Evaluation of Land-Use Transformation in Grazing Systems Using Soil Quality and Primary Productivity in a Semi-Arid Areas, Israel.

Land-use transformations have crucial effects on the structure and function of the ecosystems.  This study deals with four long-term land-use transformations in the semi-arid area of the northern Negev Desert, Israel: from pastoralism grazing to natural system (termed hereafter as stage A); from natural to a pastoralism grazing system (stage B); from agro-pastoral to natural system (stage C); and from agro-pastoral to pastoralism grazing system (stage D).  Changes in land-use transformation were evaluated by soil quality (SQ) and aboveground net primary productivity (ANPP) as two main indicators.  Soil Quality Index (SQI) was developed in order to incorporate the 14 physical, biological, and chemical properties of soil into a single unit.  In addition, ANPP was estimated in the years 2010-2012.  In state A we found significant increase in the SQI (0.61 to 0.70 score) and ANPP (201.3 to 323.5 mg/m²).  In state B significant reduction in the SQI (0.66 to 0.54 score) and ANPP (280.3 to 164.4 mg/m²) were observed.  In state C no significant change were found in SQI (0.67 to 0.66 score) and ANPP (300.1 to 280.3 mg/m²).  In state D significant reduction in the SQI (0.67 to 0.54 score) and ANPP (300.1 to 164.6 mg/m²) were observed.  In addition, significant correlation were found between SQI and ANNP (0.7<R²<0.85; p≥0.05). Introducing grazing to natural system reduced the SQI and the ANNP, recovery time is nessecery for emproving the enveromental quality of the natural shrubland in semi-arid areas.  The agro-pastoral system includes intensive human management shown higher sustainability for grazing.  As our data suggests, the agro-pastoral systems may support and allow the nessecery recovery time of the natural ecosystem.  This complimentary management can prevent degradation processes and improve the enveromental quality in the semi-arid areas.  We conclude that the used procedures with regard to grazing changes in transition states by SQI and ANNP are suitable and applicable for evaluating environmental quality. 

Keyword: land-use transformations, soil quality, primary productivity, traditional pastoralism, agro-pastoral, abandoned agricultural.