NASA Johnson Space Center is developing an active synthetic soil to grow plants in space as part of their regenerative life support system. The synthetic soil is zeolite based and slowly releases nutrients but unfortunately becomes acidic with time. The proposed research evaluates using natural and synthetic components to buffer soil pH within optimum ranges for plant growth. Objectives are to characterize pH buffering properties of zeolite and apatite (primary components of NASA's active synthetic soil), evaluate pH properties of select buffering amendments, and formulate combinations of amended zeoponic soil. The effort consists of acquisition and characterization of raw materials (zeolite, apatite, and buffering agents); evaluation of pH buffering properties of individual materials using equilibration, titration, and incubation experiments; formulation of various zeoponic treatment combinations using preliminary data and acid-base balance scenarios; and feasibility testing of formulations using additional equilibration, titration, and incubation experiments. Phase II will consist of growing plants with low, medium, and high pH preferences in amended zeoponic soil to refine the innovation to meet NASA needs and allow commercialization. The expected result is development of zeoponic soil with enhanced buffering capacity. NASA will use the innovation in their Regenerative Life Support System.
