Soil Test Based Phosphorous Calibration for Fababean (Vicia faba L.) Production on Nitisols in Central Highlands of Ethiopian

Chala Girma,Keneni Gemechu,Obsa Zeleke

doi:10.15580/gjas.2018.1.011818007

Abstract

Soil test based phosphorous calibration study was conducted fababean on Nitisols of farmers’ fields in West Shewa, in central highlands of Ethiopia. The experiment was arranged in a complete block design with six levels of phosphorous fertilizer (0, 5, 10, 15, 20 and 25 kg ha-1) with three replications. Results showed that grain yield of fababean were significantly affected by P fertilizer application rate. The application of phosphorous fertilizer at different rates increased grain yield, up to 58% more than the control. Extractable soil P concentrations (Bray II, 0- 20 cm depth) three weeks after planting significantly responded to P fertilizer rate. Correlations of relative yield with Bray-2 soil test phosphorous values showed that the soil test phosphorous levels greater than 12.5 mg kg-1 (critical phosphorous concentration) was found to be sufficient for fababean production. The average phosphorous requirement factor (Pf) calculated from soil test phosphorous values of all treatments for the study area was 7.02

Highlights

Soil fertility is considered to be the major constraint in the highlands of Ethiopia due to continuous cultivation of these soils without adequate replenishment for long years
Soil samples were analyzed for pH using a ratio of 2.5ml water to 1 g soil available P using Bray-II method, Organic carbon was determined by the method of Nelson and Sommers (1982) and total nitrogen using Kjeldahl method (Jackson, 1958), exchangeable cations and cation exchange capacity (CEC) using ammonium acetate method at the soil and plant analysis laboratory of Holeta Agricultural Research Center
Deficiency of moisture in September and October critically limited the numbers of pod and grain filling of fababean production

Summary

Introduction

Soil fertility is considered to be the major constraint in the highlands of Ethiopia due to continuous cultivation of these soils without adequate replenishment for long years. This made highland soils nutrient deficient Nitrogen and Phosphorous. In Ethiopia, century-long, low-input agricultural production systems and poor agronomic management practices, limited awareness of communities and absence of proper land-use policies have aggravated soil fertility degradation. This has encouraged the expansion of farming to marginal, non-cultivable lands, including steep landscapes and range lands

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Discussion

Conclusion