Table 1.

Structure of the search equations (and examples) used for the systematic review of meta-analyses, for each farming practice category. Search equations for all farming practice categories are available in section 2 of the dataset²⁰.

Farming practice	Keywords related to the practice*	Boolean	Keywords used to focus the search on agriculture**	Boolean	Keywords used to select MAs and systematic reviews ***
Organic farming systems	TOPIC: (“organic farm*” OR “organic agriculture” OR “organic system*” OR “organic product*”)			AND	TOPIC: (“meta-analy*” OR “systematic* review*” OR “evidence map” OR “global synthesis” OR “evidence synthesis” OR “research synthesis”)
Soil amendment with biochar	TOPIC: (biochar OR charcoal OR “black carbon”)	AND	TOPIC: (soil* OR agricultur* OR farm*)	AND	TOPIC: (“meta-analy*” OR “systematic* review*” OR “evidence map” OR “global synthesis” OR “evidence synthesis” OR “research synthesis”)

* provide as many synonyms and/or sub-practices definitions as possible, using stemming when possible

** Not always used. It is only used to restrict the search when a high number of papers not related to agricultural activities are retrieved.

*** standard query to avoid retrieval of primary studies