Effect of water absorbing soil amendments on plant growth and soil chemical properties for potato production in a semi-arid region

Effect of synthetic and natural water absorbing soil amendments on plant growth and soil chemical properties 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 combined amendments (natural combined with a synthetic) and a no amendment control. Soil amendment showed a significant ( P ≤ 0.05) effect on plant height, stem diameter and leaf area index in the potato growing period in all three years, and improved the plant parameters respectively by 0.49%-36.90%, 2.59%-21.12% and 1.85%-37.57%. Soil amendments showed a significant ( P ≤ 0.05) effect on soil chemical parameters in different soil layers in all three years, and improved soil organic matter, soil available nitrogen, phosphorus and potassium respectively by 1.03%-11.20%, 0.82%-13.99%, 1.24%-16.61% and 4.50%-22.20%. Soil amendments significantly ( P ≤ 0.05) affected fresh tuber yields in the 150 g size categories; 150 g was increased by 10.4 to 77.5%. The accumulative effect of soil amendments on soil chemical indicators was enhanced with repeated yearly application in the same field, and the effect of soil amendment on soil chemical indicators was reduced with increasing soil depth. Amendment treatment with PAM+HA always had the greatest effect on plant morphological parameters and soil chemical properties among all amendment treatments and thus merits further research.