From Industrial Residue to Agronomic Asset: Gyplime’s Role in Enhancing Wheat Yield and Soil Health

Abstract Gyplime, a by-product of lithium extraction, contains high levels of gypsum (calcium sulfate) and lime (calcium carbonate), making it a potentially valuable amendment. This study examined gyplime’s effect on wheat growth, yield, nutrient uptake, and soil health. A glasshouse experiment was conducted using two soil types: Shenton Park and Kojonup, and four gyplime rates: 0, 2.5, 5.0, and 10 g pot -1 (equivalent to 0, 1, 2, and 4 t ha -1 ). All treatments received 100 kg N ha -1 (420 mg N pot -1 ) as urea. The experiment followed a randomised complete block design with six replicates. The parameters considered were plant biomass, grain yield, nutrient content, and soil physicochemical properties. Gyplime application significantly increased soil pH depending on soil type, application rate, and soil depth. A potential liming effect was observed in the topsoil under both soil types. Moderate gyplime application rate (2.5 g pot -1 = 1 t ha -1 ) improved wheat growth, yield, and nutrient uptake in Kojonup soil. However, higher rates (5–10 g pot -1 = 2–4 t ha -1 ) led to a reduction in biomass in sandy Shenton Park soil. Microbial biomass carbon (MBC) was significantly influenced by the interaction of soil type and gyplime rate (p < 0.001), with MBC increasing in Kojonup soil and decreasing in Shenton Park soil. Gyplime shows potential as a soil amendment when applied at moderate rates, improving pH, nutrient availability (e.g., Ca, S), crop performance, and microbial activity. However, excessive application may hinder growth and nutrient uptake, highlighting the need for site-specific management. Field-based studies are essential for the broader applicability of gyplime in sustainable farming systems.