Behaviour of fertilizer-N absorbed through root and fruit in peanut

Abstract

A greenhouse experiment was conducted to study the uptake and translocation of N applied at different rates of¹⁵N fertilizer to the fruiting and rooting zones of peanut plants.

Higher N level treatments in the fruiting zone resulted in higher N concentrations in the shell and gynophore with fruit and lower N concentration in the testa when compared with the results of lower level treatments in the fruiting zone. Regardless of N levels applied in both rooting and fruiting zones, about 60–65% of¹⁵N application to the rooting zone was absorbed through the root, of which 30–35% was found in the seed. With fertilizer application to the fruiting zone and regardless of levels applied to both zones, 35–40% of the¹⁵N supplied was absorbed through the shell, and 65% of this remained in the fruit parts while 35% of it was translocated to the vegetation and roots. The percentage of N in the vegetative and root parts, derived from the fertilizer-¹⁵N through the shell, was lower in the root and nodules than in the shoot and gynophore without fruit. The translocation of N, absorbed through the roots, to the fruit as well as the amount of symbiotically fixed N were decreased by additions of N to the fruiting zone.