نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشیار
2 دانشجوی کارشناسی ارشد گروه خاکشناسی دانشگاه بوعلی سینا، همدان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Soil phosphorus supply to plant roots increases after addition of phosphorus fertilizer due to both the increase in soil solution and available phosphorus (Olsen-P). However, very little information is available on the effect of added phosphorus on the concurrent increase in soil solution phosphorus and available phosphorus. The objective of this research was to investigate the relation between added phosphorus and increase in soil solution and available phosphorus of 10 soils. Ten surface soils were equilibrated at field capacity for three weeks at 25 °C after the addition of 0, 21, 42, 104, 208, 415 and 1245 mg P kg-1 of soil. High rates of application occur where phosphorus is placed in a small fraction of the soil. There were linear relations for soil solution phosphorus and available phosphorus as functions of rates of added phosphorus with every soil. The slopes of linear functions between available P and rates of added P varied from 0.25 to 0.80 proportional to the fractions of added P extracted by Olsen procedure. The slope indicates the fraction of added phosphorus extracted with the Olsen-P method. Thus, 78 % of added P was not extractable by Olsen-P and was assumed to have been converted to non-available form. Inputs of 100-138 kg P ha-1 are required to raise Olsen-P by 10 mg kg-1 soil in the calcareous soils used in this experiment.
کلیدواژهها [English]