【摘 要】
：
Nitrogen is an essential component in forest ecosystem nutrient cycling.Nitrogen fractions,such as dissolved nitrogen,ammonium,nitrate,and microbial bio-mass nitrogen,are sensitive indicators of soil nitrogen pools which affect soil fertility and nutrient
【机 构】
：
College of Biology and the Environment,Nanjing Forestry University,Nanjing 210037,People’s Republic
论文部分内容阅读
Nitrogen is an essential component in forest ecosystem nutrient cycling.Nitrogen fractions,such as dissolved nitrogen,ammonium,nitrate,and microbial bio-mass nitrogen,are sensitive indicators of soil nitrogen pools which affect soil fertility and nutrient cycling.However,the responses of nitrogen fractions in forest soils to organic mulching are less well understood.The rhizosphere is an important micro-region that must be considered to better understand element cycling between plants and the soil.A field investigation was carried out on the effect of mulching soil in a 15-year-old Ligustrum lucidum urban plantation.Changes in total nitrogen and nitrogen fractions in rhizos-phere and bulk soil in the topsoil(upper 20 cm)and in the subsoil(20-40 cm)were evaluated following different levels of mulching,in addition to nitrogen contents in fine roots,leaves,and organic mulch.The relationships between nitro-gen fractions and other measured variables were analysed.Organic mulching had no significant effect on most nitrogen fractions except for the rhizosphere microbial biomass nitro-gen(MBN),and the thinnest(5 cm)mulching layer showed greater effects than other treatments.Rhizosphere MBN was more sensitive to mulching compared to bulk soil,and was more affected by soil environmental changes.Season and soil depth had more pronounced effects on nitrogen frac-tions than mulching.Total nitrogen and dissolved nitrogen were correlated to soil phosphorus,whereas other nitrogen fractions were strongly affected by soil physical properties(temperature,water content,bulk density).Mulching also decreased leaf nitrogen content,which was more related to soil nitrogen fractions(except for MBN)than nitrogen con-tents in either fine roots or organic mulch.Frequent appli-cations of small quantities of organic mulch contribute to nitrogen transformation and utilization in urban forests.
其他文献
结合渭南经济林水肥一体化栽培管理实践,以花椒生物学特性为根本,系统考虑花椒栽植区地形、地块、坡度、土壤质地、树木种植方式、水源特点等基本情况,分析现有花椒栽培水肥管理技术方式,提出了花椒土肥水一体化管理主要技术措施.
辽宁朝阳地区的大铃铛枣是国家地理标志保护产品.大铃铛枣嫁接苗冻害现象的发生,与当地的干冷气候有直接的关系,目前的天气预报手段,还解决不了大铃铛枣嫁接苗的冻害预测问题,一旦发生会造成无法估量的损失.大铃铛枣嫁接苗预防冻害冬季窖藏的新技术,为省内外大铃铛枣产业的发展提供了技术支撑.
This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate.Microbial carbon metabolism diversity was assessed using community-level physiological profiles(CLPP)with 3
In southern China,the eucalyptus plantation industry has been severely restricted by government pol-icy over concerns on negative environmental impacts.In its place,large-scale plantations of high-value tropical tree species such as nitrogen-fixing Dalber
Although petroleum is an important source of energy and an economic driver of growth,it is also a major soil pollutant that has destroyed large swathes of vegetation and forest cover.Therefore,it is vital to develop affordable and efficient methods for th
Reducing greenhouse gas emissions is one of the major challenges in combating global warming.Car-bon,including in the form of carbon dioxide(CO2),is con-sidered an essential greenhouse gas under human control to demonstrate success in emission reductions.
为了掌握滇黄精(Polygonatum kingianum Coll.et Hemsl.)不同种植模式下病虫害的发生情况,通过普查和样地调查相结合的方法对普洱市3个滇黄精种植基地进行调查.调查结果表明,3个种植基地滇黄精病虫害种类共15种,其中虫害9种,病害6种.大田种植基地病虫害发生最为严重,共有病虫害12种,其中重度危害2种,中度危害2种;林下种植基地病虫害4种,均为轻度危害;茶地套种基地病虫害8种,其中重度危害1种,中度危害2种.通过调查,掌握了普洱市3种种植模式下滇黄精病虫害发生种类及发生规律,了
The shortage of information regarding the effects of root damage on forest plants,especially trees and shrubs,is the most critical gap in our knowledge of belowground insect herbivory.This study examines how the tea-leaved willow,Salix phylicifolia,respon
Soil microorganisms and physicochemical prop-erties are considered the two most influencing factors for maintaining plant diversity.However,the operational mech-anisms and which factor is the most influential manipulator remain poorly understood.In this s
为筛选出对中药材三叶青(Tetrastigma hemsleyanum)叶斑病具有良好防效又保持其总黄酮含量的药剂,选择了2种化学杀菌剂和1种生物药剂,及其配对混合药剂进行田间防治效果试验.试验结果表明,0.133％浓度的5％香芹酚溶液和0.067％浓度的33.5％哇啉铜溶液各50％容积比混合制剂,对三叶青叶斑病防效指数为92.73％;并能有效保持三叶青总黄酮含量6.01％,优于其它处理.因此生物药剂0.133％浓度的5％香芹酚溶液和化学药剂0.067％浓度的33.5％哇啉铜溶液各50％容积比混合制剂,可