EM对黄瓜根系发育及幼苗生长的影响分析

选取西安松岭黄瓜研究所研发的3511作为试验黄瓜品种,分别通过苗床表面喷施和拌入土壤两种方式来开展试验,以明确EM在不同浓度下对于黄瓜根系发育及幼苗生长的影响情况。试验结果显示,均匀拌入土壤更有助于促进黄瓜根系发育;浓度一定的EM能够改善黄瓜根系活力,增加幼苗株高与叶面积,改善茎粗;EM菌肥拌入土壤的最佳比例为0.5%。     

如何提高杀菌剂使用功效

杀菌剂是一类用来防治植物病害的药剂，凡是对病原物有杀死作用或抑制生长作用，但又不防碍植物正常生长的药剂，统称为杀菌剂。生产上如何高效使用杀菌剂，对提高农作物产量具有十分重要的意义。现将使用技术介绍如下。1．合理配置浓度。使用杀菌剂（包括水剂和可湿性粉剂）喷雾时，     

西瓜药害补救措施

西瓜生长发育旺盛,植株含水量高,对多种化学药剂都很敏感,一旦施药浓度过大或药剂选用不当,很容易发生药害。西瓜发生药害后的补救措施是:1.清水冲洗。多数化学药剂都不耐水冲刷,如果因施     

西瓜药害解救四法

西瓜生长发育旺盛，植株合水量高，对多种化学药剂都很敏感，一旦施药浓度过大或药剂选用不当，很容易发生药害。西瓜发生药害后的解救措施是：     

鸡树条荚种子浸提液对小白菜种子萌发和幼苗生长的影响

通过研究鸡树条荚种子的种皮和胚乳的不同浓度甲醇浸提液对白菜种子萌发和幼苗生长及保护酶活性的影响,探讨鸡树条荚种子内源抑制物质的活性。结果发现,鸡树条荚种皮、胚乳中含有抑制白菜种子萌发及幼苗生长的物质,随着该物质浓度的增加,抑制作用更为显著;相同浓度的胚乳浸提液对白菜种子萌发及幼苗生长的抑制作用显著高于种皮浸提液。随着胚乳浸提液浓度升高,SOD酶活显著降低,丙二醛（MDA）含量持续增高。结果表明鸡树条荚种皮和胚乳均有抑制物质存在,鸡树条荚种子浸提物可能通过影响保护酶的活性进而影响白菜幼苗的正常生长。     

农药浸种六要点

注意选择药剂的剂型药剂浸种用的是药剂的稀释液,所用药剂一定要溶于水。不能用粉剂浸种,因为粉剂不溶于水,药粉浮于水面或下沉,种子沾药不匀,达不到浸种灭菌的效果。准确配制药液浸种所用的药剂浓度是根据种子重量计算的,一般按照药剂的有效成分含量或制剂量计算。浸种的药剂浓度一般和浸种时间有关,浓度低时浸种时间可略长一点,浓度高时浸种时间要缩短,如果不准确掌握好浓度,就容易发生药害或降     

常用叶面肥的适宜浓度

作物叶面追施又叫根外追肥,是快速补充营养,解除作物因缺乏营养元素出现的生理病害,促进作物健壮生长,提高产量的有效办法。叶面肥的浓度十分重要,浓度过高,不仅造成肥害,甚至“烧”伤叶面和组织,而且微量元素如浓度过高还可能造成毒害;而浓度过低,则肥效不明显。下面介绍几种常用叶面肥的浓度。     

农药制剂英文标志含义

PC（百分浓度）：表示药剂中有效成分的百分含量。 ppm（百万分浓度）：如1ppm，就是百万分之一。     

不同浓度铅、锌对玉米生长的生态毒理学效应研究

利用盆栽试验,研究不同浓度铅、锌处理对玉米生长的生态毒效应。结果表明:铅浓度在250mg/kg内促进玉米发芽,高于此浓度则抑制发芽,所有锌处理均提高了玉米的发芽率,低浓度锌可提高种子的发芽势,高浓度则有抑制作用;铅浓度为125mg/kg时就对叶面叶绿素、芽、根、株高、干鲜重产生影响,随着铅用量的加大抑制性越大;锌处理对叶绿素含量、芽、根、株高、干鲜重的作用表现为随着用量的加大,促进作用先逐渐增大然后逐步减弱直至产生抑制;各个器官中铅富集量高低顺序为:根系>秸秆>叶>籽实,各个器官中锌富集量高低顺序为:叶>籽实>根系>秸秆;土壤不同形态铅含量随铅用量的加大而增大,同时也改变了土壤中铅形态分配的比例,使非残渣态含量增加;随着外源锌的投入量的加大,改变了锌在土壤中形态分配的比例,矿物态、碳酸盐结合态锌比例逐渐下降,晶体氧化铁结合态、无定型氧化铁结合态、氧化锰结合态比例逐步增大,但无论是原状土还是外源污染土其交换态锌和有机结合态锌含量所占比例很低,不足0.1%。     

稻田移栽用化学防草剂五忌

一、用量忌过多过少。常规移栽稻田按除草剂的有效成分适量施用,即按除草剂使用说明用。若用量过少,药力不够,难以将杂草杀死;用量太大,浪费了药剂,经济上划算不来,药液浓度过高,会出现副作用,严重时会产生药害。二、时间忌过早过迟。稻田适时掌握施用除草剂将直接影响除草效果,一般选择在大田移栽后。早稻5～7天,晚稻4～5天为宜。过早施用,禾苗处于恢复返青期,苗体弱小,对药剂的抗性较差,容易产生药害;施用太迟,杂草对药剂敏感的萌芽期已过,难以达到除草的效果。三、灌水忌过浅过深。施药后田间保持一周左右的4～6厘米水层,把出水缺口定好…     

马尾松采脂林下田七种植可行性与经济效益初探

该文对梧州市马尾松采脂林下种植的0.33hm21年生田七进行了取样分析,结果表明,1年生田七5个样地的生长量指标(株高、叶柄长、茎长、茎粗、根长、根粗、株鲜重、叶鲜重、根鲜重)、干样指标(叶干重、茎干重和根干重)相互间差异皆不显著。另外,叶、茎、根干鲜重比值分别达到66.7%、13.3%和35.5%;复叶数、复叶长、复叶宽、小叶数和叶面积这些与光照相关的指标,不同样地间差异不显著。可知,松林下辅以遮阳网的田七栽培模式能够满足田七对环境的需求。目前,林下1年生田七保存率为80.8%,单株平均根干重为2.7g,每公顷田七产量已达850.5kg,收益可达39.0882万元。可见,在梧州地区松林下种植田七模式具有较大的推广应用价值。     

氮素水平对五味子幼苗生长的影响

以2年生五味子苗未为试验材料,在田间条件下,施以不同水平的氮素,分析了叶片可溶性蛋白、叶绿素含量、根系及茎叶中全氮含量、生物量等季节的动态变化规律,探讨了不同氮素水平对五味子苗未生长的影响.结果表明:(1)随着供氮水平的增加五味子茎叶全氮含量、可溶性蛋白、叶绿素含量都呈先升高后下降的变化趋势,不同生长时期表现出的峰值不...     

Incorporating the effect of urbanization in measuring climate adaptive capacity

Measuring the ability of a community to face climatic changes, or its adaptive capacity, is necessary in order to plan and guide development as the global climate continues to warm. One factor that has not been thoroughly addressed by previous attempts at measuring adaptive capacity is urbanization. This study looks to measure adaptive capacity in relation to urbanization, as many areas of the world are undergoing this rapid transition. An indicator system was created with land-use sensitive measures and applied to three different land use projection scenarios (A, BAU, and B − high, medium, and low growth, respectively) to 2030 and 2050 for two case study areas, Tamsui, Taiwan and West Palm Beach, USA. In Tamsui, the adaptive capacity decreased in all scenarios, but most dramatically for the high growth scenario. The low growth scenario decreased more slowly through each time slice. For West Palm Beach, the high growth scenario had the highest score in 2030, but declined in 2050. The medium growth Scenario BAU, also had a higher adaptive capacity score in 2030 than in 2050. The low growth Scenario B had a score that improved less dramatically but continued to rise through 2050. Scenario A would be ideal for short term gains, but its benefits would plateau in the long term. Scenario B, with conservation measures and more restricted growth would be the most ideal alternative. This study shows that urbanization has short term socioeconomic gains, but long term environmental consequences. The results also successfully incorporates the effect of land use change into an adaptive capacity indicator system, and can be applied in other localities expecting significant increases in urbanization.     

Agent‐based modeling for ex ante assessment of tree crop innovations: litchis in northern Thailand

This study uses an agent‐based model for ex ante assessment of agricultural innovations. The model builds on whole farm mathematical programming (MP) and extends the methodology with a spatial representation of the system, the heterogeneity of farm households and landscapes, and the interaction between farm households. We apply the model in a northern Thai watershed to study the potential of four innovations to increase the profitability of litchi orchards. Cost‐benefit analysis shows that each innovation would increase the profitability of litchi growing; however, the results of the agent‐based model show that at current price levels these innovations alone would not be enough to stem the decline in the area under litchis. The model was validated and the sensitivity of the results tested for variations in the irrigated water supply and liquidity. We report on how farmers responded to these results and discuss the implications for other areas in northern Thailand.     

模型模拟华北地区气候变化对冬小麦产量的影响

该文利用IPCC AR4模式资料和基于多年观测资料生成的格点数据,建立降水、最高/最低气温的统计降尺度关系,获取华北地区高分辨率未来气候情景空间分布;利用作物模型模拟IPCC-B1情景下冬小麦生长期和产量变化。结果表明:最高/最低气温模拟结果与观测值比较,相关系数(R2)大于0.70;降水模拟结果与观测值比较,相关系数最小为0.63;IPCC-B1情景下,华北地区冬小麦生长期总体上变短,产量下降。     

Modelling the urban heat island effect of smart growth policy scenarios in Brisbane

Smart growth policy has been identified as a panacea to tackle a range of undesirable outcomes of sprawl development. Various neighbourhood planning concepts have been developed following smart growth principles such as transit oriented development, and infill development. Existing empirical studies, however, do not answer to a key policy question: can smart growth policies reduce the urban heat island (UHI) effect? If so, what type of smart growth policy would be most effective? This research examined the questions by deriving five alternative neighbourhood planning scenarios for Brisbane for 2023: a) business as usual, b) transit oriented development (TOD), c) infill development, d) motorway corridor oriented development, and e) sprawl development. The research utilises Landsat remote sensing images of 1991, 2004, and 2013 to: first, estimate and validate a Geographically Weighted Regression model in order to identify statistically significant factors influencing the UHI intensities in Brisbane; and second, predict the UHI intensities of the five policy scenarios. Two factors were identified to have significant influence on the UHI intensities in Brisbane: population density, and porosity. Results show that compared to the 2004 and 2013 levels, Brisbane will respectively experience a higher and lower levels of UHI effect in 2023, irrespective of the policy scenarios. On average, the infill development scenario, as a smart growth policy, has a marginally better potential to mitigate the UHI effect in Brisbane in 2023 compared to the sprawl development scenario conditional on the definition applied in this research. The UHI effect would be more equitably balanced spatially under the sprawl development scenario.     

Agricultural Payments and Land Concentration: A Semiparametric Spatial Regression Analysis

Over the last twenty years, both crop production and agricultural payments have shifted toward larger operations. This study examines whether payments from federal farm programs contributed to increased concentration of cropland and farmland. Using zip code–level data constructed from the microfiles of the 1987–2002 agriculture censuses we examine the association between government payments per acre and subsequent growth in land concentration. A semiparametric generalized additive model (GAM) controls for location and historical concentration, sales per acre, and ratio of cropland area to zip code area. Findings indicate, both with and without nonparametric controls, government payments are strongly associated with subsequent concentration growth.     

不同培养时间对决明子芽菜生物学产量和黄酮含量的影响

本文使用控温豆芽机恒温20℃培养决明子芽菜,研究不同培养时间(5 d、7 d、9 d、11 d和13 d)对决明子芽菜生物学产量和黄酮含量的影响。结果表明,决明子芽菜的胚根长度、子叶长度、胚轴长度、单株鲜重和单株净菜重在培养7 d采收时均高于5 d采收,且差异显著,7 d后各指标数值虽呈增加趋势,但是差异不显著。黄酮含量随生长期增加不断增加,但在5 d、7 d、9 d和11 d之间差异不显著,13 d时采收黄酮含量最高为16.17 mg·g^-1,且与之前不同生长期差异显著。综合生物学产量、黄酮含量及时间成本决明子芽菜培养7 d即可以进行采收。     

不同外源物质调控对紫花槭生长的影响

本实验拟为解决紫花槭圃地育苗生长势弱、生长缓慢提供技术参考,通过利用赤霉素(GA3)、吲哚乙酸(IAA)、腐殖酸液肥、尿素、磷酸二氢钾、氯化钾等外源物质,对圃地紫花槭幼苗进行生长调控,测定分析其对紫花槭各项生长指标的影响。实验结果:高浓度的赤霉素使紫花槭徒长,浓度为300ppm吲哚乙酸,6ml·L-1腐殖酸液肥,4g·L-1尿素和5g·L-1磷酸二氢钾对紫花槭各生长指标有不同的促进作用;氯化钾作用不明显且易对紫花槭叶产生药害。     

大气CO_2浓度增加对蝗虫的影响

近些年来全球气候变暖逐渐受到国内外的关注,特别是大气内CO_2浓度的增加,随着其浓度的的上升,不仅改变着动植物体内的化学含量与组分,更影响着其生长和发育。通过对三个CO_2浓度环境内蝗虫Locust(Grasshopper)形态数据的比较,结果得出:蝗虫的形态随着CO_2浓度的增加而呈下降趋势。可见当环境中CO_2气体浓度越大,温室效应越明显,蝗虫(当前CO_2浓度水平,550×10~(-6),700×10~(-6))会通过降低自己的形态(0.12g,0.047g,0.044g)来适应环境。