仪器测墒按需补灌对冬小麦产量和水分利用效率的影响

利用频域反射法(FDR)、时域反射法(TDR)和驻波率法(SWR)三种便携式土壤水分快速测试仪,在田间条件下测定土壤田间持水量(FCv)和体积含水量(WCv),于冬小麦越冬前、拔节期和开花期设补灌的目标土壤相对含水量分别为80%、70%和70%,每一补灌时期设20 cm、40 cm和60 cm三个测墒土层深度,研究不同仪器法在冬小麦生育期间对土壤水分测定的准确度和稳定性,探索用不同仪器测定数据计算灌水定额进行冬小麦补灌的效果及其差异原因。结果表明,FDR和SWR仪器测得的FCv换算为以水土质量百分比表示的田间持水量FCv-m,与传统方法测得的田间持水量FCm之间的相对误差为0.4%~2.6%;TDR仪器测定计算得出的WCv-m值与烘干法测得的WCm值的相对误差与相应土层土壤温度呈极显著正相关,在冬小麦播种期、开花期和成熟期较高,在越冬前和拔节期较低;SWR仪器测定计算得出的WCv-m值与WCm值的相对误差与相应土层土壤含水量呈极显著负相关,在土壤含水量较高的条件下测量的准确度较高。FDR仪器在冬小麦生育期内测量的准确性受土壤温度和水分的影响较小,准确度和稳定性均较高,直接利用其测定的FCv和WCv值计算灌水定额补灌,获得了与传统烘干法测墒补灌一致的效果。     

基于电阻率成像的沙地土壤水分监测技术

土壤水分是影响干旱半干旱区植物生长的主要因素,快速准确、长期连续地监测土壤水分时空动态可为干旱半干旱区植被建设与生态恢复提供科学依据。以乌兰布和沙漠东北部灌木林地土壤为研究对象,应用多电极电阻仪对林地土壤电阻率进行了测量,同步采取土样用烘干法测定了土壤实际含水率,建立了2者之间的相关关系,并对剖面上土壤水分空间特征进行了分析。结果表明:1)土壤含水率(y)与土壤电阻率(x)之间为极显著负相关关系(R2=0. 81,P <0. 01),可用幂函数y=88. 68x-0. 63表示。2)强降水之后,二维剖面上土壤水分整体呈增加趋势。随着雨后时间的延长,1m以上土层的含水率由于受蒸发和植物蒸腾耗水而明显降低,1m以下土层的含水率由于受上层水分入渗有增加趋势,说明连续强降雨(81. 2mm)能对1m以下土层的土壤水分进行有效补给。3)多电极电阻率成像技术在野外能够快速准确,长期定位监测土壤水分含量;且对地表扰动小,实现了非破坏性测量;能够提供尺度较大、分辨率较高的土壤水分二维分布图像及水分入渗过程的图像,是今后中等尺度上监测土壤水分的一种新途径。     

TDR在测量农田土壤水分中的室内标定

给出了一种较简便、准确的时域反射仪(TDR)室内标定方法,该方法工作量小,克服了田间土壤水分空间变异的影响,更适用于粘壤土质的TDR标定。通过对昆山地区粘壤土质的实例标定发现,TDR测量值较烘干法明显偏低,绝对偏差范围0.02~0.09 cm3/cm3,相对偏差随着土壤含水量的减小有增加趋势。但TDR的测量值与真实值之间有较高的相关性(R2=0.9837,P<0.001),可以用一个简单的线形函数进行校正,校正后的TDR测量值中将有98.4%的值接近土壤含水量真实值,说明该校正公式可以作为昆山地区进行TDR校正的参考。     

HH2型土壤湿度计测定土壤含水量的标定研究

就HH2型土壤湿度计在黄土高原沟壑区黑垆土表层的应用进行了标定研究,分析了HH2测量的准确性,各容重标定曲线的精度和灵敏度。结果表明:在各种容重条件下用HH2测量土壤水分,输出电压的变异系数小于6%,仪器的准确性较高。线性标定方程斜率a随容重的增大而增加,常数b则相反。容重标定曲线对HH2的可调参数a0、a1影响较小。当土壤水分含量为18%～19%时,不同容重的标定曲线的差别最低。     

民勤荒漠绿洲过渡带粘土夹层水力性质及其生态水文意义探讨

土壤水力性质是土壤水文功能的重要组成部分及影响因子，其对土壤水分分布状态、土壤水分循环的强度与速率具有重要影响。粘土夹层虽在干旱区呈不连续分布的状态，但其植被覆盖率却远高于相同水热条件下的非夹粘土壤。文中以民勤荒漠绿洲过渡带粘土夹层为研究对象，对其土壤物理性质、土壤持水性和导水性质进行测量，同时利用壕沟法对该地15年林龄的深根系乡土物种多枝柽柳根系进行了调查，分析了夹粘土壤剖面的水力性质变化特征及其影响因素，探讨了粘土夹层对干旱区植被恢复和重建的生态水文意义。结果表明：1)土壤颗粒组成和有机质含量是影响土壤持水性和导水性的重要因子。2)15年林龄多枝柽柳根系生物量(d<2mm)在粘土夹层上下界面处呈现明显增加的趋势。3)粘土夹层具有较高的持水性，其可通过毛管作用补给其他土层，同时，粘土夹层阻滞了土壤水分的运移，二者的共同作用改善了粘土夹层上下界面处的土壤水分条件。粘土夹层可以改变土壤水分入渗和存储的环境，在含有粘土夹层的土壤上进行植被建设，有助于干旱区固沙植被的恢复和建设。文中研究为了解荒漠绿洲过渡带土壤水文过程、生态恢复和重建提供了一定的数据支持。     

土壤水分电磁测量方法的研究进展

从广义电磁波角度，讨论了土壤水分电磁测量方法的物理机理，详细分析了土壤水分广义电磁测量方法的研究历史、现状和问题。指出现有各种土壤水分电磁测量方法误差大的核心原因是由于土壤理化特性空间变异造成的，因此，深入研究田间土壤理化特性空间变异对土壤电磁特性影响规律，寻找水分敏感性强而土壤容重、质地、含盐量影响小的测量方法和测量频率，并把这一理论研究与传感测试技术研究结合是土壤水分电磁测量理论与技术的研究方向。     

频率域反射仪测定土壤含水量的校正与田间验证

为了获得精确的土壤含水量测定数据,在室内和田间分别进行了频率域反射仪(FDR)测定土壤含水量的校正,并在田间运用土钻取样和烘干法对模型参数进行了验证。结果表明,室内试验获得了较好的模型参数,均方根误差平均达到了0.023 m3/m3,但是应用到田间条件下误差很大,均方根误差平均为0.066 m3/m3;田间条件下也间接获得了较好的模型参数,均方根误差的平均值为0.026 m3/m3,应用于田间时测定含水量的精确度较高,均方根误差的平均值为0.026 m3/m3。因此,对于构成复杂的城市或园林土壤,在不挖剖面或土钻取样破坏土壤的前提下,建议采用田间间接法进行校正。     

宁夏黄土丘陵区冬小麦农田土壤呼吸特征及影响因素分析

土壤呼吸是陆地碳循环研究的关键环节,是大气CO2的重要来源,文中以冬小麦农田为研究对象,利用ACE土壤呼吸自动监测系统,研究了冬小麦农田土壤呼吸、土壤温度、土壤水分和光合有效辐射的变化特征、相互关系以及碳释放量。结果表明:1)土壤呼吸日变化呈现"单峰型",最大值出现在13:00左右,最小值出现在夜间;2)土壤呼吸日变化表明土壤呼吸与土壤温度(0-10cm)和光合有效辐射呈显著正相关关系(P<0.01),与土壤水分的关系不确定;3)土壤呼吸季节变化表明土壤呼吸与土壤温度呈显著正相关关系(P<0.01),与土壤水分和光合有效辐射无显著相关关系;4)冬小麦农田碳释放量168gC·m-2·a-1。     

内蒙古东北部大豆灌溉动态预报模型

为实现内蒙古东北部大豆农田灌溉动态预报,应用多项式拟合方法将大豆适宜土壤湿度下限值插值到全生育期的每一天,形成适宜土壤水分下限动态连续指标曲线,并从土壤-作物-大气连续体角度出发,依据农田土壤水分平衡理论,利用内蒙古突泉农业气象试验站2001—2007年土壤水分数据和气象资料,建立了适合内蒙古东北部旱作农区的大豆灌溉动态预报模型,实现了灌溉日期和灌溉量的时域滚动预报;利用2008—2011年实测数据验证该模型模拟结果,土壤相对湿度预测值与实测值的均方根误差(RMSE)和平均绝对百分比误差(MAPE)分别为2.44%和3.42%,预报灌溉日期的误差在-3~3 d之间,表明模型准确性和实用性较强,可为东北大豆产区节水灌溉提供一定的科学依据。     

黑龙港地区夏玉米生长期综合ET试验研究

为了研究人类活动影响下流域二元水循环中农作物耗水通量特征,在华北平原黑龙港地区夏玉米生长期内,使用FDR与中子仪对土壤表层和剖面含水率分别进行了田间测量,对玉米的不同生长阶段特性、生长期内降雨以及土壤含水率的变化进行了分析.并以此为基础,对玉米苗期,拔节,抽雄,灌浆等各生长阶段利用水量平衡法进行了蒸散发量(ET)计算和...     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

Richtlinien der Verbände des ökologischen Landbaus zum Vorratsschutz

Zusammenfassung Verbände des ökologischen Landbaus wie z. B. Bioland, Gäa, Demeter; Naturland, Ernte für das Leben oder Bio Suisse beschränken ihre Mitglieder bei der Wahl von Vorratsschutzmaßnahmen. Vorrang besitzen Maßnahmen zur Vermeidung von Schädlingen gegenüber Bekämpfungsmaßnahmen. Fallen müssen zur Befallsüberwachung eingesetzt werden, um einen Befall durch Vorratsschädlinge frühzeitig zu erkennen. Diese Maßnahmen sollen den weitgehenden Verzicht auf chemisch-synthetische Mittel ermöglichen. In diesem Beitrag werden die Empfehlungen der Verbände mit den derzeit verfügbaren chemischen Mitteln für den Vorratsschutz abgeglichen. Erfahrung in der praktischen Umsetzung von physikalischen und biologischen Verfahren werden diskutiert und Defizite bei der Befallsüberwachung und Bekämpfung beschrieben.