Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings

Effect of shade regimes on gradients of microclimate, canopy extent (leaf area index: LAI) and light integrals in dry season field-grown cocoa (cacao) seedlings was investigated in a rainforest zone of Nigeria. The shade regimes tested were: unshaded/open-to-sun, dense shade and moderate shade. Shad...

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Autores principales:	S Agele, B Famuwagun, A Ogunleye
Formato:	article
Lenguaje:	EN
Publicado:	Society for Promotion of Horticulture - Indian Institute of Horticultural Research 2016
Materias:	cacao cocoa shade canopy lai extinction radiation temperature drought Plant culture SB1-1110
Acceso en línea:	https://doaj.org/article/70b1d09e9e6844e3a03b84c0146ea861
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spelling	oai:doaj.org-article:70b1d09e9e6844e3a03b84c0146ea8612021-12-02T12:07:32ZEffects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings0973-354X2582-4899https://doaj.org/article/70b1d09e9e6844e3a03b84c0146ea8612016-06-01T00:00:00Zhttps://jhs.iihr.res.in/index.php/jhs/article/view/105https://doaj.org/toc/0973-354Xhttps://doaj.org/toc/2582-4899Effect of shade regimes on gradients of microclimate, canopy extent (leaf area index: LAI) and light integrals in dry season field-grown cocoa (cacao) seedlings was investigated in a rainforest zone of Nigeria. The shade regimes tested were: unshaded/open-to-sun, dense shade and moderate shade. Shade intensity affected solar radiation transmission through cacao canopy, photosynthetic active radiation (PAR) and canopy light attenuation (extinction coefficient, k). Intensity of transmitted radiation below the canopy from incident radiation was highest for open-to-sun, followed by moderate and dense shade, respectively. The temporal trend of intercepted radiation showed that intercepted radiation increased from December to May, and, the values were highest for open-to-sun, followed by moderate and dense shade. The ratio of transmitted (Io) to incident (I) radiation (IO/I) was higher for open sun. Significant differences were found between open-to-sun (unshaded) and moderate and dense shade intensity for value of canopy extinction coefficient (k). The association of growing degree days (GDD), and, total leaf number (TLN) and leaf area index (LAI), were characterized by high coefficient of determination (R2) for the respective open, dense and moderate shade treatments. Inverse of the slope of the regression of relationship between estimated thermal time (°Cdays) and corresponding total leaf number (TLN) denotes leaf appearance rate (phyllochron, in °Cdays/leaf). Rate of leaf appearance was faster in open sun compared with to that in moderate or dense shade intensity. Characteristics of the cacao canopy development were measured by leaf area index (LAI), a parameter which affects the intercepted photosynthetic active radiation (PAR). Higher LAI was obtained in no shade (open sun) compared to that in moderate or dense shade treatments. Unshaded plants had a higher radiation use efficiency (RUE) and RUE values were significantly higher compared to the other two treatments. Low light intensity and LAI for under-storey cacao had negative implications for growth and biomass development. Air temperatures within the cacao field were highest for open sun cacao, followed by moderate and dense shade, respectively; the values increased from December to April, with peak values seen in April.S AgeleB FamuwagunA OgunleyeSociety for Promotion of Horticulture - Indian Institute of Horticultural ResearcharticlecacaococoashadecanopylaiextinctionradiationtemperaturedroughtPlant cultureSB1-1110ENJournal of Horticultural Sciences, Vol 11, Iss 1, Pp 47-56 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	cacao cocoa shade canopy lai extinction radiation temperature drought Plant culture SB1-1110
spellingShingle	cacao cocoa shade canopy lai extinction radiation temperature drought Plant culture SB1-1110 S Agele B Famuwagun A Ogunleye Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
description	Effect of shade regimes on gradients of microclimate, canopy extent (leaf area index: LAI) and light integrals in dry season field-grown cocoa (cacao) seedlings was investigated in a rainforest zone of Nigeria. The shade regimes tested were: unshaded/open-to-sun, dense shade and moderate shade. Shade intensity affected solar radiation transmission through cacao canopy, photosynthetic active radiation (PAR) and canopy light attenuation (extinction coefficient, k). Intensity of transmitted radiation below the canopy from incident radiation was highest for open-to-sun, followed by moderate and dense shade, respectively. The temporal trend of intercepted radiation showed that intercepted radiation increased from December to May, and, the values were highest for open-to-sun, followed by moderate and dense shade. The ratio of transmitted (Io) to incident (I) radiation (IO/I) was higher for open sun. Significant differences were found between open-to-sun (unshaded) and moderate and dense shade intensity for value of canopy extinction coefficient (k). The association of growing degree days (GDD), and, total leaf number (TLN) and leaf area index (LAI), were characterized by high coefficient of determination (R2) for the respective open, dense and moderate shade treatments. Inverse of the slope of the regression of relationship between estimated thermal time (°Cdays) and corresponding total leaf number (TLN) denotes leaf appearance rate (phyllochron, in °Cdays/leaf). Rate of leaf appearance was faster in open sun compared with to that in moderate or dense shade intensity. Characteristics of the cacao canopy development were measured by leaf area index (LAI), a parameter which affects the intercepted photosynthetic active radiation (PAR). Higher LAI was obtained in no shade (open sun) compared to that in moderate or dense shade treatments. Unshaded plants had a higher radiation use efficiency (RUE) and RUE values were significantly higher compared to the other two treatments. Low light intensity and LAI for under-storey cacao had negative implications for growth and biomass development. Air temperatures within the cacao field were highest for open sun cacao, followed by moderate and dense shade, respectively; the values increased from December to April, with peak values seen in April.
format	article
author	S Agele B Famuwagun A Ogunleye
author_facet	S Agele B Famuwagun A Ogunleye
author_sort	S Agele
title	Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
title_short	Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
title_full	Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
title_fullStr	Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
title_full_unstemmed	Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings
title_sort	effects of shade on microclimate, canopy characteristics and light integrals in dry season field-grown cocoa (theobroma cacao l.) seedlings
publisher	Society for Promotion of Horticulture - Indian Institute of Horticultural Research
publishDate	2016
url	https://doaj.org/article/70b1d09e9e6844e3a03b84c0146ea861
work_keys_str_mv	AT sagele effectsofshadeonmicroclimatecanopycharacteristicsandlightintegralsindryseasonfieldgrowncocoatheobromacacaolseedlings AT bfamuwagun effectsofshadeonmicroclimatecanopycharacteristicsandlightintegralsindryseasonfieldgrowncocoatheobromacacaolseedlings AT aogunleye effectsofshadeonmicroclimatecanopycharacteristicsandlightintegralsindryseasonfieldgrowncocoatheobromacacaolseedlings
_version_	1718394696010563584

Effects of Shade on Microclimate, Canopy Characteristics and Light Integrals in Dry Season Field-Grown Cocoa (Theobroma cacao L.) Seedlings

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