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Soil Salinity (soil + salinity)

Distribution by Scientific Domains

Earth and Environmental Science	42%
Life Sciences	34%
Engineering	19%

Selected Abstracts

Medium-term vegetation dynamics and their association with edaphic conditions in two Hungarian saline grassland communities

GRASSLAND SCIENCE, Issue 1 2010
Tibor Tóth
Abstract Medium-term (5.5 years) changes in the cover of major species in "Artemisia saline puszta" (Ass) and "Pannonic Puccinellia limosa hollow" (PPlh) grassland communities in the Kiskunság region, Hungary, were monitored and analyzed in relation to abiotic factors (e.g. air temperature, precipitation, soil moisture, salinity and alkalinity). Soil salinity varied considerably, indicating leaching and desalinization of surface layers as the most typical process occurring in the region. Yearly average covers of Artemisia santonicum and Plantago maritima were negatively and positively related to surface soil salinity, respectively, in accordance with their salt tolerance. Multiple regression analysis showed soil pH and salinity to be the most important factors determining yearly average cover of plants at Ass. Increasing pH increased the cover of A. santonicum and P. maritima, but decreased the cover of Podospermum canum. Increasing salinity decreased the cover of A. santonicum and P. canum. At PPlh, pH of groundwater had a positive effect and the lakewater level had a negative effect on the cover of Puccinellia limosa. The results provide information on the ongoing changes in the soil properties and the resulting changes in plant composition in these Hungarian salt-affected grasslands. [source]

Na+ transport in glycophytic plants: what we know and would like to know

PLANT CELL & ENVIRONMENT, Issue 4 2010
DARREN CRAIG PLETT
ABSTRACT Soil salinity decreases the growth rate of plants and can severely limit the productivity of crop plants. The ability to tolerate salinity stress differs widely between species of plants as well as within species. As an important component of salinity tolerance, a better understanding of the mechanisms of Na+ transport will assist in the development of plants with improved salinity tolerance and, importantly, might lead to increased yields from crop plants growing in challenging environments. This review summarizes the current understanding of the components of Na+ transport in glycophytic plants, including those at the soil to root interface, transport of Na+ to the xylem, control of Na+ loading in the stele and partitioning of the accumulated Na+ within the shoot and individual cells. Using this knowledge, strategies to modify Na+ transport and engineer plant salinity tolerance, as well as areas of research which merit particular attention in order to further improve the understanding of salinity tolerance in plants, are discussed. [source]

Wide-area estimates of saltcedar (Tamarix spp.) evapotranspiration on the lower Colorado River measured by heat balance and remote sensing methods,,

ECOHYDROLOGY, Issue 1 2009
Pamela L. Nagler
Abstract In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced the native shrubs and trees, including arrowweed, mesquite, cottonwood and willows. Some have advocated that by removing saltcedar, we could save water and create environments more favourable to these native species. To test these assumptions we compared sap flux measurements of water used by native species in contrast to saltcedar, and compared soil salinity, ground water depth and soil moisture across a gradient of 200,1500 m from the river's edge on a floodplain terrace at Cibola National Wildlife Refuge (CNWR). We found that the fraction of land covered (fc) with vegetation in 2005,2007 was similar to that occupied by native vegetation in 1938 using satellite-derived estimates and reprocessed aerial photographs scaled to comparable spatial resolutions (3,4 m). We converted fc to estimates of leaf area index (LAI) through point sampling and destructive analyses (r2 = 0·82). Saltcedar LAI averaged 2·54 with an fc of 0·80, and reached a maximum of 3·7 with an fc of 0·95. The ranges in fc and LAI are similar to those reported for native vegetation elsewhere and from the 1938 photographs over the study site. On-site measurements of water use and soil and aquifer properties confirmed that although saltcedar grows in areas where salinity has increased much better than native shrubs and trees, rates of transpiration are similar. Annual water use over CNWR was about 1·15 m year,1. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Calcite and gypsum solubility products in water-saturated salt-affected soil samples at 25°C and at least up to 14 dS m,1

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2010
F. Visconti
Calcite and gypsum are salts of major ions characterized by poor solubility compared with other salts that may precipitate in soils. Knowledge of calcite and gypsum solubility products in water-saturated soil samples substantially contributes to a better assessment of processes involved in soil salinity. The new SALSOLCHEMIS code for chemical equilibrium assessment was parameterized with published analytical data for aqueous synthetic calcite and gypsum-saturated solutions. Once parameterized, SALSOLCHEMIS was applied to calculations of the ionic activity products of calcium carbonate and calcium sulphate in 133 water-saturated soil samples from an irrigated salt-affected agricultural area in a semi-arid Mediterranean climate. During parameterization, sufficiently constant values for the ionic activity products of calcium carbonate and calcium sulphate were obtained only when the following were used in SALSOLCHEMIS: (i) the equations of Sposito & Traina for the free ion activity coefficient calculation, (ii) the assumption of the non-existence of the Ca (HCO 3)+ and CaCO3o ion pairs and (iii) a paradigm of total ion activity coefficients. The value of 4.62 can be assumed to be a reliable gypsum solubility product (pKs) in simple aqueous and soil solutions, while a value of 8.43 can only be assumed as a reliable calcite solubility product (pKs) in simple aqueous solutions. The saturated pastes and saturation extracts were found to be calcite over-saturated, with the former significantly being less so (p IAP = 8.29) than the latter (p IAP = 8.22). The calcite over-saturation of saturated pastes increased with the soil organic matter content. Nevertheless, the inhibition of calcite precipitation is caused by the soluble organic matter from a dissolved organic carbon threshold value that lies between 7 and 12 mm. The hypothesis of thermodynamic equilibrium is more adequate for the saturated pastes than for the saturation extracts. [source]

Medium-term vegetation dynamics and their association with edaphic conditions in two Hungarian saline grassland communities

Evaluation of model complexity and space,time resolution on the prediction of long-term soil salinity dynamics, western San Joaquin Valley, California

HYDROLOGICAL PROCESSES, Issue 13 2006
G. Schoups
Abstract The numerical simulation of long-term large-scale (field to regional) variably saturated subsurface flow and transport remains a computational challenge, even with today's computing power. Therefore, it is appropriate to develop and use simplified models that focus on the main processes operating at the pertinent time and space scales, as long as the error introduced by the simpler model is small relative to the uncertainties associated with the spatial and temporal variation of boundary conditions and parameter values. This study investigates the effects of various model simplifications on the prediction of long-term soil salinity and salt transport in irrigated soils. Average root-zone salinity and cumulative annual drainage salt load were predicted for a 10-year period using a one-dimensional numerical flow and transport model (i.e. UNSATCHEM) that accounts for solute advection, dispersion and diffusion, and complex salt chemistry. The model uses daily values for rainfall, irrigation, and potential evapotranspiration rates. Model simulations consist of benchmark scenarios for different hypothetical cases that include shallow and deep water tables, different leaching fractions and soil gypsum content, and shallow groundwater salinity, with and without soil chemical reactions. These hypothetical benchmark simulations are compared with the results of various model simplifications that considered (i) annual average boundary conditions, (ii) coarser spatial discretization, and (iii) reducing the complexity of the salt-soil reaction system. Based on the 10-year simulation results, we conclude that salt transport modelling does not require daily boundary conditions, a fine spatial resolution, or complex salt chemistry. Instead, if the focus is on long-term salinity, then a simplified modelling approach can be used, using annually averaged boundary conditions, a coarse spatial discretization, and inclusion of soil chemistry that only accounts for cation exchange and gypsum dissolution,precipitation. We also demonstrate that prediction errors due to these model simplifications may be small, when compared with effects of parameter uncertainty on model predictions. The proposed model simplifications lead to larger time steps and reduced computer simulation times by a factor of 1000. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Salinity patterns in irrigation systems, a threat to be demystified, a constraint to be managed: Field evidence from Algeria and Tunisia,

IRRIGATION AND DRAINAGE, Issue S3 2009
S. Bouarfa
irrigation; gestion de la salinité; alcalinité résiduelle; perception des agriculteurs et stratégies; Maghreb Abstract Salinity problems induced by irrigation are often presented in the literature as a threat that can only be managed at the irrigation scheme scale by installing subsurface drainage. On the other hand, salinity is a constraint that has often been successfully managed locally by farmers adapting their practices. However, the continuing expansion of irrigation with related water scarcity problems plus the increasing use of groundwater of marginal quality has resulted in a new challenge that is difficult to handle at the farm level only. To assess the dynamics of soil salinity and water quality together with farmers' salinity management practices, we adapted a common approach to analyze two contrasted salinity patterns: a traditional salinity pattern in an oasis (Fatnassa, Tunisia), and a recent sodicity pattern in a large irrigation scheme (Lower Chelif, Algeria). This approach which combines surveys on farmers' perceptions and practices and salinity measurements and geochemical analysis paves the way for more integrated management of salinity problems related to water scarcity. Copyright © 2009 John Wiley & Sons, Ltd. Les problèmes de salinité en systèmes irrigués sont souvent présentés dans la littérature comme une menace dont la seule solution réside dans l'installation de systèmes de drainage. La salinité est cependant une contrainte qui peut également être gérée localement avec succès par les agriculteurs par une adaptation de leurs pratiques. Le développement continu de l'irrigation et les tensions sur l'eau qui en découlent contraignent à un usage accru d'eau de nappe de mauvaise qualité dont les conséquences sont difficilement maitrisables à la seule échelle de l'exploitation. Ce nouveau contexte nécessite le développement de nouvelles approches permettant d'appréhender à la fois les processus de salinisation et d'adaptation des agriculteurs. Nous avons adopté une démarche commune pour évaluer la dynamique d'évolution de la salinité et les pratiques des agriculteurs dans deux situations contrastées: un schéma de salinisation classique (oasis de Fatnassa, Tunisie) et un schéma récent d'évolution vers un processus de sodisation (plaine du Bas-Chelif, Algérie). L'utilisation de cette approche qui combine des enquêtes sur les perceptions et les pratiques des agriculteurs, des mesures de salinité et des analyzes géochimiques ouvre des perspectives pour une vision et une gestion plus intégrée des problèmes de salinité liés à la pénurie d'eau. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Drainage and salinity assessment in the Huinong Canal Irrigation District, Ningxia, China,

IRRIGATION AND DRAINAGE, Issue 2 2005
Peter Hollanders
irrigation; drainage; salinisation; développement durable Abstract In the Huinong Canal Irrigation District, Ningxia, China, annually almost half of the amount of irrigation water, which is supplied from the Yellow River, is drained back to the river through an open drainage system. Waterlogging and salinization occur in parts of the irrigated area and part of the water drains to the surrounding desert. While 85,90% of inflow to the area is irrigation water there are good possibilities for water saving. To analyse water movement at field level and resulting drainage needs, from autumn 1998 until spring 2001 observations were made in two experimental areas: Pingluo and Huinong. The data were used for the calibration and validation of three computer models: SWAP, MODFLOW and DUFLOW. Different scenarios of water and salt behaviour in the unsaturated and saturated zone were simulated, as well as the flow through one of the main drains. The effects of various irrigation amounts and groundwater tables on crop growth, percolation and drainage needs were analysed. The present average irrigation water application during the growing season is 630,mm. On average 15% of the supplied water (665 million m3,yr,1) remains in the area. This is mainly irrigation water that was not used by the crops and did not reach the drainage system. It was found that an irrigation level of 75% of the present practice with a groundwater table of 1.0,m below the surface during the growing season gave the best results. Under such a practice the soil salinity will fluctuate around 3,3.5,dS,m,1, resulting in a good growth of wheat and a yield reduction for maize of about 20%. When adequate amounts of irrigation water are supplied in combination with local drainage improvements, the areas with middle and low-yielding crops can be reduced, as well as the area of wasteland. Copyright © 2005 John Wiley & Sons, Ltd. Annuellement presque la moitié de la quantité d'eau d'irrigation dans le district d'irrigation du canal Huinong, Ningxia, Chine, alimenté par la Rivière Jaune, est retournée à la rivière par un système de drainage à ciel ouvert. Des cas de saturation d'eau et de salinisation surgissent dans certaines parties de la zone irriguée et une partie de l'eau suinte vers le désert environnant. Comme 85,90% de l'entrée de l'eau dans la zone est de l'eau d'irrigation il y a de bonnes possibilités pour économiser de l'eau. Pour analyser la circulation de l'eau au niveau du champ et la nécessité de drainage des observations ont été effectuées pendant la période d'automne 1998 jusqu'au printemps 2001 dans deux zones expérimentales, Pingluo et Huinong. Les données rassemblées ont servi pour le calibrage et la validation de trois modèles informatiques: SWAP, MODFLOW et DUFLOW. Ces modèles ont été employés pour simuler plusieurs scénarios de comportement de l'eau et du sel dans la zone non saturée et dans la zone saturée tout comme l'écoulement par un des tuyaux d'écoulement principaux: le cinquième tuyau d'écoulement. L'effet de l'apport de différentes quantités d'eau d'irrigation, de différents niveaux de la nappe phréatique sur la croissance des cultures, la percolation et la nécessité de drainage a été analysé. L'actuel apport d'eau d'irrigation est de 630,mm en moyenne pendant la saison de croissance. Quinze pour cent en moyenne de l'eau fournie (665 millions m3/année) reste dans la zone, principalement de l'eau d'irrigation qui n'a pas servi aux cultures et qui n'a pas atteint le système de drainage. Un niveau d'irrigation représentant 75% des valeurs actuelles et une surface de la nappe phréatique de 1.0,m sous la surface donnent les meilleurs résultats pendant la saison de croissance. De tels apports entretiennent une salinisation du sol qui fluctuera entre environ 3 et 3.5,dS,m,1, donnant un bon résultat de la croissance du blé et une diminution du rendement pour le maïs d'environ 20%. Lorsque l'alimentation par des quantités adéquates d'eau d'irrigation sera assurée en combinaison avec des améliorations du drainage local, la zone donnant des récoltes moyennes et basses peut être réduite ainsi que les zones incultes. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Brackish water subirrigation for vegetables,

IRRIGATION AND DRAINAGE, Issue 2 2003
R. M. Patel
eaux saumâtres; irrigation souterraine; poivron vert; pommes de terre Abstract As freshwater resources for irrigation are being depleted rapidly, recent emphasis has been on the development of nonconventional water sources: reuse of agricultural drainage water, use of industrial or municipal wastewater, and use of brackish water for irrigation. Experiments conducted in field lysimeters over three seasons sought to investigate the feasibility of using brackish water for growing moderately sensitive crops. Brackish waters, with salinity levels of 1, 5 and 9 dS m,1, were used. In 1993 the effects of a factorial combination of three subirrigation water salinity levels, two water table depths and four NPK fertilizer combinations on salt buildup in an initially nonsaline soil and on green pepper (Capsicum annuum L.) performance were assessed. A gradual increase in soil solution salinity (ECsw) from the water table to the soil surface was evident; however, throughout the growing season, the ECsw did not reach a level that could seriously damage the crop. There was no significant difference in pepper yields due to either salinity of subirrigation water or water table depth. In 1994, two potato (Solanum tuberosum L.) cultivars were grown in the soil, which was salinized with 3.5 dS m,1 water before planting tubers. The salt buildup pattern was similar to that observed in 1993; however, the ECsw levels were higher in 1994 due to the higher initial soil salinity. Moreover, a decrease in ECsw was observed near the water table in lysimeters subirrigated with 1 dS m,1 water. For both cultivars, no significant difference in tuber yield was observed due to either water table depth or subirrigation water salinity. In 1995, three potato cultivars were grown in a nonsaline soil as well as a soil presalinized with 2 dS m,1 water. In the topsoil layer, higher rate of increase in ECsw was observed in the saline soil compared to the nonsaline soil. No significant difference in total tuber yield was observed due to either the initial soil salinity levels or subirrigation water salinity levels. Brackish water with salinity levels of up to 9 dS m,1, when applied through subirrigation, could be used to successfully produce green peppers and potatoes under semiarid to arid conditions. Copyright © 2002 John Wiley & Sons, Ltd. RÉSUMÉ Comme les ressources en eau douce utilisées poor l'irrigation s'épuisent rapidement, les récentes recherches tentent de mettre l'emphase sur le développement de sources d'eau non-conventionnelles: la réutilisation de l'eau de drainage agricole, l'utilisation des eaux usées municipales et des eaux saumâtres pour l'irrigation des cultures. Lors de pénuries d'eau douce les eaux saumâtres ont été utilisées pour l'irrigation souterraine de maïs, mais la salinité de la couche supérieur du sol a été réduite en raison de la pluie. Dans les régions arides et semi-arides cette méthode s'est limitée à quelques essais seulement. En raison des quantités limitées d'eau de bonne qualité, on ne peut irriguer de vastes étendues agricoles en régions arides. Or, si l'utilisation des eaux saumâtres s'avérait un succès il serait possible d'améliorer les rendements agricoles. Il est donc nécessaire d'évaluer l'utilisation des eaux saumâtres dans les systèmes d'irrigation souterrains en milieu aride. Des expériences en lysimètres au cours de trois saisons, dans le but d'étudier la faisabilité d'utiliser des eaux saumâtres pour l'irrigation souterraine de cultures moyennement sensibles, furent entreprises en 1993 et 1994. Des eaux saumâtres avec des niveaux de salinité de 1, 5 et 9 dS m,1, furent utilisés. En 1993, les effets d'une combinaison factorielle de trois niveaux de salinité, deux profondeurs de nappe phréatique et quatre combinaisons de fertilisation NPK ont servi à évaluer l'accumulation de sel dans un sol initialement non-salin où le poivron vert (Capsicum annuum L.) a été cultivé. Une augmentation graduelle de la salinité de la solution du sol, de la nappe d'eau souterraine jusqu'à la surface, fut évidente. Bien que durant la saison de croissance, la conductivité électrique de la solution du sol (ECsw) n'ait pas atteint un niveau qui aurait pu endommager sérieusement la culture. Ni les différents niveaux de salinité ni la profondeur de la nappe d'eau souterraine n'ont affecté de façon significative les rendements de poivrons. En 1994, deux cultivars de pommes de terre (Solanum tuberosum L.) furent cultivés dans un sol rendu salin, après avoir été irrigué avec une eau d'un niveau de salinité de 3.5 dS m,1, préalablement à la plantation des tubercules. L'accumulation de sel suivit une tendance semblable à celle observée en 1993. Cependant, les niveaux de ECsw enregistrés en 1994 furent plus élevés en raison du taux de salinité initial plus élevé. De plus, une baisse de ECsw fut observée près de la nappe d'eau souterraine dans les lysimètres irrigués avec une eau d'un niveau de salinité de 1 dS m,1. Ni les différents niveaux de salinité ni la profondeur de la nappe d'eau souterraine n'ont affecté de façon significative le rendement de pommes de terre de chacun des cultivars. En 1995, trois cultivars de pommes de terre ont été cultivés dans un soil non salin ainsi que dans un sol rendu salin au moyen d'une eau avec une conductivité électrique de 2 dS m,1. Dans la couche supérieure du sol, un plus important taux d'augmentation de conductivité électrique a été observé dans le sol salin que dans le sol non salin. Il n'y a pas eu de différence significative observée en raison des taux initiaux de salinité ou encore en raison des taux de salinité de l'eau dans le système d'irrigation souterrain. Cette étude suggère que les eaux saumâtres d'un niveau de salinité jusqu'à 9 dS m,1 pourraient être utilisées dans les systèmes d'irrigation souterrains pour la culture du poivron vert et de la pomme de terre en régions semi-arides et arides. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Evaluation of DRAINMOD-S for simulating water table management under semi-arid conditions,

IRRIGATION AND DRAINAGE, Issue 3 2002
M. A. S. Wahba
modèl e dela direction dela table d'eau souterraine; le drainage conventionnel; le drainage contrôlé Abstract The water table management simulation model, DRAINMOD-S, was evaluated under semi-arid conditions using field data from the Maruit experimental field in the western delta of Egypt for three cropping seasons; maize 1999, wheat 1999/2000 and maize 2000. Two water table management systems (conventional drainage (FD) and controlled drainage (CD)) were applied in the study area. The recorded data included daily ground water table depths, drain outflows during flow events, soil salinity to depth of 1.20 m from the soil surface (0.30 m interval), and relative crop yield. DRAINMOD-S was run to simulate the applied water table management systems for the same study periods. The reliability of the model was evaluated by comparing measured and predicted values of the daily ground water table depth, cumulative outflow based on total monthly outflow, soil salinity during each season, and relative crop yield. Good agreement was found between the measured and predicted values. DRAINMOD-S predicted values within an absolute deviation ranged from 11.0 to 16.0 cm for ground water table depth, from 18 to 75 mm for drain outflows, from 0.22 to 1.08 dS m,1 for soil salinity, and from 4.62 to 4.86% for relative crop yield. The model showed the potential for long-term simulation and planning of ground water table management systems under semi-arid conditions of the western delta of Egypt. Copyright © 2002 John Wiley & Sons, Ltd. RÉSUMÉ Le modèle DRAINMOD-S pour simuler la direction de la table d'eau sous des conditions demi-arides á été évalué en utilisant le data des champs experimentaux du Mariut delta denileouest d'Égypte pendant trois saisons agricoles: le maïs 1999, le blé 1999/2000 et le maïs 2000. Deux systèmes de direction de la table d'eau (drainage conventionnel (FD) et drainage contrôlé (CD)) ontété appliqués àla superficie de l'étude. Le data qui s'est remis en ordre s'inclut les mesures des profondeurs de la table d'eau souterraine, les écoulements des drains pendant les évènements de l'écoulement, la salinité du sol au profondeur de 1.20 m souterrain aux intervalles de 30 cm, etles produits agricoles relatifs. DRAINMOD-S S'est mis en courant pour simuler l'application des systèmes de la direction pour la même période d'étude. La véracité du modèle aété évaluée en comparant les valeurs mésurées avec lcelles des produits agricoles sur le profondeur de la table d'eau quotidien, l'écoulement cumulatif basé sur l'écoulement total du mois, la salinité du sol pendant chaque saison, et les produits agricoles relatifs. On a trouvé un bon accord entre les valeurs mésurées et celles qu'on avait prédites avec une déviation absolue qui rangeait de 11.0 à 16.0 cm pour la profondeur de la table d'eau, de 18 à 75 mm pour l'écoulement du drains, et de 0.22 à 1.08 dS m,1, pour la salinité du sol et de 4.62 à 4.86% pour les produits agricoles relatifs. Le modèle a indiqué une éfficacité pour une simulation allongée et pour projeter les systèmes de la direction dela table d'eau souterraine auprès les conditions demi-arides du delta ouest en Egypte. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Juvenile shrubs show differences in stress tolerance, but no competition or facilitation, along a stress gradient

JOURNAL OF ECOLOGY, Issue 1 2000
Lisa A. Donovan
Summary 1,We investigated experimentally differences in abiotic stress tolerance and the effects of plant,plant interactions for two desert shrubs, Chrysothamnus nauseosus and Sarcobatus vermiculatus, along a soil salinity (NaCl) and boron (B) gradient at Mono Lake, California, USA. Based on differences in natural distribution, and the classical expectation of a trade-off between competitive ability and stress tolerance, we hypothesized that (i) Chrysothamnus would have greater competitive ability than Sarcobatus at the low salinity end of the gradient, and that (ii) Sarcobatus would be more stress tolerant than Chrysothamnus. 2,Juvenile target plants of Chrysothamnus and Sarcobatus were planted into four sites along the gradient. Biomass was determined by destructive harvests over two growing seasons. At each site, interspecific relative competitive ability was assessed as the effect of Sarcobatus neighbours on Chrysothamnus targets compared to the effect of Chrysothamnus neighbours on Sarcobatus targets. Stress tolerance was assessed as the ability of each species to survive and grow, in the absence of neighbours, at different sites along the gradient. 3,The two species did not differ in the relative strength of plant,plant interactions, providing no support for the expectation that Chrysothamnus had greater competitive ability than Sarcobatus. Furthermore, there was no evidence for competition or facilitation, either interspecific or intraspecific, at any site in either year of the study. However, fertilization treatments demonstrated nutrient limitations, soil water reached limiting levels and root systems of targets and neighbours overlapped substantially. It is therefore surprising that plant,plant interactions among juveniles apparently play little role in the growth and survival of shrubs in this saline desert habitat. 4,Sarcobatus was more stress tolerant than Chrysothamnus and the two species performed optimally at different sites along the gradient. Sarcobatus juveniles grew best at the two most saline sites and survived at all sites, whereas Chrysothamnus juveniles grew best at a low-salinity site and did not survive at the most saline site. The difference in site of optimal performance may be due to differences in nutrient limitations or to interactions between nutrient availability and sodium (Na) and B tolerance. [source]

Effects of wastewater irrigation on soil and cabbage-plant (brassica olerecea var. capitate cv. yalova-1) chemical properties

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2007
Fatih M. Kiziloglu
Abstract The use of wastewater for irrigation is increasingly being considered as a technical solution to,minimize soil degradation and to restore nutrient contents of soils. The aim of this study is to increase fertility and minimize degradation of soils irrigated with wastewater exposed to different purification treatments. A field experiment was conducted to investigate the effects of control and irrigation with wastewater, which had undergone different purification treatments, on macro- and micronutrient distribution within the soil profile and nutrient contents of cabbage (Brassica olerecea var. Capitate cv. Yalova-1) in Erzurum, Turkey. Wastewater irrigation and preliminary treatment,wastewater irrigation significantly affected soil chemical properties especially at 0,30,cm soil depth and plant nutrient contents after one year. Application of wastewater increased soil salinity, organic matter, exchangeable Na, K, Ca, Mg, plant-available P, and micro-elements and decreased soil pH. Wastewater increased also yield and N, P, K, Fe, Mn, Zn, Cu, B, and Mo contents of cabbage plants. Undesirable side effects were not observed in plant heavy-metal contents, due to salinity and toxic concentrations of metals from the application of wastewater to soil. [source]

The effect of salinity on the growth, yield and essential oils of turnip-rooted and leaf parsley cultivated within the Mediterranean region

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2009
Spiridon A Petropoulos
Abstract BACKGROUND: Turnip-rooted parsley, a field-crop of northern Europe, has recently been introduced to the Mediterranean region for fresh consumption or production of essential oil. Because of soil salinity within this area, the sensitivity of turnip-rooted and two other parsley subspecies (plain- and curly-leafed) to salt was studied. RESULTS: NaCl or CaCl2 additions to the irrigation water raised the electrical conductivity (EC) in increments from 0.5 dS m,1 to 4.5 dS m,1 (year 1) or 6.0 dS m,1 (year 2), reducing parsley foliage weight in year 2, but increasing the root weight of turnip-rooted parsley in year 1. Raising the EC with NaCl increased the yield of foliar essential oil from curly-leafed parsley (both years), but not from the other cultivars. CaCl2 had less effect on oil yield. The relative concentrations of the principal aroma constituents (,-phellandrene, myristicin, ,-myrcene and apiole) of the foliar essential oil were affected by NaCl or CaCl2 in a way that differed between cultivars. Oil yield from parsley roots was very low and apparently unaffected by salinity. CONCLUSION: All three parsley subspecies are moderately sensitive to salinity, but may be cultivated at <4.5 dS m,1 EC. Salinity may assist oil production by increasing oil yield (curly-leafed parsley) and positively affecting certain aroma constituents. Copyright © 2009 Society of Chemical Industry [source]

Subsurface drainage for reversing degradation of waterlogged saline lands

LAND DEGRADATION AND DEVELOPMENT, Issue 6 2006
D. P. Sharma
Abstract In irrigated agriculture of arid and semiarid regions waterlogging coupled with salinity is a serious problem. Experimental evidence at several locations has led to the realization that subsurface drainage is an essential intervention to reverse the processes of land degradation responsible for the formation of waterlogged saline lands. This paper presents the results of a study conducted from 1995 to 2000 to evaluate the impacts of subsurface drainage on soil properties, groundwater-table behaviour and crop productivity in a waterlogged saline area of 2200,ha. A subsurface drainage system was installed at 1·6,m depth with 60,m drain spacing covering an area of 1200,ha (23 blocks) during 1997,99 and compared with an undrained block of 1000,ha. Subsurface drainage facilitated the reclamation of waterlogged saline lands and a decrease in the soil salinity (ECe, dS,m,1) that ranged from 16·0 to 66·3,per,cent in different blocks. On average, 35·7,per,cent decrease in salt content was observed when compared with the initial value. Provision of subsurface drainage controlled the water-table below the root zone during the monsoon season and helped in bringing the soil to optimum moisture content for the sowing of winter crops. In the drained area, the increase in yields of different crops ranged from 18·8 to 27·6,per,cent. However, in the undrained area the yield of different crops decreased due to the increased waterlogging and soil salinity problems. Overall the results indicated that investment in subsurface drainage is a viable option for reversing the land degradation of waterlogged saline lands in a monsoon climate. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Costing yield loss from acidity, sodicity and dryland salinity to Australian agriculture

LAND DEGRADATION AND DEVELOPMENT, Issue 5 2005
S. Hajkowicz
Abstract Salinity, sodicity and acidity are three major soil constraints that limit crop and pasture yields in Australia. In this paper estimates are made of the potential benefits arising from their treatment by measuring and mapping their impact on agricultural profit. This is achieved by estimating the increase in profit for Australia's main commodities that would occur if the three soil constraints were costlessly ameliorated. These estimates reveal the upper achievable limit on investment returns. They are also indicative of each soil constraint's economic significance to Australian agriculture. It was found that costless removal of salinity would increase annual profits by A$187 million, sodicity by A$1034·6 million and acidity by A$1584·5 million. This equates to 2·9,per,cent, 15·8,per,cent and 24·2,per,cent of total net economic return. It was also found that worsening salinity extent and severity over 2000,2020 has a present value of A$496,A$712 million. Although soil salinity is currently the focus of much public attention, this analysis suggests that from a production viewpoint the correction of sodic and acidic soils may create greater private economic benefit. Opportunities vary considerably among industries. In particular, there is considerable opportunity for the horticultural and viticultural sector to address acidity issues. Whether gross benefits translate into net benefits is a complex question requiring access to context and location-specific information. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Sodium removal from a calcareous saline,sodic soil through leaching and plant uptake during phytoremediation

LAND DEGRADATION AND DEVELOPMENT, Issue 3 2003
M. Qadir
Abstract Saline,sodic and sodic soils are characterized by the occurrence of sodium (Na+) to levels that can adversely affect several soil properties and growth of most crops. As a potential substitute of cost-intensive chemical amelioration, phytoremediation of such soils has emerged as an efficient and low-cost strategy. This plant-assisted amelioration involves cultivation of certain plant species that can withstand ambient soil salinity and sodicity levels. It relies on enhanced dissolution of native calcite within the root zone to provide adequate Ca2+ for the Na+Ca2+ exchange at the cation exchange sites. There is a lack of information for the Na+ balance in terms of removal from saline,sodic soils through plant uptake and leaching during the phytoremediation process. We carried out a lysimeter experiment on a calcareous saline,sodic soil [pH of saturated soil paste (pHs),=,7.2, electrical conductivity of the saturated paste extract (ECe),=,4.9,dS,m,1, sodium adsorption ratio (SAR),=,15.9, CaCO3,=,50,g,kg,1]. There were three treatments: (1) control (without application of a chemical amendment or crop cultivation), (2) soil application of gypsum according to the gypsum requirement of the soil and (3) planting of alfalfa (Medicago sativa L.) as a phytoremediation crop. The efficiency of treatments for soluble salt and Na+ removal from the soil was in the order: gypsum,,,alfalfa,>,control. In the phytoremediation treatment, the amount of Na+ removed from the soil through leaching was found to be the principal cause of reduction in salinity and sodicity. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Labyrinthula terrestris: a new pathogen of cool-season turfgrasses

MOLECULAR PLANT PATHOLOGY, Issue 6 2007
MARY W. OLSEN
ABSTRACT A new disease of turfgrass known as rapid blight is caused by Labyrinthula terrestris, a newly described member of the Labyrinthulids. This unusual group of microorganisms previously has been found in marine systems, and L. terrestris is the only member of the genus Labyrinthula known to be a pathogen of terrestrial plants. Members of this genus are defined by the formation of ectoplasmic networks in which the unicellular somatic cells move or ,glide'. Infections of cool-season turfgrasses occur most commonly when they are irrigated with suboptimal irrigation water with elevated salinity. Disease has been observed in 11 states in the United States and in the United Kingdom. A phylogenetic study indicates that isolates from turfgrass in the United States fall firmly within a clade containing other Labyrinthula spp. and that they came from a common lineage. Its rapid emergence as a turfgrass pathogen may coincide with increased use of relatively high-salinity water or reclaimed water for irrigation. L. terrestris is a potential problem in susceptible turfgrass varieties wherever soil salinity is allowed to accumulate as a result of poor soil structure or suboptimal quality irrigation water is used for irrigation. [source]

Carbon isotope discrimination: potential for screening salinity tolerance in rice at the seedling stage using hydroponics

PLANT BREEDING, Issue 3 2005
R. Shaheen
Abstract Rice is a moderately salt-sensitive crop species and soil salinity is the single most widespread soil toxicity problem lacing rice production. The quantification of salinity resistance poses serious problems in the field because of climatic factors and field heterogeneity. In the present study. rice germplasm obtained from the International Rice Research Institute (IRRI). Philippines, was screened in a naturally lit (11 h daylight) glasshouse-based hydroponics unit at two salinity levels (4 and 6 dS/m), Phenotypic performance based on survival of tolerant, moderately tolerant and susceptible isogenic lines along with tolerant and susceptible parents was evaluated after 10 and 13 days of salt stress. Plants were harvested after second scoring and carbon isotope discrimination in the leaves (A) was measured. ,1 ranged from 19.5 to 22.9%, A highly significant negative correlation (r =,0.95. P < 0.001) between , and visual scoring was observed. Data indicated the potential of using , as a physiological indicator for salinity tolerance in rice seedlings grown in hydroponics. [source]

Naturally Saline Boreal Communities as Models for Reclamation of Saline Oil Sand Tailings

RESTORATION ECOLOGY, Issue 4 2005
Brett G. Purdy
Abstract Reclaimed landscapes after oil sands mining have saline soils; yet, they are required to have similar biodiversity and productivity as the predisturbance nonsaline landscape. Given that many species in the boreal forest are not tolerant of salinity, we studied the effects of soil salinity on plant communities in natural saline landscapes to understand potential plant responses during the reclamation process. Vegetation,soil relationships were measured along transects from flooded wetlands to upland forest vegetation in strongly saline, slightly saline, nonsaline, and reclaimed boreal landscapes. In strongly saline landscapes, surface soil salinity was high (>10 dS/m) in flooded, wet-meadow, and dry-meadow vegetation zones as compared to slightly saline (<5 dS/m) and nonsaline (<2 dS/m) landscapes. Plant communities in these vegetation zones were quite different from nonsaline boreal landscapes and were dominated by halophytes common to saline habitats of the Great Plains. In the shrub and forest vegetation zones, surface soil salinity was similar between saline and nonsaline landscapes, resulting in similar plant communities. In strongly saline landscapes, soils remained saline at depth through the shrub and forest vegetation zones (>10 dS/m), suggesting that forest vegetation can establish over saline soils as long as the salts are below the rooting zone. The reclaimed landscape was intermediate between slightly saline and nonsaline landscapes in terms of soil salinity but more similar to nonsaline habitats with respect to species composition. Results from this study suggest it may be unrealistic to expect that plant communities similar to those found on the predisturbance landscape can be established on all reclaimed landscapes after oil sands mining. [source]

Salt Marsh Restoration in Connecticut: 20 Years of Science and Management

RESTORATION ECOLOGY, Issue 3 2002
R. Scott Warren
Abstract In 1980 the State of Connecticut began a tidal marsh restoration program targeting systems degraded by tidal restrictions and impoundments. Such marshes become dominated by common reed grass (Phragmites australis) and cattail (Typha angustifolia and T. latifolia), with little ecological connection to Long Island Sound. The management and scientific hypothesis was that returning tidal action, reconnecting marshes to Long Island Sound, would set these systems on a recovery trajectory. Specific restoration targets (i.e., pre-disturbance conditions or particular reference marshes) were considered unrealistic. However, it was expected that with time restored tides would return ecological functions and attributes characteristic of fully functioning tidal salt marshes. Here we report results of this program at nine separate sites within six marsh systems along 110 km of Long Island Sound shoreline, with restoration times of 5 to 21 years. Biotic parameters assessed include vegetation, macroinvertebrates, and use by fish and birds. Abiotic factors studied were soil salinity, elevation and tidal flooding, and soil water table depth. Sites fell into two categories of vegetation recovery: slow, ca. 0.5%, or fast, more than 5% of total area per year. Although total cover and frequency of salt marsh angiosperms was positively related to soil salinity, and reed grass stand parameters negatively so, fast versus slow recovery rates could not be attributed to salinity. Instead, rates appear to reflect differences in tidal flooding. Rapid recovery was characterized by lower elevations, greater hydroperiods, and higher soil water tables. Recovery of other biotic attributes and functions does not necessarily parallel those for vegetation. At the longest studied system (rapid vegetation recovery) the high marsh snail Melampus bidentatus took two decades to reach densities comparable with a nearby reference marsh, whereas the amphipod Orchestia grillus was well established on a slow-recovery marsh, reed grass dominated after 9 years. Typical fish species assemblages were found in restoration site creeks and ditches within 5 years. Gut contents of fish in ditches and on the high marsh suggest that use of restored marsh as foraging areas may require up to 15 years to reach equivalence with reference sites. Bird species that specialize in salt marshes require appropriate vegetation; on the oldest restoration site, breeding populations comparable with reference marshland had become established after 15 years. Use of restoration sites by birds considered marsh generalists was initially high and was still nearly twice that of reference areas even after 20 years. Herons, egrets, and migratory shorebirds used restoration areas extensively. These results support our prediction that returning tides will set degraded marshes on trajectories that can bring essentially full restoration of ecological functions. This can occur within two decades, although reduced tidal action can delay restoration of some functions. With this success, Connecticut's Department of Environmental Protection established a dedicated Wetland Restoration Unit. As of 1999 tides have been restored at 57 separate sites along the Connecticut coast. [source]

Effects of potassium carbonate as an alternative de-icer on ground vegetation and soil

ANNALS OF APPLIED BIOLOGY, Issue 3 2000
E ERHART
Summary The effects of the new de-icer potassium carbonate on the growth and species composition of a mixed sward and on the pH and electrical conductivity of the soil were examined in a four-year field trial and compared with sodium chloride. There were small positive effects of K2CO3 on the biomass yield of the sward at application rates up to 200 g m,2 yr,1, while effects were less negative than those of NaCl at annual application rates of 200 , 400 g m,2 yr,1. The species composition of the sward changed considerably with K2CO3 application, Agropyron repens becoming the dominant species. The pH was elevated slightly more by K2CO3 than by NaCl application. Electrical conductivity as an index of soil salinity was increased by both de-icers. K2CO3 was more adsorbed to soil colloids than NaCl, so that the rise in E.C. resulting from application of the former was restricted to the uppermost 10 cm of soil. [source]

Seed dispersal in a polder after partial tidal restoration: Implications for salt-marsh restoration

APPLIED VEGETATION SCIENCE, Issue 1 2008
Armel Dausse
Abstract Question: The vegetation in a polder after partial tidal restoration does not resemble the targeted salt-marsh vegetation. Is this difference in vegetation due to lack of dispersal or unsuitable abiotic conditions? What could be done for a better restoration of the site? Location: Northwestern France. Methods: Seeds were trapped at the single inlet of the polder with a 200- , m mesh net to estimate inputs of seeds from the bay. In parallel, seed dispersal was studied in the polder by placing Astroturf® seed traps on the surface of the sediment at three different elevations in three distinct areas. Abiotic conditions such as flooding frequency, water table level and soil salinity were monitored. Results: All but one species from the adjacent salt marshes were trapped at the inlet. Not all of these species were on the seed traps inside the polder. Seed dispersal was not homogeneous in the polder and seed trap content mostly discriminated in function of their elevation. Salinity and water logging at the bottom of the slope were very high compared to tolerance of most halophytes but decreased rapidly higher up the slope. Conclusions: The development of salt marsh target species is highly restricted by limited hydrochory inside the polder but also by unfavourable soil conditions induced by the actual hydrological regime. Halophytes are excluded at the bottom of the slope by abiotic conditions and out-competed by sub-halophytes higher up. In order to restore salt marsh vegetation inside the polder, a larger opening should be induced in order to increase the flooded surface, and diminish water logging and flooding frequencies. [source]

Vegetation change in a man-made salt marsh affected by a reduction in both grazing and drainage

APPLIED VEGETATION SCIENCE, Issue 1 2002
Peter Esselink
Abstract. In order to restore natural salt marsh in a 460-ha nature reserve established in man-made salt marsh in the Dollard estuary, The Netherlands, the artificial drainage system was neglected and cattle grazing reduced. Vegetation changes were traced through two vegetation surveys and monitoring of permanent plots over 15 yr after the management had been changed. Exclosure experiments were started to distinguish grazing effects from effects of increased soil waterlogging caused by the neglect of the drainage system. Both vegetation surveys and permanent plots demonstrated a dichotomy in vegetation succession. The incidence of secondary pioneer vegetation dominated by Salicornia spp. and Suaeda maritima increased from 0 to 20%, whereas the late-successional (Phragmites australis) vegetation from 10 to 15%. Grazing intensity decreased towards the sea. The grazed area contracted landward, which allowed vegetation dominated by tall species to increase seaward. Grazing and increased waterlogging interacted in several ways. The impact of trampling increased, and in the intensively grazed parts soil salinity increased. This can probably be explained by low vegetation cover in spring. Framework Ordination, an indirect-gradient-analysis technique, was used to infer the importance of environmental factors in influencing changes in species composition. Many changes were positively or negatively correlated with soil aeration and soil salinity, whereas elevation was of minor importance. Grazing accounted for only a few changes in species frequency. Changes in permanent plots were greater during the first than during the second half of the study period. In exclosures that were installed halfway through the study period, there was a relatively rapid recovery of previously dominant species that had decreased during the first half of the study period. Species richness per unit area in the reserve increased. At the seaward side of the marsh, the altered management allowed succession to proceed leading to establishment of stands of Phragmites australis, whereas on the landward side, the combination of moderate grazing with neglect of the drainage system appeared an effective measure in maintaining habitats for a wider range of halophytic species. [source]

Determinants of floristic diversity and vegetation composition on the islands of Lake Burollos, Egypt

APPLIED VEGETATION SCIENCE, Issue 2 2000
Abdel-Hamid Khedr
Täckholm 1974; Boulos 1995 Abstract. A floristic and environmental survey was carried out on 22 uninhabited islands (0.1-8.4 ha) in Lake Burollos, Egypt. A total of 58 vascular plant species was recorded. The number of habitats on each island was counted. There was a positive correlation between island area and number of habitat types. Island area was significantly positively correlated with various measures of floristic diversity, including the total number of species present, and the numbers of annual, herbaceous, and shrublet species. Perennial and shrub species numbers did not differ significantly with island area. In addition to island area, elevation and soil salinity, as well as distance to the Mediterranean Sea, all contributed significantly to variation in species composition in the terrestrial habitats. Water salinity and transparency accounted for 69% of the variation in aquatic species numbers. There was a weak effect of isolation on similarity of species composition on islands. Eight vegetation types, represented by 13 indicator species identified after TWINSPAN analysis, were distinguished by soil characteristics. Species richness was inversely correlated with clay, organic carbon and total nitrogen in the soil, but positively correlated with calcium carbonate content. From a management perspective, long-term monitoring of threatened habitats in the lake is urgently required as a starting point to preserve biodiversity. Finally, we conclude that the present study supports the hypothesis indicating that larger areas feature higher species richness due to increased numbers of habitats. [source]

Stream salinization is associated with reduced taxonomic, but not functional diversity in a riparian plant community

AUSTRAL ECOLOGY, Issue 3 2006
ROBERT G. DOUPÉ
Abstract Dryland salinity presents an overwhelming threat to terrestrial and aquatic habitats in Australia, and yet there remains very little empirical evidence of the impacts of secondary salinization on the biodiversity of riparian communities. Here we describe the response of a riparian plant community to stream and soil salinization, 25 years after the experimental clearing of a catchment in south-western Australia. Riparian plant species diversity was inversely related to soil salinity, and plant species composition was significantly altered by increased soil salinity. Despite the evidence for an impact of salinization on the taxonomic diversity and composition of the riparian plant community, there was little evidence for any effect of salinization on functional group diversity, or on ecological functioning, as measured by the percentage of above-ground plant cover. [source]