Redistribution of Resources in Drylands of the U.S.A. and Israel

Project Number:

96R-18

Project Duration:

24 months

Dates:

May 1, 1996 to April 30, 1998

Institution of Principle Investigator while on this project:

Ben-Gurion University of the Negev

Investigators (most current known information)

Shachak, Moshe (PI)

Professor, Ben-Gurion University of the Negev, Mitrani Center for Desert Ecology, Institute for Desert Research, Sede Boqer 84990, ISRAEL

TEL: +972-8-659-6786, FAX: +972-8-659-6772, Email: shachak@bgumail.bgu.ac.il

Proposal Abstract

This report analyzes the results of our study on dry deposition and its redistribution by runoff in the northern Negev, Israel. The report presents a preliminary analysis; 1) of dry deposition data in relation to seasonality, landscape patchiness and dry deposition components; and 2) runoff, soil erosion relationships in relation to patchiness and rainfall events.

We found that dust, organic matter and feces deposition are higher in the winter. Our results also showed that dust deposition was higher in the soil crust patches. We assume that dry deposition is higher in the winter due to climate and biological activity. We also propose that the shrub is not a trap for dust but acts as an umbrella that prevents dust deposition under it.

We found that during the four-year study, dust deposition is higher than soil erosion. This indicates that the system is in a state of soil accumulation. Our data show that soil accumulation is nonuniform. Runoff redistributes the dust deposition in a manner that the rate of soil accumulation under the shrub is higher than on the soil crust. This difference in soil accumulation is responsible for creating the differences between the flat crust and the soil mound under the shrub. This patchiness which originates from dry deposition and redistribution is the main controller of the productivity and diversity of the whole system.