The method of the invention comprises the following steps:(i) cutting the maize stalks so as the less leafy stalk segments, higher than 70 cm, stay on the field; (ii) cutting the less leafy stalk segments as close to the ground as possible; (iii) harvesting the less leafy stalk segments cut in step (ii); (iv) cutting the in step (iii) harvested less leafy stalk segments into 5-50 mm stalk sections; (v) providing a mechanical impact to the stalk sections of step (iv) to obtain a mix containing: f1. said spongy cores forming the superabsorbent pellets fraction, f2. said elongated fiber pieces forming the fibrous matter fraction, f3. and said leaf matter forming the leafy fraction, (vi) separating the 3 fractions from each other; (vii) recovering the three fractions f1-f2-f3; The invention also pertains to the so obtained products and to their uses in treatments of liquids or gases.