玉米幼苗对风速变化的逆境生理响应     

赵哈林  李瑾  周瑞莲  曲浩  云建英 《干旱地区农业研究》2015,33(6):242-246

为了解玉米幼苗对不同强度风吹危害的逆境生理响应特征,2013年在内蒙古东部科尔沁沙地研究了0（CK）、9、15 m·s^-1和18 m·s^-1净风吹袭20 min下玉米幼苗丙二醛含量（MDA）、膜透性、保护酶活性和渗透调节物质含量的变化。结果表明：随着风吹强度增加,玉米的株高、茎粗生长量和地上生物量下降,其中18 m·s^-1处理的株高和茎粗生长量及地上生物量分别较CK下降4.48%、11.28%和13.23%;风吹胁迫下玉米幼苗丙二醛含量与CK没有显著差异,但各处理膜透性均显著高于CK,其中15 m·s^-1和18 m·s^-1处理膜透性分别较CK增加84.36%和116.62%;随着风吹强度增强,SOD、POD和CAT活性均趋于增加,其中18 m·s^-1处理分别较CK增加37.45%、94.65%和82.14%;随着风吹强度增强,可溶性糖含量明显增加,脯氨酸含量趋于下降,和CK相比,18 m·s^-1处理的可溶性糖含量增加31.48%,脯氨酸含量下降40.26%。结果表明,20 min风吹处理已对玉米生长产生抑制作用,虽未导致玉米幼苗明显的膜脂过氧化,却使其细胞膜受损,SOD、POD和CAT在防止其膜脂过氧化过氧化过程中共同发挥了保护细胞膜的作用,可溶性糖起到了渗透调节作用。  相似文献   

培肥措施对侵蚀坡耕地春玉米产量与土壤养分的影响     

周丽娜  孙婕  雷金银  王天宁 《干旱地区农业研究》2015,33(5):121-125

针对宁南山区坡耕地土壤养分流失严重和作物产量较低的问题,通过剥离表层土壤0、10 cm和20 cm模拟不同侵蚀程度,研究单施化肥(NP)、有机无机配施(M+NP)和单施有机肥(M)、不施肥(CK)4个培肥措施对春玉米产量、耕层土壤有机质、碱解氮、土壤有效磷和土壤速效钾含量的影响,从而提出侵蚀坡耕地增产和培肥效果俱佳的施肥模式。结果表明,相对于CK处理,M和M+NP处理均能改善不同侵蚀程度下坡耕地春玉米的穗长、穗行数、穗粒数和百粒重等农学性状,达到增产目的。随着坡耕地土壤侵蚀程度的增加,春玉米的各产量构成因素和产量都出现显著降低趋势。相对于0 cm土层,表土剥离10 cm和20 cm侵蚀处理下春玉米分别显著减产了26.4%和38.5%。在同等侵蚀条件下,施肥措施能显著增加0~20 cm土壤碱解氮、有效磷和速效钾含量,而对土壤有机质含量影响不大;但随着土壤侵蚀程度的增加,土壤有机质和速效氮、磷、钾养分平均含量呈降低趋势。施用有机肥或有机无机配施还能降低土壤砂粒比例,提高粘粒含量,有效地改善土壤物理结构。  相似文献   

Effect of applications of organic solid cattle manure on Hungarian vetch and barley intercropping mixtures grown on soils of different depths          下载免费PDF全文

H. Yolcu 《Grass and Forage Science》2015,70(3):428-438

Sloping fields on soils of shallow depth to tillage are commonly left uncultivated in many parts of the world. This study was conducted to compare the effects on morphological traits, dry‐matter (DM) yield, legume ratio (LR), crude protein content (CP), crude protein yield (CP yield) and mineral concentrations (N, P, K, S, Ca, Cu, Fe, Mg, Mn, Na, B and Zn) of Hungarian vetch (Vicia pannonica Crantz.) and barley (Hordeum vulgare L.) grown in intercropping mixtures in response to three rates of organic solid cattle manure application (M₀: 0, M₁: 10, M₂: 20 t ha^?1). Experimentation was conducted on soils of two different soil depths [shallow (8–12 cm; low‐medium erosion risk) and normal soil depth (18–22 cm; no erosion risk)] on a sloping field in the 2006–2007 and 2007–2008 growing seasons at Gumushane, Turkey. Herbage harvested on the shallow depth area had 22–73% less DM yield, 14–72% less CP yield, 6–9% greater CP content and generally higher minerals contents than herbage from the normal soil depth area. Cattle manure applications increased DM yield by about 23%, increased CP content and CP yield, and also increased the contents of most minerals in herbage of the intercropping mixtures, relative to the control, averaged over the two soil depths. It is suggested that, for areas with shallow soil depths that are prone to erosion, plant cover should be used for forage production, and that fertilization with solid cattle manure at 20 t ha^?1 can support production of quality forage of acceptable DM yield.  相似文献   

Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau     

JianHua XIAO  JianJun QU  ZhengYi YAO  YingJun PANG  KeCun ZHANG 《干旱区科学》2015,7(1):10-26

The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za’gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes. Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a "narrow-pipe effect", which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form:(1) strong winds, sufficient sand, suitable obstacles and a dry climate;(2) one or both sides of the obstacle forming the shadow zone must have a hill pass; and(3) the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology.  相似文献   

Changes of forest fire regime and landscape pattern under different harvesting modes in a boreal forest of Northeast China     

CHEN Hongwei 《干旱区科学》2015,7(6):841-851

Forest management such as timber harvesting shapes fire regimes and landscape patterns, and these patterns often differ significantly from those under natural disturbances. Our objective was to examine the effects of timber harvesting modes on fire regimes and landscape patterns in a boreal forest of Northeast China. We used a spatially explicit landscape model, LANDIS, to simulate the changes of forest landscape in the Huzhong forest region of the Great Khingan Mountains under no-cutting, clear-cutting, gradual-cutting and selective-cutting modes. Results showed that:(1) the fine fuel loadings generally decreased while the coarse fuel loadings increased with the increase of timber harvesting intensity;(2) the potential burn area significantly varied among different cutting modes, but the potential fire frequency had no obvious difference. Moreover, timber harvesting generally increased the potential fire risk;(3) clear-cutting mode significantly decreased the mean patch size and the aggregation of larch forests and increased the mean patch size and the aggregation of white birch forests. Therefore, clear-cutting mode should be abandoned, and selective-cutting mode be recommended for the sustainable forest management in the Great Khingan Mountains.  相似文献   

Changes in the distributions of freshwater mussels (Unionoida: Hyriidae) in coastal south‐eastern Australia and implications for their conservation status          下载免费PDF全文

Hugh A. Jones  Maria Byrne 《水产资源保护:海洋与淡水生态系统》2014,24(2):203-217

低风速下H型垂直轴风力机气动性能     

杨从新  李寿图  王秀勇 《排灌机械工程学报》2014,32(10):888-893

为了准确地研究低风速下H型垂直轴风力机的特性,以自主研发的H型垂直轴风力机为研究对象,采用数值模拟方法,分析了低风速下H型垂直轴风力机的气动性能和三维效应特征.分析结果表明:低风速区域,保持叶尖速比不变,改变风轮转速或来流风速,对H型垂直轴风力机的功率系数影响较大,且风速对叶尖速比的影响比转速的影响更敏感;在低风速区域,即使转速较大,风力机实际仍工作在低叶尖速比区域;在数值模拟中,设定合理的风速和转速的匹配有利于提高模拟结果的可靠性;在不考虑风剪切的情况下,三维效应受叶尖涡影响,且叶尖涡在0°方位角的位置时影响较大,同时还受风轮内流场的作用,且这种作用随着转速的增加而增强.计算结果为进一步研究H型垂直轴风力机提供了参考.  相似文献   

基于GIS的黑龙江省拉林河流域土壤侵蚀空间特征分析   总被引：1，自引：0，他引：1  

周宁    李超  满秀玲 《水土保持研究》2014,21(6):10-15

以黑龙江省拉林河流域为研究区,利用USLE计算土壤侵蚀模数,并建立了基于GIS的空间栅格数据库。采用地统计分析方法,进行研究区的土壤侵蚀模数空间特征分析。对比现行两种土壤侵蚀强度分级标准,分析确定适用的土壤侵蚀强度分级标准。采用空间和趋势分析方法,进行研究区的土壤侵蚀强度空间分布特征分析。结果表明:（1）研究区的土壤侵蚀模数分布具有强烈的空间相关性,自西向东、由北至南呈线型增大的分布趋势;（2）《黑土区水土流失综合防治技术标准标准》中规定的土壤侵蚀强度分级标准适用性更强;（3）研究区的土壤侵蚀面积占总面积的94%,强烈、轻度和中度水力侵蚀为主要的侵蚀强度类型;强烈水力侵蚀主要分布于西部的洪积台地,轻度水力侵蚀主要分布于东部的低山丘陵宽谷,中度水力侵蚀主要分布于中部的地貌过渡带,极强烈和剧烈水力侵蚀主要呈零散状分布于东部的低山丘陵沟壑,中部和西部也有零星分布;随植被覆盖度的降低,土壤侵蚀强度等级自东向西呈增大趋势。  相似文献   

基于WEPP模型的多级梯田暴雨侵蚀模拟初步研究     

贾立志    高建恩    许秀泉    白先发    张元星 《水土保持研究》2014,21(6):1-5

针对2013年6—9月份安塞县马家沟多级梯田遭受暴雨侵蚀严重等问题,运用新一代水蚀预报模型WEPP模型对马家沟多级梯田在暴雨条件下的侵蚀情况进行模拟,并将WEPP模型模拟的结果与实测资料进行了对比。结果表明:WEPP 模型能够较好地模拟黄土丘陵区多级梯田在暴雨条件下的径流量以及土壤侵蚀量,随着梯田级数的增加,WEPP模型对径流量与侵蚀量的模拟精度逐渐降低。由于受该区地下水的影响,模拟径流量总体小于采用径流系数法算得的径流量,由于梯田田埂的防蚀作用,模拟土壤侵蚀量总体大于实测侵蚀量。研究为黄土丘陵区梯田防蚀以及梯田修筑提供科学依据及有效方法,为黄土丘陵区多级梯田的暴雨侵蚀预测提供了合理化建议。  相似文献   

璧山县土壤侵蚀特征及影响因子研究     

兰明娟  魏虹  朱韦  熊春妮 《中国水土保持》2009,(2):15-18

在ArcG IS平台下,利用璧山县2001年DEM图、土地利用现状图和土壤侵蚀等级图等数据源,对研究区土壤侵蚀在不同坡度、不同海拔和不同土地利用方式下的分布特征进行了研究。结果表明:6°—15°坡度是各级侵蚀发生最多的地带;200—400 m海拔梯度是各级侵蚀发生的主要地带;耕地是导致土壤侵蚀的主要土地利用方式。针对璧山县实际,提出了加强水土保持生态建设的建议。  相似文献