Effects of Irrigation Water and Mineral Nutrients Application Rates on Tissue Contents and Use Efficiencies in Seed Potato Tuber Production

 

Gathungu, G.K., Aguyoh, J. N. and Isutsa, D. K. 2014. 

 

Soil fertilityand unreliablerainfalhave becomeimportantin seed potato  (Solanum tuberosum L.)productioninKenya.Knowledge onwaterandmineralnutrientuse efficiencieswillhelppredictthebestapplicationratesforoptimalseedpotatoproduction. AstudywasconductedatEgertonUniversity,Horticultural ResearchandTeachingFarm todeterminetheeffectofintegration ofirrigationwater,nitrogen(N)andphosphorus (P) nutrient onwater,NandPuseefficiencies andtissuecontent. Inasplit-splitplot,the irrigationwatersupply(40%,65%and100%field capacity)wasassignedto mainplots,N (0,75,112.5and150kgN/ha)tosubplotsandP(0,50.6,75.9,101.2kg P/ha)tosub- subplots,eachtreatment replicated threetimesandtrialrepeatedonce.Irrigationwater wasdripappliedthroughoutthepotatogrowthperiod,withNsupplied asurea(46%N)in twosplits,andPastriplesuperphosphate (46%P2O5) at planting time.Data on seed potatyielcollected from each treatment at harvest was used to calculate water,Nand Puseefficiencies. OvendriedgroundtuberswereusedtodetermineNandPcontents. Analysisofvariancewasdoneandsignificantlydifferent meansseparatedusingTukeys StudentizedRangeTestatP0.05.Highirrigationwaterat100%comparedto65and 40%rateresultedinrelatively highNandPuseefficiencies,butdecreasedwateruse efficiency. High (100%) compared to 40% irrigation rate when integrated with high comparedwithlowNandPapplication ratesreducedtheWUEby6.1and8.1kg/m3, increasedNUEby14.4and13.3kg/kg, andPUEby73.4and69.5kg/kg, inTrialsIandII respectively.ApplicationofintermediatetohighNandPnutrientincreased thewater,N andPuseefficiencies. RegardlessofirrigationwaterratetubertissueNandPcontents increasedwithNandP applicationrate.Applicationoflowto intermediateirrigationwater, intermediateto highNandPwill increasetheiruseefficienciesandtissuecontentsduring seedpotatoproduction.

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