Effect of nitrogen fertilization and inoculum on soybean yield

Abstract

A three-year (1999-2001) trial was carried out in order to analyze the effect of nitrogen nutrition (fertilization and inokulation) on soybean seed yield. In combination with and without inokulation fertilization was employed using 50, 100 and 150 kg/ha of nitrogen and the non-fertilized control. Under favorable humidity conditions (1999 and 2001) seed yield varied from 4.33 to 5.48 t/ha. Under dry weather conditions (2000) seed yield ranged from 1.81 to 1.93 t/ha. On the average, over the three trial years an 11.7% higher seed yield was registered using the highest nitrogen amount (150 kg/ha) compared with the non-fertilized variant. In combinations with nitrogen fertilization soybean seed yield in variants with inoculation in relation to non-inoculation was higher by 1.47- 7.30% in years with favorable humidity conditions. Under unfavorable humidity conditions and low seed yield the effect of inoculation was insignificant. In addition, in 2001 the efficacy of the preparations (nitragin, azotofixin end bioselfix) were tested on three different soil types (carbonate chernozem, brown forest soil and pseudogley) with regard to nitrogen fixation parameters and soybean yield. There was a significant difference with regard to the nodules formed and nodule mass between the preparations tested and an insignificant difference between the nitrogen content in the nodules and seed yield. Considering the three preparations tested, plants grown on the chernozem soil type established on the average by 9.45-11.27% greater number of nodules, 49.19-55.21% greater nodule mass and the content of nitrogen in the nodules was by 17.32-25.72 index points greater compared with the plants grown on brown forest soil and pseudogley soil type.

U trogodišnjem periodu (1999 - 2001) su vršena ispitivanja uticaja načina ishrane (đubrenjem i inokulacijom) azotom na prinos semena soje. U kombinacijama sa inokulacijom i bez inokulacije vršeno je đubrenje sa 50 100 i 150 kg/ha azota, plus kontrola (bez đubrenja). U godinama sa povoljnim uslovima vlažnosti (1999. i 2001) prinos semena je varirao od 4,33 do 5,48 t/ha, a u sušnoj (2000) od 1,81 do 1,93 t/ha. Pri đubrenju sa najvećom količinom azota (150 kg/ha) postignut je, u proseku za tri godine, veći prinos semena za 11,7% od varijante bez đubrenja. U kombinacijama đubrenja sa azotom, prinos semena soje varijanata sa inokulacijom bio je, u godinama sa povoljnim uslovima vlažnosti, veći za 1,47-7,30% nego bez inokulacije. Pri nepovoljnim uslovima vlažnosti, kada je prinos semena bio nizak, efekat inokulacije je bio vrlo slab. Osim ovoga, u 2001. godini na tri različita tipa zemljišta (karbonatni černozem, lesivirana gajnjača i pseudoglej) vršena su istraživanja efikasnosti preparata za inokulaciju (nitragin azotofiksin i bioselfiks) u pogledu parametara azotofiksacije i produktivnosti soje. Između ispitivanih preparata postignuta je vrlo velika razlika u pogledu broja obrazovanih kvržica, zatim mase kvržica, a mala razlika u sadržaju azota u kvržicama i prinosu semena. Na biljkama gajenim na černozemu obrazovan je, u proseku za tri preparata, veći broj kvržica za 9,45-11,27%, veća masa kvržica za 49,19-55,21%, a sadržaj azota u kvržicama bio je veći za 17,32-25,72 indeksnih poena nego na gajnjači i pseudogleju.