Effects of polymer compounds on soil aggregate composition and cotton yield in salted cotton field

ObjectiveThe objective of this study was to compare the effects of different polymer compounds on soil aggregates and cotton yield of salted cotton field,and to determine the suitable polymer compounds to improve the salted cotton field so as to increase cotton yield.MethodThe experiment was conducted at Regiment 146,Shihezi,Xinjiang Uygur Autonomous Region. Four treatments were used in the study:M1(poly acrylic acid salt treatment,K-PAM),M2(poly acrylamide treatment,PAM),M3(cellulose treatment,HEC)and control treatment(no application of compound,CK). Soil aggregates and soil samples were collected at different growth stages to determine soil pH and conductivity,and yield was estimated at the harvest stage of cotton.ResultThe results showed that soil conductivity in different soil layers was significantly reduced at flowering period and boll period under the M1 and M2 treatments compared with CK (P<0.05,the same below),which effectively reduced salt poisoning,and soil conductivity in 0-20 cm soil layer was sig-nificantly increased in M3 treatment compared with CK,while that in 20-40 cm was significantly reduced compared with CK. Soil pH in 20-40 cm soil layer was significantly lowered in M2 and M3 treatments compared with CK in cotton boll stage. There was no significant effects of M2 treatment on soil pH compared with CK in other growth stages(P>0.05). The application of polymer compounds improved salted soil structure,mainly increasing 2.000-0.053 mm aggregates;three polymer compounds all increased cotton yields significantly,among which M1 treatment had the best effect and increased the yield by 107.4%.ConclusionPolymers application can improve salted soil structure,increase cotton yields. The effects of poly acrylic acid salt application is the most remarkable,which can be regarded as the first choice for soil improvement in salted cotton field in Xinjiang.