Seed Germination Characteristics ofRhus tripartitum(Ucria) Grande andZiziphus lotus(L.): Effects of Water Stress

Ziziphus lotus(L.) Lam. (Rhamnaceae) andRhus tripartitumor Sumac (Anacardiaceae) are two indigenous species from arid and semiarid regions of Tunisia, characterized by a severe climate where dry seasons are very long. The combined action of anthropogenic factors and climate in arid regions caused a gradual threat of plant assets. In this context, an experimental study of the effects of water stress (0 to −1 MPa) on seeds has identified the water requirements germinal stage of both species. The results showed that both species were able to germinate at relatively low water potentials. However, beyond −0.6 MPa, germination was completely inhibited forR. tripartitum, when it reached for another 50% forZ. lotus. Increasing the concentration of PEG6000progressively inhibited germination in both species. OnlyZ. lotuscould be considered tolerant of water stress, because, to −1 MPa, seeds germinated with a rate of 17%. It resulted in that the speciesZ. lotuspresented an adaptive capacity to aridity much greater than that observed forR. tripartitum.

Download Full-text

MOSAICITY OF THE VEGETATION COVER OF THE KOCHUBEY BIOSPHERE STATION PASTURES

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2020/3/40-42 ◽

1970 ◽

pp. 40-42

Author(s):

М. А. Babaeva ◽

S. V. Osipova

Keyword(s):

Plant Species ◽

Vegetation Cover ◽

Cynodon Dactylon ◽

Plant Cover ◽

Avena Fatua ◽

Living Environment ◽

Anthropogenic Factors ◽

Indigenous Species ◽

Fodder Plants ◽

Falcaria Vulgaris

The regularities of changes in the resistance of different groups of fodder plants to adverse conditions were studied. This is due to the physiological properties that allow them to overcome the harmful effects of the environment. As a result of research species - plant groups with great adaptive potential to the harsh continental semi-desert conditions were identified. Monitoring observation and experimental studies showed too thin vegetation cover as a mosaic, consisting of perennial xerophytic herbs and semishrubs, sod grasses, saltwort and wormwood, as well as ephemera and ephemeroids under the same environmental conditions, depending on various climatic and anthropogenic factors. This is due to the inability or instability of plant species to aggressive living environment. It results in horizontal heterogeneity of the grass stand, division into smaller structures, and mosaic in the vegetation cover of the Kochubey biosphere station. The relative resistance to moderate stress was identified in the following species from fodder plants Agropyron cristatum, A. desertorum, Festuca valesiaca, Cynodon dactylon, Avena fatua; as for strong increasing their abundance these are poorly eaten plant species Artemisia taurica, Atriplex tatarica, Falcaria vulgaris, Veronica arvensis, Arabidopsis thaliana and other. On the site with an increasing pressure in the herbage of phytocenoses the number of xerophytes of ruderal species increases and the spatial structure of the vegetation cover is simplified. In plant communities indigenous species are replaced by adventive plant species. The mosaic of the plant cover of phytocenoses arises due to the uneven distribution in the space of environmental formation, i.e. an edificatory: Salsola orientalis, S. dendroides, Avena fatua, Cynodon dactylon, Artemisia taurica, A. lercheanum, Xanthium spinosum, Carex pachystyli, under which the remaining components of the community adapt. Based on the phytocenotic indicators of pasture phytocenoses it can be concluded that the vegetation cover is in the stage of ecological stress and a decrease in the share of fodder crops and an increase in the number of herbs indicates this fact.

Download Full-text

Study on Prediction Model of Karstic Large Spring Water Level Dynamic Coupling Multiple Factors in Jinan

The Open Fuels & Energy Science Journal ◽

10.2174/1876973x01508010309 ◽

2015 ◽

Vol 8 (1) ◽

pp. 309-317 ◽

Cited By ~ 1

Author(s):

Xing Liting ◽

Zhou Juan ◽

Zhang Fengjuan ◽

Wang Song ◽

Dou Tongwen ◽

...

Keyword(s):

Prediction Model ◽

Water Level ◽

Spring Water ◽

Anthropogenic Factors ◽

Karst Water ◽

Multiple Factors ◽

Factors Influencing ◽

Heterogeneous Features ◽

Dry Seasons ◽

Natural Decay

In karst regions, due to the heterogeneous features of karst medium, the characteristics of the groundwater flow turn to be of high complexity. Researchers have been seeking proper forecasting methods for karst water dynamic for many years. This paper, taking the spring in Jinan as an example, using regression analysis, analyzed the factors influencing spring water dynamic, and quantitatively evaluated the influencing coefficients of spring water level concerning rainfall, exploitation and recharge as well as the natural decay coefficient of spring water in dry seasons. The prediction model coupling multiple factors was built by investigating natural and anthropogenic factors influencing groundwater level, which could be used for forecasting dynamic of spring water in Jinan. The calculated value of model was highly coincided with the observed value. In consideration of the characteristics of uneven precipitation in Jinan, the suitable zones and volume of artificial recharge were investigated finally, which could help to sustain the spewing of Jinan springs significantly.

Download Full-text

Investigation of Water Stress on Kochia Scoparia L. in Arid and Semiarid Areas

Handbook of Irrigation System Selection for Semi-Arid Regions ◽

10.1201/9781003050261-8 ◽

2020 ◽

pp. 81-91

Author(s):

Mona Golabi ◽

Reza Sadegh Mansouri ◽

Saeed Boroomand Nasab ◽

Maasomeh Salehi

Keyword(s):

Water Stress ◽

Kochia Scoparia ◽

Semiarid Areas ◽

Arid And Semiarid Areas ◽

Arid And Semiarid

Download Full-text

Atmospheric Optical Turbulence Profile Measurement and Model Improvement over Arid and Semi-arid regions

10.5194/amt-2021-55 ◽

2021 ◽

Author(s):

Hao Yang ◽

Zhiyuan Fang ◽

Cheng Li ◽

Xu Deng ◽

Kunming Xing ◽

...

Keyword(s):

Observational Data ◽

Arid Regions ◽

Northwestern China ◽

Profile Measurement ◽

Height Distribution ◽

Optical Turbulence ◽

Different Seasons ◽

Combined Action ◽

Model Improvement ◽

Improved Model

Abstract. From August 4th to 30th, 2020 and from November 27th to December 25th, 2020, a self-developed radiosonde balloon system was used to observe high-altitude atmospheric optical turbulence at three sites in northwestern China, and an improved model based on the observational data was established. Through comparative analysis of the observational data and the improved model, the distribution characteristics of atmospheric optical turbulence under the combined action of different meteorological parameters and different landform features in different seasons were obtained. The improved model can show the variation of the detailed characteristics of turbulence with the height distribution, and the degree of correlation with the measured values is above 0.82. The improved model can provide a theoretical basis and supporting data for turbulence estimation and forecasting in northwestern China.

Download Full-text

Under-vine cover crops: impact on weed development, yield and grape composition

OENO One ◽

10.20870/oeno-one.2020.54.4.4149 ◽

2020 ◽

Vol 54 (4) ◽

pp. 975-983

Author(s):

Javier Abad ◽

Marín Diana ◽

Santesteban L. Gonzaga ◽

Cibriáin José Félix ◽

Sagüés Ana

Keyword(s):

Water Stress ◽

Cover Crops ◽

Drip Irrigation ◽

Vegetative Growth ◽

Cover Crop ◽

Sustainable Management ◽

Arid Regions ◽

Management Tool ◽

Second Year ◽

Semi Arid

This study aims to evaluate the interest of using an under-vine cover crop as a sustainable management tool replacing herbicides or tillage to control weeds, evaluating its effects on yield and berry parameters in a semi-arid climate. The performance of Trifolium fragiferum as an under-vine cover crop was evaluated in 2018 and 2019 in a Merlot vineyard in Traibuenas (Navarra, Spain). This trial showed that the soil under the vines was covered by 80 % of the cover crop in August 2018 and 100 % in Aug 2019, with clover (T. fragiferum) comprising around 26 % and 70 % of the cover crop surface, respectively. The presence of the cover crop only reduced the number of shoots in the second year, although both years there was an increment in water stress. Neither yield, cluster weight nor berry weight were affected by the presence of the under-vine cover crop. Similarly, no changes in grape composition were observed. The use of T. fragiferum-like cover crops under the vine allows for better control of weeds, provided a good installation is achieved. In the first two years, this cover crop reduced vegetative growth and increased water deficit slightly. However, no changes in yield and grape composition were observed.In a context of herbicide suppression and search for sustainable management, under-vine clover cover crops constitute a viable alternative in semi-arid regions provided drip irrigation can be applied.

Download Full-text

A conceptual dynamic vegetation-soil model for arid and semiarid zones

Hydrology and Earth System Sciences ◽

10.5194/hess-12-1175-2008 ◽

2008 ◽

Vol 12 (5) ◽

pp. 1175-1187 ◽

Cited By ~ 17

Author(s):

D. I. Quevedo ◽

F. Francés

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Water Balance ◽

Water Availability ◽

Leaf Biomass ◽

Soil Conditions ◽

Model Parameters ◽

Arid Zones ◽

Soil Model ◽

Arid And Semiarid

Abstract. Plant ecosystems in arid and semiarid climates show high complexity, since they depend on water availability to carry out their vital processes. In these climates, water stress is the main factor controlling vegetation development and its dynamic evolution. The available water-soil content results from the water balance in the system, where the key issues are the soil, the vegetation and the atmosphere. However, it is the vegetation, which modulates, to a great extent, the water fluxes and the feedback mechanisms between soil and atmosphere. Thus, soil moisture content is most relevant for plant growth maintenance and final water balance assessment. A conceptual dynamic vegetation-soil model (called HORAS) for arid and semi-arid zones has been developed. This conceptual model, based on a series of connected tanks, represents in a way suitable for a Mediterranean climate, the vegetation response to soil moisture fluctuations and the actual leaf biomass influence on soil water availability and evapotranspiration. Two tanks were considered using at each of them the water balance and the appropriate dynamic equation for all considered fluxes. The first one corresponds to the interception process, whereas the second one models the evolution of moisture by the upper soil. The model parameters were based on soil and vegetation properties, but reduced their numbers. Simulations for dominant species, Quercus coccifera L., were carried out to calibrate and validate the model. Our results show that HORAS succeeded in representing the vegetation dynamics and, on the one hand, reflects how following a fire this monoculture stabilizes after 9 years. On the other hand, the model shows the adaptation of the vegetation to the variability of climatic and soil conditions, demonstrating that in the presence or shortage of water, the vegetation regulates its leaf biomass as well as its rate of transpiration in an attempt to minimize total water stress.

Download Full-text