Effects of ages of plug transplants and planting depths on the growth and yield of sweetpotato

Sweetpotato [Ipomoea batatas (L.) Lam. cv. Beniazuma] plug transplants produced from single node leafy cuttings under artificial light in a closed-type growth chamber were planted with roots and substrate of 11- and 15-day old (ca. two to three unfolded leaves with 0.08 m shoot length and three to four unfolded leaves with 0.11 m shoot length, respectively). The plug transplants of both the 11- and 15-day old were planted with one and three nodes depth (ca. 4 and 25 mm deep, respectively) inside the soil ridges (called one- and three-node depth, respectively, hereafter). The conventional vine cuttings (ca. 0.3 m long with seven to eight unfolded leaves) without roots were planted as Control treatment to compare the growth and yield of sweetpotato with each of the treatments of plug transplant. The main objectives of the study were to see the effects of ages of plug transplants and depths of planting for greater growth and yield of sweetpotato in the field. The yield of storage roots 115 days after planting in the field was 33 t ha⁻¹ when using 15-day old plug transplants planted with three-node depth and was 10 t ha⁻¹ greater than that in the Control. The mean storage root length was about 259 mm when using 11-day old plug transplants planted with three-node depth and was 33 mm greater than that in the Control. The mean diameter of storage roots was 70 mm when using 11- and 15-day old plug transplants planted with one-node depth and was 21 mm greater than that in the Control. The plug transplants planted either 11- or 15-day old showed greater overall performances than those of the conventional cuttings. The plug transplants planted with three-node depth showed greater performances than did the plug transplants planted with one-node depth.     

基于穴盘苗力学特性的自动取苗末端执行器设计

通过对穴盘苗进行夹苗拉拔试验、钵体摩擦试验、钵体平板压缩抗压试验,研究分析了与自动移栽相关的穴盘苗力学特性,为机构设计提供依据。对穴盘苗自动取苗进行技术设计,得到两针钳夹式取苗末端执行器自动取苗的拉拔力与钵体抗压强度、夹持角度、夹持面积、静摩擦因数等参数的关系。利用建立的夹持参数关系,结合穴盘苗力学特性试验数据,设计了一种适应穴盘苗力学特性的自动取苗末端执行器。试制了物理样机,进行了自动取苗夹持力测试。测试结果表明,夹持力测试数据与理论计算数据无显著性差别,验证了理论设计的可靠性。在所测试的含水率下,当取苗频率为30株/min时,取苗成功率达到95.16%。     

黄瓜穴盘育苗播后灌溉施肥技术研究

以黄瓜品种中农203 为试材,研究了与播前启动肥配套的播后不同施肥种类、施肥浓度及施
肥频率对黄瓜幼苗生长发育及壮苗形成的影响,通过测定黄瓜幼苗茎粗、全株干质量等形态指标及叶绿素
含量、根系活力等生理指标,筛选出黄瓜穴盘育苗播后灌溉施肥较优处理为：子叶平展至第1 片真叶平展
时12-2-14、20-10-20 两种肥料交替施用,施肥浓度为N 100 mg·kg^-1;第1 片真叶平展至第2 片真叶
平展时12-2-14、20-20-20 两种肥料交替施用,施肥浓度为N 200 mg·kg^-1 ,两个阶段施肥频率均为1
次肥、2 次水。黄瓜幼苗表现为壮苗指数增加、叶绿素含量升高和根系活跃吸收比增强,分别比其他处理
提高了6.13%～15.44%、3.75%～16.41%、5.85%～14.85%。     

茄果类蔬菜穴盘基质育苗的菌肥添加量研究

为筛选适合茄果类蔬菜穴盘育苗基质的最佳配方,以草炭与蛭石的复合基质为基础,添加不同数量的菌肥和氮磷钾复合肥组成6种育苗基质,在温室条件下研究不同配方对番茄和辣椒出苗率以及生长发育指标的影响。结果表明：6个配方基质的物理特性都处于基质育苗的适宜范围,番茄和辣椒的出苗率均≥85%;6个配方基质育出的番茄和辣椒幼苗壮苗指数均〉CK,但与CK无显著差异,其中6号配方基质〔V（草炭）∶V（蛭石）=1∶1,添加菌肥30 kg/m3〕育出的番茄幼苗壮苗指数最高,且株高、茎叶鲜重、茎叶干重和根干重均最大,秧苗质量最好,可作为番茄工厂化育苗的首选基质;5号配方基质〔V（草炭）∶V（蛭石）=1∶1,添加菌肥25 kg/m3〕育出的辣椒幼苗壮苗指数较高,且株高、茎粗、茎叶鲜重、茎叶干重和根干重均较大,秧苗质量最好,可作为辣椒工厂化育苗的首选基质。     

蚯蚓粪基质在辣椒穴盘育苗中的应用

以蚯蚓粪为主要原料配合不同体积比的蛭石作为穴盘育苗基质与草炭对比,研究了复合基质对辣椒种子出苗率及幼苗生长发育的影响.结果表明:与草炭相比,蚯蚓粪容重较大、孔隙度和持水力较小,高P、K含量和低N含量;蚯蚓粪复合基质促进了辣椒幼苗生长发育,其作用效果与基质混合比例有很大关系,3:1(V:V)蚯蚓粪复合基质育苗效果最佳.     

基于机器视觉的育苗穴盘定位与检测系统

针对嫁接苗自动移栽机器人,提出了一种基于器视觉的育苗穴盘定位与检测系统.该系统不仅能够确定育苗穴盘在传送带上的位置,而且能够获得各穴孔内的基质深度和三维形状信息.其方法是利用彩色图像与深度图像的注册,从彩色图像中检测穴盘轮廓,结合穴盘规格,实现深度图像中穴盘各穴孔的分割;利用分割后的深度图像对每个穴孔生成三维点云,结合最近邻算法与主成分分析算法计算各点的法向量,基于该法向量实现穴孔侧壁与穴底基质的分割,进而获得基质的深度.试验表明,该系统能够有效定位穴盘并检测基质深度,平均定位误差为3.5 mm,深度检测误差为4.9 mm,满足嫁接苗自动移栽机器人的控制要求.     

不同覆盖物对黄瓜穴盘苗生长发育的影响

研究了工厂化育苗中不同覆盖物对黄瓜穴盘苗生长发育的影响。试验结果表明,细砂作为覆盖物,在出苗率、G值、壮苗指数和叶绿素含量方面都高于对照(营养基质),其他各项指标都和对照基本接近,且节约成本达18.46%,如果大量应用于产业化生产,将体现出较大的经济效益。     

不同规格穴盘对远距离运输辣椒幼苗生长的影响

[目的]揭示不同规格穴盘对远距离运输辣椒幼苗生长的影响,为辣椒工厂化育苗提供技术支撑。[方法]研究4种不同规格穴盘（33、54、60、72孔）对远距离运输辣椒幼苗生长的影响。[结果]4种不同规格的穴盘育苗中,在行程800 km远距离运输后,以33孔的辣椒幼苗素质最好,但受运输影响较大,而54、60、72孔穴盘处理下对远距离运输辣椒幼苗生长影响结果基本一致。[结论]综合考虑经济成本和幼苗素质,在辣椒工厂化育苗中,远距离运输宜选用72孔穴盘。     

添加保水剂对甜椒穴盘育苗效果及水肥利用效率的影响

以腐熟棉籽壳菇渣、草炭、蛭石的复合物[V(腐熟棉籽壳菇渣)∶V(草炭)∶V(蛭石)=1∶1∶1]为育苗基质,研究添加保水剂(1、2、4、8、16g·L-1)对育苗基质理化性状、甜椒穴盘育苗效果及水肥利用效率的影响。结果表明,添加适量保水剂可提高基质总孔隙度和持水孔隙;随着保水剂用量增加,甜椒幼苗生长和生理指标均呈先升高后降低的变化趋势,4g·L-1用量下幼苗生长最好,叶绿素质量分数、净光合速率(Pn)、根系活力、叶片脯氨酸和可溶性糖质量分数最高,壮苗指数比对照提高46.6%;添加保水剂可使甜椒苗期节水、节肥率达到12.8%~51.8%。     

Computational fluid dynamics characterization of a novel mixed cell raceway design

Computational fluid dynamics (CFD) analysis was performed on a new type of mixed cell raceway (MCR) that incorporates longitudinal plug flow using inlet and outlet weirs for the primary fraction of the total flow. As opposed to conventional MCR’s wherein vortices are entirely characterized by the boundary conditions at inlet nozzles and outlet center drains in the center of each cell, the new MCR design can develop a wider variety of fluid behaviors due to the additional boundary conditions at the inlet and outlet walls where the weirs are placed. In this study, we investigated how the primary longitudinal flow would affect vortex formations in the cells by designing three different MCR models and simulating three major cases for each model. Through this process, performances of two numerical CFD models (transition k-kl-ω vs. k-ε) were compared, along with two vortex quantification methods (Q-criterion vs. a proposed method). We found that the k-kl-ω CFD model more accurately predicted vortex formation than the k-ε model. The three MCR models differed only by weir geometry or drain size, in order to see their individual influence on cell vortex formation. Each case had its own unique weir flow rate and center drain loading rate values that combined to a total flow rate resulting in 15-min hydraulic retention time (HRT) for the MCR. The ratio of (expressed as percentage) of center drain loading rate to total flow rate (R = 7.5%, 12.5%, and 20.1%.) was defined to establish a relationship between R and vortex strength or size. Simulations demonstrated that inlet weir aspect ratio impacted cell vortex formation and strength. Unlike weir geometry effects, the drain size had non-significant impacts on fluid behavior other than the velocity very near the drains. While R did have positive correlations with vortex strength, vortex size, and self-cleaning performance, an R of 20.1% was sufficient to create uninterrupted vortex formations. Too low of a center drain rate or R value can result in lack of any meaningful cell vortex formation which then obviates any self-cleaning action in an MCR. Our key finding through extensive computational analysis was that an R value of 20% was required in order to maintain effective vortex formation. Expressed more explicitly, this can be described as maintaining a center drain loading rate of 0.010094 m³/s per cell (160 gpm), which correspond to unit loading rates of 16.3 lpm/m² per cell (0.40 gpm/ft² per cell).