RESUMEN El objetivo de esta investigación fue evaluar la dinámica poblacional de los nematodos Heterodera glycines raza 5 y Pratylenchus brachyurus en cultivos sucesivos de soya y garbanzo. El experimento se llevó a cabo en Campos Novos dos Parecis, estado de MT, Brasil, de febrero a mayo de 2017. Se sembraron seis cultivares de garbanzo en febrero y se evaluaron en un área naturalmente infestada de 60 ha. Se recolectaron cinco muestras de suelo al azar en ubicaciones georreferenciadas y equidistantes, formando una muestra compuesta por replicación. Se recolectaron cinco plantas por punto georreferenciado y también nuevas muestras de suelo a intervalos regulares de aproximadamente 30 d. Los nematodos se extrajeron, identificaron y contaron. Los datos fueron sometidos a análisis de varianza y regresión. Se observó una reducción en los niveles poblacionales de H. glycines raza 5 a lo largo del ciclo del garbanzo, lo que indica que es posible cultivar esta especie en sucesión con soya en presencia de este nematodo. Sin embargo, debido al mantenimiento en la población de P. brachyurus en las raíces, no se recomienda la rotación de soya con garbanzos en campos naturalmente infestados con este nematodo.

ABSTRACT The objective of this research was to evaluate the population dynamics of the nematodes Heterodera glycines race 5 and Pratylenchus brachyurus in a succession crop of soybeans and chickpeas. The experiment was carried out in Campos Novos dos Parecis, MT State, Brazil, from February to May 2017. Six chickpea cultivars were planted in February and evaluated in a naturally infested area of 60 ha. Five soil samples were collected at random in georeferenced and equidistant locations, forming a composite sample by replication. Five plants per georeferenced point and new soil samples were collected at regular intervals of about 30 d. The nematodes were extracted, identified, and counted. Data were subjected to variance and regression analyses. A reduction in the population levels of H. glycines race 5 was observed throughout the chickpea cycle, indicating that this species can be cultivated in succession with soybeans in the presence of this nematode. However, due to the maintenance in the population of P. brachyurus in the roots, rotation of soybean with chickpeas is not recommended in fields naturally infested with this nematode.

A evapotranspiração é o processo de perda de água do solo vegetado devido à evaporação e à transpiração, podendo ser estimada por vários métodos empíricos. Objetivou-se, com o presente trabalho, realizar a avaliação do desempenho dos métodos de Blaney-Criddle, Jensen-Haise, Linacre, Radiação Solar, Hargreaves-Samani, Makkink, Thornthwaite, Camargo, Priestley-Taylor e Penman Original na estimativa da evapotranspiração potencial em comparação com o método-padrão Penman-Monteith (FAO56), para as condições climáticas do município de Uberaba-MG. Utilizou-se um conjunto de dados mensais de 21 anos (1990 a 2010), trabalhando-se com os elementos climáticos temperatura, umidade relativa, velocidade do vento e insolação. Os métodos empíricos para a estimativa da ETo foram comparados com o método-padrão utilizando-se de regressão linear, análise estatística simples, índice de concordância de Willmott (d) e índice de confiança ou desempenho (c). Os métodos de Makkink e de Camargo apresentaram os melhores desempenhos, com valores de "c" de 0,75 e 0,66, respectivamente. O método de Hargreaves-Samani apresentou a melhor relação linear com o método-padrão, com coeficiente de correlação (r) de 0,88.

Evapotranspiration is the process of water loss of vegetated soil due to evaporation and transpiration, and it may be estimated by various empirical methods. This study had the objective to carry out the evaluation of the performance of the following methods: Blaney-Criddle, Jensen-Haise, Linacre, Solar Radiation, Hargreaves-Samani, Makkink, Thornthwaite, Camargo, Priestley-Taylor and Original Penman in the estimation of the potential evapotranspiration when compared to the Penman-Monteith standard method (FAO56) to the climatic conditions of Uberaba, state of Minas Gerais, Brazil. A set of 21 years monthly data (1990 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 methods Makkink and Camargo showed the best performance, with "c" values of 0.75 and 0.66, respectively. The Hargreaves-Samani method presented a better linear relation with the standard method, with a correlation coefficient (r) of 0.88.