Comparison of Lime Requirement Determination Methods to Amend Acidic Nitisols in Central Highlands of Ethiopia

Abstract

አህፅሮት

የአፈርን ኮምጣጣነት ለመቀነስ ኖራን መጠቀም አንዱ ጠቃሚ ዘዴ መሆኑ ይታወቃል፡፡ ይሁን እንጂ የኖራ መጠን የምንመጥንበት የአሰራር ሂደት ተለይቶ ባለመታወቁ ቅድሚያ መሰጠት የሚገባው የምርምር ርዕስ ነው፡፡ ስለዚህ ይህ የምርምር ሙከራ በኮምጣጣ ቀይ አፈር (ኒቶሶል)ላይ ታቅዶ ሙከራው በ2009 ዓ.ም በሆለታ ግብርና ምርምር የአፈር ትንተና ላቦራቶሪ የተሰራ ነው፡፡ የተለያዩ የኖራ መመጠኛ ዘዴዎችን ማለትም የተሻሻለ የአዳምስ ኢቫንስና የመሊች በፈር እንዲሁም ታይትሬሽን አሰራሮችን በመጠቀም የኖራ መጠን ተወስኗል፡፡ እነዚህ አሰራሮችም በእንኩቤሽን ዘዴ እንድፈተሹ ተደርገዋል፡፡ ውጤቱ እንደሚያሳየው የመሊች በፈር እና ታይትሬሽን አሰራሮችን በመጠቀም የኖራ መጠን መወሰን በኮምጣጣ ቀይ አፈር ላይ ሰብል ለሚያመርቱት አርሶ አደሮች የሚያስፈልገውን የኖራ መጠን ለይቶ ለማወቅ የተሻለ መሆኑን ያመላክታል፡፡

Abstract

Liming acid soils is one of the available intervention options to amend soil acidity and increase crop production and productivity. Nevertheless, selection of lime requirement determination method suitable to the soil conditions in a particular area is a pressing issue. Therefore, this research was carried out to evaluate lime requirement determination methods to amend soil acidity, in Holetta Agricultural Research Center laboratory in 2017. A total 24 soil samples were collected from acidic Nitisols in the central highlands. The buffers of modified Mehlich (MMB) and modified Adams-Evans buffers (MAEB) were separately prepared. Initial soil pH; soil, water and buffer pH measurements were taken. Soil pH buffer capacity was calculated for each buffer solution from the change from initial pH water and buffer pH. The titrations were performed and lime rate determined. Finally, lime rates determined were validated by soil incubation. The MAEB, MMB and titration with 0.022 M Ca(OH)₂ methods predicted the lime requirement at the rate of 24.7, 4.0 and 3.12 t ha^-1 respectively. The MMB and titration methods predicted the LR almost in the range affordable to the farmers who produce crops on Nitisols. Contrary to this, the MAEB method overestimates LR above the requirements of the soil. Therefore, areas covered with Nitisols can use the Modified Mehlich Buffer or titration to determine the lime rates required to amend their soils. However, field calibrations are required using crops soil pH requirements before these tested methods are taken the best methods to amend the acidic Nitisols to pH 6.0.