Nitrogen use efficiency in lowland rice cultivars

Abstract

The objective of this research was to study the efficiency and response of using nitrogen in lowland rice cultivars grown in the southwest of Tocantins, Brazil. The experiments involved nine commercial rice cultivars (BRS-Jaçanã, Metica-1, Best-2000, BRSGO-Guará, BRS-Alvorada, BRA-01381, AN-Cambará, BRS 7-Taim and EPAGRI-109), which were cropped in two distinct environments. In order to stimulate areas with high and low nitrogen levels, rates of 20 and 120 kg ha^-1 of nitrogen were used, respectively. The experiments were carried out in a completely randomized block design, with four replicates. The cultivars were classified according to the use and response to the applied nitrogen. No cultivars were considered to be efficient in the use and responsive to the supply. The cultivars EPAGRI-109, BRSGO-Guará, BRS 7-Taim and BRA-01381 demonstrated efficiency in the use of nitrogen and not responsive to its application.