Use of an hydrophilic polymer to improve water storage and availability to crops grown in sand dunes I. Corn irrigated by trickling

Abstract The polyacrylamid (PAM) hydrophilic gel Agrosoak® was tested as a soil conditioner for improving water availability to crops grown on sand dunes. Corn ( Zea mays L.) was grown in the field, in a factorial design array using four rates of Agrosoak (0.00, 0.15, 0.30, 0.45% by weight in the upper 25 cm of the soil), three water amounts (70, 85 and 100% of the recommended Class A evaporation pan ratio), and two water salinity levels (1.2 and 6.5 dS·m −1 ). Irrigation and fertilization were provided by trickling. The water storage capacity of the soil increased with the rate of Agrosoak but the applied water was accumulated and stored in the vicinity of the emitters leaving relatively dry sections between the drippers. This caused a reduction in the density of the plants. Even so, yield components, except shoot dry weight per meter (cob yield per plant and per meter, and shoot dry weight per plant) increased with the Agrosoak application rate. Concentrations of nitrogen and sodium in the leaves increased, but phosphate and potassium were unaffected by the Agrosoak application rate with the use of fresh water or brackish water. The use of Agrosoak did not avoid salinity damage to the plants. The results show that the use of trickle irrigation with PAM soil conditioner require a reevaluation of the method of irrigation.