Effects of smashing ridge tillage and spring irrigation combination treatment on water, salinity and cotton yield in drip irrigation cotton fields

Abstract

Background and Aims Soil salinization in Xinjiang seriously restricts the growth of cotton. In recent years, smashing ridge tillage technology has been introduced into saline-alkali land management. However, the effects of different smashing ridge tillage depths and spring irrigation amounts on soil water and salt and cotton yield are not clear. Methods This study was conducted in Tumushuk, Xinjiang, through a two-year field experiment (2021 and 2022), to analyze the effects of smashing ridge tillage depth (F1: 40, F2: 60 and F3: 80 cm) and spring irrigation amount (W1: 2400, W2: 3000 and W3: 3600 m3/ha) on saline cotton fields, the optimal smashing ridge tillage depth and spring irrigation amount zone were determined by the multi-objective optimization method. Results The results reveal the ability of the smashing ridge tillage and spring irrigation combination treatment to significantly increase soil moisture (P<0.01) and reduce soil salinity (P<0.01), and altered of salinization degree from severe to moderate and mild. Moreover, the soil salt ions (Na+, Cl-, SO42- and Ca2+) were effectively leached, and the soil hydrochemical species gradually changed from SO42-—Ca2+·Na+ to SO42-·HCO3-—Ca2+. The emergence rate and cotton yield significantly increased following the application of smashing ridge tillage and spring irrigation (P<0.05), the average yield was maximized under the W2F2 treatment (6025 kg/ha) in two years. The yield, economic benefit, water productivity and salt leaching efficiency were maximized at the spring irrigation amount of 2862-2923 m3/ha and smashing ridge tillage depth of 71-73 cm. The results of this study provide scientific basis and technical guidance for the improvement of saline-alkali land in southern Xinjiang.