黄河故道沙土地夏花生灌溉研究

黄河古道沙土的裸地土壤含水量在正常降水补给下可达到田间持水量的水平，直到１０月时，０－１００ｃｍ土壤含水量仍为１５％。造靠天然降水的对照处理，其土壤含水量在雨水补给下也达到田间持水量水平，在１０月花生收获时０－１００ｃｍ土壤含水量为１４％，不同灌溉处理对花生产量影响不大。     

Water-table management in lowland UK peat soils and its potential impact on CO2 emission

The rate of oxidation of peat soils is highly seasonal and varies with temperature and soil moisture content. Large variations in soil moisture content result in wet–dry cycles that can enhance peat degradation. Water‐table management plays a crucial role in controlling and damping the effect of these environmental factors. However, maintaining high ditch water levels in fields bounded by ditches does not guarantee a high field groundwater level. The effect of installing subsurface irrigation at different spacings on water table elevation was studied in a low‐lying peat grassland. The water table elevation data were compared against values predicted with a water balance model. In addition, greenhouse experiments were carried out on undisturbed soil core samples collected from the peat grassland as well as a low‐lying peatland under intensive arable faming to measure CO₂ evolution under different water regimes. The field data from the peat grassland suggest that sub‐irrigation spacing as low as 10 m is necessary during summer periods to maintain groundwater levels similar to those in the ditches. Over the same period of observation, the difference in water level between the ditches and the non‐irrigated fields is as high as 0.7 m. Modelled outputs are in good correlation with the field observations, and demonstrate that simple water balance models can provide an effective tool to study the effect of water management practices and potential changes in subsurface conditions, climate and land use on water‐table levels. The measurement of CO₂ emission from undisturbed peat soil columns shows that the rate of oxidation of soil organic matter from peat soils is highly seasonal and that drainage exacerbates the rate of peat mineralization.     

The estimation of losses of potassium and magnesium from chalky soils in southern England: laboratory studies

Abstract. Ten chalk topsoils (0-25 cm) were repacked into columns in the laboratory. After leaching similar to one year's throughflow in the field, loss of K was equivalent to between 9 and 74kg K/ha. This represented between 3 and 30% of the initial exchangeable K with which loss was poorly correlated. Loss was dependant on the soil solution concentration and was inversely proportional to potassium buffer power.
The loss of magnesium in the same columns was between 10 and 22 kg Mg/ha (6-21% of the initial exchangeable Mg). Magnesium loss was poorly correlated with exchangeable Mg.
When KCl fertilizer was incorporated into the soils, the increase in leaching of potassium was 1–35% of the K addition. Application to the top of the column resulted in less leaching than when the K was incorporated. Leaching of magnesium was increased by up to 5 kg Mg/ha.
Potassium leaching may be delayed by the underlying A/C horizon but pure chalk, with an extremely low buffer power for K, has little ability to retain K. Extremely calcareous topsoils were the most leaky although in practice it is the organic chalk soils on which it is most difficult to attain adequate K levels. On all chalk soils, maintenance of a high K level with K fertilizer is likely to cause unnecessary long-term leaching losses. Annual, rather than biennial, fertilizer applications are to be preferred.     

榆林沙区乡土树种与外来树种的和谐应用

榆林沙区自然环境恶劣,植被稀少。因此在生态环境建设中不仅要应用乡土树种,还要引进外来优良树种,以丰富榆林市的树木资源,使绿化达到更完美的效果。而如何将乡土树种与外来树种协调应用是关键所在。只有在保护好乡土树种资源的同时,有原则、有目标、有步骤地进行引种,使之不发生生物入侵,才是正确的培育措施。     

北京市典型沙地景观动态变化分析——以康庄为例

本研究通过选取北京典型沙地-康庄为研究对象,借助遥感技术、地理信息系统技术、全球定位技术、景观生态学理论和相关数学研究方法,对康庄80年代、90年代和2000年以后3三时期的景观动态进行分析和比较。从80年代至今,康庄沙化土地景观类型发生巨大变化。露沙地面积大幅度减少,由2117.03 hm^2减少到1 249.65hm^2减少了59.03%。通过选取相关景观指数对研究区景观类型进行分析可知,康庄风沙危害区先增加后减缓;对研究区景观类型的变化的分析表明,变化的原因与研究区所处地理位置,社会经济发展背景和人为干扰、政策导向密切相关。对影响研究区景观动态变化的主要因素分析可知,研究区主要受自然和人为两种条件影响最大。自然因素中,沙化土地变化主要与地形地貌、地表物质、降雨、温度、大风、水文条件等因素关系较密切;人为因素中,主要受人口增长、农业结构调整、林业工程实施和社会经济发展背景等因素的影响。     

砂壤土强筋小麦应用杀菌剂对产量和品质的影响

运用田间小区试验方法,在豫东平原砂壤土生态类型区麦田,初步探讨了杀菌剂对强筋小麦产量及品质的影响。试验结果表明,使用三唑酮、多菌灵、灭菌丹、烯唑醇及病虫灵等5种杀菌剂,强筋小麦千粒重提高0.8～1.9g,产量增加147.6～471.3kg/hm2,平均增产5.4%。于小麦抽穗后喷洒1次杀菌剂效果较好,增加喷洒次数以后对强筋小麦品质有不良影响。不同生育期应用杀菌剂,基本上不影响强筋小麦的品质,其应用效果主要取决于杀菌剂种类及喷洒次数。既使强筋小麦增产,又基本不影响其品质指标的杀菌剂为三唑酮和烯唑醇,其中又以三唑酮的增产效应最为突出,一般增产8%以上,千粒重提高2g左右,生产中可以考虑优先选用。     

沙质荒漠化土地生物沙障结构与配置技术研究

自从1994年联合国防治沙漠化公约的颁布,受到世界各国的普遍关注[1,2].目前,我国荒漠化面积已达174.3万km2,每年沙化面积3 436 km2.因此防治荒漠化是生态环境建设的主要任务之一.     

沿海沙岸林果组合模式的建立──柑桔栽培

在沿海沙质岸段进行在林复合经营时，建立以柑桔为主的林果组合模式，可以提高沿海防护林经济效益，使防护林从生态型逐步向生态经济型方向发展。文中着重介绍了沙滩柑桔栽培技术。     

The dehesa: an agrosilvopastoral system of the Mediterranean region with special reference to the Sierra Morena area of Spain

A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. This paper summarizes its findings on the various agro-ecological features of the system and evaluates the system's functional aspects vis-a-vis the trends and developments in land use in the region over the past few centuries. The synergistic effects of tree cover on understorey grassland vegetation is discussed in terms of soil fertility build-up and favourable micro-climatic and hydrological features, and the potential use of this information in future research and development programmes to improve the dehesa system in the Mediterranean region is outlined.     

福建滨海沙地造林树种的适应性与选择研究

对不同树种滨海沙地适生性进行测定 ,不仅可以筛选出适宜于在不同滨海沙地的树种 ,丰富滨海防护林的树种资源 ,同时 ,也是防护林生态系统管理的要求。本文通过对各树种在不同滨海沙地立地上的成活率 (或保存率 )、生长量和抗风性的比较 ,筛选出适宜在福建东南滨海后沿沙地上栽植的树种有巨尾桉、刚果1 2 #桉、厚荚相思、纹荚相思和马占相思等 5个树种 ;较适宜的树种有山地木麻黄、柠檬桉、大叶相思、湿地松等 1 0个树种 ;适宜于木麻黄基干林带更新改造的树种有木麻黄无性系 70 1 #、60 1 #、厚荚相思等 3个树种 ,较适宜的树种为刚果 1 2 #桉 ,但建议慎重使用 ;适宜于前沿有少量稀疏木麻黄老林带保护的风口沙地立地上造林的树种有厚荚相思 ,较适宜的树种有纹荚相思和马占相思等 2个树种 ;适宜于滨海风口沙地立地上造林的树种有木麻黄惠安 1号无性系和木麻黄澳大利亚种源C3 8,具有一定潜力但尚需做进一步观察的树种有短枝木麻黄、木麻黄澳大利亚 1 5 1 98种源、木麻黄无性系 70 1 #和细枝木麻黄。