WResidual sodium carbonate index
WBjerrum plot
WCalcareous
WCarbon cycle
WClay mineral
WFulvic acid
WIntegrated pest management
WLiming (soil)
WSoil pH
WPhosphorus cycle
WRedox
WSahysMod
WSaltMod
WSchikorr reaction
WSoil salinity
WSoil contamination
WSulfur cycle