Effectiveness of soil conditioners to enhance salt extraction ability of Salicornia ramosissima in saline-sodic soil for different soil moisture contents.

Soil salinity is considered one of the main types of soil degradation in semiarid environments around the globe. This work aims to evaluate the effectiveness of soil conditioners to enhance the growth and salt extraction ability of Salicornia ramosíssima for different soil moisture contents. Salicornia plants were cultivated in pots in which the soils were treated with the following conditioners: control; gypsum + organic matter; elemental sulfur + organic matter; and gypsum + elemental sulfur + organic matter. Salicornia plants were subjected to two soil moisture rates - at 35 and 85% field capacity. Soil conditioners associated with higher contents of soil moisture promoted significant increases, compared to control, in fresh (6.20 - 11.13 g) and dry matter (1.20 - 2.07 g), relative biomass (100 - 179%) as well as significantly increased the concentrations of Na+ (56.09 - 65.64 mg kg-1) and Cl- (110.83 - 150.0 mg kg-1) in plant tissues. Soil conditioners significantly increased salt extraction ability under the two moisture levels, mainly by promoting higher values for both transfer factor and phytoremediation potential. The best performance of Salicornia in terms of plant yield and salt extraction, regardless of the moisture level, was the gypsum + organic matter.Novelty statementThere are no studies in the literature relating the use of conditioners as a strategy to enhance Salicornia's ability to extract salts.This work contributes to the management of salinized areas around the globe in two main aspects. The first is that many of these salt-degraded areas are desertified and through this study, it is possible to revegetate and recover them. The second one is that, since Salicornia is a plant with economic value, this can serve as an incentive for farmers to grow Salicornia in saline areas.

Spectral reflectance characteristics of soils in northeastern Brazil as influenced by salinity levels.

In northeastern Brazil, large swaths of once-productive soils have been severely degraded by soil salinization, but the true extent of the damage has not been assessed. Emerging remote sensing technology based on hyperspectral analysis offers one possibility for large-scale assessment, but it has been unclear to what extent the spectral properties of soils are related to salinity characteristics. The purpose of this study was to characterize the spectral properties of degraded (saline) and non-degraded agricultural soils in northeastern Brazil and determine the extent to which these properties correspond to soil salinity. We took soil samples from 78 locations within a 45,000-km2 site in Pernambuco State. We used cluster analysis to group the soil samples on the basis of similarities in salinity and sodicity levels, and then obtained spectral data for each group. The physical properties analysis indicated a predominance of the coarse sand fraction in almost all the soil groups, and total porosity was similar for all the groups. The chemical analysis revealed different levels of degradation among the groups, ranging from non-degraded to strongly degraded conditions, as defined by the degree of salinity and sodicity. The soil properties showing the highest correlation with spectral reflectance were the exchangeable sodium percentage followed by fine sand. Differences in the reflectance curves for the various soil groups were relatively small and were not significant. These results suggest that, where soil crusts are not present, significant challenges remain for using hyperspectral remote sensing to assess soil salinity in northeastern Brazil.