北方石质山区小流域综合治理的一个典型

一、流域概况常家沟小流域在永定河上游重点治理县-怀安县境内白云山脚下,属石质山区范围.地质条件以石灰岩为主,並有部分风化的花岗片麻岩。植被稀疏,有小叶杨、洋槐、榆树、油松、侧柏、柳树及灌木沙棘、紫穗槐、锦鸡儿、黄芦等生长.土壤为黄土,仅保存于阴坡半阴坡.属干旱寒冷气候区域.无霜期在100-140天,年平均气温7℃.年降雨量在400毫米以上.     

中国土壤胶体研究—Ⅶ.内蒙暗栗钙土的粘土矿物

内蒙栗钙土区属半干旱而温和的大陆性气候,年平均温度-2.4-6.5℃,冬夏温差很大,约差30-49℃,夏季平均温度为20-25℃,比黑钙土地区高,年降水量200-350毫米,多集中夏季。由于气候干旱,相对湿度很低,蒸发量大于降水量数倍,大陆性气候十分明显。植被以禾本科草及篙属的短草为主。地形主要为高平原,包括一部分丘陵岗地。     

雅鲁藏布江源区近35年气候变化特征

为揭示雅江源区风沙化土地发育的气候变化背景,通过对雅江源区周边4个基本气象站1973-2007年的逐日气象资料进行等权平均取值.采用气候线性趋势分析法,研究了气温、降水、日照时数、风速等气象因子近35 a的变化特征及趋势.结果表明:(1)雅江源区多年平均降水量为206.12 mm,日平均气温为2.77℃、最高气温为10.72℃、最低气温为-4.81℃,年日照时数为3 295.16 h,年平均风速为2.92 m/s.(2)近35 a来,雅江源区气候变暖趋势明显,1986年以后,平均气温线性升温率为0.77℃/10 a,高于近35 a来的平均值0.47℃/10 a和珠峰地区5站平均线性升温率为0.234℃/10 a.(3)年平均降水量的波动较大,增加趋势不明显,平均增长率为0.43 mm/10 a.降水量主要集中于5-9月,占全年降水量的89.72%.年平均日照时数波动性较大,上升趋势不显著.以5月和10月较高,1月最低.年平均风速下降趋势明显,以3月最大,为3.67 m/s,11月最小,为2.20 m/s.可见,雅江源区是中国同期升温最显著的区域.     

陕县小麦隐性灾害发生及防控现状研究

陕县地处河南省西部丘陵山区,位于西北黄土高原东部边缘,黄河南岸。属暖温带大陆性季风气候,光照充足,气候温和,四季分明。年平均气温13.9℃,年日照2354.3小时,无霜期219天,年平均降雨量652.6mm。年     

小麦高产土壤的养分状况及其调节

陕西省关中地区,土质肥沃,气候温和,年平均气温12.0-13.6℃,≥10℃的积温为4000-4400℃,年降雨量600-700毫米,无霜期200-220天,很适宜于农作物生长,主产粮棉,以种植小麦面积为最大。     

吉林省低温冷害发生规律及其防御措施

吉林省地处祖国的北方,气候寒冷,无霜期短。除珲春等沿海地方外,绝大部分地区属大陆性气候。农业生产区气候条件为:年平均气温2.7—6.7℃;年大于十度活动积温2180—3240℃;无霜期120—160天;年日照时数2341—3116小时;年降水量350—1000毫米,其中60%以上集中在6—8月。我省的     

玉米的水分供需特征及提高其利用率的途径——以河北省青县为例

<正> 一、前言青县位于冀中东部,处于冀中低平原和滨海平原之间,属中温带半湿润大陆性季风气候。全年日照时数为2769.8小时,年太阳总辐射量为526.2焦尔·厘米~(-2),年平均气温12.1℃,≥0℃积温4721.1度一日,≧10℃积温4302.6度一日,初霜期在10月18日,终霜     

阿勒泰地区近30年气候特征分析

利用阿勒泰地区7个站点1987—2016年气象数据资料,采用回归分析、趋势线分析、距平百分比累计等方法,对阿勒泰地区气候变化进行分析。结果表明:近30年平均气温为4.5℃,气候变暖趋势明显,气候倾向率为0.315℃/10a,春季气候变暖最明显;年均日照时间2881.1h,近30年日照时间趋于减少,气候倾向率为-14.921h/10a,日照时间月分布不均,以6月最多,12月最少。总的看来,阿勒泰地区近30年呈现出气温升高、日照时间减少变化趋势。     

近40年青海浅层地温的变化特征

利用1971-2010年青海25个观测站5-20cm土层的逐月平均地温资料,采用气候统计诊断分析方法,对近40a青海年、季平均地温的气候变化趋势及突变特点进行研究.结果表明,近40a青海5-20cm土层年平均地温呈上升趋势,大柴旦升温幅度最大,为0.79℃/10a(P ＜0.01).5、10、15、20cm 4个土层年平均地温均呈上升趋势,升幅最大值为0.77～0.82℃/10a(P＜0.01),均以大柴旦升温幅度最大,10cm土层自1981年以来增温尤为明显.近40a四季平均浅层地温均呈上升趋势,增幅为0.30 ～0.53℃/10a(P ＜0.05),以夏季增幅最大,冬季最小.1971-2010年大部站点各层在1997年发生了气候突变,浅层地温与地表温度和气温均呈明显的正相关,气温、地表温度的显著升高在很大程度上解释了浅层地温呈明显升高趋势的原因.研究结果对合理利用气候资源,调整农作物种植结构并合理安排农业生产布局具有参考价值.     

延边地区稻田土壤的主要类型及其生产性能

延边地区位于吉林省东北部半山区,属北方海洋性暖流气候区,无霜期135-150天,年平均气温3-5℃,适于一季水稻生长。     

THE IDENTIFICATION AND DETERMINATION OF GLUCURONIC AND GALACTURONIC ACIDS IN SCOTTISH SOILS AND SOIL FRACTIONS USING ION-EXCHANGE AND GAS-LIQUID CHROMATOGRAPHY

Two methods have been used for the identification and determination of uronic acids in soils and soil fractions. The uronic acids were released by hydrolysis with sulphuric acid. After partial purification by ion-exchange chromatography they were separated either by further ion-exchange or by gas-liquid chromatography of derivatives. The latter method is preferable for determination of the specific activities of uronic acids in soil tracer work. Both galacturonic and glucuronic acids were detected in the four Scottish soils examined, the galacturonic acid being present in slightly greater amounts in each soil. Mannuronic acid was not detected. The total amount of uronic acids found ranged from about 4 mg to 6 mg/g soil.     

坡面汇流汇沙与侵蚀—搬运—沉积过程

侵蚀、搬运和沉积过程是土壤侵蚀过程中相互影响又相互制约的三个子过程。自从 2 0世纪 40年代Ellison[1～ 4] 将水蚀过程分为四个子过程 ,即雨滴侵蚀过程、径流侵蚀过程、雨滴搬运过程和径流搬运过程以来 ,许多学者从不同角度对其进行了研究。Meyer和Wischeier[5] 及Meyer和Fo     

有机无机肥配施对小麦吸收氮磷及土壤肥力的影响

￣（１５）Ｎ示踪试验表明，有机无机肥配施促进了有机叉的矿化和小麦对有机氮的吸收利用，基施氮肥主要用于营养器官的形成，返青追肥主要用于生殖器官的形成。有机无机氮肥配施提高了总氮生产效率。配施处理小麦对磷素的吸收总量稍高于单施无机氮肥处理，磷素在籽粒中的分配率稍低于单施无机氮肥处理是导致磷素生产效率下降的重要因素。有机无机肥配施提高小麦产量的同时也培肥了地力，是小麦高产稳产的重主措施之一     

甲酸甲烷杆菌和甲烷八叠球菌的分离和特征

本文介绍从德国哥廷根污水处理厂腐化塔污泥中分离出的两株甲烷细菌，其中一株为甲酸甲烷杆菌（Ｍｅｔｈａｎｏｂａｃｔｅｒｉｕｍｆｏｒｍｉｃｉｃｕｍ），其细胞杆状，可利用甲酸或Ｈ２／ＣＯ２作为碳源和能源，另一株为甲烷八叠球菌属（Ｍｅｔｈａｎｏｓａｒｃｉｎａ），其细胞球状，成堆排列，可利用甲醇或Ｈ２／ＣＯ２作为碳源和能源。     

MAKING SOIL AND WATER CONSERVATION SUSTAINABLE: FROM COERCION AND CONTROL TO PARTNERSHIPS AND PARTICIPATION

For close to a century, rural development policies and practice have taken the view that farmers are mismanagers of soil and water. This paper reviews the history of farmers being advised, paid and forced to adopt new soil and water conservation measures and practices. Many have done so, and environments and economies have benefited in the short term, but ill-conceived policies and badly designed programmes and projects have undermined these efforts in the name of conservation. Most efforts have been remarkably unsuccessful, often resulting in more erosion. They have undermined the credibility of conservation and wasted huge sums of money. For a new era of soil and water conservation, new initiatives are showing how to make conservation sustainable. Farmers are now considered the potential solution rather than the problem, and so the value of local knowledge and skills is being put at the core of new programmes. This involves a major focus on building farmers' capacity to innovate and develop technologies appropriate to their own conditions. Local organizations are strengthened through participatory processes, this participation being interactive and empowering. Recent evidence is indicating that these new interactions between professionals and farmers are producing considerable productive and sustainable benefits. For widespread impact, enabling policy frameworks are still needed to encourage the spread of more sustainable practices for agriculture. © 1997 John Wiley & Sons, Ltd.     

水肥耦合对小麦玉米带田产量效应及土壤水分动态研究

采用3414最优回归设计方案,研究了水肥耦合对小麦玉米带田产量效应及土壤水分动态规律。结果表明：不同水肥耦合模式对带田作物的产量差异达极显著水平。在灌水量4800m3/hm^2,施氮肥420kg/hm^2,磷肥120kg/hm^2的处理（W2N2P2）中,带田产量和水分利用效率达最高值,决定带田总体产量性状主要因子为氮...     

黄土与古土壤中重金属的存在形态及风化成土作用对其影响

本文采用了七步连续萃取方法，研究了洛川黄土剖面黄土与古土壤中Ｆｅ，Ｃｕ，Ｚｎ，Ｃｏ和Ｎｉ五种重金属的存在形态。结果表明：黄土与古土壤中上述元素主要存在于残余态和晶形，无定形氧化铁的结合态中，而且线性回归分析表明Ｃｕ，Ｚｎ，Ｎｉ与晶形氧化铁之间存在关；ｃＵ，ｃＯ，Ｎｉ与无定形氧化铁之间存在相关；黄土风化为古土壤后，碳酸盐结合态的重金属含量增加是古土壤相对于黄土重金属增加的主要原因。     

稻草和尿素配施时水稻对肥料氮和土壤氮的吸收利用

利用＾１５Ｎ同位素示踪技术,研究了稻草和尿素配施时水稻对肥料和土壤氮的吸收。结果表明,稻草单施导致土壤速效氮的生物固定,氮素供应不足是影响水稻分蘖成穗的限制因子,稻草配合尿素施用,明显改善肥料氮和土壤氮的供应,既有利于当季水稻增产,也有利于培养土壤肥力,还有利于后茬物作产量的提高 。     

MIGRATION AND AGGREGATION OF Na AND Ca CLAYS BY THE FREEZING OF DISPERSED AND FLOCCULATED SUSPENSIONS

The ability of clay to move ahead of an ice-liquid interface depends on the rate of freezing, the particle size, the release of dissolved air from the water through its probable effect on local freezing rates, and on the electrolyte and its concentration through their effects on interparticle forces and particle mobility. A freezing-rate of 1 cm per hour did not move flocculated clay in most cases, but moved dispersed clay up to 0.7 cm before being trapped in the ice with released air. Aggregates of clay (0.1 to 1 mm) were produced by freezing. After thawing they swelled and dispersed depending on the electrolyte and its concentration in a similar manner to aggregates formed by drying.     

GROWTH AND POTASSIUM TRANSPORT IN COMMON AND DURUM WHEAT AS AFFECTED BY ALUMINUM AND NITRITE STRESS

Aluminum (Al) toxicity has been identified as one of the most important factors limiting plant growth in acid soil. Besides Al, nitrite (NO₂ ^?) may also be a significant stress factor in an acid environment. The objective of this study was to examine the effects of Al and NO₂ ^? stress on the growth and potassium (K⁺) uptake of roots and their transport toward the shoots of an Al-resistant common wheat (Triticum aestivum L. cv. Jubilejnaja 50) and an Al-sensitive durum wheat (T. durum Desf. cv. GK Betadur) grown in 0.5 mM CaSO₄ solution at pH 4.1 or 6.5. Root elongation of durum wheat was inhibited with 30% at 10 μM AlCl₃ treatment, while this low Al-concentration did not show a significant effect on root growth of common wheat. In all cases shoot growth was not influenced under low-salt conditions by 10 μ M AlCl₃, but exposure to 100 μM KNO₂ (alone or in combination with Al) had a definite stimulatory effect on growth. Aluminum was found to stimulate the K⁺(⁸⁶Rb) influx in short-term (6 h) experiments, but to inhibit it in long-term (3 days) experiments. This treatment was thought to damage the plasma membrane. When 10 μM 2,4-dinitrophenol was present in the uptake solution the Al-stimulated K⁺ uptake stopped even in short-term experiments. In the case of nitrite and nitrite + Al treatment combinations, however, a striking inhibition was observed in the K⁺(⁸⁶Rb) influx and the K⁺ concentration of the roots and shoots of both species.