两种荒漠土壤和牧草矿物元素含量的比较研究

对砾石和沙质２种不同的荒漠土壤和牧草矿物元素含量进行了分析,结果表明：砾石荒漠土壤和牧草中Ｆｅ,Ｃｏ,Ｍｏ含量极显著高于沙持荒漠（Ｐ〈０．０１）,牧草Ｃｕ：Ｍｏ仅为１．３：１,沙质荒漠牧草Ｃａ含量过高,Ｐ含量偏低,导致牧草中Ｃａ：Ｐ高达５０;１,同时发现,２种荒漠牧草中Ｓｅ,Ｍｎ,Ｚｎ含量均低于反刍动物的营养需要量,其原因可能与土壤中这些元素含量偏低有直接关系。     

两种土壤类型对羊草生物学特征的影响

研究两种土壤类型对羊草个体和群落生物学特征的影响。结果表明,在碱化草甸土,羊草的叶宽、净光合速率和气孔导度均低于风沙土型,而单株重则高于后者,而叶长、蒸腾速率和水分利用效率差异不显著。碱化草甸土型羊草的群落密度、地上生物量均高于后者,而根冠比则低于后者。株高、凋落物量及地下生物量在两者间差异不明显,碱化草甸土型羊草群落土壤呼吸及凋落物分解排放的CO₂量均高于风沙土型。     

塔里木沙漠公路风沙危害研究

通过分析沙漠公路不同时段和地段风沙危害的特点 ,找出了从北向南风沙危害强度趋于减弱 ,公路及防沙体系受害程度逐渐降低的规律。注意到防沙体系所受风沙危害类型和程度在公路东西两侧和不同地貌部位差异明显。并且查明随着时间推移 ,公路受害面积扩大 ,重型沙害所占比例明显增长的公路沙害发展状况。     

Application of the Tamping Method on ImprovingUnsolidated Sand and Gravel Foundation

This paper presents a method of tamping for improving unconsolidated sand and gravel foundation backfilled on the flood land,and introduces the principles of soil improvement with some engineering cases. Results from the field tests show that this method is reliable,economical and feasible.It provides reliable basis for applying this method on other similar engineering projects hereafter.     

Study on Optimum Operating Parameters of Air-WaterBackwashing of Common Sand Filter

In this paper, the optimum operating parameters for air-water backwashing of common sand filter with three different backwashing manners are chosen by single factor optimization and multiple cross experiments. It is concluded that the three-phase combined backwashing manner is the best one.     

Study on the Technology and Engineering Application Method of Sodium Silicate Bonded Sand Cured by Microwave Energy

The Influences of modulus and dosage of sodium silicate and microwave energy heat up technology for instant strength and retained strength are measured and analyzed by the numbers. The results show that instant strength is reduced when the time of microwave energy heat up is too long. The engineering application design is recommended.     

Density Distribution of Sand Packing in Vacuum Suction Molding Process and its Influential Factors

By means are measured of the direct observation of the packing behavior of sand in the vacuum suction molding process.The air and powder pressure,density distribution of sand core.The packing mechanisms are studied based on these experimental results.It found that the density distribution of sand core is elucidated by powder pressure theory,and the density distribution is decided by air flowing,sand chocking and shearing.     

榆林沙区主要人工固沙灌丛营养成分及对放牧羊只生育影响的研究

人工固沙灌丛粗蛋白、粗脂肪平均含量比天然草地牧草分别高出１６．２２％、４３．５０％,钙的含量除紫穗槐外,平均高出２７．３７．％。磷的含量低于天然牧草,氨基酸总量平均值为１０．８５％,略低于草地牧草,７种必须氨基酸含量与天然牧草接近,沙柳、紫穗槐的镁、锌含量高,踏郎铁含量。铜的含量各灌丛均高。灌丛地放牧,杂交绵羊体重平均加３．４￣３２．０％,羊毛增加２０．０￣７９．３％,产羔率也有较大提高。     

黄河流域粗泥沙集中来源区径流及输沙特征分析

本研究以黄土高原粗泥沙集中来源区面积最大且连续的区域(即北起皇甫川流域南至佳芦河流域地区)为研究对象,以1960~1999年为研究时段,分析了该区内水沙变化特征。结果表明:降水变化的作用和人类活动的影响已交叉融合在一起,使得该区降雨量、径流量、输沙量呈现减少的趋势。在同一时段内,皇甫川流域的降雨损失量最大,而秃尾河流域的降雨损失量最小。40年间皇甫川和佳芦河流域的洪峰和沙峰出现的月份基本上吻合,而孤山川、窟野河和秃尾河流域的输沙量最大的月份同时或滞后于径流量最大的月份。孤山川流域的水沙异源,长时段序列又进一步掩盖了其水沙关系,使得该流域的水沙关系较差,其余4条流域的水沙关系较好,且呈正相关增长趋势。     

光照、温度和沙藏对草珊瑚种子萌发的影响

在三明市三元区研究草珊瑚种子发芽率和发芽指数与光照、温度和沙藏时间的关系.结果表明,光照、温度和沙藏时间对草珊瑚种子的发芽率和发芽指数影响极显著,最高发芽率是最低的3.10倍,最高发芽指数是最低的8.63倍.有光照的草珊瑚发芽率显著高于无光照的发芽率;随着温度的增加,草珊瑚种子发芽率表现出先升后降的趋势,25℃时种子发芽率和发芽指数最高;沙藏时间对种子发芽率和发芽指数影响最大,沙藏90 d的种子发芽率在90.00％以上.影响草珊瑚种子发芽率的各因素作用大小依次为沙藏时间＞光照＞沙藏时间×光照＞温度＞沙藏时间×温度,影响发芽指数的各因素作用大小依次为沙藏时间＞光照＞温度＞沙藏时间×温度＞沙藏时间×光照.因此,草珊瑚种子宜分批采种、晾干后即沙藏,3月底到4月间播种,播种时宜浅播.