Assessing the Effects of Whey Hydrogel on Nutrient Stability in Soil and Yield of Leucosinapis alba and Hordeum vulgare

Agriculture and related crop production are highly dependent on climate and economic factors, and agricultural intensification is associated with a dramatic increase in the consumption of fertilizers. A significant amount of the elements from the most commonly used fertilizers is degraded and lost due to climatic and environmental factors. The soil application of novel whey-based hydrogel represents an innovative approach toward efficient fertilizing and soil water balance that resonates with the concepts of sustainable agriculture and circular economy of waste products. Results of previous research show the positive effect of whey-based hydrogel on water retention after the various levels of hydrogel have been applied into artificial soil. With a view to verifying the effect of the whey hydrogel on soil quality and related crop cultivation in real conditions, the pot experiment compared two different doses of whey hydrogel with control soil, with the conventional NPK treatment of soil and with a mixing strategy combining the conventional NPK treatment with hydrogel application. The controlled pot experiment was conducted with haplic Cambisol, with white mustard (Leucosinapis alba) and spring barley (Hordeum vulgare) as the testing crops. Soil pH, organic carbon (C), total nitrogen (N), available forms of the essential macronutrients (P, K, Ca, and Mg), and the cation exchange capacity (CEC) were determined in Cambisol samples before and after the experiment. The crop yields of barley and mustard were compared among the various treatments of experimental soils. Results demonstrated that the amendment of whey-based hydrogel increased the bioavailable nutrients' concentrations, which persisted even after the harvest. The nutritional quick boost after the whey-based (co)-application significantly increased the experimental crop yield.