Nutrients in litterfall,forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ.     

青岛文昌鱼自然保护区营养盐时空分布特征及富营养化评价

本研究分析了2017年9月(夏季)和11月(秋季)青岛市文昌鱼(Branchidermus fasciatus)水生野生动物市级自然保护区营养盐含量的季节变化和平面分布,并对该海域进行了富营养化评价。研究结果显示,2017年溶解无机氮(DIN)平均含量夏季高于秋季,NO_(2-)N、NH_(4-)N平均含量分别是秋季的1.98倍、1.44倍,而NO_(3-)N和PO_(4-)P平均含量低于秋季,分别是秋季的88.8%和47.6%。夏季DIN总体水平优于海水一类标准值,PO_(4-)P总体水平优于海水一类标准值;秋季DIN总体水平优于海水一类标准值,PO_(4-)P总体水平劣于海水一类标准值。从水平分布来看,夏季海水的DIN浓度分布趋势大致呈核心区实验区缓冲区的趋势;秋季海水的DIN浓度分布呈缓冲区实验区核心区。夏季N/P比值略高于Redfield比值,而秋季N/P比值较低于Redfield比值,DIN相对缺乏。根据潜在性富营养化评价模式,2017年保护区海域夏季和秋季营养水平较低,均属于贫营养水平。     

不同有机肥用量对芋头生长、食味品质和土壤肥力的影响

以‘香荷芋’为供试材料,于泰州、泰兴分别设置T1、T2和T3共3种有机肥用量和CK（对照）处理,探索有机肥施用对芋头生长、食味品质及土壤养分的影响,以期为泰州地区芋头科学施肥技术提供依据。结果表明：泰州、泰兴点T2和T3处理6叶期、12叶期株高均显著高于CK处理(P<0.05),泰兴点T1处理株高在12叶期显著高于CK处理,在6叶期和泰州点6叶期、12叶期与CK处理均无显著差异;泰兴点T3处理6叶期叶面积指数平均为0.31,均显著高于其他处理,其他处理间差异均不显著,泰州、泰兴点T3处理12叶期叶面积指数分别为0.71、0.75,均显著高于CK处理;有机肥用量与子芋口感、香味指标及土壤有机质含量均呈显著正相关,相关系数分别为0.89、0.86、0.79;泰州、泰兴点T2、T3处理碱解氮、有效磷均显著高于CK处理;泰州点土壤有效钾以T2处理最高,为174 mg/kg,T3处理最低,为159 mg/kg,泰兴点则以CK处理最高,为172 mg/kg,T3处理最低,为140 mg/kg。     

生草对南疆温室桃园土壤理化性状的影响

研究生草措施对温室桃园土壤环境和养分的影响,为温室桃栽培优质生产提供理论支持。以温室桃园为研究对象,设置行间种植三叶草和小黑麦为处理,以清耕为对照,测定温室桃园土壤理化性质、体积质量、孔隙度及养分含量的变化。结果表明,温室桃园行间种植三叶草和小黑麦能减缓土壤温度变化幅度,提高土壤含水量,降低土壤水溶性总盐含量,显著增加0～20 cm土层和20～40 cm土层土壤有机质及养分含量,其中种植三叶草的效果好。生草能增加土壤pH,显著降低0～20 cm土壤体积质量,增加土壤总孔隙度。温室桃园生草可以有效调节土壤温度,改善土壤结构和通透性,提高土壤肥力。     

Explaining variation in Brazil nut fruit production

Brazil nut is widely recognized as the cornerstone of the Amazonian extractive economy. Tight linkages between Brazil nut production, regional income, and intact mature forests have thrust this species into focus as a key component of Amazonian conservation and income generation strategies. Nonetheless, a comprehensive synthesis of factors explaining Brazil nut fruit production variation is lacking. We aimed to address this knowledge gap, asking: (1) What are the rates and annual variation of Bertholletia excelsa fruit production at individual and population levels? (2) What factors explain B. excelsa production variation, focusing on spatial and temporal variables, diameter at breast height (dbh), crown attributes, liana loads, and soil attributes? and (3) Does liana cutting affect fruit production?     

子午岭林区常见野生蔬菜营养成分分析

对子午岭林区19种野生蔬菜鲜样的水分、粗纤维、Fe、可溶性糖、可溶性蛋白和VC含量等进行了测定。试验结果表明,玉竹根部膨大部分纤维素含量最高,水芹Fe含量最高,蒲公英叶片可溶性糖含量最高,短柄五加叶片可溶性蛋白含量最高,VC含量最高的是苜蓿。除水分和可溶性糖含量外,野生蔬菜中其他营养指标基本上高于常见栽培蔬菜。     

The effect of multi-nutrient fertilization on understory vegetation nutrient concentrations in inland Northwest conifer stands

This study looked at the effects that multi-nutrient fertilization had on understory vegetation nutrient concentrations at four conifer forested locations in the inland Northwest. Multi-nutrient fertilization of conifer stands cannot only enhance the overstory species in the inland Northwest but also the understory vegetation. Determination of nutrient concentration response to fertilization treatments can provide managers the ability to better manipulate their forests for grazing and wildlife habitat. We grouped the understory vegetation into three general life forms: forbs, grasses and grass-likes, and shrubs. Multi-nutrient fertilization had little effect on nitrogen concentration across all life forms. Potassium and sulfur generally increased in concentration. Micronutrients as a whole showed less variability in response to multi-nutrient fertilization. Boron, copper, molybdenum, and zinc generally showed increases in concentrations across all life forms. We were able to conduct analyses on a selected number of understory vegetation species. Individual species showed variability in nutrient concentration response to multi-nutrient fertilization. Wildlife habitat and grazing quality were both increased and decreased following multi-nutrient fertilization. Increases in nutrient concentrations will provide more nutritious vegetation to these animals and vice versa for decreases in concentrations.     

Concentration variations of several ions in stream after a wildfire

In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing＇an Mountains, China. The concentration changes of eight ions （K^＋, Na^＋, Ca^2＋, Mg^2＋, Cl^-, Br^-, NO3^- and SO4^2-） were measured in burned and tmbumed streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca^2＋, whose average concentration was 5.50 mg·L^-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca^2＋〉SO4^2- 〉Na^＋〉Mg^2＋〉NO3^- . The average concentrations of Ca^2＋, SO4^2- , Na^＋＇Mg^2＋,NO3^- showed an increase trend, but those of K^＋, Cl^- , Br had a decreased trend. SO4^2- had the largest loss among these anions, followed by NO3^-. Overall, the increase degree of cation was greater than that of anion after burning.     

Leaf-litter decomposition of 15 tree species in a lowland tropical rain forest in Sarawak: decomposition rates and initial litter chemistry

In a lowland tropical rain forest in Sarawak, leaf-litter decomposition and the initial litter chemistry of 15 tree species were studied. During 13 months of field experiment, weight loss of litter samples was between 44% and 91%, and calculated decomposition rate constants (k) ranged from 0.38 to 2.36 year⁻¹. The initial litter chemistry also varied widely (coefficients of variation: 19%–74%) and showed low N and P concentrations and high acid-insoluble residue (AIS) concentration. For nutrient-related litter chemistry, correlations with the decomposition rate were significant only for P concentration, C/P ratio, and AIS/P ratio (r _s = 0.59, −0.62, and −0.68, n = 15, P < 0.05, respectively). For organic constituents, correlations were significant for concentrations of AIS and total carbohydrates, and AIS/acid-soluble carbohydrate ratio (r _s = −0.81, 0.51, and −0.76, n = 15, P < 0.05, respectively). These results suggested that the relatively slow mean rate of decomposition (k = 1.10) was presumably due to the low litter quality (low P concentration and high AIS concentration), and that P might influence the decomposition rate; but organic constituents, especially the concentration of AIS, were more important components of initial litter chemistry than nutrient concentrations.     

杨树超短轮伐期经营的生产力及材性的研究

以美洲黑杨２个无性系为供试材料，研究杨树超短轮伐期经营中地上部分生物量生产、分配模式、Ｎ、Ｐ、Ｋ的输出量及材性。结果表明，在３种密度和３种轮伐期的组合中，２个无性系均以造林密度为１００００株·ｈａ－１、轮伐期为３年的林分生物生产力最高，Ｉ－６９杨为１０．５２ｔ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨约为１２．００ｔ·ｈａ－１·ａ－１；在生物量的分配比率和作为造纸材的经济生物量上也以这种组合模式最为合理，经济生物量最大，Ｉ－６９杨为７．１４ｔ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨为８·４７ｔ·ｈａ－１·ａ－１。养分输出量的多少与林分的生物量生产和分配比率密切相关。轮伐期为３年，密度为１００００株·ｈａ－１的林分Ｎ、Ｐ、Ｋ的输出量最高，Ｉ－６９杨为３３．９７ｋｇ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨为３８．５０ｋｇ·ｈａ－１·ａ－１，但ＮＬ－８０３５１杨每生产１吨经济生物量所输出的Ｎ、Ｐ、Ｋ总量略低于Ｉ－６９杨。杨树超短轮伐期经营中生产出的木材都可用作中、低档的造纸原料，其中Ｉ－６９杨的制浆性能优于ＮＬ－８０３５１杨。