Determination of Essential Mineral Contents in Salty Soils Used for Supplementary Food to Ruminants in Wolaita Zone

Abstract

Minerals are essential for life to fulfil the needs of growth and production and to replace cells lost during the course of normal metabolism. On this account, they need to be replenished continuously through food, water or supplements. Although not well studied, rural people in Ethiopia have been using soil supplements for ruminants with the assumption to improve livestock production. Therefore, this study was conducted to examine the mineral content in red and brown salty soils used for supplementary food to ruminants in Wolaita Zone and to compare the findings against the national standards, and forward appropriate recommendation. Representative samples of minerals were taken from different sites of SNNPR around Wolaita Zone, Humbo worada, near Lake Abaya to test the contents and concentration of elements. Sixteen Aduwaa(salty soil) samples were collected, air dried, any visible external particles were removed crashed, homogenized, sieved by using 2 mm mesh, accurately weighed, labelled in plastic bags and sent to mechanical and chemical laboratory and tested using XRF spectroscopy in South Africa and Ethiopian Conformity Assessment Enterprise, in Addis Ababa. One way ANOVA was used for test significance. The findings of XRF spectrometry test showed that there are more than forty six (46) elements in the soil sample. Among them Na (1.790 - 7.562%), Mg (0.461- 0.832%), P (0.023  - 0.092%), S (0.014 – 0.084%), K (2.722 – 3.186%), and Ca (0.404 – 0.844%) are essential macronutrients and Mn (0.190 – 0.216%), Fe (4.908 – 7.292%), Cu (0.00026 – 0.00062%), Co (0.00064 – 0.00089%) and Zn (0.016 - 0.032%), are essential micronutrients which can become toxic when the threshold limits for normal growth are exceeded. The study also showed Aduwaa did not contain heavy metals such as Ir and Hg which have; so far, unknown roles in living organisms, and are toxic even at very low concentrations. However, it contained Pb (0.00048 – 0.00076%), Cd (0.00025 – 0.00128%) and As (0.00425 – 0.00528%) in relatively at very low concentration. The sample contained Fe at extremely high concentration which have antagonistic role in copper absorption and metabolism.

Keywords: Supplementation, macro and micro minerals, XRF spectrometer, ANOVA, Aduwaa, Boole, Ruminants, Calcinations.