桑树夏秋期不同采收程度对种茧育的影响

试验表明,在其他桑园管理措施一致的前提下,夏秋期留叶5～12片,能显著提高卵质及下代孵化率,适当提高4龄结茧率、虫蛹统一生命率及茧质。综合考虑桑叶的产量和质量,实际生产中,夏秋期留叶5-6片,既能保证桑叶产量,又能提高蚕种质量。     

Local perceptions of Matsutake mushroom management, in NW Yunnan China

Matsutake mushrooms are among the most prized and expensive mushrooms on earth. Since the 1980s NW Yunnan Province has become the largest exporter of Matsutake in China, and money from their sale has become crucial to local livelihoods and to the provincial tax base. Amid fears of declining productivity, regulations have been enacted to control Matsutake harvest, though enforcement remains largely in the hands of harvesters themselves. Here, we measure local harvesters’ perceptions of the ecological determinants of mushroom productivity in contrast to that of the outsider conservation community. We interview 122 harvesters in eight villages in Diqing province, NW Yunnan to determine what is perceived to be detrimental to Matsutake yield, how yield can be improved in the future and who harvesters trust for information. Our results indicate that village leaders and forestry officials are overwhelmingly the most trusted sources for information. Mann and Whitney U tests show general consensus among villages, and MRPP analysis shows general consensus within villages. One village showed significantly higher levels of trust in NGOs. Of the 86% of harvesters who had perceived declining productivity trends over the past 10 years, soil disturbance, climate change, and habitat degradation were most often-cited as causal factors. Log-linear analysis showed almost no significant interactions between perceptions and harvester demographics. Environmental protection and reducing soil disturbance were most often-cited as potentially increasing future yields. We suggest that local and outsider knowledge are complimentary in this system, and that forestry officials and village leaders provide the best conduits for management information.     

不同筋性春小麦籽粒不同发芽程度下的品质分析

为了解穗发芽不同程度下对不同筋性春小麦品种品质的影响,该实验选取强筋小麦品种克春1号、克丰6号,中筋品种克旱16、克旱21,弱筋小麦品种新克旱9、克丰9为实验材料,利用人工智能气候培养箱模拟自然环境,人为控制种子发芽程度并测定相关数据,结果表明:出粉率在萌动状态下,强筋>中筋>弱筋,随着发芽程度的加深,出粉率并未表现出与小麦筋性相关的规律性;强筋粉降落值在萌动状态下,较正常状态下降幅度大于中筋粉,中筋粉大于弱筋粉;各筋性小麦品种其湿面筋含量、干面筋含量以及面筋指数均随发芽程度的加深,而降低。     

制种高粱适宜收获时期研究

以高粱雄性不育系Ａ２Ｖ４Ａ为研究对象，对植株在不同成熟时期各器官的干物质积累动态进行了研究，并进行子粒收获产量比较。结果表明，高粱子粒在完熟期干物质的积累达到最高值，种子生活力也达到最高，此期是制种高粱的适宜收获时期。     

Physicochemical analysis of mountain bananas from the French West Indies

The physicochemical characteristics of bananas grown at two different altitudes (L: 50 m and H: 300 m) in Martinique, French West Indies (FWI) were compared at four harvest stages with the aim of potentially promoting mountain bananas – which differ from current standard bananas – or export to the European market. At an equivalent harvest stage, highland (H) bananas were significantly thicker in diameter (grade), denser and firmer than lowland (L) bananas. After ripening, H bananas were significantly firmer and their peel was harder as compared to L bananas. Their dry matter and dry soluble extract contents and citrate concentrations were significantly higher than noted in L bananas. P contents were significantly higher in L bananas whereas Zn contents were higher in H bananas. A principle component analysis differentiated H and L bananas on the basis of their physicochemical characteristics. It was found that the “altitude” factor had a more marked effect than the “harvest stage” factor on the physicochemical characteristics of ripe fruit.     

中国作物的收获指数

本文对中国300个农业气象试验站各种作物的收获资料进行统计分析,计算了收获指数、谷草比和有关的统计参数。结果指出：1.各作物的平均收获指数差别较大,主要粮食作物的收获指数在0.35—0.45之间,谷草比在0.55—0.80之间。2.收获指数和谷草比的变动范围较大,对于同一作物,绝大多数样本的谷草比都分布在平均值附近,而少数的可以偏离平均值较远。3.由粮食产量推算秸秆量,对于大面积的估算有较满意的结果,而对于个别地块,其误差可能较大。4.一些主要作物谷草比的频率分布曲线接近正态分布,而多数则属正偏类型。5.同一作物在丰、平、歉年的平均谷草比各不相同,一般丰年大,歉年小,平年介于其间。6.谷草比与产量水平有关,随着产量的提高而增加,其关系可用一元回归方程表示。     

A nutrient balance model (NuBalM) to predict biomass and nitrogen pools in Pinus radiata forests

Forest managers are increasingly required to enhance the productivity and profitability of plantation management while simultaneously reducing the negative ecological effects associated with forest operations. NuBalM (from Nutrient Balance Model) is presented here as a decision support tool that has the potential to assist forest managers in meeting these requirements in Pinus radiata D. Don (radiata pine) plantations. NuBalM incorporates nutrient dynamics and allocation into projections of growth, allowing management techniques to be optimised for productivity and nutrient pool retention over single or multiple rotations.NuBalM was developed using data from biomass, nutrient allocation and soil nutrient dynamics studies conducted in New Zealand radiata pine plantations. The capability of NuBalM to predict stem wood mass based on nitrogen supply and demand was tested against data from multiple trial sites established to examine the effects of variations in stocking, thinning and fertilization regimes. NuBalM satisfactorily predicted stem wood masses across a range of stand ages, with the exception of a trial examining ultra-high applications of nitrogen fertilizer. With the exclusion of the data from this trial, the predicted stem wood masses underestimated the observed figures by a mean value of 1.1 ± 1.0 t ha⁻¹ (95% CI, n = 92).The utility of NuBalM as a tool to predict biomass allocation in radiata pine and nitrogen pools in the forest floor and soil was assessed using comprehensive biomass, nutritional and site data collected from two radiata pine trial sites subjected to differences in organic matter removal at site establishment. NuBalM performed acceptably, generating accurate estimates of stem mass (mean overestimate of 5.5 ± 7.4 t ha⁻¹, 95% CI, n = 6) and total above ground biomass (mean overestimate of 3.1 ± 9.6 t ha⁻¹, 95% CI, n = 6). The effects of organic matter removal and fertilization on total nitrogen pools were also predicted with a reasonable degree of accuracy (mean overestimate of 52 ± 53 kg N ha⁻¹, 95% CI, n = 9).From these results we conclude that NuBalM can be utilised to provide projections of productivity and nitrogen pools in radiata pine plantations, and enables the effects of various management practices to be predicted with a reasonable degree of confidence.     

玉米籽粒机收影响因素及其栽培调控研究进展

全程机械化对玉米生产的发展具有非常重要的意义,而机械化收获是玉米全程机械化的重要环节,也是当前推进玉米全程机械化的难点。本文介绍了国内外玉米机械化发展的现状,分析了籽粒含水率、苞叶性状、茎秆特性与穗轴特性对玉米机收的影响,总结了行距、播期、收获时期、施氮量与密度等玉米机收栽培调控措施,并从宜机收品种筛选、收获机械研发与配套栽培技术研究等角度为玉米机械化收获的研究与发展提出了建议。     

采伐参数对森林景观格局的影响

合理的森林采伐方式是国内外众多学者研究的热点.中国提出"生态采伐",对于合理采伐、保护森林资源起到了极大的促进作用(唐守正,2005;张会儒等,2007;2008).随着景观生态学的迅速发展,森林景观研究为合理采伐提供了新思路(Baskent et al.,1996;Bettinger et al.,2003;Zollner et al.,2008;Gustafson,1998;2007;邓华锋,1998;张会儒等,2008;张正雄等,2006).     

采收成熟度对清香型烤烟质量的影响

[目的]找出2种不同特性的烤烟品种,不同部位成熟采收的外观差异对烤烟质量的影响。[方法]针对烤烟清香型质量风格,结合红花大金元与云烟85的烘烤特性,对不同部位的烟叶设置不同的采收标准,对烤后烟叶的品质进行检测。[结果]2个品种在不同采收标准下,烤后烟叶的质量变化有所差异。随采收成熟度的提高,2个品种的烤后烟叶总氮、烟碱、钾含量呈下降趋势,总糖、还原糖含量呈先上升下后降趋势,但变化幅度有所不同。在评吸质量上,红花大金元随着采收成熟度的提高,中、上部烟叶香气质、香气量有所增加,烟气浓度降低,上部烟叶杂气、刺激性增强。云烟85随着采收成熟度的提高,香气质、香气量有所增加,中下部烟气浓度有所降低,上部烟叶杂气、刺激性增强。[结论]研究可为烟农准确把握不同品种成熟采收的标准做指导,提高种烟的经济效益,同时也为满足卷烟工业对特色烟叶原料的需求及烤后烟叶的提质增香提供参考。