Distribution and Speciation of Chromium and Cadmium in an Organic and Inorganic Fertilized Chernozem

Fertilizers are widely applied in agricultural practice to improve crop yield and quality. However, they can also alter the behavior of soil pollutants. A field experiment was conducted on a chernozem in Heilongjiang Province, China. Various proportions of inorganic nitrogen (N), phosphorus (P), and organic (manure) fertilizers were applied. Soil samples were collected four times over 2 years, and the total concentrations and speciation of chromium (Cr) and cadmium (Cd) were analyzed. Inorganic fertilizer addition had little effect on the total concentration of Cr and Cd, while organic fertilizer addition reduced the total concentrations of both Cr and Cd. Inorganic fertilizers increased the concentration of Cr in the exchangeable form, but decreased that of the residual form (P < 0.05). Addition of inorganic or organic fertilizer alone decreased concentrations of exchangeable Cd (P < 0.05), but the combination of inorganic and organic fertilizers had the opposite effect. High concentration of total Cd exceeding the upper limits of the Environmental Quality Standard for Soils proposed by the Ministry of Environmental Protection of China could result in an environmental risk, and fertilizer application could lower that risk. Results of risk assessment code calculated as the percentage of the sum of metal concentrations in the exchangeable and carbonate-associated form in total metal concentration showed that Cr and Cd risks were lowered when organic fertilizer was applied alone or in combination with inorganic fertilizers. Our study highlighted that organic fertilizer should be applied alone or in combination with inorganic fertilizers to lower the environmental risks of Cr and Cd pollution in the chernozem.     

Key Characteristics of a Novel Silk Yarn from Fresh Cocoons

We studied the key characteristics of a novel silk yarn reeled from fresh cocoons. Compared with traditional silk yarn, this novel silk yarn displayed better mechanical properties, especially in terms of a higher breaking stress and toughness, and exhibited a different surface morphology. A cross-sectional observation and the sericin content results illustrated that different sericin coatings on the silk yarn reeled from fresh cocoons surface did not improve the mechanical properties. The degumming and tensile testing analysis indicated that degummed silk fibroin of novel silk yarn is able to resist deformation and fracture better than silk fibroin of traditional silk yarn. The FTIR results revealed that the selected techniques is an important contributor to the silk fibroin mechanical properties, because novel technique brought higher percentage beta-sheet structures in novel silk yarn fibroin than traditional silk yarn. The new technique that using novel silk yarn has improved its mechanical properties and it is expected that the silk yarn with superior mechanical properties could be used in fabrics transistors, electrodes and reinforced biomaterials.     

天津市滨海新区小区园林绿化的设计构思

针对天津地区土质为盐碱性土壤这一特点,选择合理树种,合理配置,从绿化作用出发,使居住环境更好的适应现代化建筑,创造清新宜人的生活、休息场所。     

水产品中氯霉素、甲砜霉素、氟苯尼考、氟苯尼考胺多残留的同时测定—GC/MS法

采用气相色谱-质谱法建立基质加标标准曲线,对中国对虾、大菱鲆、鲫鱼、鳗鱼、蟹、甲鱼6种主要养殖水产品肌肉组织中氯霉素类药物:氯霉素(CAP)、甲砜霉素(TAP)、氟苯尼考(FF)及其代谢物氟苯尼考胺(FFA)的多残留同时进行检测。结果显示,CAP在2–200 ng/ml浓度范围内,线性关系良好;TAP、FF和FFA在5–200 ng/ml浓度范围内,线性关系良好,其相关系数均大于0.990。加标回收率在76.4%–94.3%之间,相对标准偏差在5.7%–13.9%之间。检出限:CAP为0.2μg/kg,TAP、FF和FFA均为1.0μg/kg。定量限:CAP为0.5μg/kg,TAP、FF和FFA均为3.0μg/kg。研究表明,该方法具有准确、高效、灵敏、特异性强的特点,可以满足水产品中CAP、TAP、FF和FFA多残留的同时检测的要求。     

黔东南州油菜测土推荐施肥研究

通过油菜小区试验研究,结果表明:不同施肥量,不同N、P、K配比,均有不同的化肥利用率;土壤养分测定值与目标产量、空白田产量均正相关;土壤养分测定值与化肥利用率负相关;利用测土施肥公式,建立了N、P、K化肥施用量与土壤养分测定值的函数关系,能在产前提出合理的施肥计划。     

食品生物技术小规模实训基地建设与运行研究

食品生物技术小规模实训基地是食品生物技术专业学生的校内实训场所,在实现人才培养目标中起着重要作用。综述了四川工商职业技术学院食品生物技术小规模实训基地建设与应用的现状、存在问题和解决途径。     

国内外农业信息服务体系构建现状及对云南省的启示

叙述了国内外农业信息服务体系构建现状,针对云南省农业信息服务体系建设等相关问题,通过案例分析总结经验及不足,为云南省农业信息服务体系构建提供参考。     

荆门市国库储粮重量及质量损失调查

抽样调查结果表明，荆门市国库常规储存稻谷在１～６年的不同储存期平均自然损耗为０．２２％，薄膜密闭储粮的损耗率为０．１３％；露天常规储粮损耗率为０．３８％，薄膜密才储粮损耗率为０．２９％。储粮虫蚀率：仓内常规储粮为０．１７％，薄膜密闭储粮为０．１％；露天常规储粮为０．２５％，薄膜密闭储粮为０．１８％。储藏稻谷品质测定结果：只要在通风控温措施，无论仓内或露天存放，其差异不明显，一般储存期在两年以内的回     

我国农业技术推广典型模式及其效应与创新

农业技术推广对农业的可持续发展具有重要的作用。现阶段我国存在政府主导型、农业科研教学单位主导型、农业龙头企业主导型和农村经济技术合作组织(NGO)主导型4种典型的农业技术推广模式,在总结我国农业技术推广面临的挑战的基础上,从农业技术推广主体、要素两方面进行了模式创新,并从社会力量协同、技术成果传递、推广要素结合和推广人员奖励4方面进行了农业技术推广机制创新,以促进我国的农业技术推广工作持续、健康发展。     

十字花科根肿病菌在不同温度、pH值条件下致病性差异研究（英文）

[目的]探讨十字花科白菜根肿病菌在不同温度、pH值条件下致病性。[方法]采用根肿病菌和土壤混合法,在休眠孢子浓度1×108(个/g土)条件下,设置7个温度及6个土壤pH值梯度,进行根肿病菌对白菜致病性测定,90 d后拔根调查根肿病菌侵染发病情况。[结果]在pH值6时,不同温度梯度间白菜根肿病发病株率存在较大差异,其发病株率从高到低的温度为30℃25℃20℃35℃15℃10℃5℃。5℃和10℃条件下,其根肿病菌侵染力弱,不发病或发病株率较低;15~30℃条件下随温度升高发病率增加,但在35℃条件下,发病株率降低。温度25℃条件下,pH值为4、5、6、7、8、9的白菜发病株率分别为80.36%、100%、65%、10.77%、3.23%、0.0%。pH值4发病率虽高,但白菜生长受抑制,生长弱,存活率低。pH值7和8时,发病率较低,pH值9时没有发病,在pH值5和6时,植株生长良好,发病率也较高。[结论]该研究结果表明根肿病菌侵染发病与温度、土壤pH值关系密切。