Phosphorus Status, Inorganic Phosphorus Forms, and Other Physicochemical Properties of Acid Soils of Farta District, Northwestern Highlands of Ethiopia

Abstract

Soil acidity and low availability of P limit crop production in the highlands of Ethiopia. The objective of this study was to determine the P status, distribution and forms of inorganic P and relate them to selected chemical properties of eight representative acidic surface soil samples from Farta District. Soil pH (H 2 O) varied between 4.74 and 5.50. The moderate to high CEC suggests that besides kaolinite, the soils also contain expandable 2 : 1 clay minerals. Though the total P content was high, the available Olsen P content was very low or low in all soils except one. In most soils, the abundance of inorganic P fractions was as follows: P bound by oxalate extractable iron (Fe ox -P) > reductant soluble Fe-P > occluded Al-Fe-P > P bound by oxalate extractable aluminum (Al ox -P) > calcium bound P (Ca-P). Olsen P had a very strong positive correlation ( ≤ 0.01) with Al ox -P ( = 0.98), Fe ox -P ( = 0.96), and oxalate extractable P ( = 0.94). Though Fe bound P reserves were quite abundant and the degree of P saturation of Al ox + Fe ox (median 3.3%) was moderate, the extremely low P saturation of Al ox (median 0.5%) explains the P deficiency of the soils.

Effects of clinoptilolite zeolite on phosphorus dynamics and yield of Zea Mays L. cultivated on an acid soil

“…This observation corroborates findings by Melese et al . [ 76 ] and Adhami et al ., [ 77 ] but contradicted those reported for less weathered soils. However, the contrary observation of Ca-P following application of ERP treatments in this study could be due to the undissolved rock phosphate.…”

Effects of land use types on selected soil physical and chemical properties: The case of Kuyu District, Ethiopia

“…This deficiency of available P on the study area could be due to the high CaCO3 content of the soil since the available P can precipitate in the form of calcium phosphate in calcareous soil. Similarly, Melese et al (2015) reported that in calcareous soil, the available P was low due to the precipitation of P in the form of calcium phosphate.…”

Characterization and classification of soils of Yikalo Subwatershed in Lay Gayint District, Northwestern Highlands of Ethiopia

“…Most of the studies reported depletion of cation exchange capacity (CEC), organic carbon (OC), and total nitrogen (TN) (Ashenafi et al, 2010;Yitbarek et al, 2016). Available soil phosphorus (P) was found to be deficient in most soils of cultivated lands (Mekonnen, 2015;Melese et al, 2015). More recently, variations of soil properties such as TN, organic matter (OM), and CEC with topographic positions and soil depth in some areas of north and south Wollo of the Amhara region have been reported (Nahusenay et al, 2014;Alem et al, 2015).…”