Influence of Blast on the Nutrition and Yield of Irrigated Rice in Southern Brazil

• Published in: Journal of soil science and plant nutrition 2020-09, Vol.20 (3), p.1378-1386
• Main Authors: Ogoshi, Claudio, Carlos, Filipe Selau, Waldow, Daniel, Miranda, Fernando Fumagali, Reginato, Júlia Lima, Ulguim, André
• Format: Article
• Language: English
• Subjects: Agricultural production; Agriculture; Biomedical and Life Sciences; Crop diseases; Crop yield; Cultivars; Design of experiments; Ecology; Environment; Experimental design; Fertilization; Fungicides; Grain; Influence; Irrigated farming; Life Sciences; Nitrogen; Nutrition; Original Paper; Pesticides; Plant Sciences; Plant tissues; Rice; Rice blast; Rice fields; Soil Science & Conservation; Variables
• ISSN: 0718-9508; 0718-9516
• DOI: 10.1007/s42729-020-00219-9

In recent decades, nitrogen fertilization rates have increased significantly in irrigated rice fields in southern Brazil. However, there is a gap in knowledge concerning the use of these high rates of nitrogen fertilization in cultivars with a high yield potential, and susceptible to rice blast. We therefore conducted a field experiment in the 2014/2015 and 2015/2016 crop year to evaluate blast severity, plant tissue nutrition, and yield and grain quality with increasing nitrogen fertilization levels in a rice blast-susceptible cultivar (Guri Inta CL). The experiment had three factors, with factor 1: N doses (0, 60, 120, and 180 kg ha −1 ), factor 2: sowing dates (early and late), and factor 3: with and without fungicide application. The experimental design was randomized blocks with four replications. The area under the disease progress curve was positively influenced by the increase of N rates in the two crops years. Grain yield had a negative quadratic effect as a function of N rates. Increased N levels reduced the thousand grains weight. Late sowing and non-application of fungicide increased disease severity; there was reduced yield, grain quality, and N use efficiency. It is concluded that the use of N levels greater than 60 kg ha −1 in rice blast-susceptible cultivars in southern Brazil increases disease severity with lower N use, reduces grain yield and grain quality.