نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار دانشکده کشاورزی، دانشگاه یاسوج
2 یاسوج، دانشیار و استاد بخش خاکشناسی
3 استاد بخش خاکشناسی، دانشکده کشاورزی دانشگاه شیراز
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Phosphorus (P) is an essential nutrient in crop production. On the other hand its effect on micronutrients deficiencies and environmental quality has raised more concern about it. Since moisture level and soil properties are among the most important factors affecting P reaction in soils, the present study was carried out to evaluate the effects of P rates ( 0 and 300 mg P Kg-1 soil, as KH2PO4), and two moisture levels (waterlogging and 20% w/w water content) on native Olsen-P and recovery of added P in 20 calcareous soils with different physico-chemical properties at 1, 2, 5, 10, 20, 40, 80 and 160 d incubation in a completely randomized design in duplicate. Path analysis was used to evaluate direct and indirect effects of soil properties on P recovery. Results showed that waterlogging significantly increased native Olsen-P in 1, 2, 5 and 10 d, compared to that of 20% w/w, but had no significant effect in other incubation times. Waterlogging significantly decreased the recovery of added P in 80 and 160 d compared to that of 20%w/w, but did not affect other incubation times. Analysis of variance showed that moisture level and the interaction of moisture level and soil properties was significant on P recovery in 80 and 160 d. thus the effect of soil properties on P recovery was evaluated for these time periods. Under waterlogging conditions Fe, Al, and Mn compounds, clay and the ratio of clay/ACCE (active carbonate calcium equivalent) negatively; and CCE positively affected the recovery of applied P. A similar trend was observed for 20% w/w, however the effect of Fe compound and CCE was not significant. Path analysis showed that the direct effect of CCE and ACCE on P recovery was higher in 20 %w/w than water logging. Path analysis also revealed the importance of direct and indirect effect of CCE and clay/ACCE in both moisture levels on P reaction in our highly calcareous soils. Since P reaction is considerably affected by Fe, Al and Mn compounds, it is suggested that to evaluate the effect of chemical transformation of Al, Fe, and Mn on adsorption and desorption of P under different moisture regimes.
کلیدواژهها [English]