Agriculture History 423 Economic aspects 237 Research 218 Agriculture and state 109 Environmental aspects 91 Agricultural innovations 84 more ... Landwirtschaft 83 Statistics 76 Periodicals 69 Histoire 64 Agricultural extension work 57 Economic conditions 54 Agricultural ecology 49 Congresses 46 Food supply 45 Technology transfer 44 Rural conditions 43 Social aspects 41 Farmers 37 Recherche 37 Sustainable agriculture 37 Agricultural productivity 36 Landbouw 36 Farm life 35 Farm management 34 Soils 32 farming (activity or system) 32 Aspect économique 31 Livestock 31 less ...