Characterization of the Soil Organic Matter in Agricultural Mine Spoils and Reclaimed Soils Treated with Organic Amendments

Recycling organic waste in agricultural soils is a valid solution. We performed short‐term experiments to investigate the fate of urban sludge and composts, in mine spoils, cultivated or uncultivated, and reclaimed soils located in Florence and Milan, Italy. The samples, either treated or untreated, were fractionated by density into light (<1.63 Mg m^?3) and heavy (>1.63 Mg m^?3) fractions. The fractions were analyzed for total carbon (C) and nitrogen (N) contents and for δ ¹³C and δ ¹⁵N isotopes, and they were characterized by ¹³C NMR spectroscopy. Treatment increased the heavy fraction. The addition of sludge in the Florence area acts in synergy with the cultivation, increasing the light fraction (LF). In the Milan area, the LF tends to be decomposed and apparently transformed into HF. The addition of amendments or cultivation enhances the decomposition with release of carbon dioxide. For future research, we suggest lengthening the time of the experiments to integrate climatic variations.     

Relationships between soil penetration resistance and soif nematode burden in barley on Prince Edward Island

Fifty sloping fields of barley with different short-term cropping histories across Prince Edward Island were examined for variations in root-zone depth and the severity of soil parasitic nematodes as part of a wider study of relationships between cropping sequence, topographic position, soil physical conditions and crop performance. Root lesion nematode (Pratylenchus penetrans) density in the roots was significantly greater (13%) at foot slopes than at top slopes, and stunt nematode (Tylenchorhynchus spp.) was significantly greater (8%) at top slopes where the soil was drier. The density of stunt nematodes and root lesion nematodes in the soil was significantly greater (>15%) under miscellaneous cereals-barley sequences than under potato-barley or hay-barley, attributable to level of carryover. Root lesion nematode density in the roots was significantly greater (12%) under hay-barley than either of the other two sequences. This nematode also showed a strong tendency to increase in number with increasing root-zone depth, and may be explained on the basis that increased root-zone depth provides increased host root mass (substrate). Stunt nematodes, on the other hand, increased with decreasing root-zone depth and may be explained by the known propensity of these organisms for drier, shallower soil conditions.     

阿拉尔垦区不同栽培密度下骏枣果实外观色度的比较

[目的]探究不同栽培密度下骏枣果实色度的差异,为新疆红枣产业的发展提供选择依据和指导信息.[方法]以3-5年生不同栽培密度(1 100、592和317株/667 m2)的骏枣为研究对象,采用X - rite色差计可以快速、准确获得果实的色品坐标系(L、a、b).通过新复极差法分析各栽培密度之间果实色度的差异.[结果]栽培密度为592株/667 m2的骏枣试验地果实色度较其他两个栽培密度(317、1 100株/667 m2)显著,尤其是果实亮度(L)和果实饱和度(C).[结论]充足的光照更有利于提高红枣果实的色度品质,主要是果实的红色程度得到提高.     

水稻不同育苗移栽方式的比较研究

试验结果表明，摆秧的产量高于插秧，二的产量均显地高于抛秧，品种间及品种与栽培方式互作间的差异均不显。摆秧的增产机理是秧苗素质好，移栽植伤很轻，分蘖早生快发，最高茎蘖数和成穗率均较高；叶面积指数高，且变化加速度小；在抽穗前比叶重增加快，此后增加慢；在生育后期，叶层面积大且占据层次多，群体基部绿叶面积大，穗层面积大且分布集中，位置偏中上，SOD含量高，丙二醛含量低。     

辽东山区紫椴、花曲柳碳素积累及主要营养元素分布特征1）

以辽东山区天然阔叶混交林重要组成树种紫椴和花曲柳为研究对象,通过生物量实测法,探究紫椴和花曲柳的碳素积累的变化特征以及不同器官氮（N）、磷（P）、钾（K）元素的分配格局。结果表明：花曲柳树干的平均固碳量和连年固碳量整体上高于紫椴,随林龄的增长差距有逐渐增大的趋势;40年生花曲柳树干平均碳素密度为322．18 kg· m－3,36年生紫椴为272．63 kg· m－3。在养分分配方面,紫椴和花曲柳单株N、P、K元素的积累量顺序一致（N＞K＞P）,但在不同器官中各元素积累顺序有些差异。紫椴各器官养分积累总量顺序为：树干＞树根＞树枝＞树叶;花曲柳各器官养分积累总量顺序为：树根＞树干＞树枝＞树叶。紫椴与花曲柳树叶的养分归还量占各自总体的比例分别为4．11％和17．32％,而树叶、树枝与根的养分积累比重合计分别为57．07％和75．31％,三者在生态系统养分循环中占有重要作用。     

不同种植密度对烤烟生长发育和经济性状的影响

[目的]探讨种植密度对烤烟K326生长发育和经济性状的影响,为永川烟草的田间栽培提供参考。[方法]测定并比较不同种植密度处理下烤烟农艺性状、叶绿素含量和经济性状。[结果]各处理农艺性状指标差异不显著。不同处理相对叶绿素含量差异显著,不同时期的相对叶绿素含量以16 500和18 180株/hm2密度处理较高,不同处理均表现为打顶期旺长期成熟期。22 725株/hm2密度处理各项经济性状指标较差,18 180株/hm2密度处理各项经济性状指标较高。[结论]总体比较,以种植密度18 180株/hm2较适宜烤烟生长。     

饲养密度对罗曼粉祖代种母鸡产蛋性能的影响

选择73周龄经过强制换羽的健康罗曼粉B系和D系祖代蛋种鸡各180只,分别分为3组,每个单笼(38cm×36cm)内分别放置4、3和2只,每只鸡占有的笼底面积相应为342、456和684cm2,其他各项饲养管理条件相同,以研究饲养密度对罗曼粉祖代种母鸡产蛋性能的影响。结果表明:饲养密度与鸡群的产蛋率和种蛋合格率呈负相关,随着饲养密度的降低,鸡群的产蛋率和种蛋合格率不断提高;品系母鸡对饲养密度的反应相似。     

二氧化碳气调防治储粮害虫的试验研究

具体的试验表明,利用二氧化碳气调防治储粮害虫,可取得理想的杀虫效果,而且无污染.     

不同倾斜角度对应力木生长应力、木材密度和干缩性质的影响

通过在安徽农业大学人工林场选取3年生马尾松实生苗和1年生杨树扦插苗进行栽培(其中马尾松杨树各60株,每12株为1组,共5组,每组对应1个角度,共5个角度0°、15°、30°、45°和60°),跟踪测定其生长应力指示值(growth stress indicator,简称GSI)、基本密度、干缩性质,并对它们的关系进行研究.结果表明:(1)杨树、马尾松GSI绝对值大小和倾斜角度呈显著正相关关系;(2)杨树、马尾松的基本密度和倾斜角度都呈显著正相关关系;(3)杨树、马尾松径向干缩率和倾斜角度关系不显著,杨树、马尾松轴向干缩和倾斜角度呈正相关关系,杨树弦向干缩和倾斜角度呈正相关关系,马尾松弦向干缩和倾斜角度呈负相关关系;(4)杨树应拉木区的弦向干缩大于对应拉木区,径向干缩变化不大;马尾松应压木区的弦向和径向干缩均小于对应压木区,应力木区的轴向干缩远大于对应力木区.     

晚播对不同基因型小麦花药培养中绿苗诱导率的影响

为了探讨提高小麦花药离体培养中绿苗诱导率的途径,本研究将66份小麦杂交组合材料分成花培组合、常规组合、复交组合3种不同的基因型组合,将其播种期推迟24 d,在小麦抽穗期取其花药进行室内愈伤组织诱导和绿苗分化培养。结果表明,经过晚播处理的小麦花培组合、常规组合、复交组合的绿苗诱导率分别为2.6％、1.5％、1.2％,分别比对照（正常播种期）提高1.8、1.0、0.6个百分点;愈伤诱导率分别为10.7％、9.1％、7.7％,分别比对照提高3.8、－2.8、－5.4个百分点。