Title:	Soil-surface straw influences micrometeorological conditions affecting canola mortality during nighttime frosts.
Authors:	KOVALESKI, S. HELDWEIN, A. B. DALMAGO, G. A. GOUVEA, J. A. de CUNHA, G. R. da FOCHESATTO, E.
Affiliation:	SAMUEL KOVALESKI, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil; ARNO B. HELDWEIN, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil; GENEI ANTONIO DALMAGO, CNPT; JORGE ALBERTO DE GOUVEA, CNPT; GILBERTO ROCCA DA CUNHA, CNPT; ELIZANDRO FOCHESATTO, Universidade Alto Vale do Rio do Peixe, Caçador, Santa Catarina, Brazil.
Date Issued:	2020
Citation:	Journal of Agricultural Science, v. 12, n. 11, p. 246-29, 2020.
Description:	Our objective was to measure alterations in the micrometeorological conditions surrounding canola seedlingsduring frost periods, and to quantify seedling mortality as a function of straw distribution on the ground surface. The data was acquired from 15 frosts in 2014. We used four treatments, comprising ground surface without straw (SWS), ground surface entirely straw-covered (SEC), sowing line without straw (SLW), and soil with preexisting surface straw (SES), over three experiments. Net radiation (NR), soil heat flux (G), air (Ta), leaf (Lf), rosette (Tr), and surface temperature (Ts), and plant mortality were evaluated. NR was higher in the SEC treatment and lower in the SLW treatment, whereas G was higher on straw-covered ground; Ts and Ta were lower in the SEC than in the other treatments during the most intense frosts. On 06/19, Tr in the SEC and SLW treatments was -0.66 °C and 0.42 °C, respectively; on 08/14, Lf was -3.62 °C and -2.88 °C in the SEC and SLW treatments, respectively. Plant mortality due to the frost on 06/19 was 30% in the SEC treatment, but 0% in the SLW treatment; the frost of 08/14 caused 33.8% mortality in the SEC treatment and 1.25% in the SLW treatment. This therefore showed that removing straw from the sowing line improved the microclimate around the plants, thus reducing canola mortality at the beginning of the growth cycle, which is when frost events most frequently occur. Keywords: air temperature, Brassica napus L., freezing, leaf temperature, microclimate
NAL Thesaurus:	Air temperature Freezing Microclimate
Keywords:	Brassica napus L Leaf temperature
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CNPT)