Biodegradable poly(lactic acid)/cellulose‐based superabsorbent hydrogel composite material as water and fertilizer reservoir in agricultural applications

The work presents a fully degradable superabsorbent composite material to be used in agricultural and horticultural applications. It is designed to retain and release fertilizer solutions to the soil in a controlled manner, permitting resource optimization. Because of its ability to absorb and release large amounts of saline water, a natural superabsorbent hydrogel derived from cellulose was chosen. Potassium nitrate was chosen to model the fertilizer. Poly(lactic acid) was added to the final composition in order to delay solution release. The composite material was obtained using easily available and low‐cost starting materials and using a simple manufacturing process, using a standard mixer. After being analyzed for morphological (scanning electron microscopy), physical (X‐ray diffraction), chemical (energy‐dispersive X‐ray spectroscopy), and thermal properties (thermogravimetric analysis and differential scanning calorimetry), the material was tested using two different Mediterranean cultivations (Pomodoro di Morciano di Leuca and Cicoria Otrantina) and two different kinds of soil (red and white soils). The analysis revealed different water release characteristics for different soils. These findings have been confirmed by measuring plant growth for both species, as well as fruit yield of the tomatoes.