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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item High rates of agricultural gypsum affect the arbuscular mycorrhiza fungal community and coffee yield(Instituto Agronômico (IAC), 2020) Cogo, Franciane Diniz; Saggin Júnior, Orivaldo José; Guimarães, Paulo Tácito Gontijo; Siqueira, José Oswaldo; Carneiro, Marco Aurélio CarboneHigh rates of agricultural gypsum, above the recommended levels, have been used on a regular basis to deepen plant roots and to alleviate recurrent water stress in Cerrado areas. However, very little is known about the consequences of this practice to arbuscular mycorrhizal fungi (AMF). Therefore, the objective of this study was to evaluate whether or not applying high rates of agricultural gypsum affects the mycorrhizal fungi community, glomalin content and coffee yield. The study rates were: 0; 3.5; 7.0; 14 and 56 t·ha-1 of agricultural gypsum applied in the planting row of the coffee plantation on top of the previous recommended gypsum application. Samples were collected for analysis at the depths of 0-20, 20-40 and 40-60 cm at the end of dry and rainy seasons of the year. In the coffee plantation, 16 AMF species were identified. Gigaspora sp. and Glomus macrocarpum were dominant in all situations. The rate of 7 t·ha-1 favored greater diversity of AMF species and the rate of 56 t·ha-1 reduced AMF diversity and mycorrhizal colonization in deeper layers. In the rainy season, there was a linear decrease of easily extractable glomalin-related soil protein (EE-GRSP) levels as the agricultural gypsum rate was increased. Coffee yield was reduced with the highest gypsum rate (56 t·ha-1), even though the coffee plantation had higher phosphorus contents in beans and leaves. This may have resulted from a number of reasons, including a negative effect on the AMF community.Item Estimation of reference evapotranspiration for coffee irrigation management in a producutive region of Minas Gerais cerrado(Editora UFLA, 2018-10) Fernandes, André Luís Teixeira; Mengual, Rafaella Esthefania Cardoso Gomes; Melo, Giovani Luiz de; Assis, Leonardo Campos deEvapotranspiration (evaporation and transpiration) represents vegetated soil water loss to the atmosphere and can be estimated by various empirical methods. The aim of this study was to evaluate the performance of methods of Blaney- Criddle, Jensen-Haise, Linacre, Solar Radiation, Hargreaves-Samani, Makkink, Thornthwaite, Camargo, Priestley-Taylor and Penman in the estimation of potential evapotranspiration comparing to the standard method Penman-Monteith (FAO56) regarding the climatic conditions of the city of Araxá, MG. A set of 35 years of monthly data (1976 to 2010) was used, working with the climatic elements: temperature, relative humidity, wind speed and insolation. The empirical methods to estimate reference evapotranspiration were compared with the standard method using linear regression, simple statistical analysis, Willmott agreement index (d) and performance index (c). The method of Makkink showed the best performance according to the set of parameters evaluated and it is recommended to calculate ETo in Cerrado of Minas Gerais, for coffee irrigation management.