Effect of Adding Mineral Fertilizer NPK and Biochar on the Potential Buffering Capacity of Potassium and its Relation to Corn Yield in Calcareous Soil in Northern Iraq

Abstract

To study the state of potassium in the soil using the intensity and capacitance relationships, and to find out the effect of adding mineral fertilizers NPK and biochar on the dry weight of the vegetative part and seeds, as well as on the potassium content in the vegetative part and seeds of corn crops, we chose the field of the College of Agriculture and Forestry at the University of Mosul. The field was divided into nine blocks with three replications according to a randomized complete block design. Urea was used as a source of nitrogen at three levels (0, 160, 320) kg h-1, while potassium sulfate was added as a source of potassium at three levels (0, 40, 80) kg K2O h-1, and also tri-superphosphate fertilizer was used as a source of phosphorus at three levels (0, 100, 200) kg ha-1, noting that nitrogen was added in two batches, the first before planting and the second batch a month after germination. Biochar was added at three levels: %0, %1, and %2. The results indicated that the values of the ionic activity ratio ranged between (0.056 -0.141) mol. L-0.5, while the values of labile potassium ranged between (2.980-7.852) Cmolc.kg-1, and the free energy values ranged between (-1705.371) cal. mole kelvin-1 and (-1160.957) cal. mole kelvin-1, whereas the values of the Potential Buffering Capacity ranged between (45.346 -55.737) Cmolc.kg-1/mol-1.L0.5.

Keywords

• maize crop,,
• ,،q/i,,
• ,،potassium,,
• ,،calcareous soil