Agroecology: the path to agricultural biodiversity

Why do we want to reduce the impact of agri­cul­ture on the environment?

Because this impact is major. The IPCC con­siders that, at glob­al level, one third of green­house gas emis­sions come from agri­cul­ture. There is also a dir­ect impact on biod­iversity, through the trans­form­a­tion of hab­it­ats – this is of course a con­sequence of defor­est­a­tion – the use of fer­til­isers and pesti­cides, the expan­sion of invas­ive spe­cies, and the with­draw­al of bio­mass and water neces­sary for eco­sys­tems. Agri­cul­ture is the human activ­ity that has the greatest impact on biod­iversity, lead­ing to a ser­i­ous phe­nomen­on known as “defaun­ation”. The future of biod­iversity depends to a large extent on the type of agri­cul­ture that is developed, and con­versely, the future of agri­cul­ture depends on agri­cul­tur­al biod­iversity. It should be remembered that every year, $235–577bn of agri­cul­tur­al pro­duc­tion world­wide is at risk because of the dis­ap­pear­ance of pollinators.

We often talk about the use of agro-eco­logy to lim­it the envir­on­ment­al impact of agri­cul­ture… But what is it?

Agri­cul­ture has developed on the basis of an indus­tri­al mod­el, with uni­form­ity and stand­ard­isa­tion of prac­tices. But from a sci­entif­ic point of view, this approach is ill-suited to the diversity of agri­cul­tur­al land­scapes. You can­’t grow maize and soya every­where, or there will be ser­i­ous envir­on­ment­al impacts! Agri­cul­tur­al pro­duc­tion is not diverse enough because some farms stick to very basic rota­tion sys­tems, such as the maize/soya com­bin­a­tion, where­as they should be made more com­plex, with legumes and longer rota­tions to max­im­ise the syn­er­gies in each crop.

Agroe­co­logy is a mod­el that takes into account eco­lo­gic­al pro­cesses and biod­iversity. It emphas­ises crop diversity and the import­ance of soil, fauna and flora biod­iversity; it integ­rates more eco­lo­gic­al infra­struc­tures such as hedges, thick­ets, and ponds. Hedges and thick­ets are home to birds, pol­lin­at­ors, and pest con­trol spe­cies such as para­sit­oids and ground beetles. It is also neces­sary to reduce the size of the plots. The entire organ­isa­tion of farms must there­fore be reconsidered.

To do so, it is neces­sary to cre­ate rel­ev­ant and ambi­tious fin­an­cial and oth­er incent­ives. We need to go fur­ther than the Com­mon Agri­cul­tur­al Policy (CAP)².

What about the soil? Is it a ques­tion of cul­tiv­at­ing it less?

In real­ity, this is a com­plic­ated ques­tion, which is not sci­en­tific­ally clear-cut. Work­ing the soil less deeply allows us to bene­fit more from the work of micro-organ­isms and earth­worms. How­ever, it can help with weed con­trol and improve soil aer­a­tion… The bal­ance between all these factors is there­fore com­plex to find. But the stakes are high: soil degrad­a­tion has reduced the pro­ductiv­ity of the entire world’s land sur­face by 23%.

Agri­cul­ture is also being called upon to provide energy…

But the sus­tain­ab­il­ity of this is being called into ques­tion. Pro­du­cing addi­tion­al crops for first-gen­er­a­tion agro­fuels (bioeth­an­ol, biod­ies­el) has many impacts on biod­iversity. Mak­ing bio­fuels or bio­gas from waste also has its lim­its, as its avail­ab­il­ity is prob­ably not that great. For example, there is little organ­ic waste on a farm. Straw, for example, is used in anim­al hus­bandry or to regen­er­ate the soil: it is a pre­cious com­mod­ity! Agri­cul­ture is thus essen­tially a recyc­ling economy.

Soil degrad­a­tion has reduced the pro­ductiv­ity of the entire world’s land sur­face by 23%.

More and more farm­ers are invest­ing in bio­meth­an­isers, install­a­tions that pro­duce bio­gas from plant products or live­stock manure. This is cur­rently extremely prof­it­able, as it is sup­por­ted by sub­sidies. But is it really worth­while from an eco­lo­gic­al point of view, espe­cially if crops are grown spe­cific­ally to fuel them?

But then, is agroe­co­logy also organ­ic farm­ing? Sus­tain­able agri­cul­ture? Con­ser­va­tion agriculture?

It is indeed an “umbrella: concept that cov­ers all these prac­tices and many oth­ers. It remains dif­fi­cult to assess the advant­ages and dis­ad­vant­ages of each prac­tice from a sci­entif­ic point of view. They can all con­trib­ute to redu­cing the impact of agri­cul­ture on biod­iversity. The European Academy of Sci­ences pro­poses yet anoth­er vari­ant, “regen­er­at­ive agriculture”.

These prac­tices engage us as con­sumers but also as cit­izens. We need to ensure that our pub­lic policies sup­port envir­on­ment­ally and socially rel­ev­ant agri­cul­tur­al prac­tices. But it isn’t easy! Agroe­co­logy requires more work, and there­fore more labour on the farm. This will inev­it­ably have an impact on the price of products, which may be dif­fi­cult for con­sumers to accept – polit­ic­al sup­port is needed.

So polit­ic­al will is key. There is now talk of an agri­cul­tur­al Green Deal on a European scale, is this good news?

This is a very rel­ev­ant con­tri­bu­tion pro­duced by the Pres­id­ency of the European Uni­on, while the CAP has just been reformed by the European Com­mis­sion for the next five years… in a rather dif­fer­ent vein from the Green Deal. So, we cur­rently have two com­pet­ing agri­cul­tur­al philo­sophies in Europe, which need to be reconciled.

Interview by Agnès Vernet