WHEAT YIELD AND NPK UPTAKE AS AFFECTED BY NITROGEN FERTILIZATION IN COMBINATION WITH RHIZOBACTERIN INOCULATION

Abstract

Two field experiments were performed at the experimentalFarm Station of Sids Agricultural Research Station, AgriculturalResearch Center during the two successive seasons 2003/2004 and2004/2005 to study the effect of inorganic nitrogen fertilizerapplications (0, 25, 50 and 100% of recommended dose (75 kg N/fed)for wheat plants in alluvial clay soil in Beni Suef Governomrate, andseed inoculation with biofertilizer, namely, Rhizobacterin on bothgrains and straw yields as well as N P K concentrations and uptake bygrains and/or straw. The experiment was laid out in a split plot designin randomized complete blocks with four replicates.Data indicated that both grain and straw yields significantlyresponded to nitrogen fertilizer additions till the full recommendednitrogen rate, i.e. 75 kg N/fed. Results also, showed that both grainand straw yields significantly increased by seed inoculation withRhizobacterin inoculant, where the grain yield increases were 9.6 and8.3% as compared with uninoculated in the two growing seasons,respectively. The best grain and straw yields were obtained whenammonium nitrate (33.5% N) was applied at 75% of recommendedrate, i.e. 56.25 kg N/fed in combination with Rhizobacterininoculation.It was also found that increasing inorganic nitrogen fertilizerincreased both N and K concentrations and uptake in both grains andstraw, while P concentrations and uptake did not respond to inorganicnitrogen fertilization. Also, biofertilizer application significantlyincreased nitrogen concentration in grains and potassiumconcentrations in grains and straw. Moreover, nitrogen and potassiumuptake in grains and/or straw were significantly affected byRhizobacterin inoculation. On the other hand nitrogen concentrationin straw as well as phosphorus concentration in grains or straw and itsuptake in straw were not affected by biofertilizer treatments. Thecombination between inorganic nitrogen and Rhizobacterininoculation exert the same trend of the effect of biofertilization onNPK concentration and uptake, where, in general the highest valuesof NPK concentration and uptake were produced by wheat plantsfertilized with full recommended nitrogen rate (75 kg N/fed) or theplants inoculated with bacterial Rhizobacterin inoculant and receivedthree fourth of recommended nitrogen rate, i.e. 56.25 kg/fed.It could be concluded that 75% from recommended nitrogenlevel combined with seed inoculation by Rhizobacterin satisfied thedemands of plant nutrition and the optimum yield production, avoidedexcessive fertilizer applications and accordingly, reduced the costs ofchemical fertilizer applications and environmental pollutions.