land agriculture 20 soil science 11 water 6 fertilization 5 drainage 5 phosphorus 4 more ... environment protection 4 soil physics 4 environment 4 analysis 3 biodegradation 3 decontamination 3 ecology 3 quality 3 feeds 3 cultivation 3 soil biology 3 půdy (zemědělství) 3 plant production 3 soil 3 tillage equipment 3 landscape forming 3 moisture 3 využití půdy 3 agricultural engineering 3 agricultural machinery and equipment 3 environmental pollution 3 treatment 3 fertile soils 3 less ...