高寒草甸鼠丘土壤种子库结构特征的研究

本研究以青海省河南县高山嵩草高寒草甸高原鼠兔鼠丘土壤种子库为研究对象,采用野外取样和室内镜检、萌发试验,探究了鼠丘土壤种子库的种子数量状况、垂直分布格局及季节动态规律,旨在为鼠丘土壤植被的恢复演替提供科学依据。结果表明：天然草地土壤种子库中的种子数量和种子质量均高于鼠丘土壤种子库,10-11月土壤种子库无论在种子数量上还是质量上均较高;发芽率表现为天然草地土壤种子库 > 新鼠丘 > 旧鼠丘;旧鼠丘土壤种子库种子数量多于新鼠丘;原生植被的土壤种子库呈明显的上层多下层少的垂直分布格局,新、旧鼠丘上下层间无明显的垂直分布规律;鼠丘土壤种子库与天然草地土壤种子库的相似性越高,鼠丘植被向原生植被恢复演替的几率越大。     

机插穴苗数对不同穗型粳稻品种产量及品质的影响

以盐粳9号(小穗型)、淮稻9号(中穗型)和9优418(大穗型)为机插材料,研究了每穴栽插苗数对不同穗型水稻产量、品质的影响。结果表明,随穴栽苗数的增加,3种穗型品种的穗数均呈增加趋势,每穗颖花数、结实率和千粒重均呈减小趋势,但变化程度不一。3种穗型品种的产量随穴栽苗数增加均呈先增后减二次曲线变化。小、中、大穗型品种最高产量对应的穴栽苗数分别为4、3、2苗。3种穗型品种稻米的品质性状受穴栽苗数影响的变异程度存在差异,但均表现随穴栽苗数的增加而垩白度和垩白率上升,糙米率、精米率和整精率下降,蛋白质含量变低,直链淀粉含量增加,胶稠度变长;峰值黏度、热浆黏度、崩解值、最终黏度和起始糊化温度等RVA特性值先增后减,而消减值先减后增。对产量与品质指标综合评价,以小穗型品种每穴栽插4苗、中穗型品种每穴3苗、大穗型品种每穴2苗,最利于相对实现高产与优质的协调。     

Use of multipurpose trees in hill farming systems in Western Nepal

A large number of multipurpose trees and shrubs are deliberately retained or incorporated on farms in the subsistence farming systems on the steep slopes in parts of Nepal. Woody perennials are maintained in contour strips across the slopes and around the fields. The contribution of these trees is the production of foder and firewood and their protective function in reducing the erosion hazards and thereby making crop production possible in those steep slopes where profitable cropping would otherwise be extremely difficult. Based on a case study in two villages of the Western Development Region, this paper presents some data on basic farm management aspects, production of crops and other components, etc. of the system. The performance of the system is assessed and its merits and weakness highlighted.Although the hill farming system extends over quite a large area and accounts for a large number of Nepal's population, it has not received any research attention nor benefitted by any scientific innovations. Improvement possibilities in terms of component technologies as well as farming systems including the incorporation of the several locally available medicinal plants are indicated.     

Nitrogen budget of a rehabilitated forest on a degraded granitic hill

Rehabilitated forests established about 100 years ago on denuded lands in a hilly granitic area are widespread in the Kyoto–Osaka area, the second largest megalopolis in Japan. From 2001 to 2003, we monitored the annual nitrogen (N) budget of a rehabilitated forest watershed dominated by Quercus serrata and Ilex pedunculosa. The ion concentrations of bulk rain in the watershed were similar to those of other watersheds in Japan. The annual bulk rain input of N ranged from 5.1 to 6.3 kg N ha⁻¹ year⁻¹, and the N deposition from throughfall and stem-flow ranged from 7.5 to 8.2 kg N ha⁻¹ year⁻¹. Estimated annual outputs of N from the stream ranged from 3.3 to 10.6 kg N ha⁻¹ year⁻¹. These results indicate that the amount of N deposition in this area is less than that in urban Tokyo (>10 kg N ha⁻¹ year⁻¹), but the N output of the watershed is comparable with that of the Tokyo area. We discuss the characteristics of N dynamics in rehabilitated forests, focusing on the biogeochemical processes of this watershed.     

饲料型四倍体刺槐引种及抗逆特性初探

引进饲料型四倍体刺槐在内蒙古呼和浩特栽培,并在内蒙古中部的半干旱区山地、黄土沟壑区、盐碱覆沙地等3种不同立地类型造林,进行了4年抗寒、抗旱、抗病虫害、生长适应性等一系列大田观察测定,并采用PV曲线对该树种进行了抗旱特性分析,结果表明:饲料型四倍体刺槐具有较强的抗逆特性,在内蒙古半干旱区适宜的立地类型,采用抗旱造林技术,可以栽培。     

高山引种黄甜竹试验初报

经过两冬三夏高山引种黄甜竹试验，其出笋期延迟至5月上旬，笋期延长为一个半月，引种初获成功。     

关于山地城市的城市形态浅见

运用城市形态学的方法对山地城市的城市形态进行分析,探讨了山地城市的形态模式、演变机制、构成要素以及其、形态空间的启示。     

孟加拉吉大港地区丘陵森林有机物积累

在孟加拉吉大港丘陵地区,调查了热带季风气候条件下的3种人工林(7年生大叶相思(Acacia auriculiformis)林、15年生大叶相思林和18年生混交林)和1种天然林的森林凋落物及其对土壤性质的作用.结果表明,总的有机质积累随人工林树龄增加而增加,但是年积累量随之降低.在同一植被类型内,不同坡位新鲜或部分分解的凋落物有机质累计量变化较大,坡底部有机质积累量最高,沿着山坡向上逐渐减少.在15年生大叶相思人工林内,土壤整合有机物积累量变化趋势与新鲜或部分分解有机质积累量变化趋势相反.在7年生和15年生的大叶相思林以及18年龄的阔叶混交人工林内,新鲜、部分分解和完全分解(含土壤整合有机质)有机质总生产速率分别是2554.31、705.79和1028.01kg.ha-1·a-1,新鲜凋落物有机质在3种林分中的生产速率分别是38.23,19.40和30.48 kg·ha-1·a-1.3种人工林和自然林内,平均新鲜凋落物的有机质积累占有机质产出总量的32.45%,部分分解凋落物占13.50%,而全分解整合土壤有机质占54.56%.森林土壤酸度随凋落物分解阶段的深入而增加.     

人工塑山的工艺特点及施工要点

假山是中国园林中的重要造景元素。它造形多变,易与周围景物协调统一,同时它布置灵活,巧于变化,既能丰富园林的景观,又能增加园林的空间和层次感。时至今日,假山在园林中仍然起着重要的造景作用。但假山施工的正确与否对假山的成败和艺术效果会产生巨大影响。因此,假山堆筑的技艺是值得每个园林建设者研究、探讨的课题。     

塔里木油田某地区分支井类型优选研究

塔里木油田某地区储层为裂缝溶洞发育地层,采用分支井技术有利于增大井眼与油藏的接触面积,提高泄油效率和油井原油产量。在分析和研究该地区油藏具体特点、井身结构特点以及分支井类型的具体特点的基础上。利用分支井类型优选原则,优选出适合于开发该地区古潜山油藏的分支井类型为双反向分支井和多底三分支井。