毛乌素沙地不同治理措施植被恢复效果分析

从群落数量结构与干物质生产方面对刘家窑头流域赵家塘不同治理措施下的植被恢复效果进行初步分析.结果表明林草复合措施植被恢复效果最好,灌木林地植被恢复优于乔木林地,杨树纯林地效果较差;草方格固沙能使植被迅速恢复;喷撒化学固沙剂对迎风坡植被恢复的效果较为显著.     

班玛县圈窝种草情况调查

利用圈窝地种植一年生牧草，是解决高寒牧区牲畜冬春饲草不足，增强抗灾保畜能力的有效途径；圈窝地因粪肥反复堆积和分解，表土层有机质含量和有效养份高，种植燕麦或其它牧草均可获得高产，比一般人工草地产草量高０．７２倍。     

灌木围障预防兔害对油松高影响研究

产生兔害的根本原因是竞争有限的空间和食物资源,灌木围障将野兔与林木隔离,不限制其在林内的活动,是一种环境友好型的林木兔害预防方法.为了掌握灌木围障对林木高的影响,研究了用沙棘、黄刺玫和其他灌木枝条围罩处理对油松高的作用.试验在当年油松定植时布设,设罩盖与不罩盖处理,5次重复,苗龄3 a,各处理300株.2006年5月定植时对处理区的油松进行测量、标记.处理后2007-2011年5月各调查1次油松高生长量.结果表明:灌木围障隔离对油松高有促长作用,且灌木篱笆促长作用优于灌木围墙.桥北灌木篱笆区定植5 a的油松综合增益指数为20.6％±1.35％,比灌木围墙处理提高了9.3％±1.90％,差异极显著(F=23.299,p=0.000).而旬邑林区两种处理间油松净高增益指数差异不显著(F=2.429,p=0.126),综合增益指数相差2.7％±1.03％.两地各处理油松净高增益大小依次为桥北篱笆＞桥北围墙＞旬邑篱笆＞旬邑围墙.随着定植年限的延长,两地油松净高增益指数有进一步扩大的趋势,油松高生长差距逐渐扩大.     

阳台栏板三议

本文针对栏板的高度安全性、档光问题进行了分析,提出了设计阳台栏板所考虑的影响因素及解决方法。     

Effects of postfire seeding and fertilizing on hillslope erosion in north-central Washington,USA

After the 1998 North 25 Fire in the Wenatchee National Forest, eight study sites were established on steep, severely burned hillslopes to examine the effectiveness of postfire seeding and fertilizing treatments in increasing cover to reduce hillslope erosion, and to measure the nutrient content of the eroded sediment. At each site, four 4 by 9 m plots were located with four randomly applied treatments: seed (winter wheat, Triticum estivum) at 34 kg ha^− 1, fertilizer (75% ammonium nitrate and 25% ammonium sulfate) at 31 kg ha^− 1, seed and fertilizer, and untreated control. Sediment fences were installed at the base of each plot to measure erosion rates and sample the eroded sediments. In addition, precipitation amounts and intensities, surface cover, canopy cover, and nutrient concentrations in the eroded sediments were measured for four years after the fire. Total precipitation was below average during the four-year study period, and most erosion occurred during short duration, moderate intensity summer rainfall events. The overall first year mean erosion rate was 16 Mg ha^− 1 yr^− 1, and this decreased significantly in the second year to 0.66 Mg ha^− 1 yr^− 1. There were no significant differences in erosion rates between treatments. In the first year, the seeded winter wheat provided 4.5% canopy cover, about a fourth of the total canopy cover, on the seeded plots; however, the total canopy cover on the seeded plots did not differ from the unseeded plots. The below average precipitation in the spring after seeding may have affected the winter wheat survival rate. In the fourth year of the study, the mean canopy cover in the fertilization treatment plots was 74%, and this was greater than the 55% mean canopy cover in the unfertilized plots (p = 0.04); however, there was no accompanying reduction in erosion rate for either the seeding or fertilization treatments. Revegetation by naturally occurring species was apparently not impacted by seeding during the four years of this study. The pH of the sediment as well as the concentrations of NO₃–N, NH₄–N, and K was not affected by seeding or fertilizing. The nutrient loads in the eroded sediment were minimal, with most of the nutrient loss occurring in the first postfire year. These results confirm that seeding success is highly dependent on rainfall intensity, amounts, and timing, and that soil nutrients lost in eroded sediments are unlikely to impair the site productivity.     

沙质海岸风口区风障阻沙特征及初步治理试验

为了研究沙质海岸风口区风障配置和堆积沙丘治理模式,为防沙治沙提供理论依据。在沙质海岸前沿风口地段设置15%、30%、45%和60%4种不同透风率的风障,开展其风速变化规律及阻沙特征研究,并选择黄花月见草、厚藤和单叶蔓荆3种草本植物在形成沙丘进行种植尝试。结果表明:1)透风率15%的风障最大防风效能达到89.23%,风速减半的防护距离为5H(H为风障高度),因堆沙效果显著,适合设置为堆沙风障;2)透风率30%与45%的风障最大防风效能分别为76.70%和71.53%,防护距离最大为6H,可在堆沙风障后设置为防风风障;3)透风率60%的风障最大防风效能为59.47%,由于堆沙能力较弱,防护距离较短而不适宜采用,在风障形成的堆沙上,种植的厚藤具有良好的生存能力和蔓延速度,是闽东南沿海前沿裸露沙地固沙的先锋草本。     

植物篱笆与金属护栏网在果园防护中的应用效果

经济林童期相对较长,前期经济收益较低,因此提高综合收益,降低前期管护成本是目前生产中急需解决的主要问题之一。为了降低经济林前期投入成本,提高经济收益,文中对枳和花椒两种植物篱笆与设施工程中常用的金属护栏网这3种防护措施的造价、维护费用、防护效果和经济收益进行了调查和比较分析。结果表明:植物篱笆中,花椒篱笆的经济收入最高,达到7.88元/m,而枳篱笆的防护效果较好,其经济收益较高,可达到7.00元/m;但是,植物篱笆的前期防护效果较差。而金属护栏网的造价和维护费用均最高,可达6.67元/m,但建置后即可起到防护作用,前期防护效果较好。文中综合分析认为,植物篱笆适合童期较长的经济林树种,而金属护栏网则适用于城镇近郊农业观光园、果树采摘园和经济价值不高的育苗基地,若将植物篱笆和金属护栏网结合起来使用,则可兼顾长短期效益,值得在生产中推广应用。     

草原煤矿排土场2种常用生物工程措施植被恢复效果评价

以锡林郭勒草原乌兰图嘎煤矿排土场为主要研究对象,通过对生物笆与沙障2种不同治理措施下的土壤状况（温度、湿度、有机质、pH值）和植被状况（种类组成、密度、盖度）的测定与分析,对其植被恢复效果进行了评价。初步分析表明,生物笆区的表土温度比沙障区低2～5℃,生物笆具有遮阴性;生物笆区的表土湿度比沙障区增加0.60%～1%,生物笆具有增湿性。在措施实施5 a后,生物笆区的表土有机质比沙障区增加了2～5.80 g/kg。在整个植物群落中,多年生草本所占植物种类总数的比例,生物笆区比沙障区多13.84%;生物笆区以多年生植物的重要值较大并占有绝对优势,沙障区以一年生植物占优势;生物笆区的植被平均密度比沙障区多2.60株/m²,盖度大18.50%。在锡林郭勒草原矿区目前常用的生物笆（单网格20 cm×20 cm）治理措施比沙障（行距30 cm,株距10 cm）更有利于植被恢复。     

作物残茬与生物篱组合对减轻土壤风蚀的作用

为了探究中国北方农牧交错带冬春风蚀季节生物篱与作物残茬组合对间作裸露秋翻地的防护作用,采用风蚀圈和野外移动式风洞试验的方法对研究区土壤风蚀情况进行监测,利用PC-3型自动气象站进行风速测定。结果表明,油葵秆生物篱减小了间作裸地近地面风速,提高了地表粗糙度;从防风蚀效果看草谷子茬优于油葵秆生物篱;在距油葵秆生物篱或草谷子茬下风向裸地不同位置处,土壤风蚀量基本呈先增加后减小的单峰曲线变化趋势,在4 m左右土壤风蚀量最大,在篱和茬的双重保护下,距茬5 m处发生了风积现象;土壤风蚀量降低率基本呈“V”字型分布;土壤风蚀模数随风速增大而增加,在生物篱的保护下5～15 m/s风速时土壤风蚀降低率为5.03%～20.53%。因此,油葵秆生物篱具有防风蚀作用,而且与草谷子残茬组合对间作裸地会起到更好的固土防蚀作用。     

多效唑在绿篱化学修剪中的应用研究

在大叶黄杨和小叶女贞绿篱上喷布不同浓度的多效唑药液抑制新梢试验结果表明,采用15%多效唑可湿性粉剂稀释成0.5%的药液喷布绿篱,能明显地抑制新梢生长,在一定程度上代替人工修剪,可节省大量人力、物力。