航测在南方森林采伐中的应用

<正>一 引言 森林采伐,首先要进行生产工艺和工程设计,由于这项工作大部分在野外进行,作业范围大,特别是南方山地林区地形复杂,导致外业工作量大,效率低。因此,我们尝试利用航测技术来解决。利用它把大量的外业工作移至室内进行,节省人力、物力,并能提高工作效率和工艺设计精度。同时航片上所反映的信息很多,借助一定的仪器设备进行立体观察,分析,测量和比较,这样在进行生产工艺和工程设计时,便于综合考虑多种影响因素,从而保证所选择的工艺方案经济上合理,技术上先进可行。由此可见利用航测技术进行森林采伐工艺设计,对改善作业条件,提高劳动效率,作业精度,以及提高林业现代化水平都具有重要意义。为此,我们就应用航测技术进行工艺设计做了些试验,探讨其可行性及适用程度。然而本文仅是最初的探讨,有些问题还有待于讲一步解决与完善。     

大拱棚四膜覆盖栽培马铃薯高产技术

在马铃薯二季作地区,采用四膜栽培新技术进行早春马铃薯高产栽培。结果表明:通过早春四膜栽培技术的实施,马铃薯生育期比露地栽培提早近2个月,平均产量达到42000kghm-2,每公顷收入15万元以上,经济效益明显提高,值得在生产上推广。     

从野外昆虫体内分离的5株微孢子虫的生物学特性与分子系统发育研究

从广西蚕区的野外昆虫菜粉蝶(Pieris rapae)、桑尺蠖(Hemerophila atrilineata)、斜纹夜蛾(Spodoptera litura)的体内收集到5株对家蚕有一定食下感染力的微孢子虫,通过生物学性状、分子系统发育研究,为其分类鉴定提供依据。来自野外昆虫的5株微孢子虫均具有Nosema属的生物学特性:显微镜下观察形状均呈长卵圆形,与家蚕微孢子虫(Nosema bombycis,Nb)有较明显差异;在生活史的各发育阶段均为双核,以二分裂方式增殖,最后形成双核成熟孢子;与Nb抗血清均产生阳性凝聚反应;超微结构观察均具双核,极丝圈数在12～14圈之间,极丝倾斜角与Nb有差异。根据5株野外昆虫微孢子虫与其它昆虫微孢子虫基于SSU rRNA基因序列构建的系统发育树,以及基于SSU rRNA和rRNA ITS基因序列进行的相似性和遗传距离分析,初步认为5株野外昆虫微孢子虫与家蚕微孢子虫同属异种。     

氯虫苯甲酰胺对小菜蛾的室内毒力测定及防治效果

为研究5%氯虫苯甲酰胺悬浮剂（SC）对小菜蛾的防治效果,利用4种药剂进行了室内毒力测定和田间药效试验。室内毒力测定结果表明：药后48 h 5%氯虫苯甲酰胺SC对小菜蛾的毒力最高,LC50为0.563 0 mg·L-1|其次是10%多杀霉素水分散粒剂（WG）,LC50为0.856 7 mg·L-1|1.9%甲氨基阿维菌素苯甲酸盐乳油（EC）和1%阿维菌素EC的毒力较低。田间药效试验结果表明：5%氯虫苯甲酰胺SC 1 000倍液对小菜蛾的防效最好,达到95.04%,显著优于其他3种药剂|10%多杀霉素WG 5 000倍液的防效次之,为82.01%|而1.9%甲氨基阿维菌素苯甲酸盐EC 1 500倍液和1%阿维菌素EC 750倍液的防效较低,分别为71.67%和63.95%。     

Consumption of Bark and Seeds by Voles in Relation to Habitat and Landscape Structure

Voles cause damage in forestry by eating the bark of seedlings and the seeds of conifers. Folivorous field voles ( Microtus agrestis ), restricted to various types of grassland, are mainly responsible for damage to bark, and granivorous bank voles ( Clethrionomys glareolus ), supported by most forest environments, for the consumption of seeds. Densities of bank and field voles, consumption of bark on indigenous and experimental woody plants, and consumption of experimentally supplied seeds were measured during the vole cycle 1997-2000 in relation to three habitat and three landscape variables. Landscape variables explained field vole densities and consumption of bark to a considerable extent, while habitat variables were more adequate for densities of bank vole and consumption of seeds. Field vole populations may demonstrate a ''mass effect'', where the success of early development and dispersal from subpopulations will decide peak numbers over entire landscapes. Numbers of field voles may affect numbers of the inferior bank vole. Thus, predicting the exact location of vole damage is principally difficult.     

Factors Influencing the Frequency of Pregnancy Loss among Thoroughbred Mares in Hidaka,Japan

Pregnancy loss in mares is thought to be a main problem associated with reproductive efficiency. To clarify the situation of pregnancy loss in Thoroughbred mares in Japan, the occurrence of pregnancy loss before and after 35 days of gestation was investigated with 1,476 Thoroughbred mares in Hidaka, Japan, from 2007 to 2009. Pregnancy loss on days 17-35 was determined by ultrasound examination between 17 and 35 days after the last mating. Follow-up surveys were conducted between 35 days and foaling to determine pregnancy loss on day 35 until foaling in 843 of these mares. Using multiple logistic regression analysis, we assessed the influence of mare age, reproductive status, twin pregnancy reduction, body condition score (BCS), estrus type in foaling mares (foal heat or not), progesterone therapy, and endometrial cysts on pregnancy loss rates on days 17-35 and on day 35 until foaling in this population of mares. The pregnancy loss rates on days 17-35 and on day 35 until foaling were 5.8% and 8.7%, respectively. The overall pregnancy loss rate (day 17 until foaling, including parturient losses) was 14.7%. Risk factors for pregnancy loss included decrease in BCS between 17 and 35 days, <5 BCS at day 35, mating during foal heat, and endometrial cysts. In all, 14.7% of pregnancies were lost between day 17 and birth, contributing significantly to reduced reproductive efficiency in Thoroughbred mares in Japan. These observations indicate that mares should be maintained at high BCS and should be prevented from mating in foal heat to decrease the pregnancy loss rates.     

Patterns in the aggregate stability of Mancos Shale derived soils

Salt and sediment contributions to the Colorado River and its tributaries pose economic and environmental concerns for the United States and Mexico. Land use decisions promoting the aggregation of Mancos Shale derived soils are one way to reduce the transportation of salts and sediments to water resources. We used a simple field test of soil aggregate stability to determine the site characteristics influencing the soil stability of sedimentary marine shale in the Gunnison Gorge National Conservation Area in Southwestern Colorado. Ninety-six 1 m² plots were intensively sampled to explore relationships between soil stability and the biological, chemical and physical site characteristics.     

Inhibition of native arbuscular mycorrhizal fungi induced increases in cadmium loss via surface runoff and interflow from farmland

Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with most crops, but their impact on the environmental migration of cadmium (Cd) in farmland is limited. A field experiment was performed in the rainy season (May–October) for two years in Cd-polluted farmland used for maize cultivation. A fungicide (benomyl) was used to specifically inhibit native AMF growth in the farmland. The growth and Cd uptake of maize and the Cd concentration and loss in runoff and interflow were investigated. Benomyl strongly and significantly inhibited AMF colonization rate in maize roots, reduced the contents of total and easily extractable glomalin-related soil protein (GRSP) in soil and the Cd uptake in maize roots, and increased the Cd uptake in shoots. Particulate Cd was the main form of Cd loss in runoff, while dissolved Cd was the main form of Cd leaching loss at depths of 20 cm and 40 cm. Inhibiting AMF increased the Cd concentration in runoff and interflow and promoted dissolved Cd loss in runoff and interflow at 20 cm depth by 34.7% and 68.0% and particulate Cd loss by 46.4% and 19.7%, respectively. Furthermore, the AMF colonization rate in maize roots and the GRSP content in soil were significantly positively correlated with Cd uptake in roots and negatively correlated with the concentration and loss of Cd in runoff and interflow. These results indicated that the benomyl-induced inhibition of native AMF promoted Cd transfer to maize shoots and increased Cd loss via runoff and interflow from polluted farmland.     

新疆煤田灭火区植被恢复无土基质配比试验研究——以乌鲁木齐松树头煤矿为例

以乌鲁木齐松树头煤矿为研究对象,采用无土基质配比方法,针对研究区土壤特点,选取选用粘合剂（A）、保水剂（B）、复合肥（C）和秸秆（D）为试验因素,进行无交互作用的正交试验,并对结果进行极差、方差分析影响.结果表明,粘合剂对植物高度、盖度均有显著影响,复合肥对植物盖度有极显著影响,同时也是生物量指标的主要影响因子.各因素主次顺序为C（复合肥）＞B（保水剂）＞A（粘合剂）＞D（秸秆）.基质最优配比方案为A2B1C1D1,即当粘合剂用量为16 g/m2,保水剂为5 g/m2,复合肥为30 g/m2,秸秆为90g/m2时,可获得最佳的植被恢复效果.     

土壤无限制水分区间的修正研究

土壤无限制水分区间(NLWR)是指土壤水势、通气状况和机械阻力对作物生长发育没有限制作用的土壤水分含量区间。在保持其上限即土壤田间持水量或通气孔隙为10%时的土壤含水量不变的基础上,该研究对下限进行了修正,取土壤总水势为-0.3 MPa时的含水量或土壤机械阻力为0.85 MPa时的含水量作为NLWR的下限,代替原有的是永久萎蔫点或土壤机械阻力为2.0 MPa时的含水量。用上限的最小值减去下限的最大值,即可计算出NLWR。与原有的NLWR或土壤最小限制水分区间相比,修正后的NLWR更具有现实意义。NLWR为0时所对应的土壤容重(D b)称为临界容重(D b-thr),可以作为田间土壤物理质量管理的判断标准。当D bD b-thr时,土壤物理性质对作物产生阻碍作用,需进行土壤改良;当D bD b-thr时,只要土壤含水量处于NLWR之内,土壤物理性质对作物生长无影响,此时NLWR可以作为农田水分灌溉管理的依据。