Effect of synthetic and natural water absorbing soil amendment soil physical properties under potato production in a semi-arid region

Abstract Effect of synthetic and natural water absorbing soil amendmentson soil physicalproperties, fresh tuber yield and size of potato production was investigated in a field experiment in a semi-arid region in northern China in 2010–2012. Treatments included two different synthetic water absorbing amendments(potassium polyacrylate-PAA, polyacrylamide-PAM) and one natural amendment( humic acid-HA), both as single amendments, and compound amendments(natural combined with a synthetic) and a no amendmentcontrol. Soil amendmentshad highly significant effect ( P ≤ 0.01) on soil water holding capacity, soil cone penetration resistance and soil aggregate size fractions, but had no significant effect ( P > 0.05) on soil bulk density. Soil amendmentsincreased fresh tuber yield by 4.2–32.9%, increased the proportion of tuber size category 1 (>150 g) and decreased size category 3 (