基于GIS的生态脆弱区林地生态适宜性研究

为了探讨生态脆弱区林地生态适宜性评价机制,在对广西南丹县典型样地共41个作业区调查基础上,综合考虑与林地生态适宜性密切相关的地形地貌、土壤、植被等因素,利用ARCGIS分析方法对空间数据进行组织与计算,结合AHP方法研究各参评因子权重,并选择适当的隶属函数和模糊算法对南丹县林地生态适宜性进行模糊综合评判。结果表明：林地生态适宜性各等级比重排序为：III级（45.62%）＞IV级（27.84%）＞V级（17.61%）＞II级（8.93%）＞I级（0%）,整体隶属度值为3.5413,位于IV级水平;影响因子排序为：坡度＞石砾含量＞高程＞土层厚度＞郁闭度＞坡向＞灌木覆盖度＞草本覆盖度。同时,根据研究结果,分析了林地生态适宜性较差的主要原因及生态恢复重建的重点。     

气候变化影响下长江流域油菜产量模拟初步研究

为油菜主产区油料作物种植结构调整、合理布局以及制定适应气候变化的管理措施提供理论依据。以中国三大油料作物之一的油菜为代表,针对油菜主产区之一的长江流域的油菜生产,利用引进的澳大利亚APSIM-Canola油菜模型,结合英国Hadley中心的区域气候模式PRECIS,对SRES A2、B2 2种排放情景下油菜生产状况进行模拟。同时结合多元回归统计方法,分析长江流域气候变化对油菜生产已经造成和未来可能造成的影响,并提出可能的适应性对策。研究表明：（1）油菜雨养产量与关键生育时期（现蕾-抽苔期、抽苔-开花期）内辐射和温度呈显著的负相关,与降水呈正相关。（2）A2、B2气候变化情景下油菜单产均随时间呈降低趋势,21世纪80年代减产幅度最为明显,A2情景下近期（21世纪20年代）、中期（21世纪50年代）、远期（21世纪80年代）油菜产量波动呈加强趋势,且同一时期内A2情景下产量波动趋势均大于B2情景。（3）适当采用调整播种期和栽培方式、改良作物品种等适应性对策可有效降低油菜的减产趋势。     

陕北黄土丘陵区大扁杏优良品种试验研究

本文通过对大扁杏六个不同品种连续5年的生长量、单株产量及抗性分析,结果表明优一、一窝蜂两个品种具有抗性强、产量高和品质优等特点,是适于陕北黄土地区栽培和大面积推广的优良品种。     

区域生态系统治理企业——基于区域生态认证的生态系统管理专业化

区域生态认证是实现可持续发展的一种市场机制, 区域生态系统治理企业(REME)是这一动力机制的关键结点。分工理论和企业理论的推导表明, 应建立REME以实现区域生态系统管理专业化。对区域生态认证机制中REME的博弈分析进一步表明, 每个区域只应由1个REME申请认证, 该REME与政府构成代理人-委托人关系, 与其他企业和组织在讨价还价博弈中互利合作。除了通过REC标志使用权转让获利外, REME还应当开辟其他的获利途径以改变风险偏好, 争取在博弈中的有利地位。     

岩溶地区石漠化综合治理模式的试验研究

广西凌云和都安岩溶地区几种石漠化综合治理模式的试验研究一是林草模式,采用任豆加桂牧1号的混交方式,树高年平均生长量为2.77 m、胸径为2.10 cm。牧草种植当年即可采收,每年可采收5次,年平均产量150 t/hm2,产值达1.5万元/hm2。二是林果模式,采用任豆加山葡萄、肥牛树加澳洲坚果、香椿加大果枇杷的套种方式,任豆树高年平均生长量为2.74 m、胸径为2.14 cm。种植的山葡萄2005年初已开花并少量挂果,到第五年可进入丰产期。三是林竹模式,采用柚木加吊丝竹的套种方式,柚木树高年平均生长量为1.77 m、胸径为1.52 m,柚木林下套种的吊丝竹5 a达到丰产期。四是林药模式,采用香椿加金银花的套种方式,香椿混交示范林树高年平均生长量为1.72 m、胸径为1.36 m。3 a生单株鲜花产量可达0.5 kg,产值30元,亩产值达1 200元。四种综合治理模式均取得良好的生态恢复效果。     

马尔可夫链模型在森林资源预测中的应用

应用马尔可夫链建立了鄂西三峡库区森林资源时空变化预测模型。预测结果表明：库区到2010年时林地面积达到830165hm^2,比目前增加4022hm^2,到2030年前后达到相对稳定状态,林地面积达到834638hm^2,比目前约增加10495hm^2,比现有林地增加12．7％。达到稳定状态时,森林资源总体结构与目前相比不会发生根本性改变,林地覆盖率由目前的46．8％增加到62．4％,林地质量和生产潜力都有所提高。     

黄土丘陵区坡地林草间作土壤水分的动态变化

通过对黄土丘陵区坡地林草间作土壤水分动态监测,结果表明:山杏林地土壤水分高于苜蓿地13.7%;苜蓿地土壤水分变化主要在0~40 cm;山杏林地土壤水分变化主要在60~100 cm。     

半干旱退化山区不同土地利用方式土壤物理性质的特征分析

通过对宁夏南部半干旱退化山区不同土地利用方式土壤物理性质的定位监测,结果表明:半干旱退化山区采取不同土地利用方式,改善了土壤结构和肥力,增加了土壤的通透性,改变了土壤水肥气热状况。但不同措施对土壤理化性质的改善具有一定的差异性,"88542"水平沟整地(林地)对土壤的改良效果最好。     

Performance and Microstructure of Ultra Low Ion Permeability Cementitious Materials

Microstructure and macro performance of Ultra Low Ion Permeability Cementitious Materials (ULIPCM) were investigated by Micro hardness, MIP and SEM EDXA. It was shown that the compressive strength of ULIPCM was more than 80 MPa, flexural strength was more than 11.0 MPa, and elastic modulus was in the range of 38.0 to 42.0 GPa at the age of 28 days; chloride diffusion coefficient was lower than 0.8×10－13m2·s－1, conductive charge for 6 hours was lower than 300 coulombs; sulfate attack resistance was good; shrinkage at the age of 28 days was lower than 400×10－6. Compared with ordinary concrete with which thickness of interfacial transition zone is 60 to 100 μm, the thickness of interfacial transition zone of ULIPCM was lower than 30 μm. Penetration paths of corrosive medium were effectively interrupted in ULIPCM. And pore structure parameters, such as porosity and the most probable pore radius of ULIPCM, were also obviously optimized in ULIPCM. Besides, few CH crystals were in the ULIPCM aggregate and the interfacial transition zone of ULIPCM. And the orientation of CH crystals was poor.     

Comparative productivity of Prosopis cineraria and Tecomella undulata based agroforestry systems in degraded lands of Indian Desert

Tree-crop interactions were monitored by measuring tree growth characters of Prosopis cineraria L. and Tecomella undulata L. and yields of Vigna radiata (L) in agroforestry systems in degraded lands of Indian Desert. Potential competition for resource between the trees and associated crop was analyzed by measuring soil water contents, soil organic matters and NH₄-N at different depths of soil layers i.e., 0–25 cm, 25–50 cm and 50–75 cm in the experimental plots. The plots size were 16 m × 18 m (D₁), 20 m × 18 m (D₂) and 32 m × 18 m (D₃) with tree densities of 208, 138 and 104 trees·ha⁻¹ after June 2002, respectively. Results showed that tree height increased by 3% to 7% during June 2002 to June 2004. Collar diameter increased by 30% and 11% in D₁, 23% and 19% in D₂ and 18% and 36% in D₃ plots, respectively, in P. cineraria and T. undulata in two years period. The increase in crown diameter was 9% to 18% in P. cineraria and 11% to 16% in T. undulata. Tree growth was relatively greater in 2002 than in 2003. Yield of V. radiata increased linearly from D₁ to D₃ plots. Lowest soil water content at 1 m distance from tree base indicated greater utilization of soil water within the tree rooting zone. Concentrations of soil organic matters and NH₄-N were the highest (p<0.05) in 0–25 cm soil layer. P. cineraria was more beneficial than T. undulata in improving soil conditions and increasing crop yield by 11.1% and thus more suitable for its integration in agricultural land. The yield of agricultural crop increased when density of tree species was appropriate (i.e., optimum tree density), though it varied with tree size and depended upon resource availability. The result indicated bio-economic benefits of optimum density of P. cineraria and T. undulata over traditional practices of maintaining random trees in farming system in arid zones. Biography: G. Singh (1961– ), male, Scientist E and Head, Division of Forest Ecology, Arid Forest Research Institute, New Pali Road, Jodhpur-342005, India.