Use of Geoinformatics Techniques for the Assessment and Mapping of Soil Salinity: Concepts and Applications

Irrigated agriculture has a major impact on the environment, especially soil degradation. Soil salinity is a critical environmental problem, which has great impact on soil fertility and overall agricultural productivity. Since, soil salinity processes are highly dynamic, the methods of detecting soil salinity hazards should also be dynamic. Remote sensing data are modern tools that provide information on variation over time essential for environmental monitoring and change detection, as they also help in the reduction of conventional time-consuming and expensive field sampling methods, which is the traditional method of monitoring and assessment. This chapter thus reviewed the concepts and applications of remote sensing, GIS-assisted spatial analysis and modelling of the salinity issue in irrigation fields. Generally, compared to the labour, time and money invested in field work devoted to collecting soil salinity data and analysis, the availability and ease of acquiring satellite imagery data and analysis made this concept very attractive and efficient.

Effects of Arbuscular Mycorrhizal Fungi on Plant Adaptation to Arid Ecosystem of Bou-Hedma National Park in Tunisia

Plants interact with beneficial microbes living in their rhizosphere, promoting their growth and development. In arid ecosystems, specific plant-associated microbes grant plants access to nutrients that would otherwise be inaccessible. Arbuscular mycorrhizal fungi (AMF) are probably one of the better known belowground functional networks with plants. AMF plays a crucial role in plant performance and consequently in ecosystem functioning. AMF activities also determine the bio-availability of nutrients and therefore soil fertility. The main objective of the present study was to evaluate the plant-AMF interactions on soil functions under arid ecosystem in Tunisia. AMF colonization was evaluated by visual observation of AMF in fine roots of Astragalus corrugatus and Lotus creticus on Bou-Hedma National Park in Tunisia. Mycorrhizal colonization varied between plants, and the spore number was significantly different across rhizosphere soils. Statistical analysis showed a clearly positive correlation between the number of spores and plant-mycorrhizal intensity. For microbiological proprieties, our results showed that mycorrhizal plants improved significantly the different microbiological parameters. The results of the present study specified the association plant-AMF and highlight AMF importance as a tailored mechanism of plant adaptation to arid ecosystems.