Nitrogen and potassium sources of fertilizers may affect wheat blast and Fusarium head blight under favorable weather conditions

Abstract

Wheat blast (WB) and Fusarium head blight (FHB) are important wheat spike diseases in South America. There is evidence that the severity of these diseases is influenced by soil fertilization. The effects of nitrogen (N) and potassium (K) sources of fertilizers and phenological stages for topdressing fertilization on these spike diseases were evaluated during the 2015 and 2016 winter seasons in an endemic area for these diseases in Brazil. Two distinct field experiments were carried out, one focusing on N sources and the other on K sources. The experimental design was a complete randomized blocks, with four replicates, and the treatments were disposed in a 2 x 3 x 3 factorial: two wheat genotypes (BRS Gaivota and BRS Gralha-Azul), three sources of N or K, and three phenological stages for fertilization. The WB and FHB severities in BRS Gralha-Azul were higher than that in BRS Gaivota. FHB severity was lower when N was applied in the booting stage than in flowering. The sources of K influenced FHB severity, which was higher when K chloride was applied, compared with K nitrate. The weather condition was the determining factor in the wheat expression to WB and FHB diseases, followed by genotype resistance. Highlighted Conclusions 1. Nitrogen and K sources of fertilizers and the phenological stages for N and K fertilizations do not play a significant role on wheat expression to WB and FHB.

Wheat nitrogen utilization efficiency and yield as affected by nitrogen management and environmental conditions

“…Several studies evaluated the efficiency of N sources for some Poaceae crops, such as maize (Viero et al, 2014;Kaur et al, 2017), wheat (Viero et al, 2014;Galindo et al, 2019;Silva et al, 2019;Kaneko et al, 2020), rice (Liu et al, 2018;Amanullah et al, 2020), and sugar cane (Boschiero et al, 2018;Degaspari et al, 2020). However, the outcomes are inconclusive and with few exceptions (e.g.…”