نوع مقاله : مقاله پژوهشی
نویسندگان
استادیار پژوهش موسسه تحقیقات خاک و آب
چکیده
عنوان مقاله [English]
نویسندگان [English]
Phosphorus adsorption in soils is one of the most important processes that determine its availability to plants. Many studies have revealed that phosphorus fertilizer recommendation can be improved based on soil adsorption properties. Phosphorus adsorption isotherms were constructed for different soils under wheat crop. The sorption curves were used as a basis for fertilizing soils in pots suchthat phosphate in soil solutions varied from about 0.075 to 1.2 mgl-1. Wheat was grown for 6 weeks. Adsorption data were successfully described usingFreundlich and Van Huay sorption models (R2= 0.927-0.997 and R2= 0.949-0.999 for Ferundlich and Van Huay models, respectively). In most soils, yield approached more than 85% of the maximum when phosphate in the soil solution was adjusted to 0.3 mgl-1.The standard phosphorus requirement varied from 19 to 157 mgkg-1. There was linear relation between added P and bicarbonate- extractable P(Olsen P) in all soils(R2=0.96-0.99, andmean of0.98) and the slope of this linear equation (by plotting added P against Olsen P)varied from 0.23 to 0.47 with 0.38 as an average. The recovery of phosphorus varied from 12 to 50% with 37% as an average. This means that 63% of the added P was unavailable. There was no significant difference between the mean recoveries in the different treatments. The phosphorus critical level for sodium bicarbonate extractant (Olsen P) based on was determined at 13 mg P kg-1 soil.
کلیدواژهها [English]