Differential Responses of Nitrifier and Denitrifier to Dicyandiamide in Short- and Long-Term Intensive Vegetable Cultivation Soils

Nitrification inhibitors, such as dicyandiamide （DCD）, have been shown to decrease leaching from urea- and ammoniumbased fertilizers in agricultural soils. The effect of nitrification inhibitors on nitrifier and denitrifier in short- and long-term intensive vegetable cultivation soils was poorly understood. In this study, the pot trial was conducted to investigate the differential responses of nitrifier （amoA-containing bacteria） and denitrifier （nirK-containing bacteria） to DCD in short-（soil S） and long-term （soil L） intensive vegetable cultivation soils. Quantitative polymerase chain reaction （qPCR） and terminal restriction fragment length polymorphism （T-RFLP） were employed to detect the abundance and composition of amoA- and nirK-containing communities. The results indicated that application of DCD led to a consistently higher NH4＋-N concentration during the whole incubation in soil L, while it was quickly decreased in soil S after 21 days. Furthermore, DCD induced more severe decrease of the abundance of amoA-containing bacteria in soil L than in soil S. However, the abundance of the nirK- containing community was not significantly affected by DCD in both soils. Long-term vegetable cultivation resulted in a super-dominant amoA-containing bacteria group and less divergence in soil L compared with soil S, and DCD did not cause obvious shifts of the composition of ammonia-oxidising bacteria （AOB）. On the contrary, both amoA- and nirK-containing bacterial compositions were influenced by DCD in soil S. The results suggested that long-term intensive vegetable cultivation with heavy nitrogen fertilization resulted in significant shifts of AOB community, and this community was sensitive to DCD, but denitrifiers were not clearly affected by DCD.     

基于ARMA模型的运城市果蔬肉类价格预测研究

[目的]预测果蔬肉类价格。[方法]采用自回归滑动平均模型(ARMA模型)对价格进行预测。[结果]近6周的预测结果可信度高,具有较低的相对误差率。[结论]运用ARMA模型可对果蔬肉类价格进行预测且预测效果良好。     

福建省设施蔬菜生产现状及其发展对策研究

近年来福建省设施蔬菜发展较快.通过总结福建省设施蔬菜生产现状、设施类型及应用性能,分析设施蔬菜产业发展过程中存在的问题,并提出对策,以期为设施蔬菜产业良性、高效发展提供参考.     

宁夏设施蔬菜土壤环境生物调控的实践与理论

文章分析了宁夏设施蔬菜土壤特点及存在的问题,以及采取各项生物措施调控土壤环境的研究实践,提出了宁夏设施蔬菜土壤环境生物调控的技术途径与展望,为宁夏土壤连作障碍治理提供实践和理论参考。     

我国菜田土壤重金属污染现状及检测技术分析

为解决我国菜田土壤污染问题,该文分析了园艺作物生产过程土壤重金属检测以及保障"菜篮子"产品可持续生产系统的重要意义。通过对我国东北、华北、南方、西部等地区的菜田重金属污染已有的调查研究工作进行综述,论述了我国菜田土壤重金属污染现状,并对污染总体情况、布局及趋势进行了分析;针对菜田土壤重金属含量的有效检测问题,介绍了现有重金属含量检测方法,并进行了现有常规及新型重金属检测手段的对比,提出了目前土壤重金属含量检测中面临的主要问题,为我国菜田园艺作物生产过程重金属污染检测和防治工作提供参考依据。     

不同播期、密度和肥料对菜用板蓝根产量及品质的影响

为探索菜用板蓝根在毕节地区的优质高产栽培措施,通过田间试验研究菜用板蓝根不同播期、密度和氮钾肥施用量对产量及品质的影响。结果表明,在毕节地区,菜用板蓝根适宜播期为4月30日左右,种植密度为50．025～66．70万株/hm2,钾肥施用量为150～300 kg/hm2,氮肥施用量为778 kg/hm2左右,在此栽培条件下,产量可达73947．96～76749．35 kg/hm2,且品质较好,蛋白质、脂肪、水溶性糖及维生素含量较高,粗纤维含量较低。     

消毒剂在净菜加工中的应用研究

通过正交试验设计筛选出净菜加工过程中最优的消毒剂配方,结果表明:净菜加工过程中最佳消毒处理为O3浓度为10g/h、NaClO浓度为0.025%、浸泡时间为70 s。     

生物防治在设施蔬菜生产中的应用

生物防治是利用生物界本身存在的天敌等措施来防治病虫害的方法。作为一种环境友好型和资源节约型的防控技术措施,生物防治发展前景广阔。总结了生物防治在设施蔬菜生产中的应用,包括以虫治虫、以菌治虫、利用其他动物治虫等内容,以期为设施蔬菜的生物防治提供参考。     

基于云技术的大庆果蔬供应链信息系统平台的构建

为解决大庆现有蔬果供应链缺少统一的信息网络平台,农产品供应链节点之间信息不畅通等问题,运用系统方法和云技术,构建了大庆果蔬供应链信息系统平台,实现了农产品的求购、供应、批发、报价和在线支付等功能。通过平台,用户可及时了解大庆果蔬供应链上农产品的种植量、可供上市量、市场需求量等信息,为用户科学决策、合理安排生产提供重要参考依据。     

浅谈烟台市无公害蔬菜生产的现状及对策

蔬菜的质量和安全日益受到人们的关注,无公害蔬菜已成为蔬菜生产的发展方向。本文简述了无公害蔬菜的概念,分析了烟台市无公害蔬菜的生产现状及存在问题,提出了无公害蔬菜生产的措施与对策,以期为烟台市无公害蔬菜的生产提供参考。