Effect of Inoculating Bradyrhizobium on Phosphorus Use Efficiency and Nutrient Uptake of Soybean in Calcareous Soil, Central Rift Valley, Ethiopia

Abstract

አህፅሮት

ከ7.0 ፒ.ኤች በሊይ የአፈር ፎስፈረስ ግዑዝ ስሇማይሟማ በከፍተኛ ሁኔታ ሇዝግጠት ተጋሊጭ ስሇሚሆን ዕፅዋቶች በቀሊለ አያገኙትም፡፡ ስሇዚህ ይህ የምርምር ጥናት በመተሏራ ስኳር ፋብሪካ በ 2008 ዓ.ም ምርት ዗መን የብረዲራይዞቢዬም ባክቴሪያ ክትባት አስተዋፅዖ አኩሪ አተርን ከሸንኮራ አገዳ ጋር በማሰባጠር በፎስፈረስ አወሳሰድና የፎስፈረስ አወሳሰድ ብቃትን ሇመገምገም ዓሊማ አንግቦ በመስኖ ተተግብሯሌ፡፡ ሙከራው ሦስት መጠን የባክቴሪያ ክትባት ማሇትም ላጊዩምፊክስ፣ SB6B1እና ያሌተከተበ እንዲሁም አራት ፎስፈረስ መጠን ማሇትም 0፣ 10፣ 20 እና 30 ኪ.ግ/ሄክታር ፎስፈረስ ወስዯዋሌ፡፡ ሙከራው የተ዗ጋጀው በራንዯማይዝድ ኮምፕሉት ብልክ ዲዛይን በፋክቶሪያሌ የተዯራጀ ሲሆን ሦስት ቅጂ ግሌባጭ አሇው፡፡ የጭብጥ (መረጃ) ትንትና እንዳሚያሰየው ብረዲራይዞቢዬም ክትባት ትርጉም ባሇው ሁኔታ የዕፅዋት ናይትሮጅንና ፎስፈራስ ይ዗ት ሊይ ካሌተከተበ አንፃር አመርቂ ውጤት አሳይቷሌ፡፡ የተሇያዬ የፎስፈረስ መጠን እንዲሁም የፎስፈረስና ክትባት ጥምረት በናይትሮጅንና ፎስፈረስ ይ዗ት ሊይ ትርጉም ያሇው ሌዩነት አሊሳዩም፤ ነገር ግን 30 ኪ.ግ/ሄክታር ፎስፈረስ በጠቅሊሊ ፎስፈረስ ይ዗ት ሊይ ከፍተኛ ሌዩነት አምጥቷሌ፡፡ በብረዲራይዞቢዬም ክትባት ምክንያት ፎስፈረስን የመውሰድ ብቃት ተሻሽሎሌ፡፡ በዚህ መሠረት ከፍተኛ አግሮኖሚክ ኢፊሼንሲ፣ ሪከቨሪ ኢፊሼንሲና ዩትሊይዜሽን ኢፊሼንሲ በSB6B1 ክትባት፤ ፊዚዮልጂካሌ ኢፊሼንሲና አግሮፊዚዮልጂካሌ ኢፊሼንሲ በላጉምፊክስ ክትባት አማካይነት በ10 ኪ.ግ/ሄክታር ፎስፈረስ ሲገኝ አግሮፊዚዮልጂካሌ ኢፊሼንሲ በ30 ኪ.ግ/ሄክታር ፎስፈረስ ተመዝግቧሌ፡፡ በአጠቃሊይ በ10 ኪ.ግ/ሄክታር ፎስፈረስ መጠን SB6B1 ባክቴሪያ ክትባት አመርቂ ውጤት ያስገኘ ሲሆን ላጊዩምፊክስ ዯግሞ ይከተሊሌ፡፡ የፎስፈረስ መውሰድ ብቃትን እንዲጨምር የተሻለ አያያዝ ዗ዴዎችን ማሇትም ፎስፌት የሚያሟሙ ረቂቅ ነፍሳት ወይም ማይኮሪ዗ ብረዲራይዞቢዬም ጋር በማጣመር መጠቀም አስፈሊጊ ነው፡፡

Abstract

At a soil pH value of above 7.0, inorganic phosphorus (P) is highly susceptible to precipitation as insoluble form that is unavailable to plants. Hence, a field experiment was conducted at Metehara Sugar Estate under irrigation during the 2014/15 cropping season to evaluate the effect of inoculating Bradyrhizobium on P uptake and P use efficiency of soybean intercropped with sugarcane. The treatments consisted of three levels of inoculation (Legume fix, SB6B1 and uninoculated) and four rates of P (0, 10, 20 and 30 kg Pha-1). The experiment was laid out in a randomized complete block design (RCBD) in a factorial arrangement and replicated three times. Analysis of the data indicated that Bradyrhizobium inoculation significantly increased plant N concentration and P uptake compared to the uninoculated treatment. The effect of P rates and its interaction with inoculation was not significant on N concentration and P uptake, but significantly increased total P uptake at the application of 30 kg Pha-1. Phosphorus use efficiency indices were improved in response to inoculating the crop with Bradyrhizobium. The highest AE (13.6 kg kg-1), PRE (31.8%) and PUE (10.6 kg kg-1) were obtained by SB6B1 inoculation and the highest PE (117.2 kg kg-1) and APE (161.7 kg kg-1) were obtained by Legumefix inoculation all at 10 kg P ha-1except PE which recorded the highest at 30 kg P ha-1.Thus, it can be concluded that SB6B1 isolate can be used as the best inoculant followed by Legumefix isolate with 10 kg P ha-1of P fertilizer. However, strategies for increasing P use efficiency by adopting best management practices like co-inoculation of phosphate solubilizing microorganism or mycorrhiza with these Bradyrhizobium inoculants should be adopted to enhance P use efficiencies.