水土保持措施与水资源保护浅议

系统分析了水土保持措施中生物措施、工程措施治滩造田工程对水资源保护的功效,深入探讨了水土保持各项措施与降水、地表水和地下水“三水转化”的关系,说明了水保措施在水资源保护中的重要性。

几个树种的林冠降雨特征

本文从机制和数量关系上研究了毛竹、杉木和刺槐人工林的林冠对降雨雨谱和雨滴动能的影响 ,这是进一步深入研究森林的水土保持和水文效益的基础。结果表明 ,林冠降雨的雨滴直径 (D ,mm)大小分布即雨谱基本不受空旷地降雨类型和强度的影响 ,表现出相当稳定的特征。当采用F =1-exp(- (10Dα ) n)表示林冠降雨雨谱时 ,毛竹、杉木和刺槐的α值分别为 2 7718、2 5 939、2 5 112 ;n值分别为 1 75 93、1 9175、2 6 12 6。林冠降雨单位水体雨滴动能也基本不受林外降雨类型和强度影响。当降落高度足够大从而所有雨滴都能达到终点速度时 ,毛竹、杉木、刺槐的林冠降雨单位水体雨滴潜在动能为 2 4 16 3J·m- 2 mm- 1 、2 3 2 14J·m- 2 mm- 1 和2 3 713J·m- 2 mm- 1 ,表现为所研究 3个树种之间的差别很小。本研究建立了依据给定降落高度 (H ,m)计算这3个树种林冠降雨单位水体雨滴动能的模型 ,毛竹为ec=2 4 12 9[1-exp(0 .0 0 2 3H2 - 0 .32 5 9H) ],杉木为ec=2 3 2 14[1-exp(0 .0 0 2 5H2 - 0 .34 0 9H) ],刺槐为ec=2 3 713[1-exp(0 .0 0 15H2 - 0 .34 6 7H) ]。林冠降雨单位水体雨滴动能随降落高度降低而减小的程度表现为在 0～ 5m范围内最强烈 ;在 5～ 10m范围内较明显 ;在 10m以上时则不再很明显。文中还确?

Analysis of Land Degradation in Ethiopia and Countermeasures

In Ethiopia soil conservation is primarily meant to improve agriculture production.Therefore,assessment of the existing erosion hazards and classifying the land according to its capability are essential.This paper depicts the land degradation status and causes,through an integrated assessment,and some measures to alleviate the problem are proposed.

关帝山不同海拔和坡向土壤水分入渗特征

于2019年8月份,在山西省交城县关帝山国家森林公园设置3个海拔梯度(1800、2000、2200 m),各海拔梯度分为半阴坡、半阳坡2个坡向,根据不同海拔梯度和不同坡向共设置6个大样地(100 m×100 m),每个大样地各布设3个20 m×20 m的标准样方。在各样方内随机选取3个样点,根据土壤发生层次采用环刀对淋溶层(0~0.2 m左右,含腐殖质层)和淀积层(0.2~0.4 m左右)土壤进行分层采集土样。采用环刀法和土壤物理性质分析方法,测定土壤密度、土壤含水量、饱和持水量、毛管持水量、土壤总孔隙度、毛管孔隙度、非毛管孔隙度和土壤入渗速率;采用单因素方差分析法、最小显著差异比较法、皮尔逊(Pearson)相关性分析法,分析森林土壤基本物理性质、水分蓄持和渗透性能、不同海拔和坡向土壤水分入渗特征。结果表明:(1)不同海拔和坡向对森林土壤淋溶层的影响大于淀积层;土壤密度在0.90~1.22 g·cm^(-3)之间,淋溶层土壤密度最大值出现在海拔1800 m半阴坡(1.20 g·cm^(-3)),且不同土层间土壤密度存在极显著差异(P<0.01);土壤毛管孔隙度、总孔隙度的大小变化趋势,与土壤密度相反,均为淋溶层的大于淀积层的。(2)土壤自然贮水量、饱和持水量、毛管持水量,均为淋溶层的大于淀积层的;淋溶层饱和蓄水量、毛管蓄水量、涵蓄降雨量、有效涵蓄量,最大值均出现在1800 m半阴坡,分别为“1322.69±13.37”、“981.67±18.13”、“572.13±26.51”、“231.10±17.41”t/hm^(2),且在不同坡向间均为半阴坡的大于半阳坡的。(3)土壤初始入渗速率、稳定入渗速率,在不同海拔和坡向均为淋溶层的大于淀积层的;随海拔升高,入渗速率均为先增加后减小的趋势,不同坡向土壤初渗速率和稳渗速率均为半阴坡的大于半阳坡的;考斯加科夫(Kostiakov)模型拟合参数(a)值在2000 m半阴坡最大(12.243),土壤入渗速率较大。

Organic carbon storage in trees within different Geopositions of Chittagong （South） forest division, Bangladesh

The organic carbon storage in trees and organic carbon flow with geoposition of trees was estimated in the forest area of Chittagong （South） Forest Division within geo-position 91°47′ and 92°15′ East longitude and 21°45′ and 22°30′ North latitude. The study was conducted through stratified random sampling by identifying each sampling point through Global Positioning System （GPS）. It was found that above ground organic carbon storage （t/hm^2）, below ground organic carbon （t/hm^2） and total biomass organic carbon （t/hm^2） was respectively the highest in Dipterocarpus turbinatus （Garjan） （7.9, 1.18 and 9.08 t/hm^2） followed by Tectona grandis （Teak） （5.66, 0.85 and 6.51 t/hm^2）, Artocarpus chaplasha （Chapalish） （2.32, 0.34 and 2.66 t/hm^2）, Artocarpus lacucha （Batta） （1.97, 0.29 and 2.26 t/hm^2） and Artocarpus heterophyllus （Jackfruit） （1.7,0.25 and 2.26 t/hm^2）. From the study it was revealed that organic carbon stock was the highest （142.7 t/hm^2） in the geo-position 22° Latitude and 92° Longitude and was the lowest （4.42 t/hm^2） in the geo-position 21° 50′ Latitude and 92° 2.5′ Longitude. The forest of the study area is a good reservoir of organic carbon so has a good capacity to sequester organic carbon from the atmosphere. Sustainable forest management may help to sequester more organic carbon so that economic benefit for the country and environmental benefit in the international arena are possible from the study area.

Impact of Demographic Structure on Paddy and Forestland Management

In order to understand the impact of demographic structure on paddy and forestland managementafter the convening of the Third Plenary Session of the 11th CPC (Communist Party of China) CentralCommittee and the implementation of the Household Responsibility System (the government divided upland among peasants for cultivating and the peasants sell a set part of their produced goods to thegovernment at stipulated prices by contract in the countryside of China), 147 households in 6 villages,belonging to Xiangtan County and Zhuzhou County in Hunan Province, were selected as research samples,and interview, questionnaire survey and second hand data analyzing were used as the methods. The resultsshowed: Persons with different ages had different ideas, and young peasants would like to work in townsor cities for more income, so they used and depended on land less; In terms of sex, the male was still themain user of land, and therefore the ability, idea and activity of male played an important role in landmanagement; Generally, the labors with better educational background grasped more knowledge andtechnologies, and they had more opportunity to get jobs and had better working condition and moreincome in town or cities, so they depended on and used land less.