Soil ero­sion con­tin­ues to be a grave prob­lem in Andalusia, the Spanish and world cap­i­tal of olive oil pro­duc­tion.  Members of the olive oil indus­try are meet­ing there today, March 3rd, in Jaén to dis­cuss con­ser­va­tion mea­sures.

Jaén’s clay-​rich soil is the most prone to rain­fall run-​off- Manuel Ruiz

Biologist Manuel Ruiz, who is coor­di­nat­ing the work­shop, said it was esti­mated that 80 tons of soil per hectare were being lost each year due to the ero­sion in Andalusia, in south-​eastern Spain. “That’s equiv­a­lent to about four truck­loads of soil for every 100 olive trees.”

After cli­mate change, it’s the biggest envi­ron­men­tal prob­lem fac­ing the indus­try.  In Jaén alone, the global heart of olive-​production, about a fifth of arable land is badly affected.

Dr. Ruiz, pres­i­dent of the Jaén branch of GEA (Active Ecology Group) , said the work­shop was intended to help mem­bers of the sec­tor learn what pre­ven­tive mea­sures could be taken and why they were impor­tant.

“The mea­sures require above all a change of men­tal­ity — to take ero­sion seri­ously and change some habits. This may mean learn­ing new tech­niques and invest­ing in machin­ery or hir­ing out­side exper­tise. We need to ensure the knowl­edge trans­fer of new crop man­age­ment tech­niques to farm­ers.

Dr. Ruiz said among the best ways to con­serve soil was to avoid or elim­i­nate tillage (instead using her­bi­cides to remove weeds), reduce the amount of time the ground was left bare, and to use plant ground cover, whether native or not, between rows of olive trees.  “In itself, the ben­e­fits of using plant cover would off­set the invest­ment.”

Parts of Jaén with sloped ter­rain and clay-​rich soil (which becomes com­pacted under the weight of farm machin­ery, imped­ing drainage) are those most prone to ero­sion by rain­fall run-​off, he said.

In their 2007 research paper, “Is soil ero­sion in olive groves as bad as often claimed?”, authors Luuk Fleskens and Leo Stroosnijder warned against tak­ing an alarmist view and sug­gested that ero­sion rates were being over-​estimated. They also said that the ero­sion mainly resulted from infre­quent high inten­sity rain­fall events and that in some cases, depend­ing on loca­tion, tillage applied judi­ciously in a grove might reduce ero­sion.

They said their results sug­gest that aver­age soil ero­sion rates are unlikely to sur­pass 10 tons a hectare a year. “Which is still more than the soil renewal by weath­er­ing.”

Nevertheless the prob­lem is of great con­cern and today’s free infor­ma­tion ses­sion in Jaén is being attended by rep­re­sen­ta­tives of rural and envi­ron­men­tal groups, includ­ing COAG-​Jaén, one of Spain’s largest agrar­ian unions. Gregorio López, COAG’s olive sec­tor spokesman, said that the indus­try is increas­ingly pro-​active on the issue of soil con­ser­va­tion. Nevertheless, peri­ods of extremely heavy rain in the last two years have taken their toll.

Although another cost at a time when the sec­tor is already strug­gling to make a profit, plant cover, for instance, is becom­ing more widely used and once estab­lished is not so expen­sive to main­tain, he said.

Meanwhile, a del­e­ga­tion of farm­ers and ranch­ers from Nebraska is cur­rently vis­it­ing Andalusia to learn about its sus­tain­able agri­cul­ture and exchange ideas. As part of the LEAD Program, an agri­cul­tural lead­er­ship devel­op­ment ini­tia­tive, they have vis­ited loca­tions this week includ­ing an organic olive grove and an olive mill.


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