نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری دانشگاه شهرکرد
2 استاد دانشگاه شهرکرد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The chemical and biological conditions in the rhizosphere can be different from those in bulk soil. This could alter the quality of the diagnosis of nutrient bioavailability. Phosphorus (P) is one of the primary limiting factors of plant growth in arid areas. The objective of this research was to study the status of various inorganic phosphorus (Pi) fractions, organic phosphorus (Po), acid and alkaline phosphatase enzymes (AcP and AlP, respectively), microbial biomass phosphorus (MBP), and dissolved organic carbon (DOC) in the rhizosphere and the bulk soils of wheat plant growing in 10 calcareous soils in a rhizobox experiment. Thus, P fractions, including P absorbed by Al and Fe oxides (]NaOH+CB]-Pi), occluded P (CBD-Pi), P bounded by Ca (Ca-Pi), and residual P were determined by modified Olsen and Sommers' sequential fractionation procedure. The results showed that phosphatase activities, MBP, and DOC strongly increased in the rhizosphere soils compared with the bulk soils. Also, the pattern of distribution of the Pi fractions differed between the rhizosphere and the bulk soils. The results showed that the amount of the various P fractions in the rhizosphere and the bulk soils decreased in the following order: Ca-Pi> residual-P> organic P>]NaOH+CB[-Pi> CBD-Pi. Simple correlation coefficients showed that plant indices had positive relationship with ]NaOH+CB[-Pi, CBD-Pi fractions, MBP, and AlP in the rhizosphere soils (P≤0.05). The results indicated that P in the rhizosphere was concomitantly modified but the inner-conversion of different fractions and the mechanisms involved were less clear.