Salinization of agro-ecosystems and strategies to combat it

Professorial Chair Lecture

Metro Manila Commission Professorial Chair Lecture

Place

University of the Philippines Los Banos, College, Laguna

Date

7-10-2000

Abstract

Salinization is the accumulation of undesirable amounts of salt within a volume of the soil profile usually exploited by the plant roots. The United States Salinity Laboratory Staff defined saline soils as those for which the electrical conductivity of the saturation extract is at least 4 dSm-1. Salinization of agro-ecosystems is an environmental degradation closely associated with human activities. It is a human impact on land and has the consequence of reducing land productivity.

Green house and field studies were conducted by two groups of researchers: one in the Philippines and the other in Israel to gain a deeper understanding of the effects of salinity on common crops. Results of both types of studies were consistent. Salinity range of 10-100 mM NaCL reduced significantly the growth (dry weight and leaf area) of peanut, cotton, wheat, and rice plants, as well as the concentration of potassium and nitrogen in the shoot. These effects were minimized if NO3- rather than NH4+ were the source of nitrogen. Sodium and chloride concentration in the shoot increased. However, Photosynthesis and transpiration remained unaffected at slight to moderate salinity level. Potassium concentration and sodium concentration in the shoot were inversely proportional. It was concluded that KNO3 played a significant role in plant's adaptation to moderately saline stress.

The important role displayed by nitrogen on nutrition of plant under stress suggests that the adverse effect of salinity on plant growth is more complex than what its more popular interpretation of osmotic effect would suggests. Under saline condition, plants do not get sufficient nitrogen for their metabolic needs. Cl-/NO3- ratio in the root medium appears to be a critical factor.

Based on the above information, a K-Shuttle transport system in the plant was developed to tie up all the facts obtained. When tested under field conditions, all observations were consistent with the model. Strategies were suggested how to address the problem of salinity.

Location

UPLB Main Library Special Collections Section (USCS)

College

College of Economics and Management (CEM)

Language

English

This document is currently not available here.

Share

COinS