-The dormancy dynamics of temperate fruit tree species is complex and highly variable according to genotype and environment. Due to this variability, many phenological models of cold units have not been suitable for subtropical climatic conditions in southern Brazil. The aim of this study was to evaluate the influence of air temperature on the peach dormancy in Urussanga-SC. For this purpose, the correlations between the date of full bloom of sixteen peach varieties and the total hours in which the temperatures remain in certain thermal levels were evaluated. Two groups of varieties with highly differentiated responses to temperature in various times were identified. In the first group, consisting of ten varieties, the beginning of significant influence (p<0.05) of temperatures on the date of full bloom occurred as earlier, in February. In this group, temperatures between 16 and 22 °C accumulated from March to June were those that most contributed to the flowering advance. In the second group, the beginning of the significant influence of temperatures occurred later in April. In this group, the accumulated high temperatures from early April to late May anticipated the full bloom, but from May 25, temperatures below 10 °C were responsible for this advance. This behavior differs from traditional phenological models that consider a sequential cold and heat requirement in the resting phase. The results obtained indicate the possibility of an alternating or parallel influence of different temperature levels on dormancy. Index terms: Prunus persica, dormancy, temperature, statistical method. The phenological data used came from a collection composed of peach tree selections resulting from genetic improvement located in Urussanga, state of Santa Catarina, Brazil (28º 31 'S, and 49º 19' W, 49 m asl). Sixteen selections considered to be adapted to the climate of the region were evaluated. This collection was formed by five plants in sequence of each variety, and for the average phenological records, three central plants were used. The selections, grafted on Okinawa rootstock, were cultivated with spacing of 6 m between rows and 5 m between plants in a Typic Hapludalf of granitic origin. The climate of the region is subtropical humid, with hot summer and no defined dry season (Cfa, according to the Köppen classification). The average annual temperature is 19.4°C, with maximum average temperature of 25.9 ° C and minimum of 14.2°C. The total annual rainfall is 1624.0 mm, and is normally well distributed throughout the year. The hours of cold below 7.2 ° C occur from May to September with an average annual total of 234 hours. INFLUÊNCIA DE DIFERENTES NÍVEIS TÉRMICOS SOBREThe average daily air temperature data (T a ) were collected at the conventional meteorological station of Urussanga-SC, where T a = (T max + T min + T 9 + 2T 2 ) /5, where T max is the maximum daily temperature, T min is the daily minimum temperature, and T 9 and T 2 are temperatures from 9:00 a.m. to 9:00 p.m. respectively. For the calculation of ...
Resumo: Este trabalho objetivou desenvolver modelos de regressão para prever a duração do período florescimento-colheita em Urussanga, Santa Catarina. Essa previsão é importante por auxiliar na tomada de decisões quanto à época e à intensidade do raleamento. Foram avaliadas as correlações entre a duração do citado período, a data da plena floração e as temperaturas médias diárias acumuladas após essa data. A data de plena floração se destacou como a variável mais importante para as estimativas. Com relação à variável temperatura, a média dos primeiros 70 dias após a plena floração para as variedades de ciclo curto e médio e a média dos primeiros 100 dias para as de ciclo longo foram as que apresentaram as maiores correlações. Este estudo indicou que outros fatores intrínsecos e relacionados à data da plena floração, além da temperatura que ocorre posteriormente, podem ter influência sobre a duração da fase florescimento-colheita.
A B S T R A C TThis study aimed to determine the rainfall erosivity index in the Valley of Rio do Peixe, in the state of Santa Catarina, Brazil. The data series of three rain gauge stations in the cities of Campos Novos, Videira, and Caçador were used to determine the rainfall erosivity based on the EI30 index and to adjust the equations in order to estimate the EI30 value from the rainfall coefficient. On average, it was observed that erosive rains represents 81.4-88.5% of the annual precipitation. The adjusted equations can be used to estimate rainfall erosivity in locations with only rainfall data.
Understanding the risks of extreme events related to soil erosion is important for adequate dimensioning of erosion and runoff control structures. The objective of this study was to determine the rainfall erosivity with different return periods for the Valley of the Rio do Peixe in Santa Catarina state, Brazil. Daily pluviographic data series from 1984 to 2014 from the Campos Novos, and Videira meteorological stations and from 1986 to 2014 from the Caçador station were used. The data series of maximum annual rainfall intensity in 30 min, maximum annual erosive rainfall, and total annual erosivity were analyzed for each station. The Gumbel-Chow distributions were adjusted and their adhesions were evaluated by the Kolmogorov-Smirnov test at a significance level of 5%. The Gumbel-Chow distribution was adequate for the estimation of all studied variables. The mean annual erosivity corresponds to the return period of 2.25 years. The data series of the annual maximum individual rainfall erosivity coefficients varied from 47 to 50%.
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