Effect of long- term two- crop rotation systems on some soil characteristics and carbon fractions in Central Anatolia region

Soil fertility and soil quality decrease in monoculture areas due to deterioration of some soil properties. The fallow-crop system used to overcome this problem can not provide the desired benefits. In this study; Some physical and chemical properties and changes in organic carbon forms of soils under long-term two crop rotation systems under dry farming conditions in the Central Anatolia Region were examined. The experiment, carried out by the Central Research Institute of Field Crops at the Haymana Research and Production Farm, includes eight different crop rotation systems and three replications in a randomized block trial design. The research included fallow-wheat, continuous wheat, chickpea-wheat, winter lentil-wheat, vetch-wheat, summer lentil-wheat, sunflower-wheat and safflower-wheat two cropping rotations. Soil samples were taken from depths of 0-10 cm and 10-30 cm following wheat harvest. According to the findings, in terms of physical properties; The differences between the mean weight diameter, the amount of water stable aggregate and the hydraulic conductivity values are important. Differences in total nitrogen, total organic carbon, particulate organic carbon, available potassium and available zinc contents of soils were found to be important for both crop rotation systems and depths. Differences between the available amounts of phosphorus, iron and copper in soils were found to be significant based on depth. Differences in available manganese amounts are important in crop rotation systems. Total organic carbon accumulation in the surface soil was found in the following order: chickpea > safflower > summer lentil > vetch > winter lentil > wheat > fallow > sunflower. The findings reveal the necessity of including legumes in crop rotation systems in improving soil physical and chemical quality characteristics. Among legumes, the chickpea-wheat two crop rotation system is the most prominent practice. Alternative systems to this system are summer lentil-wheat, winter lentil-wheat and safflower-wheat crop rotation systems.