Life cycle fitness differences in Daphnia magna fed Roundup‐Ready soybean or conventional soybean or organic soybean

A lifelong feeding study with soybean from different production systems was carried out in the crustacean Daphnia magna (water flea), an acknowledged model organism for ecotoxicological studies. Experimental diets were prepared with soybean meal from different agriculture production systems: (i) genetically modified Roundup‐Ready soy (Glyphosate‐Tolerant), (ii) conventional soy and (iii) soy from organic agriculture (agriculture with neither synthetic pesticides nor synthetic fertilizers). Overall, feed produced from organic soybeans resulted in the highest fitness (higher survival, better growth and fecundity) in the model organism. Animals fed Roundup‐Ready soybean consistently performed less well compared to animals fed either conventional or organic soybeans. We conclude that accumulation of herbicide residues in Roundup‐Ready soy and related nutritional differences between the soy types may have caused the observed fitness differences. The results accentuate the need for further research clarifying qualitative aspects, including potential large‐scale consequences for food and feed quality, of this dominant crop.     

自走式肉羊饲喂机的设计与试验

介绍了自走式肉羊饲喂机的主要结构组成及工作原理。为研究其工作性能,选取多浪羊为试验对象,采用饲喂机加工后的全混合日粮进行饲喂,以肉羊增重和饲料残留量为试验指标开展试验。试验结果表明:自走式肉羊饲喂机加工的全混合日粮变异系数为8.9%,混合均匀度为91.1%,饲料搅拌混合均匀,满足肉羊饲料食用要求;对于肉羊养殖,采用全混合日粮自由采食饲养方式较人工分饲方式增重效果极显著(P0.01);饲料残留量减少极显著(P0.01)。本自走式肉羊饲喂机的研制满足了肉羊饲喂的要求,可以提高经济效益。     

甲基硫茵灵及其代谢物在不同种植模式黄瓜和土壤中的残留

采用液质联用仪比较分析了3个不同种植区域（江苏南京、广西南宁和湖南长沙）露地和大棚两种种植条件下黄瓜和土壤中甲基硫菌灵及其代谢物多菌灵的残留动态,同时对黄瓜中的最终残留量进行了比较分析。施药后,甲基硫菌灵在黄瓜和土壤中均能很快转化为多菌灵[施药后1 d甲基硫菌灵未检出（〈0.01 mg·kg-1）],多菌灵在露地黄瓜和土壤中的原始沉积量均低于大棚。3个试验点露地黄瓜中的半衰期分别为2.3、1.4 d和1.4 d,在大棚黄瓜中的半衰期分别为2.6、1.7 d和2.0 d。在3个试验点露地土壤中的半衰期分别为1.6、1.7 d和2.3 d,在大棚土壤中的半衰期分别为2.3、2.0 d和2.3 d。最终残留试验在最后一次施药后1 d采样时,大棚、露地黄瓜中的甲基硫菌灵均未检出（〈0.01 mg·kg-1）,多菌灵在3个试验点露地黄瓜中的最终残留量为0.014~0.162 mg·kg-1,而在3个试验点大棚黄瓜中的最终残留量为0.121~0.561 mg·kg-1。参照我国所制定的黄瓜中多菌灵的MRL（0.5 mg·kg-1）,露地种植方式下所有处理黄瓜中甲基硫菌灵代谢物多菌灵的最终残留量均符合国家标准的规定,但大棚种植方式下其残留量有超标的风险。     

市售猪肉及其组织中"瘦肉精"残留调查

采用德国r-Biopharm拜发公司试剂盒，用竞争性EUSA法对某市13个菜场共抽取40份瘦肉、30份猪肝、18份猪肾脏、30份猪肺、15份猪骨和30份猪血、30份猪毛，总计样品进行了瘦肉精残留检测。结果表明，在抽检的193份样品中共有38份瘦肉精含量大于1．0ng／g，占总数的19．7％，其中猪肝与猪毛的检出率最高。同时在瘦肉精含量大于1．0ng／g的样品中抽取9份，用GC／MS／MS法确证，结果与ELISA法相符。     

超临界流体萃取技术在农药残留分析中的应用进展

从萃取过程控制的角度，综述了近几年来国外超临界流体技术不同形态的基体的农药残留分析中的应用情况、研究现状及前景。     

超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量

建立超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量。猪、牛组织中残留的甲基盐霉素,经乙腈溶液提取,硅胶固相萃取柱净化,超高效液相色谱-串联质谱法测定,外标法定量。甲基盐霉素在5 ng/mL～250 ng/mL的浓度范围内呈现良好的线性关系,甲基盐霉素在猪、牛肌肉、肝脏、肾脏、脂肪中的检测限均为2.5μg/kg,定量限均为5.0μg/kg,猪牛肌肉、肝脏、肾脏、脂肪中5.0 ng/g～100 ng/g添加浓度范围内的回收率均值为71.9%～88.4%,批内批间RSD值均<15%。     

Effects of leguminous plant residues and NPK fertilizer application on the performance of yam (Dioscorea rotundata ‘c.v.’ ewuru) in south-western Nigeria

The effects of cultivating and incorporating residues of previous tropical kudzu (Pueraria phaseoloides) and soybean (Glycine max) with application of NPK fertilizer on yam performance were evaluated at the teaching and research farm, LAUTECH, Nigeria. There were nine treatments: incorporation of legume residues (5 t DM ha^?1), application of recommended fertilizer rate for yam (90–50–75 kg NPK ha^?1) in the zone or 50% of recommended rate (45–25–37.5 kg NPK ha^?1), alone and in combination with residues and a control without residues or fertilizer in a randomized complete block design. Cultivation of previous legumes reduced soil nematode population (>200%) compared with no legumes. For both years, application of Pueraria residues improved tuber yield by an average of 15.8% compared with control. Fertilizer application enhanced arbuscular mycorrhizal (AM) colonization of yam roots but AM colonization was lower (～50%) in plots where Pueraria residues were incorporated compared with other plots. Combined application of plant residues with fertilizer improved soil organic carbon, total N, exchangeable Ca and Mg compared with application of NPK fertilizer. From these results, it is concluded that half of the recommended NPK rate may be adequate and incorporation of residues with reduced NPK fertilizer application may be a sustainable soil fertility management option for continuous yam production.     

我国香蕉茎叶残体利用现状与展望

阐述我国香蕉茎叶残体资源概况,介绍香蕉茎叶残体的利用价值、还田方式以及综合利用现状,并分析其存在问题,对前景进行展望,为香蕉茎叶残体的资源化利用提供借鉴。     

施肥方式对土壤活性有机碳及碳库管理指数的影响

基于长期田间定位试验,采用田间采样与数理统计法研究不同施肥方式对紫色土活性有机碳及碳库管理指数(CPMI)的影响。施肥方式包括不施肥(CK)、单施氮肥(N)、化学氮磷钾肥配施(NPK)、单施有机肥(OM)、有机肥配施化学氮磷钾肥(OMNPK)和秸秆还田配施化学氮磷钾肥(RSDNPK)。结果显示,施肥的各处理均能够提高土壤有机碳及其活性组分含量,以OM和RSDNPK处理的提升效果最佳。相比CK,OM处理的土壤总有机碳(TOC)、易氧化有机碳(PXOC)、微生物量碳(MBC)、溶解性有机碳(DOC)含量分别提高91.4%、109.2%、57.5%、35.1%,RSDNPK处理的TOC、PXOC、MBC、DOC含量分别提高142.8%、95.4%、70.8%、46.2%。土壤PXOC、MBC、DOC占TOC的比例(分配比例)分别为36.18%~49.13%、1.64%~2.58%、0.57%~0.94%,其中,PXOC和MBC的分配比例在RSDNPK处理中较CK显著(P<0.05)降低,而DOC的分配比例在各处理间无显著差异。OM和RSDNPK处理的CPMI显著(P<0.05)高于N和NPK处理。土壤PXOC、MBC含量与氮磷养分之间,以及CMPI与MBC、PXOC、TN、AN、AP均呈现显著(P<0.05)或极显著(P<0.01)正相关性。研究结果说明,有机肥或秸秆还田配施氮磷钾化肥能够提高耕层土壤有机碳储量,改善土壤质量,PXOC与CPMI可用作表征土壤质量变化的敏感指标。