Agriculture Economic aspects 260 History 104 Agriculture and state 32 Economic conditions 26 Rural conditions 23 Social aspects 15 Addresses, essays, lectures 14 Environmental aspects 14 Food supply 13 Peasantry 13 Rural development 13 Land tenure 11 Agricultural ecology 10 Case studies 9 Origin 9 Underdeveloped areas 9 Food industry and trade 8 Land use 8 Produce trade 8 Social conditions 8 Research 7 Agricultural innovations 6 Farmers 6 Food 6 Land reform 6 Population 6 Congresses 5 Developing countries 5 Economic development 5