Process studies in aPinus radiata-pasture agroforestry system in a subhumid temperature environment. I. Water use and light interception in the third year     

I. A. M. Yunusa  D. J. Mead  K. M. Pollock  R. J. Lucas 《Agroforestry Systems》1995,32(2):163-183

In this study we determined soil moisture storage, evapotranspiration (ET) and light interception in an agroforestry trial consisting of pine trees grown over (1) control (bare ground), (2) ryegrass/clovers (Lolium perene/Trifolium spp.), (3) lucerne (Medicago sativa), and (4) ryegrass only during the third growing season between 1992 and 1993. The results show that:

1.	In the period when rainfall was frequent and exceeded the evaporative demand (Epot), ET and depletion of soil moisture were not affected by the ground cover treatments. During summer when rainfall was less frequent, but with moisture readily available in the soil profile, ET was associated with plant canopy, and was significantly higher for the pasture ground covers than for the control. Therefore, the more rapid growth by lucerne caused higher ET in this ground cover than in the ryegrass/clovers ground cover in which the pasture was slow growing. At the end of the study period, total ET was in the following order: lucerne (757 mm) > ryegrass/clovers (729 mm) > Control (618 mm).
2.	ET was dominated by pasture transpiration (Ep) during most of the growing season, but by tree transpiration (Et) in winter when large parts of the pasture canopy was shaded. Ep was always at least 16% higher for lucerne than for ryegrass/clovers species as a result of a greater radiation intercepted by the former.
3.	Fraction of incoming radiation intercepted by the tree crowns was in the following order: control > ryegrass > ryegrass/clovers > lucerne. At the end of the one-year period, fraction of intercepted radiation was 140% greater for control than for lucerne ground cover.
4.	The control produced the largest tree crowns, which were almost twice the tree crowns in the lucerne ground cover which produced the smallest trees. Accordingly, the trees in the control intercepted more radiation and rainfall, with the former being lost to evaporation, than the trees in the pasture.
5.	The fractions of radiation intercepted and ET accounted for by the trees and pastures were associated with the proportion of the plot area they occupied.

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Contrasting rooting patterns of some arid-zone fruit tree species from Botswana – I. Fine root distribution     

Armin L.?OppeltEmail author  Winfried?Kurth  Georg?Jentschke  Douglas?L.?Godbold 《Agroforestry Systems》2005,65(1):1-11

To assess the possible degree of root competition from fruit trees which could potentially be used in agroforestry systems, fine root density of fruit trees Strychnos cocculoides Bak., Strychnos spinosa Lam. (Loganiaceae) and Vangueria infausta Burch. (Rubiaceae), as well as from the shrubby species, Grewia flava DC. (Tiliaceae) was investigated. Vangueria infausta had the highest fine root densities in both vertical and horizontal extensions. In Vangueria infausta fine root density decreased with increasing soil depth. For the other species in the 80 cm soil profile investigated, no significant changes in fine root density with soil depth were found. For Strychnos cocculoides almost no fine roots were detected in the upper soil horizon (0–20 cm). Using fine root surface area densities, exploration and exploitation indices were calculated. Vangueria infausta had the highest value of the exploration index compared to the other species. For use in agroforestry systems Vangueria infausta was estimated to be the most competitive of the investigated species, whereas Strychnos cocculoides seems to be the less competitive. Strychnos cocculoides has additionally spatial arrangements of fine roots favourable for agroforestry, slowly increasing with depth and additionally low concentrations in upper soil layers.  相似文献   

我国相思类树种研究文献计量学分析     

黄烈健  詹妮 《广东林业科技》2015,31(3):113-117

以中国知网统计的源期刊为依据,通过对1965年3月-2014年10月间有关相思研究论文的发表数量、发表时间、研究内容、发文单位、期刊分布等进行统计分析,了解我国相思研究进展,指出相思树研究的不足之处以及今后研究发展方向。  相似文献   

Prevalence and incidence of the root-inhabiting fungi, Fusarium, Cylindrocarpon and Pythium, on container-grown Douglas-fir and spruce seedlings in British Columbia     

H. H. Kope  P. E. Axelrood  J. Sutherland  M. S. Reddy 《New Forests》1996,12(1):55-67

Surveys were made at the end of the 1990 and 1991 growing seasons for root-inhabiting fungi in the genera Fusarium, Cylindrocarpon and Pythium from the roots of one year-old container-grown Douglas-fir and spruce seedlings grown under greenhouse conditions. In the 1990 survey of four nurseries, it was found that 61–97% of both Douglas-fir and spruce roots were colonized with Fusarium, Cylindrocarpon or Pythium. There were significantly (p0.05) more Douglas-fir roots than spruce roots colonized by Fusarium at all nurseries, however, there were significantly (p0.05) more spruce roots than Douglas-fir roots colonized by Cylindrocarpon and Pythium. Root colonization of Douglas-fir and spruce by the three fungal genera during 1991 varied from 0–82% at three nurseries, however, only at a south coastal nursery was there significantly (p0.05) more spruce than Douglas-fir roots colonized by Cylindrocarpon. Significantly more seedlings were infected in 1990 than in 1991. In 1991, there were few significant differences between Douglas-fir and spruce, in the percentage of seedlings with colonized roots and in the percentage of growth medium colonized by the fungi. However, there were significant differences between nurseries.  相似文献   

辽宁省松毛虫监测预报信息管理系统的研究   总被引：8，自引：0，他引：8  

肖艳  常忠连 《辽宁林业科技》2004,(3):13-15

利用计算机技术，采用Visual Foxpro 6．0可视化数据库开发工具，建立了辽宁省松毛虫监测预报信息管理系统，实现了对松毛虫的系统虫情调查资料、监测调查资料及小班虫情资料的自动化管理。可以完成包括松毛虫监测预报信息的自动填写、自动提供相应默认值、表内表间数据自动计算并生成汇总表、对原始数据进行逻辑判断和自动改错以及查询等多项功能。  相似文献   

Anethole inhibits growth of recently emerged multidrug resistant toxigenic Vibrio cholerae O1 El Tor variant strains in vitro     

M. Shamim Hasan ZAHID  Sharda Prasad AWASTHI  Atsushi HINENOYA  Shinji YAMASAKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(5):535-540

To search natural compounds having inhibitory effect on bacterial growth is important, particularly in view of growing multidrug resistant (MDR) strains of bacterial pathogens. Like other bacterial pathogens, MDR Vibrio cholerae, the causative agent of diarrheal disease cholera, is becoming a great concern. As an approach of searching new antimicrobial agents, here, we show that anethole, a well-studied natural component of sweet fennel and star anise seeds, could potentially inhibit the growth of MDR O1 El Tor biotype, the ongoing 7th cholera pandemic variant strains of toxigenic V. cholerae. The minimum inhibitory concentration (MIC) of anethole against diverse O1 El Tor biotype strains is evaluated as 200 µg/ml. Moreover, the effect of anethole is bactericidal and exerts rapid-killing action on V. cholerae cells. This study is the first report which demonstrates that anethole, purified from natural compound, is a potent inhibitor of growth of toxigenic V. cholerae. Our data suggest that anethole could be a potential antimicrobial drug candidate, particularly against MDR V. cholerae mediated infections.  相似文献   

Acute renal failure associated with Amaranthus species ingestion by lambs          下载免费PDF全文

AE Kessell  J Boulton  GL Krebs  JC Quinn 《Australian veterinary journal》2015,93(6):208-213

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苌楚鸠蝠蛾的生物学特性及防治研究   总被引：2，自引：0，他引：2  

林毓银  吴志远 《林业科学》1995,31(2):144-149

苌楚鸠蝠蛾Ｐｈａｓｓｕｓ ａｃｔｉｎｉｄｉａｅ Ｙａｎｇ ｅｔ Ｗａｎｇ是福建近年来严重为害猕猴的一种新的蛀干害虫。我们于１９８４－１９８９年在建宁县猕猴桃试验站进行研究。该虫一年一代，以卵在树兜的地面越冬，幼虫为害猕猴桃植株韧皮部和髓部，外部形成虫屑包，内部形成蛀道，阻滞养分和水分的正常输送，轻者枝叶发黄，重者风折枯死。除选用抗虫品种外，采用２．５％溴氰菊脂１∶５０００液灌注；９０％敌百虫晶体１  相似文献   

Can Batesian mimicry help plants to deter herbivores?     

Massei G  Cotterill JV  Coats JC  Bryning G  Cowan DP 《Pest management science》2007,63(6):559-563

Several authors have suggested that edible plants could avoid herbivory by mimicking olfactory cues of toxic plants. However, very few studies have been carried out to test this hypothesis. The aims of the present study were to identify the volatiles of three clover species and to test whether a species lacking chemical defences, such as red clover, could avoid being grazed by rabbits by mimicking the volatiles of the cyanogenic white clover. Two main volatiles were identified in all three clover species, and a further two volatiles were present in white clover only. Rabbits presented with a choice between white clover, red clover and red clover sprayed with white clover extract ate significantly more red clover than white or white-flavoured red clover. The results suggest that the volatiles of toxic plants could be used and exploited as a source of natural, safe and effective repellents to control the impact of pest herbivores on plants.  相似文献   

Quantification of allele E198A in beta-tubulin conferring benzimidazole resistance in Monilinia fructicola using real-time PCR     

Luo Y  Ma Z  Michailides TJ 《Pest management science》2007,63(12):1178-1184

BACKGROUND: Thiophanate-methyl, a member of the benzimidazole class of fungicides, is used in California to control brown rot of stone fruit caused by Monilinia fructicola (G. Wint.) Honey. The goal of this study was to develop a real-time polymerase chain reaction (PCR) assay as an efficient method to quantify the E198A allele of beta-tubulin that confers benzimidazole resistance. RESULTS: Using the real-time PCR assay, the frequency of allele E198A (FEA) in a population was determined from the quantities of DNA amplified with the E198A allele-specific primer pair HRF/HRR and the M. fructicola-specific primer pair MfF6/MfR6. The average proportions of highly resistant isolates determined with the conventional fungicide sensitivity method were within the range of average FEA values determined with the real-time PCR assay. We also determined the FEAs of M. fructicola populations sampled from 21 stone fruit orchards in California. Only one orchard showed a high FEA over 0.20, seven orchards had values between 0.01 and 0.1, and 13 orchards had values less than 0.01. CONCLUSION: The real-time PCR assay developed in this study provides a potentially useful tool to efficiently quantify benzimidazole resistance for large M. fructicola populations.  相似文献