Nitrogen content, SPAD index and production of single head broccoli

Abstract

In the management of single head broccoli nitrogen fertilization, there is no study indicating the critical level and adequate range of N content and SPAD index in the leaves to evaluate the nitrogen nutritional status. This work was carried out in two consecutive years with control without N and three rates of N (150; 300 and 450 kg ha-1). The treatments were arranged in the experimental design of random blocks, with four replications. All productive characteristics were significantly influenced by N rates. The fresh inflorescence mass reached a maximum value of 822 g with 308 kg ha-1 N. The critical levels were 61.1 g kg-1 for total N foliar content and 71.31 ud SPAD at 40 DAT. The SPAD index presented high correlations with the total N content in the leaves (r = 0.93; p<0.034) and with the maximum fresh mass of the inflorescence (r = 0.99; p<0.001). The ranges of N content (low ≤52.5; medium 52.6 to 57.4; sufficient 57.5 to 61.1 and high >61.1 g kg-1) and SPAD index (low ≤68.48; medium 68.49 to 70.47; sufficient 70.48 to 71.31 and high >71.31 ud SPAD) are proposed for assessing the N nutritional status of single head broccoli.

Pigmentos Foliares Na Cultura Da Ervilha: Relação Entre Índice Spad E Conteúdo De Clorofila

“…A quantificação de pigmentos foliares com SPAD permite definir estratégias para manejo da cultura (PÔRTO et al, 2011;NOGUERIA et al, 2018;). Entretanto, as relações são influenciadas pela espécie, condições edafoclimáticas e tratos culturais (MAIA JUNIOR et al, 2017;VIDIGAL et al, 2021). O ajuste de modelos matemáticos entre índice SPAD e teores de pigmentos foliares permite a predição de níveis absolutos em ervilha, auxiliando a obtenção de dados com rapidez e precisão.…”

“…A caracterização dos pigmentos foliares em função do índice SPAD é empregada em diversas espécies, a fim de possibilitar a adoção do recurso para eficiência do sistema produtivo (DANIEL et al, 2016;SHAH et al, 2017;DIAS et al, 2020;VIDIGAL et al, 2021).…”