红壤旱地玉米、大豆间作生态系统的农田减灾效应

在红壤旱地进行了玉米、大豆间作生态系统的田间试验,并对试验结果进行了分析。分析结果表明,相对于单作生态系统而言,间作生态系统具有明显的减灾效应,具体表现在3个方面:一是提高土壤含水量,降低系统白天的温度,减缓温差,从而增强系统的抗旱能力;二是减轻病虫害,并且能增加天敌数量;三是抑制农田杂草的发生、发展,减轻杂草危害。研究结果认为,在红壤旱地推广该间作种植模式,可减轻灾害,减少农药使用量,保护红壤旱地生态环境,促进农业的可持续发展。     

不同品种棉田辐射平衡与小气候分析

朝阳县是辽宁省的重点棉区，植棉历史悠久，为本省积累了丰富的植棉经验，但品种单一，技术老化，产量低而不稳，管理繁琐，与当今高速发展棉花生产的要求已不相适应。因此，我们根据气候相似的原理从山西引进了高产适宜简化栽培管理的3008棉花，在朝阳县十二台乡进行栽培试验，并与辽棉10号品种进行对比分析，其产量高，品质好，经济效益比较显著，深受棉农欢迎。本文进行了农田小气候分析研究，从而为朝阳县推广棉花简化栽培管理技术提供了科学依据。     

江西红壤旱地植棉不同保护措施的温湿度相关分析

本文通过对江西红壤旱地盖草、盖膜、保水剂、沟埂和坡地(对照)五种保护措施下植棉的研究;建立了各处理田间地面温度与气温的相关模型,土壤水分含量与降雨量的相关模型,株间气温与大气温度的相关模型,通过分析得出,伏旱期间,采用沟埂措施有利于提高土壤的墒值;采用盖草措施,能缓和高温的出现,有利棉花的生育.     

四湖地区不同种植行向棉花田间小气候效应初探

从改善江汉平原涝渍地棉田生态环境以及提高棉花产量与棉田间（套）作物的整体效益出发,着重研究了棉花没种植行向增光、增温、减温的田间小气修效应及其对生育性状与产量的影响。结果表明,若实行棉田间作套种,棉花在该地以东西行向种植为好。     

湿地小气候效应特征研究

湿地对局地小气候具有调节作用,研究湿地小气候效应特征能更具体地了解湿地对局地小气候的影响。本文以河北省衡水市的衡水湖为例,利用衡水市11个常规气象观测站数据,通过对湖区及湖区外各季节不同气象要素的对比,对衡水湖各个季节的小气候效应进行了分析。结果表明:（1）衡水湖具有冷岛效应、湿岛效应和风岛效应,能够调节周围的气候特征;（2）衡水湖的小气候效应具有季节特征,衡水湖各季节平均的冷岛效应由强到弱依次为春季、冬季、秋季、夏季,湿岛效应由强到弱分别为夏季、春季、秋季、冬季,风岛效应由强到弱依次为春季、夏季、冬季、秋季,春季小气候效应最强;（3）衡水湖的小气候效应具有昼夜特征,夜晚的冷岛效应强于白天,湿岛和风岛效应正相反,白天的强度大于夜晚。     

日光温室小气候效应的分析

用１９９４～１９９６年日光温室内外的光、温、湿三大要素进行多点对比分析,得出其在时间、空间上的分布规律和特点。实验结果证明,该类温室的小气候效应显著,可大幅度提高蔬菜的复种指数,生长季可延长２７．４％。     

玉米撕叶的小气候效应研究

经两年试验发现，玉米撕叶可以使宽行的透光率增大，白天温度提高，夜间温度降低，通风状况得到改善，一定程度地解决了田间郁蔽的状况，能够大幅度提高玉米及套种作物产量。     

地膜棉田温湿效应与应用

通过对有膜棉田和无膜棉田的温度、湿度的对比试验分析,结果表明,棉田盖膜在前期有增温保湿作用,并且使棉株生理活动加强,物理过程减弱,有利于棉花干物质的积累,使棉花产量和品质都有所提高。     

大豆密植小气候效应及高产机理分析

在田间实测资料的基础上 ,研究了密植大豆田小气候效应 ,并进一步分析了密植大豆田的高产机理 ,为探索作物合理密植以及种植制度的优化提供相应的依据。     

日光温室小气候预报方法研究

利用北方节能型日光温室2007-2010年小气候要素观测资料,基于逐步回归方法,建立了不同天气类型、不同月份、不同时间段的未来24小时逐时温室气温预报模型,并对预报模型的普适性分别进行了拟合与预报检验,表明预报精度较高,可用于开展设施农业天气预报。     

2011年龙江县玉米农田土壤湿度变化及其对玉米生长的影响

以黑龙江省龙江县玉米主栽品种葫科336为试材,采用自然条件下对比观测田间试验,研究分析不同土壤湿度对玉米生长的影响。结果表明：2011年龙江县试验田不同表层(0-30 cm)土壤湿度均呈下降趋势。试验田不同表层土壤湿度对玉米生长的影响存在差异,不同土壤湿度对玉米绿叶叶面积、植株干物重影响明显,在一定土壤湿度范围内,土壤相对湿度每升高1 %,叶面积增加28.338 cm²,土壤无旱对叶面积增加具有正效应,对玉米果实重量的增加也呈有利趋势。     

Plant spacing effects on net irradiance extinction in cotton

Summary Decreasing the fraction of water that evaporates from the soil (E) is one means of increasing the water available to crops and thereby increasing the transpiration and the water use efficiency of a cropping system. In addition to soil surface wetness, net irradiance at the soil surface (R _ns ) is the predominant environmental element affectingE. TheR _ns is infrequently measured and is often estimated using an equation of the formR _ns /R _n = exp (–k · LAI), whereR _n is the abovecanopy net irradiance,k is an extinction coefficient, andLAI is the leaf area index. The effect of row spacing and plant population onk was examined for cotton (Gossypium hirsutum L.) grown on a Houston Black clay (fine, montmorillonitic, thermic Udic Pellustert). Treatments consisted of 10 and 15 plants m^–2 in 0.68- and 0.34-m north-south oriented rows and in a uniformly-spaced pattern. HourlyR _n andR _ns were measured with a domed and tubular net radiometer, respectively. TheR _n was approximately a constant fraction of global irradiance across treatments and throughout the season. Minimum values of theR _ns /R _n ratio ranged from 0.14 to 0.24. Values ofk, calculated as the slope of the regression of ln (R _ns /R _n ) with theLAI, ranged from 0.44 to 0.66. Plant population affectedk more than row spacing. Thek value calculated from pooled data was 0.52.

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Zusammenfassung Ein Weg zur Steigerung der Wasserverfügbarkeit für Feldfrüchte ist es, den Wasseranteil, der vom Boden verdunstet (E) zu verringern und damit die Transpiration und die Effektivität der Wassernutzung der angebauten Pflanzen zu erhöhen. Zusätzlich zur Oberflächennässe des Bodens ist es die Nettoeinstrahlung an der Bodenoberfläche (R _ns ), dieE dominiert.R _ns wird selten gemessen und häufig durch eine Gleichung der FormR _ns /R _n = exp (–k · LAI) abgeschätzt, wobeiR _n die Nettoeinstrahlung über dem Bestand ist,k ein Extinktionskoeffizient undLAI der Blattflächenindex. Der Effekt des Reihenabstandes und der Pflanzendichte aufk wurde für Baumwolle (Gossypium hirsutum L.), gezogen auf einer Schwarzerde untersucht. Auf den Untersuchungspunkten standen 10 bzw. 15 Pflanzen/m² in 0.68 bzw. 0.34 m breiten, nord-süd-orientierten Reihen mit regelmäßigen Pflanzabständen. StündlicheR _n - undR _ns -Werte wurden mit einem Kuppel- bzw. Tuben-Nettostrahlungsmesser gemessen.R _n war über die Untersuchungspunkte und die Anbauzeit annähernd ein konstanter Anteil der Globalstrahlung. Die Minimalwerte des VerhältnissesR _n /R _ns bewegten sich von 0.14 bis 0.24. Die Werte vonk, die als Anstieg der Regression von ln (R _ns /R _n ) mitLAI berechnet wurden, bewegten sich von 0.44 bis 0.66. Die Pflanzendichte beinflußtek deutlicher als der Reihenabstand. Derk-Wert für alle Daten war 0.52.

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With 2 Figures     

棉田干旱指标研究进展

干旱是影响作物生长发育的主要非生物胁迫因素之一,水分亏缺所造成的危害超过了一切逆境因子的总和,严重影响作物产量及农业生产。作为全国重要优质棉区之一的新疆,干旱及水资源缺乏也成为棉花产业发展的重大限制因素之一,棉花种植几乎完全依赖灌溉,而棉花或棉田是否需要灌溉,可根据土壤含水量以及植株本身受旱程度特征等指标来判断。本文从棉花干旱形态变化、生长发育进程、生理生态特征、产量结构差异、土壤水分变化、气象干旱等不同方面对绿洲棉田干旱指标研究的现状和进展进行总结,并对进一步开展滴灌模式下棉田干旱发生发展过程以及干旱敏感性指标研究提出建议。     

Assessing the impact of climate change on representative field crops in Israeli agriculture: a case study of wheat and cotton

Climate changes, associated with accumulation of greenhouse gases, are expected to have a profound influence on agricultural sustainability in Israel, a semi-arid area characterized by a cold wet winter and a dry warm summer. Accordingly this study explored economic aspects of agricultural production under projected climate-change scenarios by the “production function” approach, as applied to two representative crops: wheat, as the major crop grown in Israel’s dry southern region, and cotton, representing the more humid climate in the north. Adjusting outputs of the global climate model HadCM3 to the specific research locations, we generated projections for 2070–2100 temperatures and precipitations for two climate change scenarios. Results for wheat vary among climate scenarios; net revenues become negative under the severe scenario (change from −145 to −273%), but may increase under the moderate one (−43 to +35%), depending on nitrogen applied to the crop. Distribution of rain events was found to play a major role in determining yields. By contrast, under both scenarios cotton experiences a considerable decrease in yield with significant economic losses (−240 and −173% in A2 and B2 scenarios, respectively). Additional irrigation and nitrogen may reduce farming losses, unlike changes in seeding dates.     

喷雾降温外场试验结果的初步分析

利用重庆市2011年盛夏高温天气,开展了喷雾降温改善局部小气候的外场试验。试验结果表明:高温天气下,在广场上进行喷雾具有明显降温、改善人体舒适度的效果。降温幅度上午小,下午大。喷雾降温效果存在明显的垂直梯度变化,地表温度降幅最大,1.5 m气温次之,2.2 m气温降幅最小。喷雾工艺条件对降温效果有明显影响,喷头型号不同,地表温度的降幅差别较大,但各高度层降温效果差别不大。喷雾"喷-停"循环时间的长短与喷雾区域温度的变化有明显联系,喷的时间越长,喷雾区域温度降低的幅度就越大。环境风场状况对喷雾降温效果也有明显影响。本试验中,受试验场地周围环境影响,偏东风比偏西风条件下的降温效果好,喷雾降温效果总体随风速的增大而有所降低。     

交通运输对道路两侧土壤及植物的影响研究展望

针对我国汽车工业的快速发展和机动车保有量迅速增加的状况,结合国内外相关研究成果,介绍了交通运输污染物的分类与来源,概述了交通运输对道路周围土壤及植物的影响。根据我国道路交通的实际,探讨了相关领域未来的研究方向,提出应以开发清洁替代能源和深入研究污染物在各环境介质中的迁移转化规律,进而减少污染物对人类的健康损害及筛选对交通运输特征污染物高富集的树种以阻断污染物的迁移为主。     

交通运输对道路两侧土壤及植物的影响研究展望

针对我国汽车工业的快速发展和机动车保有量迅速增加的状况,结合国内外相关研究成果,介绍了交通运输污染物的分类与来源,概述了交通运输对道路周围土壤及植物的影响。根据我国道路交通的实际,探讨了相关领域未来的研究方向,提出应以开发清洁替代能源和深入研究污染物在各环境介质中的迁移转化规律,进而减少污染物对人类的健康损害及筛选对交通运输特征污染物高富集的树种以阻断污染物的迁移为主。     

Effects of crop residue on soil and plant water evaporation in a dryland cotton system

Summary Dryland agricultural cropping systems emphasize sustaining crop yields with limited use of fertilizer while conserving both rain water and the soil. Conservation of these resources may be achieved with management systems that retain residues at the soil surface simultaneously modifying both its energy and water balance. A conservation practice used with cotton grown on erodible soils of the Texas High Plains is to plant cotton into chemically terminated wheat residues. In this study, the partitioning of daily and seasonal evapotranspiration (E _t) into soil and plant water evaporation was compared for a conventional and a terminated-wheat cotton crop using the numerical model ENWATBAL. The model was configured to account for the effects of residue on the radiative fluxes and by introducing an additional resistance to latent and sensible heat fluxes derived from measurements of wind speed and vapor conductance from a soil covered with wheat-stubble. Our results showed that seasonalE _t was similar in both systems and that cumulative soil water evaporation was 50% ofE _t in conventional cotton and 31% ofE _t in the wheat-stubble cotton. Calculated values ofE _t were in agreement with measured values. The main benefit of the wheat residues was to suppress soil water evaporation by intercepting irradiance early in the growing season when the crop leaf area index (LAI) was low. In semiarid regions LAI of dryland cotton seldom exceeds 2 and residues can improve water conservation. Measured soil temperatures showed that early in the season residues reduced temperature at 0.1 m depth by as much as 5°C and that differences between systems diminished with depth and over time. Residues increased lint yield per unit ofE _t while not modifying seasonalE _t and reducing cumulative soil water evaporation.With 8 Figures     

Stubble height effects on seasonal microclimate,water balance,and plant development of no-till winter wheat

To investigate some of the effects of standing stubble on microclimate and on the energy and water balance in relation to plant development, winter wheat (Triticum aestivum L.) was seeded directly into spring wheat stubble of three heights: 0 (bare), 15–19, and 30–35 cm. The soil near Sidney, Montana was Williams loam (fine-loamy mixed, frigid family of Typic Argiborolls) a bench mark soil for dryland cropping in the northern Great Plains of the U.S.A. Total wind passage at 9 cm above ground level was 1.5 and 5 times greater over bare as compared with that over short and tall stubble, respectively. Snow accumulation after a late winter storm was 2 and 4 times greater on short and tall stubble treatments, respectively, than on the bare plots. The first overwinter soil recharge was 3 cm more on both stubble treatments, a difference that persisted throughout the growing season. The second overwinter recharge was ca. 1.5 and 4 cm more on short and tall treatments, respectively. Midday net radiation was as much as 15% higher over the bare treatment in the fall and varied from 5 to 11% lower over the bare treatment in the spring, as compared with that over stubble. Stubble albedo was as much as 1.5 times greater than bare albedo in the fall; differences in the spring were small. On heating days, maximum soil surface temperatures were as much as 10°C higher on bare as compared with stubble treatments and soil heat flow as much as 30% greater on bare as compared with stubble treatments; on freezing days, heat flow differences were small.