Abstract
The aim of this study was to examine the effects of soil amendments to sandy loam and soil physical indices, mainly soil aggregates, soil retention curve, and pore size distribution. Date palm waste biochar at rates 2% (B-1), 4% (B-2), 6% (B-3), and 8% (B-4) and sorbent adsorption polymer (SAP) at rates 0.2% (P-1), 0.4% (P-2), 0.6% (P-3), and 0.8% (P-4) (w/w). In addition, the combination of both as B-1:P-1, B2:P-2, B-3:P-3, and B-4:P-4, were added to the soil as amelioration materials. The results revealed that on the average, soil water content increased by 7.3%, 3.3%, and 15.0% with the addition of biochar, polymer, and the combination, respectively. The location parameters d(mode), d(median), and d(mean) decreased by 6.4%, 8.8%, and 10.6% for the biochar, and increased by 2.3%, 4.6%, and 3.4% for the polymer treatments, decreased by 4.8%, 4.4%, and 4.2% for the combination treatments, respectively. Shape parameters such as standard deviation (SD), (spread) skewness (asymmetry), and kurtosis (peakedness) were 2.2, - 0.27, and 1.6 for the biochar treatments, 2.17, - 0.27, and 1.6 for the polymer treatments, and 2.17, - 0.23, and 1.6, for the combination treatments, respectively. The aggregate stability (SA) of soils of size 0.25 and 0.13 mm increased by 50.8% and 50% with the application of biochar (B-2 = 4%) and polymer (P-2 = 0.4%) B-2:P-2 and polymer (P-4 = 0.8%) P-4 treatments, respectively. This study recommends using combination of biochar with polymer treatments on sandy loam soil in arid area due to its strong hydro-physical properties.