灌溉对心底土积盐层的溶解作用

1.心底土积盐层是引起土壤次生盐渍化不可忽略的原因土壤次生盐渍化是干旱、半干旱地区作物正常生长和发展农业生产的一个重要限制因素,综合目前的研究资料,人们对土壤次生盐渍化的发生和防治作了大量的研究工作,但对心底土积盐层与土壤次生盐渍化研究得较少,忽略了这个问题。正如罗赞诺夫指出:“人们往往忽略了土壤以及底土的原始含盐量在灌区土壤次生盐渍化中的作用,因此,我们愿意再一次强调指出,必须重视自然条件特别是土壤的原生盐渍化在次生盐渍化中的重大意义和作     

西安临潼人工林土壤干化与恢复研究

通过野外调查和室内测定,本文研究了西安临潼人工林下0-6m土壤含水量和土壤干层的变化。结果表明,临潼14龄杨树林和16龄梧桐树林下150-350cm之间土层的含水量分别为8.7%和9.0%。按土壤干层划分标准(含水量<10%),这已属于发育弱的土壤干层,说明西安地区人工林下有土壤干层存在。而在丰水年中,杨树林和梧桐树林下原有的土壤干层带水分含量增加到21.6%和21.7%,土壤干层消失,说明在降水量增加的条件下,西安地区发育弱的土壤干层可以得到恢复,人工林能够正常生长。由此推断,西安及其降水量与其类似的其他地区可以种植一些高大乔木或果树经济林。在土壤干层发育严重的黄土高原北部地区不适于广泛造林,可以优先考虑发展疏林和森林草原植被。     

半干旱黄土丘陵区小流域横断面土壤水分生态特征

在半干旱地区甘肃榆中北部中连川流域取一横断面,根据地形部位与利用条件布设11个测点,用土钻法监测土壤水分剖面分布与动态,测深到5m。各立地条件年内4月到12月土壤水分动态趋势多样。流域横断面的土壤湿度均较低,2～5m平均值一般都小于10％,其中以坡地苜蓿与半阳坡柠条林地最干燥。该地区土壤干燥化层是普遍存在的,不仅存在于人工植被,也存在于天然植被。径流富集叠加可显著改善土壤水分状况,隔坡水平梯田是其重要途径。退耕还草中要考虑各类草地的比例、苜蓿种植的适宜规模及其持续性问题。     

不同锌源对蛋鸡产蛋性能和蛋品质的影响

将300日龄伊莎蛋鸡135只,随机分为3组,在基础日粮中分别添加50mg/kg锌的蛋氨酸锌、氧化锌,基础日粮为对照组,研究不同锌源对蛋鸡产蛋性能和蛋品质的影响。试验期30d。结果表明,日粮补锌对蛋鸡产蛋率、蛋壳质量及蛋黄锌含量有提高作用,但未发现不同锌源的显著差异。     

饼粕发酵蛋白饲喂蛋鸡试验

将70%棉仁饼和30%菜籽饼混合发酵后制成饼粕发酵蛋白, 完全取代蛋鸡饲料配方中的豆饼或鱼粉进行蛋鸡饲喂试验。结果表明：在基础日粮中添加饼粕发酵蛋白分别替代豆饼和鱼粉后，平均产蛋率试验组比对照组分别降低了2.22%和2.21%，平均蛋重分别增加了2.31和2.03 g，投入产出比较对照组分别提高了3.6%和1.68%。     

Dam and Sire Effects on Sperm Penetration of the Perivitelline Layer of Eggs Produced by Two Strains of Commercial Turkeys

The reproductive performance of 2 commercial turkey breeder lines was examined using reciprocal crosses between sires and dams of each line. One line had been selected using artificial inseminations performed at biweekly intervals, whereas the second line had been selected using inseminations performed at weekly intervals. The hypothesis was proposed that sires and dams of the 2 lines differ because of different abilities for sperm to penetrate the inner perivitelline layer (IPVL) and fertilize eggs.Fertilized eggs to hatch poults for the experiment were obtained from the primary breeders and were incubated using conditions recommended by the industry. Hens (n = 72) and toms (n = 15) from each strain were identified and reared in preparation for a reproductive cycle using commercially accepted standards. Beginning just prior to the onset of egg production and at weekly intervals thereafter, half of the hens were inseminated with semen from males of the same line, whereas the remaining half received semen from the opposite line. Eggs were collected from the pens daily and set in incubators to determine fertility and embryo survival. At biweekly intervals 3 eggs per pen were used for counting sperm penetration holes in the IPVL. Data were collected for fertility, hatchability, and time that embryos died for each of the pens. Dam and sire affected IPVL penetration independently. A dam by sire interaction influenced fertility, whereas hatchability was affected only by dam. Thus, it is concluded that selection of dam and sires for commercial breeders alters IPVL sperm penetration ability of hens as well as egg-binding ability of sires.     

猪苓菌丝体多糖对小鼠免疫水平的影响

通过人工液体浅层培养方式培养猪苓菌丝体，用热水浸提法提取猪苓菌丝体多糖（PPS1），经纯化测定其糖含量，用红外光谱分析鉴定多糖，纯化鉴定的PPS1，通过小鼠进行腹腔单核巨噬细胞功能测定试验、E玫瑰花环试验、足跖肿胀厚度试验、淋巴细胞转化试验、EAC花环试验等5项免疫学试验初步探讨其免疫药理学作用，同时与猪苓菌核多糖（PPS2）进行比较。试验数据经统计学分析显示，E玫瑰花环试验中PPS1与空白对照组相比差异显著（P〈0．05）；腹腔单核巨噬细胞功能测定试验、足跖肿胀厚度试验、淋巴细胞转化试验覆EAC花环试验PPS1与空白对照组相比差异极显著（P〈0.01）；5项免疫学试验PPS1与PPS2相比差异均不显著。结果表明，PPS1能明显提高小鼠的免疫功能。     

Effects of deficit irrigation strategies on cluster microclimate for improving fruit composition of Moscatel field-grown grapevines

The grapevine plays a very important role in the economic, social and cultural sectors of many regions; however vineyards are often grown in regions under stressful conditions and thus they are vulnerable to climate change. The objective of this research was to investigate the effect of partial root-zone drying (PRD) irrigation on vine water relations, vegetative growth, plant microclimate, berry composition and yield components, compared to conventional deficit irrigation (DI, 50% ETc), full irrigation (FI, 100% of ETc) and non-irrigated vines (NI). The study was undertaken in mature ‘Moscatel’ grapevines (Vitis vinifera L.) grown in Pegões, South of Portugal. Compared to the other irrigated treatments, PRD vines showed a better microclimate at the cluster zone with higher incident photosynthetic photon flux density (PPFD). Within the more open canopies of NI and PRD treatments, berry temperatures were higher than those of denser ones (DI and FI). Compared to the conventional irrigation technique the better microclimate observed in PRD vines was a consequence of a reduction in vine growth, where lower values of leaf layer number, leaf area, canopy wideness, water shoots and shoot weight were observed. In PRD vines we observed a tendency to a development of a deeper root system, while DI and FI showed a more homogeneous root distribution throughout the different soil layers. PRD showed an improvement in berry quality with higher values of flavour precursors, and total phenols concentration without any significant yield reduction compared to DI and FI.     

覆盖对果园土壤真菌数量年变化的影响

试验结果表明，在整个果树生长期内，覆盖可明显增加各土层中真菌的数量，０ ～２０ｃｍ 土层中，年平均真菌数量增加７９ ．３９％ ，２０ ～４０ｃｍ 土层中增加２８ ．２４ ％ ，４０ ～６０ｃｍ 土层中增加８５ ．０５ ％ 。无论覆盖与对照，不同土层真菌数量年变化均呈单峰曲线变化，高峰出现在８ 月份。     

Tree identity surpasses tree diversity in affecting the community structure of oribatid mites (Oribatida) of deciduous temperate forests

The role of tree diversity and identity as determinants of soil animal community structure is little understood. In a mature deciduous forest dominated by beech we identified clusters of one, two and three tree species of beech, ash and lime allowing to investigate the role of tree species diversity and identity on the density and community structure of oribatid mites. To relate oribatid mite community structure to environmental factors we measured leaf litter input, fine root biomass, mass of organic layers, topsoil pH and C and N content. We expected oribatid mite density to increase with increasing tree diversity, but we expected the effects of tree species identity to override effects of tree diversity. Further, we hypothesized the density of oribatid mites to be reduced by the presence of beech but increased by the presence of lime and ash. As expected tree diversity little affected oribatid mite communities, whereas tree species identity strongly altered density and community structure of oribatid mites. However, in contrast to our expectations the density of oribatid mites was highest in presence of beech indicating that many oribatid mite species benefit from the presence of recalcitrant litter forming thick organic layers. Especially Oppioidea benefited from the presence of beech presumably due to an increased availability of food resources such as fungi and nematodes. Lower density of oribatid mites in monospecific clusters of lime and ash suggests that oribatid mites did not benefit from high quality litter of these species. Notably, large and strongly sclerotized oribatid mite species, such as Steganacarus magnus and Chamobates voigtsi, benefited from the presence of ash and lime. Presumably, these large species better resist harsh microclimatic conditions in shallow organic layers.