Climate Change Is Transforming How Plants and Soil Interact

One of the less-dis­cussed but more dis­rup­tive impacts of cli­mate change on agri­cul­ture will be how chang­ing weather and pre­cip­i­ta­tion pat­terns affect plant-soil feed­back sys­tems, accord­ing to a recent sci­en­tific paper out of Spain.

The plants and soils of the Mediterranean basin, where the vast major­ity of the world’s olives are grown, will undoubt­edly be impacted as the cli­mate becomes increas­ingly hot and dry.

“In Mediterranean sys­tems, as every­where, the mutual inter­ac­tions between plants and soil microbes will be affected by cli­mate change,” Francisco Pugnaire, the lead researcher of the paper and a pro­fes­sor at Spain’s Experimental Station of Arid Zones, told Olive Oil Times.

These changes to the envi­ron­ment will fun­da­men­tally alter the way in which plants inter­act with the microor­gan­isms in the soil and have the poten­tial to neg­a­tively affect the pro­duc­tiv­ity of crops.

“There are thou­sands of micro­bial species in each gram of soil that strongly inter­act with each other and with plants,” Pugnaire said. ​“Each, how­ever, has a favorite set of cli­mate con­di­tions, and changes will favor some and harm oth­ers.”

“As a con­se­quence, inter­ac­tions will change, although we do not know enough to antic­i­pate the direc­tion of changes,” he added.

Changes in the local cli­mate can alter the nutri­ent and min­eral con­tents of the organic lit­ter that falls from trees and shrubs. This, in turn, favors dif­fer­ent types of soil microor­gan­isms and may lead to changes in the types of microbes and fungi best suited for the envi­ron­ment.

Changes in the amount of pre­cip­i­ta­tion that falls in spe­cific areas can also alter the rate and amount of nutri­ents that decom­pose into the soil, which can also impact the makeup of its microor­gan­ism com­mu­ni­ties.

With a chang­ing fun­gal and micro­bial com­mu­nity in the soil, comes the oppor­tu­nity for pre­vi­ously non-native and inva­sive species to set­tle in.

In gen­eral, Pugnaire believes the bound­aries of tra­di­tional veg­e­ta­tion zones will begin to migrate north as well as toward higher alti­tudes.

“Climate change, how­ever, will force trees and plants to seek more favor­able con­di­tions in the north and moun­tain areas, and the same will hap­pen with soil organ­isms, but some will not do so at the same time,” he said. ​“They will sep­a­rate and that will alter the bal­ance between species.”

This shift­ing of veg­e­ta­tive zones may impact the pro­duc­tiv­ity of tra­di­tional and organic olive groves, where the chang­ing cli­mate will impact the soil’s microor­gan­isms but the veg­e­ta­tive cover will largely remain the same.

Intensive olive farms, how­ever, are likely to be unaf­fected since these rely on the use of fer­til­izer and irri­ga­tion to pro­duce a uni­form yield each year.

“For olive trees, I think there is ample con­sen­sus that orchards would do bet­ter higher up in ele­va­tion or in lat­i­tude,” he said. ​“However, where I am based [in Andalusia], the drier and warmer point in Europe, there is low land olive oil pro­duc­tion ranked among the best in the world.”

Pugnaire added that the meth­ods used in super-inten­sive agri­cul­ture are exac­er­bat­ing the prob­lems already being faced by plant-soil feed­back sys­tems in the wake of cli­mate change.

“Intensive agri­cul­ture leads to soils low in organic mat­ter and impov­er­ished in micro­bial species, with threats of soil loss and deser­ti­fi­ca­tion,” he said. ​“In this regard, the new hyper-inten­sive tech­niques are wor­ri­some.”

However, there are prac­tices that can be embraced by olive farm­ers and other types of agri­cul­tur­al­ists to improve soil health and mit­i­gate the impact of cli­mate change on the plant-soil feed­back sys­tems.

“In other crops, we have seen that adding organic mat­ter increases soil micro­bial diver­sity and increases pro­duc­tiv­ity,” Pugnaire said. ​“Therefore mov­ing to more sus­tain­able prac­tices like non-tillage and asso­ci­ated live­stock farm­ing will be very pos­i­tive for the qual­ity of olive oil while help­ing to mit­i­gate the effects of cli­mate change.”

“By increas­ing the num­bers and diver­sity of soil micro­bial com­mu­ni­ties, envi­ron­men­tally-friendly farm­ing could greatly con­tribute to buffer the neg­a­tive effects of cli­mate change on plant-soil inter­ac­tions, keep­ing more sus­tain­able farm­ing,” he added

Pugnaire and his col­leagues had orig­i­nally pre­pared the sci­en­tific paper, which was a review of numer­ous pre-exist­ing stud­ies on the impacts of cli­mate change on plant-soil feed­back sys­tems, for a United Nations con­fer­ence on cli­mate change that took place in Madrid last December.

“Our aim was to pro­vide updated sci­en­tific evi­dence on the impacts of cli­mate change and bio­di­ver­sity loss and alter­ations for use by sci­en­tists and pol­i­cy­mak­ers dur­ing and after the COP 25,” he said. ​“However, the out­come of the con­fer­ence was dis­ap­point­ing, as pol­i­cy­mak­ers did not reach any sub­stan­tial agree­ment to curb CO2 emis­sions and we are los­ing pre­cious time to halt changes that every day seem more evi­dent, and harm­ful.”

• Science Advances


• EFE