Influence of Sampling Date on Soil Nitrogen Availability Indices

In spite of the great effort that has been devoted to the search for a chemical laboratory index to predict nitrogen (N) mineralization capability of soils, the results have not yet been fully satisfactory. A continued effort is still needed to increase the knowledge of the sources of variation that influence potentially available soil N. The time of sampling has received little attention, taking into account its potential to influence N-mineralization patterns. In this work, soil samples from three different agrosystems, consisting of a double-crop sequence of small grains and maize, an intensively grazed pasture, and a rainfed olive orchard, were collected at different dates. Several chemical extractions were performed, and the results were correlated with N uptake by turnip (Brassica campestris, L.) grown in a pot experiment. Kjeldahl N was the chemical test that best correlated (R ² = 0.621) with N uptake by turnip. Kjeldahl N showed great versatility relative to the origin of the soil samples. However, it was not very sensitive to the time of sampling. It did not detect changes occurring in the soil over a short period of time. Soil inorganic N showed the second highest coefficient of correlation (R ² = 0.483) with N uptake by turnip. In contrast to that observed with Kjeldahl N, soil inorganic N appeared as an index that can vary greatly over the short term. The hot saline potassium chloride (KCl) extractions gave generally fair results. The poorest, however, were obtained with the ultraviolet absorption of extracts of 0.01 mol L^?1 sodium bicarbonate (NaHCO₃) measured at 250- and 260-nm wavelengths.     

Effect of hot water treatments on chilling injury and expression of a new C-repeat binding factor (CBF) in ‘Hongyang’ kiwifruit during low temperature storage

Kiwifruit is cold-sensitive and very susceptible to chilling injury (CI) during low temperature storage. In this study, kiwifruit (Actinidia chinensis cv. Hongyang) were pre-treated by water dip for 10 min at 20 (control) or 35, 45, or 55 °C (heat pretreatments) and then stored at 0 °C for 90 days to investigate the effect of hot water treatments (HWT) on chilling injury tolerance. Results showed that 35 °C and 45 °C HWT alleviated but did not completely prevent chilling injury development. By contrast, 55 °C HWT increased symptoms of chilling injury. The 45 °C HWT was the most effective at reducing chilling injury index and incidence. Compared with the other HWT, fruit treated at 45 °C exhibited higher firmness and soluble solids content (SSC), and lower malondialdehyde (MDA) content, lipoxygenase (LOX) activity and ethylene production rate. C-repeat/dehydration-responsive element binding factors (CBFs) are key regulators in cold response. To investigate the molecular regulation of HWT on chilling tolerance of kiwifruit, a 637 bp CBF gene was identified and the relative expression of AcCBF was measured by RT-qPCR. In accordance with the effects of HWT on physiological parameters of chilling injury, AcCBF expression level was highest in the 45 °C HWT. These results indicate that HWT at 45 °C for 10 min prior to low temperature storage is effective for alleviating symptoms of chilling injury in ‘Hongyang’ kiwifruit.     

竹/杨复合规格材制备工艺研究

研究以竹展平规格材和杨木单板为原料,以脲醛树脂为胶黏剂,采用竹黄-杨木-竹黄的组坯方式制备竹/杨木复合规格材,通过L9(34)正交试验,探讨涂胶量、热压温度、热压压力以及热压时间四因素对竹/杨复合规格材物理力学性能的影响。结果表明:热压温度对竹/杨复合材性能影响最大,其次是涂胶量和热压压力,热压时间影响最小。通过加权法得到的优化热压工艺参数为热压压力1.5 MPa、热压时间12 min、热压温度130℃、涂胶量(单面)240 g/m2。     

响应面法优化暗纹东方鲀鱼皮冻的制备工艺

为充分利用暗纹东方鲀资源,增加暗纹东方鲀附加值,以暗纹东方鲀鱼皮为原料,采用热水提取制备暗纹东方鲀鱼皮冻,研究确定此种鱼冻的加工工艺参数,在提取温度、提取时间和料液比3个单因素的实验基础上,以胶原蛋白提取率和冻力为指标,进行响应面优化参数,并对其进行氨基酸组成及含量分析。结果显示,时间、温度和料液比对胶原蛋白提取率和冻力影响显著。以胶原蛋白提取率和冻力为响应值,得到两个回归方程,决定系数R~2分别为0.959 7、0.886 3,失拟项的P大于0.05,显示两个模型均建立有效,最优的工艺条件为提取温度81℃、料液比1∶3.5、提取时间为2 h,在此条件下,暗纹东方鲀鱼皮冻的胶原蛋白提取率为47.62%,冻力为175.25 g,与拟合效果一致。研究表明,鱼冻富含甘氨酸和特征氨基酸,能有效利用鱼皮和保留鱼皮营养成分,初步得到一种富含胶原蛋白和凝胶性能好的暗纹东方鲀鱼皮冻,为下一步开发暗纹东方鲀鱼皮产品提供理论参考。     

辣椒新品种新湘辣2号的选育

新湘辣2号是以胞质型雄性不育系9704A为母本,以自交系R07172为父本配制而成的中熟小尖椒一代杂种。植株生长势中等,株高65cm左右,始花节位为第12～14节;果实羊角形,果顶尖,果长15～18cm,果肩宽1.9cm,果肉厚0.15cm,2个心室为主,果实肩部略皱;前后期果实一致性好,单果质量21.8g左右,青熟果绿色,老熟果亮红色,辣味中等;果实VC含量1 382mg·kg~(-1),辣椒素含量0.11%,每667m~2产量2 500kg左右。田间对疫病和病毒病的抗性强于对照湘辣2号,适合湖南、山东、贵州、山西、四川、河南、河北等地春夏季大棚或露地种植。     

施用不适用烟叶高温发酵有机肥对烤烟后茬作物大蒜品质及产量的影响

研究了在烤烟田间施用不适用烟叶高温发酵有机肥对后茬作物大蒜品质及产量的影响。试验结果表明:与施用烟草专用复合肥相比,施用该有机肥能显著提高大蒜的横径、单头重和独蒜率,使独头蒜的单位面积产量和大蒜的总产值分别提高了141.71%和37.27%;施用该有机肥还能显著提高普通蒜的维生素C含量。     

板坯预热及板坯初始温度对干法纤维板热压传热的影响

将一部分干法纤维板的板坯在不同温度和时间条件下进行热板接触预热，而另一部分不进行预热但有不同的初始温度，测定它们在热压过程中中心层的温度。通过比较分析其温度变化曲线，找出了板坯预热及板坯初始温度对干法纤雏板热压传热的影响规律。     

Mammal movements and foraging at remnant woodlands inside coniferous forest landscapes

Temporary or spatially restricted resources may affect population densities over more or less wide areas in the surrounding landscape or region. They may affect more than one trophic level by facilitation of predation. Areas of influence may differ between species. Such effects of mast-seeding in confined oak–hazel woodlands were examined for a guild of mainly seed-eating mammals and their predators. The mammals were tracked in snow in winter and the foraging of granivorous small mammals was assessed by experimental seed supplies in spring and autumn. Movements and foraging at various locations in and around the woodlands were distinguished from large-scale influences in the surrounding conifer forest landscape. Roe deer moved more abundantly inside the woodlands than in the conifer forest 50 m away and, less clearly, this was also the case for granivorous small mammals. Squirrels were particularly common at the edges while brown hares were somewhat less common at these edges. The edge effects appear therefore species-specific. Brown hares, squirrels, voles and granivorous small mammals were generally less common in the coniferous forest more than 500 m from the woodlands than in the coniferous forest 50 m from the woodlands. The most common generalist predator, the red fox, was as a mean equally common at all locations. However, it demonstrated a spatio-temporal variation in movements related to hare and, to a lesser extent, squirrel occurrence at open woodland sites. In order to sustain several mammalian species in conifer forest landscapes, not only granivorous ones, resource patches of oak and hazel should be retained, regenerated and, if possible, expanded. Such hot spots often need particular management.     

麦秸/塑料复合材料的热反应特征及复合工艺

本研究用差示扫描量热法(DSC)测定和分析了麦秸/塑料复合材料的热反应特征，并通过试验探讨了麦秸与塑料之间的复合工艺。结果表明，麦秸、塑料以及麦秸/塑料复合材料三者的热反应特征各不相同，由此可了解麦秸和塑料之间的反应状况，说明用麦秸和塑料制造麦/塑复合材料是可行的。     

竹材刨花板热压工艺的研究

利用正交试验法研究了竹材刨花板热压曲线中各因素与极材的静曲强度，弹性模量及平面抗拉强度间的关系。结果表明，第一阶段压力是影响竹材刨花板力学性能的最主要因素，热压温度及采一阶段时间对力学性能也有较大的影响。根据试验结果确定竹材刨花板的最佳热压工艺参数。