Effect of Water Salinity on the Spatial Variability of Soil and Plant Parameters (original) (raw)
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Weather determined relative sensitivity of plants to salinity: quantification and simulation
The amelioration of plant salinity tolerance due to reduction in potential evapotranspiration is a long recognized phenomenon. In spite of this, salinity tolerance of plants is generally calculated from full season, time-and space-averaged response data. We hypothesized that the HYDRUS-1D model could be used to predict dynamic changes in plant salinity tolerance for a greenhouse vegetable crop over a full season and to determine best management practices regarding blending of saline with desalinated water for optimization of yields and water use efficiency (WUE). The specific objectives of the study were to determine dynamic vapor pressure deficit (VDP)-salinity response relationships of bell pepper plants grown in lysimeters and to apply them for hypothetical management scenarios when irrigating with blended desalinated and brackish water under commercial conditions. The transpiration response of bell pepper plants to salinity in the controlled lysimeter experiment was strongly influenced by variations in potential transpiration throughout the season. The plants were relatively tolerant during periods of low VPD and relatively sensitive during periods of high transpiration demand. Data were used to develop salinity response equations as a function of VPD. In a case study for Israel's Arava Valley, transpiration and water productivity of bell peppers could be increased 5% by blending saline and desalinated water such that less saline water was applied during periods of relatively high sensitivity (high VPD) and more during periods of relative tolerance as compared to application of the same total of both sources of water blended at a constant ratio throughout the season. Sensitivity analysis of the dynamic crop response model revealed that such increases in water productivity would be even greater for more salt sensitive crops.
Optimisation of agricultural water management in arid and semi-arid regions requires the availability of watersalinity crop production functions. A two-year experiment was conducted in the northern Golestan province of Iran to assess the water-salinity production function of wheat. The treatments in the experiment consisted of four levels of irrigation water, i.e. 50 (W1), 75 (W2), 100 (W3) and 125 (W4) % of crop water requirement, and four levels of water salinity, respectively 1.5 (S1), 8.5 (S2), 11.5 (S3) and 14.2 (S4) dS m À1 . The plots were arranged in a randomised complete block design with three replications and water quantity as main plot treatment and water quality as subplot treatment. The data were analysed using linear, quadratic, Cobb-Douglas and transcendental functions, complemented with an economic analysis. The results indicate that for the given climate-soil conditions, transcendental functions best predict wheat yield under both water and salinity stress conditions. Yield reduction caused by a unit increase of matric potential is found to be larger than that caused by a unit increase of osmotic potential. The marginal rate of technical substitution indicates that each one of the two factors studied, namely soil salinity and water supply, can be substituted with the other in a wide range in order to achieve equal amount of yield.
Agricultural Water Management, 2003
The publication is a synthesis of previous publications on the results of a long-term lysimeter experiment. From 1989 to 1998, the experimental variables were soil salinity and soil type, from 1999 onwards, soil salinity and crop variety. The plant was studied during the whole growing period by measuring the saline stress and analyzing its effect on leaf area and dry matter development and on crop yield. Salinity affected the pre-dawn leaf water potential, stomatal conductance, evapotranspiration, leaf area and yield. The following criteria were used for crop salt tolerance classification: soil salinity, evapotranspiration deficit, water stress day index. The classification according to soil salinity distinguished the salt tolerant group of sugar beet and wheat, the moderately salt sensitive group comprising broadbean, maize, potato, soybean, sunflower and tomato, and the salt sensitive group of chickpea and lentil. The results for the salt tolerant and the moderately salt sensitive groups correspond with the classification of Maas and Hoffman, excepted for soybean. The evapotranspiration deficit criterion was used, because for certain crops the relation between yield and evapotranspiration remains the same in case of drought and salinity. This criterion, however, did not appear useful for salt tolerance classification. The water stress day index, based on the pre-dawn leaf water potential, distinguished a tolerant group, comprising sugar beet, wheat, maize, sunflower and potato, and a sensitive group, comprising tomato, soybean, broadbean, chickpea and lentil. The classification corresponds with a difference in water use efficiency. The tolerant crops show a more or less constant water use efficiency. The sensitive crops show a decrease of the water use efficiency with increasing salinity, as their yield decreases stronger than the evapotranspiration. No correlation could be found between osmotic Agricultural Water Management 62 (2003) 37-66
Scientific reports, 2018
We studied the effects of soil matric potential and salinity on the water use (WU), water use efficiency (WUE) and yield response factor (Ky), for wheat (Triticum aestivum cv. Mahdavi) and bean (Phaseoulus vulgaris cv. COS16) in sandy loam and clay loam soils under greenhouse conditions. Results showed that aeration porosity is the predominant factor controlling WU, WUE, Ky and shoot biomass (Bs) at high soil water potentials. As matric potential was decreased, soil aeration improved, with Bs, WU and Ky reaching maximum value at -6 to -10 kPa, under all salinities. Wheat WUE remained almost unchanged by reduction of matric potential under low salinities (EC ≤ 8 dSm), but increased under higher salinities (EC ≥ 8 dSm), as did bean WUE at all salinities, as matric potential decreased to -33 kPa. Wheat WUE exceeds that of bean in both sandy loam and clay loam soils. WUE of both plants increased with higher shoot/root ratio and a high correlation coefficient exists between them. Results...
Journal of Plant Physiology, 1996
The effects of soil salinity on growth and yield of sugarcane (Saccharum spp. hybrids) are used to illustrate how soil and plant samples (<<ground truth»), digital videographic or SPOT HRV spectral observations, and image analysis by unsupervised classification can be used jointly to quantifY and map variations in weighted electrical conductivity (WEC, dS m-I) of the root zone and YIELD (metric tons of millable stalks ha-I). The combined data for the 1992 and 1993 growing seasons of the study showed that each dSm-1 increase in WEC reduced stalk population by 0.6 stalks m-2 , stalk weight by 0.14 kg, and stalk yields by 13.7 metric tons ha-I. Sugarcane growth and yield were not affected by root zone salinities less than about 2 dS m-I, but no millable stalks were produced at salinities in excess of 10 dS m-I. The 25 pixels ha-I of SPOT is a good scale for mapping salt stress patterns and taking site-specific ameliorative actions. The combination of satellite or aerial spectral observations, ground truth, and image classification procedures demonstrated in this study is readily applicable to other vegetation stresses.
Agricultural Water Management, 1993
Response of wheat (Triticum aestivum L.) to salinity stress at different growth stages and patterns of salinisation was studied in microlysimeters. The treatments consisted of variable initial salinity profiles (salinity increasing, decreasing and uniform with depth) in combination with different salinisation patterns achieved through irrigations with waters of increasing, constant, decreasing salinity, alternating saline and non-saline, introducing saline waters after jointing, keeping the total salt input through these irrigations the same. Almost 3-fold variations in wheat yields were observed. In soil where initial salinity increased with soil depth, yields were markedly improved (30-36%) compared with the soils having uniform or inverted salt profiles. Similarly, shifting to saline irrigation at jointing, cyclically non-saline/saline water or increasing salinity, outyielded the others. Interestingly, lowest yields were obtained in soils receiving constant salinity waters. Amongst the various indices of salinity, yields were best related (r=-0.78) to root length weighted salinity over different periods of growth. Independent estimates of salinity responses showed the tolerance of wheat to increase with ontogeny. The ECso values (electrical conductivity of saturation paste extract for 50% yields) increased to 9.3, 10.8 + 0.1, 12.7 and 13.2 dS/m for periods between sowing to crown rooting, crown rooting to boot, boot to dough and dough stage to maturity, respectively. Results imply that for nonsteady state conditions such as those prevailing under monsoonal climate, the salt tolerance at critical stages of crop plants, changes in responses to salinity with modes of salinisation and initial distribution of salts need to be considered for effective use of multisalinity waters.
Successful breeding of plants for salinity stress tolerance requires realistic growing conditions and fast, non-destructive evaluation techniques for phenotypic traits associated with salinity tolerance. In this study, we used subsurface water retention technique (SWRT) as a growing condition and spectral measurements as an evaluation method to assess different agro-morphological traits of salt-tolerant (Sakha 93) and salt-sensitive (Sakha 61) wheat genotypes under three salinity levels (control, 60, and 120 mM NaCl). The effects of salinity on agro-morphological traits were evaluated and related with forty-five published vegetation-and water-spectral reflectance indices (SRIs) taken at both the heading and grain milk growth stages for each salinity level, genotype, and growth stage. In general, the agro-morphological traits gradually decreased as salinity levels increased; however, the reduction in these traits was more pronounced in Sakha 61 than in Sakha 93. The effect of salin-ity levels and their interaction with genotypes on the SRIs was only evident at the grain milk stage. The performance of the spectral reflectance indices depicted that the closest associations with agro-morphological traits depended on salinity level, degree of salt tolerance of the genotypes, and growth stage. The SRI-based vegeta-tive indices correlated better with growth and yield of Sakha 93 than SRI-based water indices and vice versa for Sakha 61. The SRI-based vegetative and water indices are effective for assessment of agro-morphological traits at early growth stages under high salinity level. The functional relationship between grain yield per hectare and the best SRIs was linear for the high salinity level and Sakha 61; however , the quadratic model was found to best fit this relationship for the control, moderate salinity level, and Sakha 93. The overall results indicate that the usefulness of the SRIs for assessment of traits associated with salinity tolerance is limited to salinity level and growth stage. K E Y W O R D S
Spatial and temporal changes of soil salinity in a cotton field irrigated with low-quality water
Journal of Hydrology, 2003
Reuse of upland drainage waters has become an acceptable and common practice among many farmers who have no access to good-quality irrigation water, and suffer long periods of droughts in arid and semi-arid regions. This study was carried out in a farmer's cotton field of 0.27 ha, located in the Eastern Mediterranean Coastal Region of Turkey, at 2.1 m mean sea level. The area presently lacking irrigation water has a typical Mediterranean climate with dry and hot summers, and cool and rainy winters. The farmers in the area use low-quality irrigation water, diverted from drainage channels, carrying irrigation return flows of upland fields. The objective of the work was to assess what effect the existing practice of irrigation can have on soil salinity using both conventional statistics and geostatistical techniques.
Agronomy
The phenomenological expression showing crop yield to be directly dependent on water deficiency, under saline conditions, has encouraged a continued focus on salinity as a viable approach to increase crop yields. This work reassesses crop response to availability of saline soil water ASW in two stages (A) Develop a simple approach suggesting that permanent wilting point (WP) increases under high saline soil water tension and relative yield of Lettuce (Lactuca sativa L., var longifolia Lam., cv. Nevada) and maize (Zea Mays L., cv. Jubilee sweet) decrease. (B) Using a deterministic numerical soil water model to validate the theory on Bermuda grass of golf courses. The experimental plots were established in the North Negev, Israel (Sweet corn) and the Algarve, Portugal (Lettuce and Bermuda grass covering the golf courses). Sprinkler irrigation and line source techniques were used for water application, creating a saline gradient under a precise irrigation water distribution. Two salini...
Environmental Monitoring and Assessment, 2020
Though water deficit and salinity effects on plants have similarities, they are physiologically different. This motivated us to separately explore the effects of salinity and water deficit on water consumption, yield, and some plant parameters for maize (Zea mays L., var. SC704). Greenhouse experiments were conducted during two seasons. In one experiment, maize was cultivated in wet soil (matric potential of − 10 kPa), and the irrigation water salinity was varied between treatments (osmotic potentials up to − 336 kPa). In a parallel experiment, five water deficit levels were maintained by irrigating with water to accomplish the same daily water uptake as in the salinity treatments. The experiments were conducted in pots with a randomized design and four replicates. Salinity and water deficit stress significantly affected yield and other plant parameters. However, root dry matter in autumn was not significant. We observed a profound effect of evaporative demand on most of the plant parameters and water use, such as water use efficiency (WUE). For same water use rate, the values of osmotic and matric potential were different. In spring season, the ratios of matric to osmotic potential were 0.25, 0.46, 0.44, and 0.43 in corresponding D 1 , D 2 , D 3 , and D 4 water deficit and S 1 , S 2 , S 3 , and S 4 salinity treatments. For autumn season, these ratios were 0.26, 0.36, 0.34, and 0.36. We concluded crop models that lump water deficit and salinity (additively or multiplicatively) to predict yields can result in inappropriate predictions. Keywords Abiotic stresses. Water uptake. Evaporative demand. Root system Abbreviations SWRC Soil water retention curve EC sw Electrical conductivity of soil solution (dS m −1) EC e Electrical conductivity of saturated paste (dSm −1) EC iw Electrical conductivity of irrigation water (dSm −1) S Salinity treatment D Water deficit treatment WUE Water use efficiency (kg m −3) Y Yield (kg) T Actual transpiration or plant water uptake (m 3) TWU Total water use (m 3)