cotton yield and some soil physical and mechanical properties against different tillage methods

In order to investigate the effect of different tillage methods on some soil physical properties and crop yield, an experiment in a randomized complete block design with four replications was conducted at the cotton research farm, located at Hashemabad of Gorgan in 2012. Three levels of tillage methods include surface tillage (disc harrow), minimum tillage (cyclo tiller + disc harrow) and conventional tillage (mouldboard plow + disc harrow) were taken as independent variable and soil physical properties include of particle density, humidity, fragmentation (MWD) in two depths (0-15 and 15-30 cm) also, cone index, residue burial and cotton yield as dependent variables were investigated. Results showed that the depth has a significant effect on soil bulk density, fragmentation and soil cone index as in first depth, surface tillage had the maximum bulk density (1.4 g/cm3), minimum fragmentation and maximum cone index (1723 kPa), additionally, conventional tillage had minimum bulk density (1.19 g/cm3), maximum fragmentation and minimum cone index (912 kPa). During all stages of cotton growth, tillage methods had no significant effect on the humidity in both depths. Residue burial, minimum and maximum values were relative to surface tillage and conventional tillage, respectively. Amount of crop yield in surface tillage as 1534 kg per hectare was higher than other tillage systems. Keywords: Tillage, Soil physics, Cone index, Cotton yeild