lower above ground (leaves and aphids) in AMF-inoculated mesocosms compared to AMF-free mesocosms (significant subsystem × AMF interaction). Aphid infestation was unaffected by AMF and/or earthworms. Generally, these results demonstrate that plants utilize nutrients excreted by earthworms and incorporate these nutrients into their roots, leaf tissue and phloem sap from where aphids suck. Hence, these results show that earthworms and plant aphids are functionally interlinked. Further, ¹⁵N-labelling earthworms may represent a promising tool to investigate nutrient uptake by plants and consequences for belowground-aboveground multitrophic interactions.     

降雨强度对优先流特征的影响及其数值模拟

为了研究优先通道发育程度对不同降雨强度下优先流特征的影响,该文选取不同深度的田间原状土样,在不同降雨强度下进行土壤优先流的室内物理模拟试验,并采用双渗透介质模型Hydrus-1D对优先流发育过程进行数值模拟。结果表明:优先通道越发育,其优先流程度越高。降雨强度对优先流速率及其增加幅度的影响随土壤优先通道发育程度的增加而增加。优先通道发育的土柱,降雨强度越大时,其土柱下端初始出流时间越短,而优先通道一般发育的土柱,其土柱下端初始出流时间均随降雨强度增加呈先减小而后增加的规律。当降雨强度小于土柱最大导水能力(原状土柱表面出现积水时的导水能力)时,优先流速率随降雨强度增加而显著增加,而当降雨强度接近或大于其最大优先导水能力时,优先流速率增加缓慢或趋于稳定。土壤优先通道对降雨入渗的导水能力(即优先流速率与降雨强度之比)随降雨强度增加而变小。双渗透介质模型能较理想地模拟优先流发育过程,对土壤基质向大孔隙排水过程的模拟较差,但模型不适用于裂隙发育的土壤。各土柱的优先流程度为93.6%~99.9%。在研究降雨强度对优先流的影响规律时,该研究考虑了优先通道发育程度对此规律的影响,丰富了优先流理论,同时对农业节水、土壤污染迁移、地下水污染风险评价以及滑坡机理等研究方面具有重要的科学意义。