Soil properties sensitive to degradation caused by increasing intensity of conventional tillage

Increased conventional tillage intensity causes soil degradation in agrosystems. In this field experiment, we evaluate the sensitivity of soil physical, chemical, and biological properties under varying soil tillage intensities. The treatments were: TI0 (tillage intensity zero); TI2 (tillage intensity two); TI4 (tillage intensity four); TI6 (tillage intensity six); and TI8 (tillage intensity eight). These treatments corresponded to two tillage seasons (dry and rainy conditions) with four tillage intensities of conventional tillage (ploughing + harrowing) performed monthly. The restorative role of crop growth and rotations in soil properties was not considered in this study, and the interval between soil tillage was short. After the second tillage season, we determined 31 soil physical, chemical and biological properties. Biological properties were more affected by conventional tillage intensity than physical and chemical properties. The most sensitive soil properties to the increasing tillage intensities were aggregate weighted mean diameter (WMD), percentage of aggregates (PA), bulk density (Bd), total porosity (TP), macroporosity (Mac), microporosity (Mic), soil pH, cation exchange capacity (CEC), soil organic matter (SOM), total microbial activity (FDA), arylsulfatase (Ary), acid phosphatase (Phos), and xylanase activity (Xyl). A minimum data set including WMD, Mac, SOM, and Xyl was suggested. The highest intensity of conventional tillage reduced WMD, Xyl and Mac by 28%, 51%, and 63%, respectively, and increased SOM by 14% relative to the control. This work may guide managers on the best soil properties for monitoring the impacts of soil tillage on soil quality in agricultural areas that routinely use conventional tillage as a management practice.