Silicon (Si) use efficiency in sandy soil amended by Si-loaded hydrogel

Abstract

ABSTRACTSilicon (Si) plays an essential role in the mineral nutrition of plants. This creates a need to improve tools can provide plant-available Si (PAS) and increase its use efficiency (UE), especially under sandy soil conditions. This study was conducted to estimate Si use efficiency (Si-UE) in sandy soil treated by a hydrogel (water-absorbing polymer) loaded by Si. A field experiment was carried out using a hydrogel (H, 0.7 g kg−1 soil) that was mixed with quartz silica (S, 98.4% SiO2) to give HS homogenous mixtures with three mixing ratios 1:0.5 (HS1), 1:1 (HS2) and 1:1.5 (HS3). The HS mixture was sprayed by potassium humate solution (K-humate, 0.5 mL g−1 hydrogel) to obtain HS1K, HS2K, and HS3K treatments. All treatments were mixed with soil subsurface before wheat (Triticum aestivumL.) cultivation. Results showed that wheat yield and seed yield (t ha−1) increased significantly by applied treatments compared to the control C in the range 9.52–23.80% and 2.59–30.60%, respectively. The HS3 treatment significantly increased the total nitrogen N (mg kg−1) in seeds by 34.99%, phosphorus P by 17.46%, and potassium K by 4.84%. Available Si in soil (mg kg−1) increased in the order HS1 < HS2 < HS3, and with K-humate in the order HS1K < HS2K < HS3K. Total Si (g kg−1) in wheat seeds increased significantly in the order HS1 < HS2 < HS3, and HS1K < HS2K < HS3K with K-humate. Silicon use efficiency may decrease as the rate of applied Si increases.