疣吻沙蚕胚胎发育观察及盐度对其孵化的影响

采用显微镜观察了疣吻沙蚕(Tylorrhynchus heterochaeta)胚胎发育不同时期特征,并依据疣吻沙蚕人工孵化经验设置6个盐度梯度组(A:0,B:5,C:10,D:13,E:15,F:20),每组3个平行,研究了盐度对疣吻沙蚕受精率和孵化率的影响。结果表明,疣吻沙蚕胚胎发育可分为受精卵、卵裂期、囊胚期、原肠期、前担轮幼虫期、后担轮幼虫期、膜内三刚节疣足幼虫期和三刚节疣足幼虫期8个时期;盐度对疣吻沙蚕孵化影响显著(P0.05),C组受精率和孵化率最高,与其他组存在显著差异(P0.05)。适宜受精的盐度范围为10~13,最适孵化的盐度为10。     

施氮对蜀恢498及其突变体株型和物质生产特性的影响

【目的】分析不同施氮量处理下水稻株型、物质生产以及产量的变化规律,为水稻新品种的选育和栽培管理提供参考。【方法】2015-2016年,以蜀恢498(R498)及其突变体sg1和sg2为材料,采用两因素裂区设计,其中施氮量为主因素(0,90,180 kg/hm~2以下简称为CK,N90,N180),水稻材料为副因素,分析了不同施氮处理下蜀恢498及其突变体节间长度、叶部特征、叶面积指数、高效叶面积率、粒叶比、干物质量、产量及其构成因素的变化。【结果】(1)施氮对R498及其突变体sg1和sg2上部N_1～N_5节间长度均有一定影响,其中N_1、N_2和N_3的节间长度均表现为R498sg1sg2,差异达到显著水平,N_4和N_5节间长度无明显变化规律。在同一节间下,低氮处理(N90)的节间长度与高氮处理(N180)的差异不显著。与CK相比,施氮增加了水稻叶片长度和宽度、单叶面积以及叶面积指数,降低了2016年高效叶面积率。(2)随着施氮量的增加,粒叶比呈降低趋势;3个材料中,sg1的粒叶比最大,比R498和sg2分别高14.97%和34.83%。(3)干物质量随施氮量的增加而增大,N90与N180处理间差异较小。2015-2016年,水稻的产量均表现为R498sg1sg2。R498、sg1和sg2产量均随施氮量的增加而增大。2015和2016年,R498、sg1和sg2 N90处理的产量比N180处理分别减少了14.96%,14.45%,23.77%和2.23%,6.25%,8.66%。有效穗数和千粒质量均表现为R498sg1sg2,而颖花数和着粒密度则表现为sg2sg1R498;施氮对有效穗数影响最大,N90与N180处理间差异总体达到显著水平。(4)2015和2016年,N90处理氮肥偏生产力处理显著高于N180处理。氮肥农学利用率表现为sg2sg1R498,氮肥偏生产力表现为R498sg1sg2。【结论】突变体sg1对氮响应较慢,在水稻育种中有很大的应用价值。在杂交品种选育中,可通过观测不同材料在不同供氮水平下的表现,从而选育出稳产增产的水稻新品种,更好地实现减氮稳产增效。     

Fertilization rate,motility, lipid peroxidation and pH changes after chilled storage of rainbow trout (Oncorhynchus mykiss) eggs and spermatozoa by a RMPI medium

The aim of this study was to evaluate the effects of Roswell Park Memorial Institute (RPMI) 1,640 medium on chilled storage of eggs and spermatozoa of rainbow trout (Oncorhynchus mykiss). After 3 days of storage, eggs in RPMI 1,640 media (pH 8.2, 9 and 10), Cortland medium and coelomic fluid were inseminated with fresh spermatozoa (Experiment 1). Eggs in RPMI 1,640 medium at pH 8.2 shown the lowest thiobarbituric acid‐reactive substances (TBARS, 0.053 ± 0.003 nmol/ml) and pH changes (from 8.20 ± 0.01 to 8.18 ± 0.01), the highest fertilization rate (82 ± 3%). Undiluted and diluted spermatozoa at ratios of 1:2 and 1:9 with RPMI 1,640 media (pH 8.2, 9 and 10) and Cortland medium were inseminated with fresh eggs (Experiment 2). Spermatozoa in RPMI 1,640 medium at pH 9 (1:9) caused the lowest TBARS content (0.037 ± 0.002 nmol/ml) and pH changes (from 9.00 ± 0.01 to 8.98 ± 0.01), the highest fertilization rate (77 ± 2%) and motility parameters. Based on Experiments 1 and 2, eggs and spermatozoa were stored for another 3 days in RPMI 1,640 medium at pH 8.2 and 9 (1:9) respectively (Experiment 3). Fertilization rate of storage eggs and spermatozoa in Experiment 3 was 79 ± 5%, showing successfully storage of rainbow trout gametes with the same medium.     

振捣提浆与侧深施肥技术模式对寒地水稻产量性状及肥水效率的影响

为解决北方寒地传统搅浆平地耕作模式造成稻田泡田灌溉水量大和肥料利用效率低等问题,于2018—2019年以稻田水整地环节振捣提浆机与侧深施肥机为材料,采用2种耕整地模式和2种施肥模式的正交试验设计：搅浆平地耕整地模式(WPF)、振捣提浆耕整地模式(VEP)、基肥撒施模式(CFA)和侧深施肥模式(SDF),分析振捣提浆+侧深施肥技术模式对泡田期灌水量、干物质积累量、产量指标、肥料利用率及经济效益的影响。结果表明：与常规搅浆平地耕整地+基肥撒施(WPF+CFA)相比,搅浆平地耕整地+侧深施肥(WPF+SDF)、振捣提浆耕整地+基肥撒施(VEP+CFA)和振捣提浆耕整地+侧深施肥(VEP+SDF)3种技术模式对水稻泡田灌溉量、产量性状、肥料利用效率和经济效益均产生显著的影响,以VEP+SDF增幅最大,WPF+SDF次之,VEP+CFA最小。与WPF+CFA相比,VEP+SDF模式能显著提高肥水效率,节约泡田灌溉水11.4%,减少肥料施用量10%,产量和经济效益分别提高7.3%和1628.7元/hm²。本研究表明,VEP+SDF模式显著改善肥水利用效率,提高植株产量和经济效益,是北方寒地水稻较为理想的机械化整地施肥技术模式。     

施肥方式对沃柑果实产量和外观品质的影响

为验证沃柑测土配方施肥的效果,推进化肥减量增效,探究有机肥、中微量元素肥料与化肥配施对沃柑果实产量和外观品质的效应,在沃柑园设置随机区组小区精确试验,试验处理包括当地习惯施肥、测土配方推荐施肥、优化施肥、优化施肥兼叶面喷施0.2%硼酸、优化施肥兼叶面喷施0.05%钼酸铵、优化施肥兼叶面喷施4%硫酸镁。结果表明,测土配方推荐施肥相较于习惯施肥增产效果显著。在同等养分施用量的情况下,用有机肥代替部分化肥处理与全化肥处理比较产量无显著差异,但前者比后者增效4.03%。在土壤交换性镁贫乏的情况下,沃柑叶面施镁可以获得极显著而稳定的增产效果。在土壤不缺硼的情况下,叶面施硼可能无效。在土壤有效钼不足时沃柑叶面施钼能够增产,但连年施用效果不稳定。由此可见,伴随果实外观品质的提升,化肥减量增效在沃柑生产上是可行的;沃柑施肥的增产潜力较大,如果配方和选材得当,可以发挥更大效益。     

水田机械式强制排肥装置设计与试验

目前水田机械施肥均匀性差，且作业时在施肥开沟器末端容易出现肥料粘结、架空、堵塞开沟器等现象。针对以上问题，本文设计了一种水田机械式强制排肥装置，并对其关键部件进行了结构设计及性能试验。将水田机械式强制排肥部件的工作过程分为3个阶段，通过运动学和动力学研究方法分析了各工作阶段肥料在螺旋强制排肥部件内的状态，以及影响排肥部件工作性能的关键因素，对螺旋强制排肥部件的直径、转速、螺距3个因素进行了设计计算。以排肥均匀性变异系数为响应指标，进行了螺旋强制排肥部件的单因素台架试验，通过对最小显著性差异进行统计分析，确定了各因素的取值范围；安排了二次正交旋转组合试验，并对试验结果进行了方差分析和响应面分析，确定了影响排肥性能指标因素的影响由大到小为转速、螺距、直径，建立了排肥性能指标与各因素之间的回归方程，运用Design-Expert软件对试验因素优化求解，确定了较优工作参数组合为螺旋输送器转速120.09r/min、直径23.90mm、螺距21.54mm，此时施肥装置台架试验的排肥均匀性变异系数为7.18%。将所设计的强制排肥部件分别安装在水稻插秧机及水稻气力式施肥播种机上，进行了田间验证试验，试验结果表明，机械式强制螺旋排肥装置工作稳定、堵塞率低，水田防堵塞效果优于无该部件的施肥机械。     

Soybean molasses as an organic carbon source in the farming of Litopenaeus vannamei (Boone, 1931) in a biofloc system

Soybean molasses was evaluated as a partial replacement for sugarcane molasses as a carbon source for biofloc development in the superintensive culture of Pacific white shrimp (Litopenaeus vannamei). A 50‐day study was conducted with juvenile (3.2 g) shrimp stocked in 16 800 L tanks at a stocking density of 250 shrimp m^?3. Control of total ammonia concentration was performed by the addition of combined mixtures of soybean and sugarcane molasses to the culture water. Three different molasses treatments were evaluated using different soybean‐to‐sugarcane molasses ratios: 15–85%, 38–62% and 60–40% respectively. The control group was treated only with sugarcane molasses. Water quality, chlorophyll a concentration, heterotrophic bacterial load, Vibrio spp. concentration and zootechnical indexes were all evaluated. Total ammonia concentration was controlled by heterotrophic and chemotrophic pathways. Biofloc formation, as quantified by measuring the total suspended solids, was not altered. The Vibrio spp. concentration showed a significant reduction in treatments with soybean‐to‐sugarcane molasses ratios of 38–62% and 60–40%. All combined mixtures of soybean and sugarcane molasses could maintain water quality and productivity in the superintensive culture of L. vannamei using the biofloc system. Thus, the potential use of a residue from agroindustry as a carbon source in a biofloc culture is demonstrated.     

土壤有机碳对沼渣或牛粪施用后温室气体排放潜力的影响—盆栽试验结果

A change in the European Union energy policy has markedly promoted the expansion of biogas production.Consequently,large amounts of nutrient-rich residues are being used as organic fertilizers.In this study,a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas (GHG) emissions following organic fertilizer application in energy maize cultivation.We hypothesized that cattle slurry application enhanced CO2 and N2O fluxes compared to biogas digestate because of the overall higher carbon (C) and nitrogen (N) input,and that higher levels of CO2 and N2O emissions could be expected by increasing soil organic C (SOC) and N contents.Biogas digestate and cattle slurry,at a rate of 150 kg NH4+-N ha-1,were incorporated into 3 soil types with low,medium,and high SOC contents (Cambisol,Mollic Gleysol,and Sapric Histosol,termed Clow,Cmedium,and Chigh,respectively).The GHG exchange (CO2,CH4,and N2O) was measured on 5 replicates over a period of 22 d using the closed chamber technique.The application of cattle slurry resulted in significantly higher CO2 and N2O fluxes compared to the application of biogas digestate.No differences were observed in CH4 exchange,which was close to zero for all treatments.Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types,whereas the highest N2O emissions were observed in Cmedium.Thus,the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.