饲用益生素与抗生素的比较研究

对饲用益生素与抗生素的研究进行了比较分析，主要对其研究的历史和现况，作用机理，合理使用的条件与可行性进行了综述。     

井渠轮灌下秸秆还田对土壤含盐量与玉米产量的影响

为探究井渠轮灌下不同秸秆还田的耕作模式对土壤含盐量及玉米产量的影响,设置“渠井渠”灌溉模式下无秸秆还田的常规耕作（CK）、秸秆表覆旋耕（BF）、秸秆深埋深翻（SM）和秸秆混拌旋耕（HB）4种处理,于2018年和2019年在河套灌区开展了井水与渠水轮灌下不同秸秆还田方式的田间试验。结果表明,井渠轮灌下各处理收获后1m土体均积盐,秸秆还田处理均显著降低土壤积盐率（P<0.05）,BF、SM和HB处理积盐率较CK处理分别下降8.7、12.4、6.9个百分点,SM处理积盐率最小,仅为3.2%,且在20~40cm土层形成脱盐区;收获后CK处理不同土层饱和浸提液的钠吸附比（SAR）较初始值提高10.2%~53.3%,土壤钠质化风险很大;秸秆还田处理有效降低了SAR,SM处理收获后不同土层的SAR最小,较初始值下降了0.4%~73.0%,可有效缓解土壤钠质化。通径分析表明,玉米产量主要决策因子是穗长,限制因子是秃尖长。BF、SM和HB处理分别较CK增产11.2%、19.8%、11.6%,水分利用效率提高18.4%、36.1%、21.2%,SM处理综合效果较好。该研究可为河套灌区地下微咸水安全利用和秸秆资源化利用提供理论依据。     

干湿交替灌溉改善稻田根际氧环境进而促进氮素转化和水稻氮素吸收

[目的]阐明不同水氮管理模式下水稻根际内外氧环境变化特征及其对土壤碳氮转化和水稻氮吸收利用的影响,以期从稻田"根际氧环境"调控角度揭示适宜水氮耦合促进水稻生长和提高氮素利用效率的内在机制.[方法]在长期定位试验基础上,采用根箱模拟培养以及Unisense微电极系统和15N同位素示踪相结合的研究方法,以常规粳稻日本晴和常...     

Complete developmental cycle of Myxobolus pseudodispar (Gorbunova) (Myxosporea: Myxobolidae)

Myxobolus pseudodispar (Gorbunova) is a common parasite of the muscle of roach, Rutilus rutilus L., whereas its actinosporean development occurs in two oligochaete alternate hosts. This paper reports the complete developmental cycle of this parasite in the oligochaete alternate host Tubifex tubifex and the roach. In laboratory experiments, parasite-free T. tubifex specimens were infected by myxospores of M. pseudodispar collected from roach in Lake Balaton. Parasite-free roach fingerlings were infected with floating triactinospores (TAMs) released from oligochaetes on day 69 after challenge. Young plasmodia and spores in roach were first recorded on day 80 post-exposure (p.e.). Myxospores collected from experimentally infected roach initiated a new development in T. tubifex and the resulting TAMs infected roach. No infection of roach resulted from feeding oligochaetes containing mature triactinospores.     

Strategies for further development of aquatic feeds

ABSTRACT: To date, aquatic feeds have depended heavily on fishmeal and fish oil as their source of protein and lipid. However, the feed industry is encountering shortfalls in the availability of these ingredients because of a decline in the number of fish captured in the wild and the increased human demand for some of the species currently being used for fishmeal and oil production. Therefore, efforts are now being directed in different parts of the world to finding alternative quality ingredients, which ideally are less expensive and readily available for use in practical diets. The data accrued have shown that a large proportion of both fishmeal and fish oil can be replaced by other protein and lipid sources. However, it is emphasized that an optimal essential amino acid balance be maintained and that the n-3 highly unsaturated fatty acid requirement be satisfied when combining economical protein and lipid ingredients. Newly developed feeds should aim at being nutrient-dense in order to reduce the output of solid, P and N waste. This can be done through improving nutrient availability, optimizing the digestible protein to energy balance of the diet, and replacing dietary fishmeal with alternate ingredients. These diets should also be effective for maintaining good health and improving disease resistance in fish through enhancement of immune responses. A wholesome approach to culturing fish would be to use appropriate feeding standards that are aimed not only at improving economic returns but also at developing a lasting cohabitation of sustainable aquaculture and a cleaner environment. Furthermore, in the 2lst century aquaculture would still retain its place as a prominent source of food protein, signifying that fish feed research remains a forceful area in discovering better feeds for the industry.     

重迎茬对大豆产量与品质影响的研究

本研究采取在五个生态区设置９圃固定轮作区与相应生态区生产地块调查相结合的方法,研究大豆迎茬,重茬一年、二年、三年对大豆生育,叶面积指数、干物质积累,构成产量因子及产量与品质的影响,三年研究结果表明,重、迎茬大豆均较正茬大豆减产,减产幅度随重,迎茬年限增加而加剧,以迎茬减产最少的６．１％,重茬一、二、三年分别减产９．９％,１３．８％和１９％。不同生态区减产程度不同,重迎茬对大豆生育,干物质积累及构成     

两级回流生物膜工艺处理农村生活污水效果

针对农村生活污水低碳高氮磷特点,研究两级回流连续曝气生物膜工艺处理农村生活污水的效果和机理。在平均处理量90t/d、水力停留时间为3.0d,稳定运行12个月结果表明,该工艺对化学需氧量、五日生化需氧量、氨氮、全氮、全磷和悬浮物的平均去除率分别为75.7%、84.8%、69.2%、68.0%、58.9%和87.9%;出水化学需氧量、五日生化需氧量、氨氮、全氮、全磷和悬浮物的平均质量浓度分别在51.0、15.8、10.8、16.5、2.3和15.7mg/L以下,满足天津市农村污水处理厂排水标准,改造后工艺运行更加稳定,出水NH3-N和TN有明显改善,符合农村污水处理要求。     

Different combinations of protein ingredients in carp diets for reducing phosphorus loading

ABSTRACT: This study was conducted to gather data on the reduction of environmental phosphorus (P) loading through the formulation of carp diets with different combinations of protein ingredients. Five experimental diets were formulated by substituting fishmeal (FM; 10–20%) with alternative protein sources such as meat meal (MM; 5–15%), blood meal (BM; 5–7%), and defatted soybean meal (dSBM; 6–10%). The control diet used was a commercial carp diet selected based on earlier experiments. Each diet was fed to duplicate groups of juvenile carp three times a day, until satiation for 12 weeks. Feed performance was proportional to the increase in dietary FM levels. Phosphorus absorption ranged between 41.6% and 52.0% among the experimental groups and was 42.6% for the control group, but there were no marked differences in nitrogen (N) absorption rates. Phosphorus retention ranged from 31.4% to 35.7% for the test diets, whereas N retention increased proportionally with dietary FM levels and ranged from 34.7% to 41.7%. The P and N retention values of the control diet were 27.6% and 41.2%, respectively. The total P loading (T-P) increased at the higher FM levels (9.1–10.7 kg/t production), whereas lower FM levels produced higher total N loading (T-N, 34.6–43.1 kg/t production), the figures for the control being 13.9 T-P kg/t production and 35.6 T-N kg/t production. These results indicate that the reduction of FM levels to 10–20% by replacing it with MM, BM, and dSBM in carp diets was effective in reducing the loading of P and N.     

小麦干湿交替条件下的水分利用效率与生物学性状

在防雨棚盆栽试验条件下,以“A115”、“4185”为材料,用干湿交替方法研究了3种水分组合下小麦的水分利用效率与生物学性状的相关关系。结果表明产量水平的水分利用效率与株高、穗数、单株生物量、光合速率、蒸腾速率和产量成显著正相关;与除此而外的其他被测生物学性状不相关或相关不显著。叶片水平的水分利用效率与气孔导度和蒸腾速率成极显著负相关关系,与穗粒数和分蘖数成显著负相关关系;与其他被测性状不相关或相关不显著。     

菌核净、代森锰锌及其混剂对烟草赤星病菌毒力测定

运用Horsfall毒力试验设计方案和孢子萌发抑制法分别测定菌核净、代森锰锌及其混剂对烟草赤星病菌(Alternaria alteranta)的毒力，并分别用Wadley方法、Gowing方法、Abbott方法和孙云沛方法等多种评价方法评价所配混剂的增效作用，结果表明，当它们按EC50剂量7：3的比例混配时所得混剂表现明显的增效作用．4种增效作用评价方法所得结果一致，田间防治结果也证明该混剂可有效防治赤星病。