闭合循环养殖车间HACCP体系的建立

水产养殖业的食品安全问题已越来越引起人们的重视。探讨了在闭合循环集约化水产养殖车间建立HACCP管理体系的可能性。通过对生产流程的各个环节的分析,HACCP小组用关键控制点(CCP)判断树的方法,确定了该养殖车间生产的关键控制点和相应的控制措施,并在生产中严格执行。实践结果表明,在闭合循环水产养殖车间建立HACCP体系是确实可行的,不仅可以保证养殖生产的顺利进行,避免饲养鱼类在养殖过程中出现非正常死亡,同时保证了养殖产品的食用安全性,为闭合循环水产养殖车间建立了科学的管理体系。     

铜对水稻和玉米污染效应及累积规律的对比研究

通过盆栽试验,分别研究了铜在吉林省砂壤水稻土中对水稻和在草甸黑土中对玉米的污染效应及吸收累积规律。结果表明:水稻和玉米各器官对铜的累积量随土壤中铜投加量的增加而增大,其分布规律为根茎叶籽粒;在本试验浓度范围内铜对水稻的毒害作用大于玉米。以使水稻和玉米减产10%为依据,确定铜在吉林省砂壤水稻土和草甸黑土中的毒性临界值分别为187.6 mg/kg(全量)、31 mg/kg(DTPA提取量)和316 mg/kg(全量)6、1 mg/kg(DTPA提取量)。     

HACCP在芦柑浓缩汁生产中的应用

本文介绍了危害分析关键控制点(HACCP)的原理及其在芦柑浓缩汁生产中的具体应用,确立了芦柑浓缩汁的关键控制点及临界参数和纠正措施。     

思茅松人工林土壤潜在养分临界值的确定

选择云南省景谷县思茅松人工林标准地进行土壤潜在养分的调查分析,在将蓄积量及其土壤潜在养分值规格化处理的基础上,运用快速聚类分析法将土壤分为4类,根据分类结果表征的土壤潜在养分与蓄积量的关系推算出土壤各潜在养分的临界值.分析结果表明:思茅松人工林各土壤潜在养分含量的临界值分别为:全N=[0.640 0,0.895 0](g/kg);全P=[0.307 8,0.431 1](g/kg);全K=[3.327 3,4.0046](g/kg).     

蚕蛹油的成分、营养价值及提取工艺研究进展

从丝绸工业的副产品即蚕蛹中提取的蚕蛹油作为昆虫油脂中的一种,具有重要的营养和经济价值。综述了蚕蛹油的研究进展,包括蚕蛹油的组成及营养价值研究、提取工艺研究、脂肪酸成分分析方法及精制研究、应用现状及前景等。     

鲶人工繁殖关键技术的研究

本是１９９５～１９９７年鲶人工繁殖关键技术研究的总结,论述了♀♂鲶的鉴别指标,产卵习性与♀♂亲鱼分池培育,催情产卵和孵化,产卵行为与♀♂亲鱼个体大小搭配等鲶人工繁殖的系列关键技术问题,本试验共催情鲶２１３６组,获卵４５３７万粒,相对产卵数２．００～２．３３万粒／ｋｇ,下塘鲶苗１８８７．３９万尾,平均产卵率８１．１２％,受精率９４．９６％,孵率率８５．４％,下塘率４１．６％。     

含水量对非饱和黄土强度的影响

试验和分析表明，在较大的含水量变化范围内，非饱和黄土的粘聚力和含水量之间呈幂函数关系。依据库伦－摩尔强度准则，非饱和黄土的抗剪强度随外部压力和含水量的变化规律可用强度曲面描述，提出了非饱和黄土强度的临界含水量计算式。     

广东土壤环境背景值和临界含量的地带性分异

广东的土壤分布，具明显的地带性，自北到南分布着红壤，赤红壤和砖红壤，综合了近年国内在该区域所开展的有关土壤中元素前景值和重金属窬一的研究成果，对广东主要的地带性土壤的环境背景值和临界含量的分异规律做了一些探讨。     

果园机械化经济效益分析——以江苏烨佳梨园为例

针对果园机械化经济评价问题,采用成本分析理论模型和敏感性分析法,对江苏烨佳梨园生产过程中疏花、采摘、施药、除草、剪枝、施肥深松和灌溉7 个环节各作业方式的最低平均成本、机械装备替代传统作业的临界规模、机械装备相对传统作业方式的平均节省成本和临界规模的影响因素进行研究。结果表明:1)机械装备作业在一定规模后可以明显比传统方式作业节省成本,如手持式疏花器在种植面积大于0.11 hm²时,是更具经济效益的疏花方式,移动式水肥一体化系统在种植面积大于34.33 hm²时,是更具经济效益的灌溉方式;2)机械装备固定成本和传统作业方式零工成本是影响临界规模的重要因素,固定成本增加20%临界规模将增大约20%,零工成本增加20%临界规模将减小15%以上;3)案例中,梨园在机械装备平均成本最低的种植面积下,使用机械装备替代传统方式作业,全作业环节可节约成本11 536.87元/hm²。机械化装备需要果园规模大于临界规模才具有经济效益,随着固定成本降低,零工工资上升,机械装备作业替代传统方式作业临界规模变小,果园机械装备经济适用范围增大。     

Response of soil Olsen-P to P budget under different long-term fertilization treatments in a fluvo-aquic soil

The concentration of soil Olsen-P is rapidly increasing in many parts of China, where P budget(P input minus P output) is the main factor influencing soil Olsen-P. Understanding the relationship between soil Olsen-P and P budget is useful in estimating soil Olsen-P content and conducting P management strategies. To address this, a long-term experiment(1991–2011) was performed on a fluvo-aquic soil in Beijing, China, where seven fertilization treatments were used to study the response of soil Olsen-P to P budget. The results showed that the relationship between the decrease in soil Olsen-P and P deficit could be simulated by a simple linear model. In treatments without P fertilization(CK, N, and NK), soil Olsen-P decreased by 2.4, 1.9, and 1.4 mg kg~(–1) for every 100 kg ha~(–1) of P deficit, respectively. Under conditions of P addition, the relationship between the increase in soil Olsen-P and P surplus could be divided into two stages. When P surplus was lower than the range of 729–884 kg ha~(–1), soil Olsen-P fluctuated over the course of the experimental period with chemical fertilizers(NP and NPK), and increased by 5.0 and 2.0 mg kg~(–1), respectively, when treated with chemical fertilizers combined with manure(NPKM and 1.5 NPKM) for every 100 kg ha~(–1) of P surplus. When P surplus was higher than the range of 729–884 kg ha~(–1), soil Olsen-P increased by 49.0 and 37.0 mg kg~(–1) in NPKM and 1.5 NPKM treatments, respectively, for every 100 kg ha~(–1) P surplus. The relationship between the increase in soil Olsen-P and P surplus could be simulated by two-segment linear models. The cumulative P budget at the turning point was defined as the "storage threshold" of a fluvo-aquic soil in Beijing, and the storage thresholds under NPKM and 1.5 NPKM were 729 and 884 kg ha~(–1)P for more adsorption sites. According to the critical soil P values(CPVs) and the relationship between soil Olsen-P and P budget, the quantity of P fertilizers for winter wheat could be increased and that of summer maize could be decreased based on the results of treatments in chemical fertilization. Additionally, when chemical fertilizers are combined with manures(NPKM and 1.5 NPKM), it could take approximately 9–11 years for soil Olsen-P to decrease to the critical soil P values of crops grown in the absence of P fertilizer.