• Title/Summary/Keyword: Semi-Arid

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The Adaptation of Ginseng Production of Semi-arid Environments The Example of British Columbia, Canada

  • Bailey, W.G.
    • Proceedings of the Ginseng society Conference
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    • 1990.06a
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    • pp.155-167
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    • 1990
  • Ginseng Is renowned for both its medicinal and herbal uses and successful cultivation of Panax ginseng in Asia and Panax quinquefolium in North America has until recently taken place in the native geographical ranges of the plants. As a consequence of the potential high capital return and anticipated increases in consumer consumption, commercial cultivation of American ginseng now occurs well outside the native range of the plant in North America. In fact, the region of greatest expansion of cultivation is in the semi-arid interior region of British Columbia, Canada. Linked with this expansion is the potential domination of the ginseng industry by agricultural corporations. In the interior of British Columbia, the native deciduous forest environment of eastern North America is simulated with elevated polypropylene shade and a surface covering of straw mulch. The architecture of these environments is designed to permit maximum machinery usage and to minimize labor requirements. Further, with only a four- years growth cycle, plant densities in the gardens are high. In this hot, semi-arid environment, producers believe they have a competitive advantage over other regions in North America because of the low precipitation rates. This helps to minimize atmospheric humidity such that the conditions for fungal disease development are reduced. If soil moisture level become limited, supplemental water can be provided by irrigation. The nature of the radiation and energy balance regimes of the shade and many environments promotes high soil moisture levels. Also, the modified environment redlines soil heating. This can result in an aerial environment for the plant that is stressful and a rooting zone environment that is suloptimal. The challenge of further refining the man modified environment for enhanced plant growth and health still remains. Keywords Panax ginseng, Panax quinquefolium, cultivation, ginseng production.

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Cultural, Morphological and Pathological Variation in Indian Isolates of Ascochyta rabiei, the Chickpea Blight Pathogen

  • Basandrai, A.K.;Pande, S.;Kishore, G. Krishna;Crouch, J.H.;Basandrai, D.
    • The Plant Pathology Journal
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    • v.21 no.3
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    • pp.207-213
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    • 2005
  • Cultural, morphological and pathogenic variation in Indian isolates of Ascochyta rabiei, the causal agent of blight of chickpea, was investigated. Fungal isolates representative of seven agroclimatic regions in north western plain zones (NWPZ) of India showed variation in colony colour as mouse gray with green hue, light mouse gray with slate gray centre and gray with dark brown centre, when grown on chickpea dextrose agar (CDA). Conidiomatal color of the isolates varied from brown to slate gray and black. The number of conidiomata and conidia formed on CDA ranged from 49.7 to 90.7 and $5.5\times10^4\;to\;3\times10^5cm^{-2}$, respectively. The size of conidiomata and conidia of A. rabiei isolates varied from $274\times232{\mu}m\;to\;156\times116{\mu}m$, and from $14.0\times6.2{\mu}m\;to\;10.7\times4.6{\mu}m$, respectively. Fourteen A. rabiei isolates from the seven agroclimatic regions of NWPZ were evaluated for their virulence on 180 chickpea genotypes in controlled environment. Cluster analysis based on the disease rating on a 1-9 scale indicated higher similarity coefficient (> 0.65) between isolates from different agroecological regions, while few isolates from the same region had less similarity. The 14 isolates were grouped into eight pathotypes at > 0.5 similarity coefficient. Sixteen genotypes were identified as probable differentials to distinguish A. rabiei isolates.

Establishment of the Chickpea Wilt Pathogen Fusarium oxysporum f. sp. ciceris in the Soil through Seed Transmission

  • Pande S.;Rao, J. Narayana;Sharma M.
    • The Plant Pathology Journal
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    • v.23 no.1
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    • pp.3-6
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    • 2007
  • Chickpea wilt caused by Fusarium oxysporum f. sp. ciceris(FOC) is the most destructive disease in India. It is seed-borne as well as soil-borne pathogen. The role of seed-borne FOC in introducing and establishing wilt in FOC free soils is unknown. Using seeds of FOC infected chickpea cultivar K 850, we provided an evidence of establishing wilt disease in the FOC free soils within three crop cycles or seasons. In the first cycle, typical wilt symptoms were observed in 24 pots in 41 days after sowing. These 24 pots were used for second and third cycles without changing the soil. These 24 pots were sown with seeds collected from healthy plants of a susceptible cultivar JG 62, one seed per pot and development of wilt symptom was recorded. Wilt symptoms appeared in all the pots 26 days after sowing in second cycle and in 16 days after sowing in third cycle. On selective medium, all of the wilted plants yielded FOC in all the three cycles indicating that the mortality was due to wilt. FOC propagules on selective medium were 172, 1197, and 2280 $g^{-1}$ soil at the end of the first, second, and third cycles, respectively. These studies indicated that Fusarium wilt of chickpea is seed-borne and seeds harvested from wilted plants when mixed with healthy seeds can carry the wilt fungus to new areas and can establish the disease in the soil to economic threshold levels within three seasons.

Evaluation of F$_1$ Hybrids Between RD$_1$ and Bivoltine Breeds of the Silkworm (Bombyx mori L.) for Exploitation in Dry Zones

  • Singh, Ravindra;Rao, D.Raghavendra;Baro, Pranakrishna;Choudhary, Nazia;Gangopadhyay, Debnirmalya;Kariappa, B.K.;Dandin, S.B.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.9 no.2
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    • pp.199-205
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    • 2004
  • With the main objective to know the feasibility of exploitation of F$_1$ hybrids in semi arid and arid climatic conditions of India, the present study was carried out by utilising RD$_1$ as female parent and six bivoltine silkworm breeds viz., CSR$_2$, CSR$_4$, CSR$_{5}$, CSR$_{17}$, CSR$_{18}$ and CSR$_{19}$ along with NB$_4$D$_2$ as male parents. Different hybrids exhibited their superiority for various economic characters during different seasons. Among F$_1$ hybrids, RD$_1$${\times}$CSR$_{5}$ was adjudicated as the best hybrid in terms of expression of significant positive hybrid vigour over mid parental value for five economic characters namely hatching %, cocoon yield, cocoon weight, cocoon shell weight and filament size, highest multiple trait average evaluation index value of 56.77 and comparatively uniform cocoon size with coefficient of variation (CV%) of 3.80 and Standard Deviation (SD) of 7.99 during September - October 2003. Results of the present study revealed that the F$_1$ hybrid RD$_1$${\times}$CSR$_{5}$ can be successfully exploited on commercial in semi arid and arid climatic conditions in India. India.dia.

The Influence of the Characteristics of Drainage Basin on Depositional Processes of the Alluvial Fan: An Example from the Cretaceous Duwon Formation in Goheung Area (유역분지 특성에 따른 충적선상지의 퇴적작용: 고흥군 백악기 두원층의 예)

  • Lee, Kyung Jin;Park, Seung-Ik;Lee, Hyojong;Gihm, Yong Sik
    • Economic and Environmental Geology
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    • v.54 no.4
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    • pp.441-456
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    • 2021
  • The Cretaceous Duwon Formation was studied on the basis of sedimentologic analysis in order to unravel geologic conditions for the development of the streamflow-dominated alluvial fan under arid to semi-arid climatic conditions. The Duwon Formation unconformably overlies the Paleoproterozoic gneiss (basement). Based on the sedimentologic analysis, the Duwon Formation is interpreted to have been deposited in gravelly braided stream (FA-1) near the basement, laterally transitional to sandy braided stream (FA-2) and floodplain environments (FA-3) with distance (< 7 km) from the basement. Lateral changes in sedimentary facies and the well development of calcrete nodules in FA-3, together with radial paleocurrent directions measured in FA-1, are suggestive of the deposition of the Duwon Formation in streamflow-dominated alluvial fan under arid to semi-arid climatic conditions. Recent analysis of detrital zircon chronology suggests that sediments of the Duwon Formation were derived from the southwestern part of the Korean peninsula, including the western part of Yeongnam Massif and the southwestern part of Okcheon Belt. This implies the alluvial fan where the Duwon Formation accumulated had the large drainage basin. Because the large drainage basin can supply the significant amounts of water and temporarily store the sediments within the basin, watery floodwater carried sediments to the alluvial fan rather than the debris flows. Furthermore, the drainage basin largely composed of coarse-grained metamorphic and igneous rocks produced sand-grade sediments, preventing evolution of floodwater into debris flows. We suggest that combined effects of the large drainage basin and its coarse-grained metamorphic and igneous rocks provided favorable conditions for the development of streamflow-dominated alluvial fan, despite arid to semi-arid climatic conditions during sedimentation.

Effect of Housing on Physiological Responses and Energy Expenditure of Sheep in a Semi-arid Region of India

  • Bhatta, Raghavendra;Swain, N.;Verma, D.L.;Singh, N.P.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.8
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    • pp.1188-1193
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    • 2005
  • An investigation was carried out to study the effect of two housing systems on physiological responses and energy expenditure of sheep in a semi-arid region of India. Two types of housing management were adopted. First was a shed- $6{\times}3\;m^2$ structure with all the four sides of 1.8 m chain link fencing with a central height of 3 m. The roof was covered with asbestos sheets and with mud floorings. Second was an open corral- $6{\times}3\;m^2$ open space with all the four sides covered with 1.8 m chain link fencing. Thirty-four (32 ewes and 2 rams) sheep of native Malpura breed aged about 18 months (body weight 28 kg ewes; 35 kg rams) were grazed together on a 35 ha plot of native range. All the sheep were grazed as a flock from 08.00 to 17.00 h during a yearlong study. The flock was divided into two groups (16 ewes+1 ram) in the evening and housed as per the systems (Shed and Open Corral). Dry and wet temperatures were recorded at 06.00 h and 21.00 h using a wet and dry bulb-thermometer both inside the shed and in the open corral and temperature humidity index (THI) was calculated. There was significant (p<0.05) difference in the THI between shed and open corral in all the seasons, indicating that shed was always warmer compared to open corral. Rectal temperature (RT) of both the groups of sheep was similar during morning as well as evening throughout the seasons. There were significant (p<0.05) differences in the skin temperature (ST) and respiration rate (RR) between the two groups at both the measurements in all the seasons. Highest energy expenditure (EE) was recorded inside the shed at 21.00 h (224 kJ/h) during monsoon and lowest at 6.00 h during winter (119 kJ/h). There was a significant (p<0.05) difference between the EE inside the shed and that in the open corral. It was concluded that housing had significant effects on the physiological responses and EE of sheep. Provision of housing at night was stressful during monsoon (with less rainfall) and summer, whereas it was protecting the sheep from acute cold during winter in a semi-arid region of India.

Stochastic simulation based on copula model for intermittent monthly streamflows in arid regions

  • Lee, Taesam;Jeong, Changsam;Park, Taewoong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.488-488
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    • 2015
  • Intermittent streamflow is common phenomenon in arid and semi-arid regions. To manage water resources of intermittent streamflows, stochactic simulation data is essential; however the seasonally stochastic modeling for intermittent streamflow is a difficult task. In this study, using the periodic Markov chain model, we simulate intermittent monthly streamflow for occurrence and the periodic gamma autoregressive and copula models for amount. The copula models were tested in a previous study for the simulation of yearly streamflow, resulting in successful replication of the key and operational statistics of historical data; however, the copula models have never been tested on a monthly time scale. The intermittent models were applied to the Colorado River system in the present study. A few drawbacks of the PGAR model were identified, such as significant underestimation of minimum values on an aggregated yearly time scale and restrictions of the parameter boundaries. Conversely, the copula models do not present such drawbacks but show feasible reproduction of key and operational statistics. We concluded that the periodic Markov chain based the copula models is a practicable method to simulate intermittent monthly streamflow time series.

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A Simple Syntax for Complex Semantics

  • Lee, Kiyong
    • Proceedings of the Korean Society for Language and Information Conference
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    • 2002.02a
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    • pp.2-27
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    • 2002
  • As pact of a long-ranged project that aims at establishing database-theoretic semantics as a model of computational semantics, this presentation focuses on the development of a syntactic component for processing strings of words or sentences to construct semantic data structures. For design arid modeling purposes, the present treatment will be restricted to the analysis of some problematic constructions of Korean involving semi-free word order, conjunction arid temporal anchoring, and adnominal modification and antecedent binding. The present work heavily relies on Hausser's (1999, 2000) SLIM theory for language that is based on surface compositionality, time-linearity arid two other conditions on natural language processing. Time-linear syntax for natural language has been shown to be conceptually simple and computationally efficient. The associated semantics is complex, however, because it must deal with situated language involving interactive multi-agents. Nevertheless, by processing input word strings in a time-linear mode, the syntax cart incrementally construct the necessary semantic structures for relevant queries and valid inferences. The fragment of Korean syntax will be implemented in Malaga, a C-type implementation language that was enriched for both programming and debugging purposes arid that was particluarly made suitable for implementing in Left-Associative Grammar. This presentation will show how the system of syntactic rules with constraining subrules processes Korean sentences in a step-by-step time-linear manner to incrementally construct semantic data structures that mainly specify relations with their argument, temporal, and binding structures.

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Biological soil crusts impress vegetation patches and fertile islands over an arid pediment, Iran

  • Sepehr, Adel;Hosseini, Asma;Naseri, Kamal;Gholamhosseinian, Atoosa
    • Journal of Ecology and Environment
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    • v.46 no.1
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    • pp.31-40
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    • 2022
  • Background: Plant vegetation appears in heterogeneous and patchy forms in arid and semi-arid regions. In these regions, underneath the plant patches and the empty spaces between them are covered by biological soil crusts (moss, lichen, cyanobacteria, and fungi). Biological soil crusts lead to the formation and development of fertile islands in between vegetation patches via nitrogen and carbon fixation and the permeation of runoff water and nutrients in the soil. Results: The present study has investigated the association of biological soil crusts, the development of fertile islands, and the formation of plant patches in part of the Takht-e Soltan protected area, located in Khorasan Razavi Province, Iran. Three sites were randomly selected as the working units and differentiated based on their geomorphological characteristics to the alluvial fan, hillslope, and fluvial terrace landforms. Two-step systematic random sampling was conducted along a 100-meter transect using a 5 m2 plot at a 0-5 cm depth in three repetitions. Fifteen samplings were carried out at each site with a total of 45 samples taken. The results showed that the difference in altitude has a significant relationship with species diversity and decreases with decreasing altitude. Results have revealed that the moisture content of the site, with biocrust has had a considerable increase compared to the other sites, helping to form vegetation patterns and fertile islands. Conclusions: The findings indicated that biological crusts had impacted the allocation of soil parameters. They affect the formation of plant patches by increasing the soil's organic carbon, nitrogen, moisture and nutrient content provide a suitable space for plant growth by increasing the soil fertility in the inter-patch space.