二种池塘底泥总氮含量的简易测定法

本实验创立了二种水产养殖池塘底泥总氮含量简易测定法,分别称为总氨法和硝酸盐法.通过与使用LECO公司的全自动CHN分析仪（Dumas仪器法）进行12个池塘底泥样品的测定结果比对,以及对所建立的回归方程经显著性检验,结果表明这两种方法均与Dumas仪器法之间存在线性相关,并回归极显著.二种土壤总氮含量的简易测定法,均实现了简化检测步骤、减少检测工作量、节省检测时间及降低成本,能满足许多水产技术推广站及养殖场等普通的实验室开展池塘底泥总氮含量的检测要求.     

Cellular and humoral immune responses of Senegalese sole,Solea senegalensis (Kaup), following challenge with two Photobacterium damselae subsp. piscicida strains from different geographical origins

The present study aimed to investigate leucocyte responses to inflammation as well as some innate immune parameters of Senegalese sole, Solea senegalensis, following challenge with two strains of Photobacterium damselae subsp. piscicida belonging to the European and Japanese clones described for this bacterium. Pathogenicity assays were performed to assess the virulence of each Photobacterium damselae subsp. piscicida strain for sole. Subsequently, fish were intraperitoneally injected with phosphate‐buffered saline (control) or two concentrations (2 × 10² and 2 × 10⁶ CFU mL^?1) of each bacterial strain and sampled after 6 and 24 h. Results showed that the European isolate induces a higher degree of response than the Japanese strain. While blood neutrophilia and monocytosis correlated well with the increase in neutrophil and macrophage numbers in the peritoneal cavity, fish infected with the European isolate presented higher peritoneal cell numbers than fish challenged with the Japanese strain. In addition, alternative complement pathway activity and respiratory burst of head kidney leucocytes increased significantly in fish infected with the European isolate. The enhanced innate immune response displayed by Senegalese sole challenged with the European isolate is probably due to the higher degree of virulence presented by this Photobacterium damselae subsp. piscicida strain.     

控制性隔沟交替灌溉玉米根系吸水模型的试验研究

以影响根系吸水强度的三大要素即作物蒸腾强度、土壤含水率和根系分布密度为影响因子,结合土壤水动力学理论得到的根系吸水率,建立了控制性隔沟交替灌溉条件下玉米的二维根系吸水模型,并进行验证得到较好的结果。模型对预报控制性交替灌溉具有重要的理论及实用价值。     

交替选择对玉米自交系抗性改良的效应

 【目的】研究交替选择对玉米自交系抗病性、耐旱性以及产量的影响。【方法】选用中国目前玉米生产上应用面积最大的杂交种郑单958的父本自交系昌7-2和母本自交系郑58,分别在河南和海南进行抗病、耐旱、丰产性交替选择。采用田间试验与盆栽试验相结合的方法,测定灰斑病病情指数、耐旱系数、丙二醛(MDA)含量和产量及其构成因素。【结果】与基础材料相比,随着交替选择代数的增加,郑58第一至第四代衍生系的灰斑病病指分别下降了16.1%、16.6%、31.5%和33.1%,昌7-2第一至第四代衍生系灰斑病病指分别下降了28.1%、29.7%、45.3%和49.5%;随选择代数增加MDA含量逐代下降,耐旱系数逐代提高;郑58和昌7-2的第四代平均产量分别比其相应基础材料提高8.3%和9.1%。【结论】经过连续四代交替选择后,郑58和昌7-2的抗病性、耐旱性以及产量都得到了明显的提高,证明交替选择对玉米自交系抗逆性改良是有效的。     

转型期资源型城市农业合作经济组织建设分析——以大庆市为例

转型期资源型城市必然面临产业替代问题,因此发展资源替代产业十分必要。产业的转型有不同的方向,农业也是其中的方向之一。本文以大庆市为例对以农业作为转型方向的产业培育及以农业合作经济组织的发展的必要性、农业合作经济组织的现状、运行效果进行了分析,并提出了对策。     

交替灌溉对间作小麦蚕豆产量和根系的影响

通过根箱试验,研究了交替灌溉对小麦间作蚕豆的产量、根质量、根长的影响,以期探讨将交替灌溉技术集成到间作中的可行性.结果表明:与传统灌溉方式相比,交替灌溉使单作小麦的经济产量、生物产量、根质量、根长分别提高了14.7%、2.9%、6.4%、7.2%,使间作小麦分别提高了21.1%、13.2%、16.1%16.0%;交替灌...     

Feasibility of Cordia trichotoma (Vell.) wood and its by-products for particleboard manufacturing

The wood panel industry uses a large volume of wood and it is essential to research the use of new tree species for these types of products. As such, the aim of this study was to evaluate the feasibility of Cordia trichotoma (Vell.) wood, both on its own and as a mixture with Pinus spp., as well as to understand the effect on particleboard quality when adding the species’ bark and shavings. The experimental design included nine treatments that assessed various mixture proportations of C. trichotoma and Pinus; for example, 10% bark, and 10% shavings of C. trichotoma with Pinus spp. and C. trichotoma particles, as well as mixtures of these two species in proportions of 25/75%, 50%/50%, and 75/25%. The results indicate that the Cordia trichotoma specie is technically feasible when manufacturing particleboards in pure form. The incorporation of bark (at 10% of the mixture) is also technically feasible. It is also feasible to use the shavings of C. trichotoma. In general, all treatments produced outputs that showed dimensional stability and mechanical strength statistically equal or higher than control treatments (Pinus spp.); thus, these products may be used for non-structural applications in dry and/or moist conditions.     

50%二氯喹啉酸WP替代药剂的筛选

为筛选出50%二氯喹啉酸WP的替代药剂,选择30%氯酰草膦EC、33.6%苯吡唑草酮SC、315 g/L异噁唑草酮·噻酮磺隆SC作为替代药剂与50%二氯喹啉酸WP在同一玉米地进行田间试验。结果表明:30%氯酰草膦EC除草效果及对玉米的安全性均未达到50%二氯喹啉酸WP同等水平,不宜作为替代药剂;33.6%苯吡唑草酮SC杂草防治效果与50%二氯喹啉酸WP相当,玉米的生长情况与50%二氯喹啉酸WP差异不显著,虽可以降低二氯喹啉酸的药害风险,但考虑到用药成本和半衰期远大于50%二氯喹啉酸WP,亦不宜作为替代药剂;315 g/L异噁唑草酮·噻酮磺隆SC的除草效果优于50%二氯喹啉酸WP,且易降解,可作替代药剂用于玉米-烤烟轮作区玉米地杂草防除,可以解决二氯喹啉酸对后茬烟草的药害问题。     

Double-Cropping Pinto Bean after Winter Barley in Western Colorado USA

A double-cropping field study was conducted at the Colorado State University, Fruita. Colorado USA to evaluate an irrigated, double-cropping system of winter barley （Hordeum vulgare L.） followed by pinto bean （Phaseolus vutgaris L.） for the valley areas of western Colorado USA and other similar environments. Double-cropping pinto bean after winter barley was successful, but to use our double-cropping technology in commercial agriculture in adapted locations will likely require identifying or developing a winter barley cultivar that matures earlier than current cultivars but does not head and flower so early that it is susceptible to freeze damage. Double-cropping was more profitable in all three years than growing either pinto bean or winter barley as a sole crop.     

垄作覆盖条件下灌溉方式与灌溉量对夏玉米田土壤呼吸的影响

在垄作覆盖条件下,研究了夏玉米生长季中常规灌溉(沟沟灌溉)和隔沟交替灌溉2种灌溉方式对土壤呼吸作用昼夜变化、阶段变化规律及不同水分胁迫下土壤含水量与土壤呼吸速率的相关关系.结果表明,夏玉米拔节期土壤呼吸速率最小,抽雄期最大,之后缓慢回落;昼夜动态变化呈单峰变化趋势,高峰、低谷分别在14:00和6:00左右;在同一水分条件下,交替灌溉方式土壤呼吸速率高于常规灌溉,处理间最大差异平均可达3.46 μmol·m-2·s-1,交替灌溉方式下土壤呼吸速率昼夜变化幅度小于常规灌溉方式下土壤呼吸速率;不同水分胁迫条件下,土壤呼吸速率呈现出轻度亏缺处理>中度亏缺处理>重度亏缺处理;玉米生长期较高土壤含水量促使土壤呼吸增强,尤其在玉米生长中期土壤呼吸速率与耕层土壤含水量呈极显著的正相关关系.