Utilization of waste office paper to reduce nitrate leaching into the Northern Guam aquifer     

P. P. Motavalli  H. Discekici 《Biology and Fertility of Soils》2000,31(6):478-483

 Rapid nitrate leaching losses due to current agricultural N management practices under the humid tropical environmental conditions of the Pacific island of Guam may contaminate fresh and salt water resources. Potential environmental contamination of the Northern Guam aquifer, which is overlain by shallow limestone-derived soils, is a major public concern because the aquifer is the sole underground source of fresh water for the island. The objectives of this study were to examine the use of waste office paper as a possible management alternative for reducing nitrate leaching due to N fertilizer applications in northern Guam while also providing sufficient N for crop growth. In a laboratory study, increasing rates of waste paper application reduced NO₃ ^–-N leaching up to approximately 200 days after incorporation of N fertilizer and paper treatments. Subsequent mineralization of immobilized N from paper applications was also observed, although cumulative NO₃ ^–-N leaching at the highest rate of paper addition was lower than the control after 394 days of incubation. The effect of waste paper on N availability and NO₃ ^–-N leaching after application of N fertilizer at rates up to 500 kg N ha^–1 was also evaluated in two field experiments planted with sweet corn (Zea mays var. rugosa Bonaf.) during consecutive dry and wet periods. Leaching losses of NO₃ ^–-N were higher during the wet cropping season, leading to lower crop yields and crop N uptake. Combining paper with N fertilizer reduced NO₃ ^–-N leaching losses but also decreased crop ear yields up to N fertilizer application rates of 250 kg N ha^–1 during the dry cropping season and up to rates of 100 kg N ha^–1 during the wet period. Although combining waste paper with N fertilizer reduced NO₃ ^–-N leaching losses, no improvements in fertilizer N recovery were observed during the field experiments. This lack of crop response may be due to the importance of early season N availability for the short-season horticultural crops grown on Guam. We suggest that the application of waste paper may be a useful management practice to reduce NO₃ ^–-N leaching losses when high soil NO₃ ^–-N levels remain after cropping due either to crop failure or to over-application of N fertilizer. Received: 11 May 1999  相似文献   

Effects of long-term waste water irrigation on soil organic matter, soil microbial biomass and its activities in central Mexico   总被引：4，自引：0，他引：4  

J. K. Friedel  T. Langer  C. Siebe  K. Stahr 《Biology and Fertility of Soils》2000,31(5):414-421

 The effect of long-term waste water irrigation (up to 80 years) on soil organic matter, soil microbial biomass and its activities was studied in two agricultural soils (Vertisols and Leptosols) irrigated for 25, 65 and 80 years respectively at Irrigation District 03 in the Valley of Mezquital near Mexico City. In the Vertisols, where larger amounts of water have been applied than in the Leptosols, total organic C (TOC) contents increased 2.5-fold after 80 years of irrigation. In the Leptosols, however, the degradability of the organic matter tended to increase with irrigation time. It appears that soil organic matter accumulation was not due to pollutants nor did microbial biomass:TOC ratios and qCO₂ values indicate a pollutant effect. Increases in soil microbial biomass C and activities were presumably due to the larger application of organic matter. However, changes in soil microbial communities occurred, as denitrification capacities increased greatly and adenylate energy charge (AEC) ratios were reduced after long-term irrigation. These changes were supposed to be due to the addition of surfactants, especially alkylbenzene sulfonates (effect on denitrification capacity) and the addition of sodium and salts (effect on AEC) through waste water irrigation. Heavy metals contained in the sewage do not appear to be affecting soil processes yet, due to their low availability. Detrimental effects on soil microbial communities can be expected, however, from further increases in pollutant concentrations due to prolonged application of untreated waste water or an increase in mobility due to higher mineralization rates. Received: 28 April 1999  相似文献   

啤酒酵母多糖的分离纯化与初步鉴定     

张丽霞  张丽萍  于文革  袁改霞  袁红梅 《安徽农业科学》2010,38(31):17371-17372,17374

[目的]从啤酒废酵母中分离纯化出多糖，并对其组成和性质进行初步鉴定。[方法]用常规方法分离纯化啤酒酵母多糖，并用HPLC、比旋度测定和醋酸纤维薄膜电泳等方法测定BPS2。[结果]粗多糖收率为9．7％，为浅色粉灰。BPS2为均一组分，苯酚-硫酸法测定其糖含量为95．2％，GC分析其单糖组成为Man和Glc，摩尔比为1．08：1．00。[结论]试验提取的粗多糖为一种新多糖，其主要成分为BPS2，为啤酒酵母的利用提供了基础。  相似文献   

废弃物处理的现状及案例研究     

王侃宏  江晓峰  罗景辉  赵亮 《绿色科技》2015,(1):187-189

指出了对工业废弃物的妥善处理不仅可以使之作为能源和资源得到有效利用,还能起到温室气体减排的效果。分析了我国在废弃物处理领域的应用现状及存在的问题,并提出了相应的措施和建议。  相似文献   

芦笋废弃秸秆利用现状与高效开发对策     

胡新龙  张岳平  陈光宇 《江西农业学报》2015,(7)

简述了芦笋废弃秸秆的利用价值及在动物饲料、食用菌培养、食品工业、沼气应用和土壤改良等方面的研究利用现状,并有针对性地提出了几点高效开发对策,以期为芦笋产业的进一步发展提供参考。  相似文献   

农产品加工剩余物焚烧过程的干燥热解特性研究   总被引：9，自引：1，他引：9  

孙振刚  马晓茜  卢苇 《农业机械学报》2001,32(2):49-51,61

为了积累垃圾焚烧炉设计的基础，对几种南方典型产品加工剩余物进行了工业分析和干燥、热解实验，得到不同温度下随时间变化的失重曲线图；分析了它们的着火和燃烬性能；拟合出相应的干燥、热解动力学曲线，得到了干燥、热解反应动力学参数。结果表明：实验的几种农产品加工剩余物的干燥、热解反应基本符合一级反应规律；这些农产品加工剩余物宜作焚烧处理，焚烧时应进行干燥或采用两段、两室炉型。  相似文献   

高热效率节能两级干燥工艺的研究   总被引：3，自引：1，他引：3  

于吉云  范训龙 《农业机械学报》1992,23(3):37-42

简述了高热效率节能两级干燥工艺流程利用余热的基本原理。经过热平衡分析,推导出单位水分汽化耗热空气量、耗热量和每千克热干空气汽化水分的能力与热风温度和尾气温度的函数关系,绘制出函数曲线图,并算出降低尾气温度的节能效果。用于指导现在所有热风干燥机提高热效率,具有明显的经济效益。在两级气流干燥机上应用,热效率高达80％～88％,节省热能20％～40％;在沸腾床上干燥玉米胚芽,两级干燥节省煤、电45％,提高效率45％。  相似文献   

发酵基料-蚯蚓-鳝鱼食物链物流与能流转化效率的研究     

周文宗  钦佩  白宇 《中国生态农业学报》2004,12(3):175-177

对废弃物食物链发酵基料 蚯蚓 鳝鱼的物质流和能量流转化效率研究结果表明 ,该食物链经济产品物质、能量转化效率较低 ,生物量转化效率为 0 .9% ,N、P转化效率分别为 2 .1 %和 0 .6 % ,能量转化效率为 1 .0 % ,其经济和生态效益明显  相似文献   

城市垃圾堆肥的生态效应与对策研究   总被引：8，自引：1，他引：8  

范海荣  华珞  傅桦  王学江 《土壤》2004,36(5):498-505

本文分析了城市垃圾堆肥的生态效应,其中包括肥力效应:提高土壤养分,改善土壤的理化性质;生物效应:改善土壤的微生物特性,提高植物的产量和品质;环境负效应:造成土壤的沙化、盐渍化、重金属积累等;环境正效应:修复被污染的土壤,防止水土流失;并阐述了垃圾堆肥环境效应的预防措施。最后提出了城市垃圾堆肥的发展对策:提高垃圾堆肥的质量,发展有机无机复合肥。  相似文献   

津郊荒地改良复合农业生态系统结构组建及其功能分析     

程治山  马翠萍  刘先觉 《中国生态农业学报》1996,4(1):45-48

本文通过对天津市北辰区双街乡荒地实施生态工程建设建成的以“基塘型果园”为景观特征,以“果-鱼-畜-禽”为生产主线的复合农业生态系统结构合理性、功能有效性的分析与评价,探讨了城郊荒地改良模式和调控途径。  相似文献