落叶松油松人工混交林经营技术探讨

通过研究落叶松、油松混交林整个发育过程中不同阶段相应的经营管理措施，总结提出了一套切实可行的落叶松、油松混交林经营管理技术。其技术能有效提高林木生长速率，调整林分结构，优化树种组成，提高木材质量，为落叶松、油松混交林的经营管理提供技术支持。     

Influence of Aguamiel (Agave atrovirens) as a Natural Feed Additive on Cecal Fermentation Kinetics of Some Forage Species in Horse Feeding

This study aimed to evaluate the effect of different dose levels of aguamiel (Agave atrovirens) on in vitro cecal gas, methane (CH₄), and carbon dioxide (CO₂) productions of five forage species (Avena sativa [hay]), Moringa oleifera, Caesalpinia coriacea, Salix babylonica, and Eichhornia crassipes using inocula from the horse. The forage samples were incubated with three doses of aguamiel: 0, 34, and 68 μg of aguamiel/g dry matter (DM) of substrate. Cecal inocula were collected from four adult female Criolla horses (3–4 years of age and weighing 300 ± 15.0 kg) grazed on native grasses for about 8 hours without supplementation. Forage type affected (P < .001) cecal asymptotic, rate and lag time of gas, CH₄ and CO₂ productions (mL/g DM), pH and DM degradability. Aguamiel dose had linear and quadratic effects (P < .05) on the asymptotic and rate of CH₄ productions and rate and lag time of CO₂ productions (mL/g DM). Forage type × aguamiel dose interactions were significant (P < .05) for asymptotic, rate and lag time of gas, and CH₄ and CO₂ productions (mL/g DM). Forage species effects were pronounced (P < .05) on CH₄ and CO₂ productions (mL/g incubated and degraded DM) and proportional CH₄ production at all hours of incubation, except for CO₂ production (mL/g incubated DM). Aguamiel dose affected (P < .05) CO₂ production (mL/g incubated DM) and proportional CO₂ production at the incubated hours. Forage type × aguamiel dose interactions were observed (P < .05) for CO₂ production (mL/g incubated DM) and proportional CO₂ production at the incubated hours but had no impact on CH₄ production. It is concluded that addition of aguamiel to five forage species affected fermentation kinetics of gas production resulting in different in vitro cecal gas, CH₄ and CO₂ productions from these substrates.     

Italian ryegrass establishment by self-seeding in integrated crop-livestock systems: Effects of grazing management and crop rotation strategies

We evaluated the re-establishment of an Italian ryegrass pasture by self-seeding on a no-till integrated crop-livestock systems (ICLS) in the southern region of Brazil. This work is part of a long-term experimental protocol initiated in 2003. We tested the effects of various management practices, such as summer crop systems (soybean vs. maize–soybean rotation), stocking methods (continuous vs. rotational) and grazing intensities (low vs. moderate), on Italian ryegrass pasture establishment. In addition, we tested resilience of the system by testing pasture's ability to re-establish following a year without seed head production. The experiment consisted in the rotation, on the same area, of Italian ryegrass pasture grazed by sheep during the winter and up to the end of the grass production cycle, and soybean or soybean-maize grain crops rotation cultivated during the summer. The pasture established itself by self-seeding since 2005. Data were collected in 2011 and 2012 stocking season. The soybean summer crop, continuous stocking and low grazing intensity, all positively affected the production of reproductive tillers in 2011. Grazing intensity in 2011 strongly influenced early vegetative tiller densities (before crop harvest) in 2012. However, none of the grazing intensity or the stocking method treatments affected herbage mass at the end of pasture establishment in 2011 or 2012. On the other hand, the soybean summer crop positively affected pasture establishment, both in term of tiller densities and herbage mass at the end of pasture establishment. The removal of all seed heads in 2011 (preventing seed production) resulted in the total failure of pasture establishment in 2012. Overall, Italian ryegrass establishment by self-seeding relies on the annual replacement of the soil seed bank. This experiment demonstrated that under various stocking methods, moderate grazing intensity and maize or soybean summer crop, Italian ryegrass pasture establishment by self-seeding remains successful even when the stocking periods extended up to the end of the grass production cycle. Self-seeding with moderate grazing intensity ensures successful pasture establishment, reduces labour and costs and allows to increase the stocking period and so animal live weight gain over the grazing season.     

基于径向基神经网络的非寿险公司财务预警研究

选取我国保险行业中40家非寿险公司2006~2008年的混合非平衡面板数据作为研究样本，采用径向基神经网络模型从偿付能力、盈利能力、成长能力三个角度对非寿险公司财务预警进行研究。实证表明，此模型可以为管理层的财务预警提供更有有效的信息，并且在我国保险业具有样本量小，有效数据少的情况下，有着良好的运用前景。     

青海扁茎早熟禾混播草地生产性能与种间关系的研究

为了探究早熟禾混播草地种间关系与生产特征,使用‘青海’中华羊茅（Festuca sinensis ‘Qinghai’）、'青牧1号’老芒麦（Elymus sibiricus ‘Qingmu No.1’）、‘同德’小花碱茅（Puccinellia tenuiflora ‘Tongde’）分别与‘青海’扁茎早熟禾（Poa pratensis var. anceps Gaund.‘Qinghai’）混播,在海北州西海镇开展了植株形态特征、生物量积累和分配、混播草地养分特征等研究。结果表明：使用老芒麦与早熟禾混播具有较高的生产性能。该处理相较于老芒麦单播草地的粗蛋白与总磷含量,分别提高7.51%与14.50%。相对饲用价值较早熟禾单播草地提高34.12%。因此,为解决青海扁茎早熟禾单播草地生产力不足的问题可以选用老芒麦与早熟禾进行混播。使用碱茅与早熟禾混播具有较高的种间相容性,因此碱茅与早熟禾混播具有较高的群落稳定性与产量稳定性。选用碱茅与早熟禾进行混播可以用于建植以生态治理为目的的混播草地。     

Horse Preference,Forage Yield,and Species Persistence of 12 Perennial Cool-Season Grass Mixtures Under Horse Grazing

Cool-season grass mixtures are rarely evaluated for preference, yield, and persistence under horse grazing. The objectives of this research were to evaluate horse preference, forage yield, and persistence of cool-season grass mixtures under horse grazing. Eight commercially marketed and four experimental perennial cool-season grass mixtures were planted in 2009 in a randomized complete block with five replicates and grazed by four adult horses during 2010, 2011, and 2012. All mixtures contained four to six cool-season perennial grass species. Specie density measurements were taken in each spring and fall, and yield was mechanically measured before each grazing period. After grazing, preference was determined by visually assessing percentage of forage removal on a scale of 0 (no grazing) to 100 (100% of vegetation removed). Data were analyzed using a mixed-model analysis of variance and liner regression. Horses preferred mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy (P < .001). Horses had less preference for mixtures containing ≥30% orchardgrass (P < .001). Mixtures had similar (P = .11) forage yields that ranged from 6,100 to 7,082 kg ha⁻¹. After 2 years of grazing, orchardgrass and tall fescue increased; Kentucky bluegrass remained stable; and festulolium, meadow fescue, and perennial ryegrass had the greatest rate of decline in mixtures. Orchardgrass became the dominate species, regardless of initial percentage in the mixture. Mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy should be planted in midwestern US horse pastures; however, mixtures will likely transition to tall fescue and Kentucky bluegrass–dominated pastures.     

农民工未来阶级、阶层走向解析

"民工"从语词上界定可以理解为:农民和工人双重身份,本文放在传统农业向现代农业转变的大背景下,着重考察了游离在城乡之间的农民工主题身份的认定,及其未来的阶级、阶层走向,按照断裂社会的运作逻辑,经过分化重组的当下社会必定会出现新的阶级、阶层.这些阶级、阶层与传统阶级、阶层有什么区别和联系,农民工如果被假定为工人阶级而客观存在.那么这些生活在城市里农民能否获得市民身份的认同?对这些问题的回答有利于我们走出"城乡二元格局"的困境,有利于构建更加稳定、和谐的社会主义新农村.     

Modelling carbon dynamics in mixed grass–red clover swards

Growth and carbon dynamics in mixed grass–red clover leys were simulated using a growth model for pure stands based on radiation use, allocation within plant and loss of biomass. The model and its parameter values were taken from previous applications of the model to pure swards of grass and red clover grown in the same experiment at the same sites and years.     

基于Landsat数据的条件植被温度指数升尺度转换方法

以陕西省关中平原为研究区域,应用点扩散函数、混合像素面积权重法和中值像素变异权重法将基于Landsat卫星遥感数据反演的分辨率为30 m的条件植被温度指数(VTCI)干旱监测结果上推至930 m的干旱监测结果,并与Aqua MODIS数据反演的分辨率为930 m的VTCI干旱监测结果进行对比分析,以期为两种空间尺度的干旱监测结果的综合应用提供技术支持。以MODIS数据反演的VTCI为参考,应用相关系数、均方根误差、半变异函数的估计值和图像纹理特征等对尺度上推的VTCI进行评价。结果表明,点扩散函数和混合像素面积权重法的尺度上推效果均较好,而中值像素变异权重法的尺度上推效果较差,说明点扩散函数和混合像素面积权重法均适用于研究区域VTCI干旱监测结果的尺度转换,且点扩散函数的数据处理过程更为简单。典型样点VTCI的尺度上推结果表明,空间异质性越小,尺度上推的结果越好。     

混合状态下散体的传热过程研究

根据热力学第一定律，利用集中参数法，导出了混合状态下散体非稳态传热方程：Ｔ－Ｔ０Ｔ∞－Ｔ０＝１－ｅ－τ上述理论与实验结果相当吻合，是研究散体传热理论问题的重要参考