The role of humic substances in mitigating the harmful effects of soil salinity and improve plant productivity

Document Type: Research Paper

Authors

1 Laboratoire des Plantes Extremphiles, Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia.

2 Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Unità di Ricerca per lo Studio dei Sistemi Colturali, 75010 Metaponto, Italy.

Abstract

The environmental, social and economical reasons indicate that the
conventional agriculture constitute a continuous pressure contributing to the
progressive worsening of environmental conditions, especially by an increasing
apply high level of inputs. In this matter, the increasing use of saline irrigation
water is one of the main factors resulting in salt accumulation in the plant
rhizosphere influencing both physical, chemical and biological soil properties
and agroecosystem productivity. In this situation, soil degradation emphasized
the need to develop strategies of salt effected soil reclamation. One of the
possible solutions is to use humic substances (HS), since there is an increasing
need to their utilization in agriculture. They are the major components of soil
organic matter, have multiple roles in plant growth and are the subject of study in
various areas of agriculture, such as soil chemistry, soil fertility and plant
physiology. Thus, our hypothesis account for a beneficial effect of HS in salt
affected rhizosphere likely due to a 'direct' action on the plant together with an
'indirect action' on the metabolism of soil microorganisms, the dynamics of
uptake of soil nutrients and soil physical conditions. In this paper we review the
HS formation and components and their influences on improving saline soil
properties as both direct and indirect effects.
Keywords: Humic substance; Salt accumulation; Soil degradation; Plant productivity;
Hormone-like activity.