Various methods and systems are provided for monitoring and control of soil conditions. In one example, among others, a method includes obtaining one or more aqueous sample from at least one suction probe within a soil substrate and analyzing the one or more aqueous sample to determine a chemical composition of the soil substrate. Amounts of an additive may be determined to adjust the chemical composition of the soil substrate. In another example, a method includes installing at least one suction probe within a soil substrate； drawing a vacuum to induce hydraulic conduction of at least one aqueous solution from the soil substrate； extracting one or more aqueous sample； and analyzing the one or more aqueous sample to determine a chemical composition.
