Dados do Trabalho

Título

EFFICIENCY OF NITROGEN FERTILIZER ON AGRONOMIC PERFORMANCE OF IRRIGATED WHEAT IN CERRADO OXISOL

Resumo

The increased demand for food production has resulted in an overuse of agricultural resources, among which the plant nutrient. Nitrogen (N) can be considered one of the most yield limiting factors for maximum yield. The integrated N management strategies could contribute significantly to improving the recovery of N applied as fertilizer (RNAF) under Cerrado (Savannah) conditions, particularly for cereals such as wheat and corn, which has high N requirements. The N, being the nutrient required in greater quantity is the highest share cost in the production of cereals in Brazil. The objective was to evaluate the effect of N rates on agronomic performance of irrigated wheat, as well on the RNAF derived from urea, using the 15N isotopic technique. The study was carried out, in autumn/winter, in Selvíria, State of Mato Grosso do Sul, Brazil, in an Oxisol (Rhodic Haplustox), under no-tillage system. The experimental design was in randomized blocks, with four replicates. The treatments were five N rates 0, 30, 60, 120 and 180 kg ha-1, as urea applied in covering, when the plants were in the tillering - decimal growth stage (GS21). The urea-15N was used at N rates of 60 and 120 kg N ha-1. The experimental area was irrigated by center pivot sprinkler irrigation system. The average wheat grain yield was: 2.86, 3,68, 4.44, 5.50 and 7.46 t ha-1, respectively, with the application of 0, 30, 60, 120 and 180 kg N ha-1, whose data fit the quadratic regression model: y = 2971.9 + 19.934x + 0.0253x2 (R2 0.991). The RNAF by wheat (grain + straw) was of 46,4% (27.8 kg N ha-1) when were applied N rate of 60 kg ha-1, and of 52.9% (47.6 kg N ha-1) when were applied N rate of 120 kg ha-1. On average, the RNAF by wheat plant (straw + grains) was 49.6% derived from N rate applied. Regardless of N rate, two thirds of the absorbed N accumulated in grains and one third in straw (crop residues). 

Palavras-chave

Triticum aestivum L.; urea-15N; N rate; Grain yield; Crop residues.

Instituição financiadora

FAPESP and CNPq (Productivity Research Grant, award number 311308/2020-1).

Agradecimentos

UNESP - Campus de Ilha Solteira