Microclimate without shade and silvopastoral system during summer and winter / Microclima no sistema sem sombra e silvipastoril no verão e no inverno

ABSTRACT

This study evaluated the microclimate in a system without shade (WS) and in a silvopastoral system (SP) with eucalyptus during summer and winter, by measuring the air temperature (Ta), black globe temperature (Tg), relative humidity (RH), wind speed (Ws), every 2 hours for 24 hours between rows, shade (SP) and no shade effect (WS). It was employed the randomized blocks design (months), in the plots (systems), subplots (hours) and sub-subplots (seasons). Except for Ta and RH, the Tg (24.73, 26.41ºC), Ws (3.16, 4.57 m s-1), Black globe-humidity index (BGHI) (71.83, 73.84), Thermal load index (TLI) (74.53, 76.11) and Radiant thermal load (RTL) (526.46, 595.80 W m-2), respectively for SP and WS, were higher in WS. Ta, RH and Ws had a quadratic effect of hour. There was an effect of season, respectively in summer and winter, on the Ta (27.55, 14.93°C), RH (72.11, 60.68%), Tg (29.80, 21.33°C), BGHI (80.04, 65.63), TLI (81.64, 69.00) and RTL (575.65, 546.61 W m-2). Tg, RH and RTL showed an interaction of season x hour, and a quadratic effect, and the RTL had an interaction of system x season. The Tg was correlated with BGHI (0.962), TLI (0.956) and RTL (0.809). The silvopastoral system decreased the Tg and Ws, and made the environment more harmonious by decreasing the climatic differences between seasons.

RESUMO

Avaliou-se o microclima em sistema sem sombra (SS) e silvipastoril (SP) com eucalipto no verão e inverno, medindo-se as variáveis temperatura do ar (Ta), globo negro (Tg), umidade relativa (UR), velocidade dovento (Vv) a cada 2 por 24h (entre renques, sombra (SP) e sem efeito de sombra (SS)). O delineamento foi em blocos casualizados (mês), na parcela (sistema), na subparcela (horas) e na sub-subparcela (estação). Com exceção da Ta e UR, a Tg (24,73 e 26,41ºC), Vv (3,16 e 4,57 m s-1), ITGU (71,83 e 73,84), ICC (74,53 e 76,11) e CTR(526,46 e 595,80 W m-2), respectivamente, para SP e SS, foram maiores no SS. A Ta, UR e Vv sofreram efeito quadrático do horário. Verificou-se efeito da estação, respectivamente, no verão e inverno a Ta (27,55; 14,93oC),UR (72,11; 60,68%), Tg (29,80; 21,33oC), ITGU (80,04; 65,63), ICC (81,64; 69,00) e CTR (575,65; 546,61 Wm-2). A Tg, UR e CTR sofreram interação da hora x estação, e efeito quadrático, a CTR interação com sistema x estação. A Tg correlacionou-se com ITGU (0,962), ICC (0,956) e CTR (0,809). O sistema silvipastoril reduziu Tg e Vv e tornou o ambiente mais harmônico diminuindo as diferenças climáticas entre as estações.