Information about effects of land use types on selected soil physical and chemical properties is essential in sustainable utilization of soil resources. Therefore, this study was conducted to evaluate effects of land use types on selected soil physical and chemical properties on Kuyu district, Ethiopia. Totally, 24 composite soil samples were collected from grass, cultivated, forest and grazing lands by two soil depths (0-20 cm and 20-40 cm) with three replications. The two way analysis of variance was used to test the mean differences of the soil physical and chemical properties. The highest mean values of sand and clay were recorded in cultivated and grasslands, respectively. The mean bulk density of the soils ranged from 1.10 and 1.37 g cm-3 and the mean total porosity ranged from 48.2 to 58.7%, which indicated the less soil compaction. The pH ranged from 7.68 to 8.00 while the mean values of OM ranged from 3.15 to 5.02%. However, the mean values of total N ranged from 0.18 to 0.26%. The mean value of available P ranged from 1.26 to 5.37 mg kg-1 , which implies that high deficiency of available P in the study area. The exchangeable basic cations and CEC values were within high to very high ranges in all land use types. Conversion of land use types from one to another has adverse effects on soil properties, especially overgrazing and cultivation of deforested land. Therefore, the proper soil and water conservation practice are important in the study area to enhance soil fertility and crop productivity.

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.

Soil resource information is vital for sound land use planning and sustainable fertility management. This study was carried out with the objective of characterizing and classifying soils of Yikalo Subwatershed at Lay Gayint district, Northwestern Ethiopia. Representative soil pedons were opened along topographic positions and described on genetic horizon basis in the field for their morphological characteristics and analyzed in the laboratory for selected physical and chemical soil properties. The soils were classified following the FAO (2014). The results revealed the presence of variations in the selected morphological properties within a pedon and along the topographic positions. Soils differed in reaction from 4.57 to 6.42. On the surface horizons of the soil pedons, available P content varied from 0.21 to 3.25 mg kg-1 , while exchangeable acidity ranged from 0.17 to 3.65 cmolc kg-1 soil. There was no consistent trend for cation exchange capacity (CEC) and PBS (percent base saturation) with soil depth and topographic positions. The soils in Yikalo Subwatershed were classified as Hyperdystric Cambisols (Humic), Haplic Alisols (Humic), Cambic Umbrisols (Colluvic), Haplic Luvisols (Epidystric), and Pellic Vertisols (Mesotrophic). Optimum rates of organic and inorganic amendments should be applied to reduce the level of soil acidity, and improve the fertility level of the soils for better crop production and productivity.

Background: Though soils in the study areas are characterized by higher iron and aluminum oxides, and low available P contents, study on P adsorption characteristics is limited. The purpose of this experiment was to evaluate adsorption properties of selected soils and determine the standard phosphorous requirements of the soils. In this experiment, separately weighed 2 g soil samples were equilibrated in 50 ml of 0.01 M CaCl 2 solution containing KH 2 PO 4 at rates of 0, 1, 2.0, 4.0, 8.0, 16.0, 24.0, and 32.0 mg P L −1 .Results: The Freundlich model was found to be the best model for the description of the P adsorption characteristics of the soils. The Freundlich coefficient K f ranged from 123.32 to 315.31 mg P kg −1 . The Goha-1 soil had the highest K f (315.31 mg P kg −1 ) as Ketasire had lowest K f (123.32 mg P kg −1 ) values. The value of SPR f was ranged from 50.50 to 154.02 mg P kg −1 for soils of the study area. Highly significant (P ≤ 0.01) correlation was observed between the Freundlich adsorption parameters and soil physicochemical properties. Conclusion:The standard P requirement of the studied soils was higher than the blanket P fertilizer rate recommendations in Ethiopia. Lack of inadequate knowledge about internal and external P requirement of each crop might have decreased yield in the study areas as it could have resulted in under-application of fertilizer P. The presence of high correlation between the adsorption parameters and the soil properties suggested the indices' prominent role in explaining P adsorption characteristics of the soils. Since higher dose of P is required by soils in the study area because of fixation, alternative P management strategies is needed to reduce P adsorption and enhance P availability. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Background: Soil acidity with associated low nutrient availability is one of the major constraints to faba bean (Vicia faba L.) production on Ethiopian highlands. Integrated use of organic and inorganic amendments is believed to reduce soil acidity and improve crop production. Therefore, this field experiment was conducted with the objective of evaluating the effects of lime, mineral P, farmyard manure (FYM), compost and rhizobium in acid soil of Lay Gayint District, northwestern highlands of Ethiopia, in 2016-2017 main cropping season. The experiment comprised twenty sole and combined treatments arranged in a completely randomized block design with three replications. Results: Combined application of 8 t FYM ha −1 + 30 kg P ha −1 + 3.6 t lime ha −1 significantly (P < 0.05) increased plant height, number of leaves and branches per plant, pod length, biological and straw yields. Grain per pod, grain yield and thousand grain weight were significantly (P < 0.05) increased with the application of 4 t FYM ha −1 + 15 kg P ha −1 + 7.2 t lime ha −1. This treatment resulted in 102% grain yield advantage over the control. The next higher grain yield advantage of 89% was achieved with 4 t FYM ha −1 + 15 kg P ha −1 + 3.6 t lime ha −1. Nodule number and nodule dry weight per plant were also improved due to 4 t FYM ha −1 + 15 kg P ha −1 + 7.2 t lime ha −1 application. Among sole treatments applied separately, 8 t FYM ha −1 was observed to be superior in all parameters considered followed by 7.2 t lime ha −1. Conclusion: Combined application of 4 t FYM ha −1 + 15 kg P ha −1 + 3.2 t lime ha −1 could be suggested as effective amendment to improve the yield of faba bean and therefore contribute the effort to insure food security in strongly acid soils of the study area.