Aplicaciones de calcio y boro aumentan la producción de híbridos de tomate Italiano (Solanum lycopersicum) en dos temporadas de cultivo

1 recurso en línea (páginas 82-93).The objective of this study was to evaluate the effect of boron soil treatments and the frequency of calcium applications on the flowering, agronomic performance, and incidence of blossom end rot in Italian tomato hybrids grown in conventional systems during two growing seasons. Two experiments were carried out in the experimental area of the Federal University of Santa Maria, Frederico Westphalen campus (Brazil) during 2012 and 2013. A randomized block experiment design was used in a 2×2×3×3 factorial scheme with two hybrids (San Vito and Netuno) in two growing seasons (Spring-Summer and Summer-Fall), three boron doses (0.0, 2.0, or 4.0 g/hole), and three frequencies of calcium application (absence of application, weekly, or biweekly application) with four replicates. The seedlings were transplanted on September 4, 2012 for the Spring-Summer growing season and on January 26, 2013 for the Summer-Fall growing season. The Netuno hybrid was more productive in comparison to the San Vito hybrid, but more susceptible to blossom end rot. Both growing seasons can be recommended for Italian tomato production in Rio Grande do Sul although the Spring-Summer growing season was more productive than the Summer-Fall growing season. The biweekly application frequency of 0.6% CaCl2 was the best option for fertilizer management, resulting in higher yields and a lower number of fruits with an incidence of blossom end rot. The increment of the boron dose defined the higher number of fruits per plant and yield increase.El objetivo de este estudio fue evaluar el efecto de tratamientos de boro edáfico y frecuencia del calcio foliar en floración, sobre la producción y ocurrencia de la pudrición apical de híbridos de tomate italiano, cultivados en el sistema convencional en dos temporadas de cultivo. Se realizaron dos experimentos en el área experimental perteneciente a la Universidade Federal de Santa Maria, campus de Frederico Westphalen (Brasil), en los años 2012 y 2013. El diseño experimental fue de bloques al azar con un arreglo factorial 2×2×3×3 cuyo factores fueron dos híbridos (San Vito y Neptuno), en dos épocas de cultivo (primavera-verano y verano-otoño), tres dosis de boro (0; 2,0 y 4,0 g/planta) y tres frecuencias de aplicación de calcio (ausencia de aplicación, aplicación semanal y quincenal) y cuatro repeticiones. El trasplante de plántulas se realizó el día 04 de septiembre de 2012 para la primavera-verano y el 26 de enero para el verano-otoño. El híbrido Neptuno es más productivo en comparación con el híbrido San Vito, pero más susceptible a la pudrición apical. Las dos épocas de cultivo pueden ser recomendadas para el cultivo del tomate italiano en Rio Grande do Sul, aunque el cultivo de primavera-verano presenta mayor productividad cuando se compara al verano-otoño. La frecuencia de aplicación quincenal de CaCl2 al 0,6% se constituye en la mejor opción de manejo de fertilización, en el sentido de obtener mayor productividad y menor número de frutos con incidencia de pudrición apical. El incremento de la dosis de boro condiciona mayor número de frutos por planta y aumento de la productividad.Bibliografía y webgrafía: páginas 92-9

Growth of tree species and sugarcane production in agroforestry systems

Abstract The appropriate choice of tree species and planting arrangement for use in agroforestry systems is very important in order to maximize productivity and sustainability. The aim of this study was to evaluate the growth of five tree species and its effect on sugarcane yields in different planting arrays in agroforestry systems. The study was conducted from 2007 to 2011 in the city of Frederico Westphalen, RS, Brazil. The five studied tree species were: guapuruvu (Schizolobium parahybae), bracatinga (Mimosa scabrella), canafístula (Peltophorum dubium), angico-vermelho (Parapiptadenia rigida) and eucalypt (Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden). Root collar diameter, diameter at breast height, plant height and mean diameter of crown were evaluated for four years with an interval of 90 days between assessments. Yield data for sugarcane were collected in June 2009, 2010, and 2011. Eucalypt presented the greatest root collar diameter values, diameter at breast height, crown development, and plant height. Angico-vermelho, canafístula and eucalypt presented a higher growth in the strip system, while guapuruvu presented the greater growth in the line system. Bracatinga was not influenced by an arrangement in the agroforestry systems. Sugarcane presented greater production in the understory of angico and bracatinga

Plant growth, radiation use efficiency and yield of sugarcane cultivated in agroforestry systems: An alternative for threatened ecosystems

Abstract Sugarcane (Sacharum officinarum L.) monocropping has had a great socio-economic and environmental impact in Brazil, and agroforestry systems have been considered as an alternative for more sustainable production; however, there is a lack of field research under such conditions. The aim of this study was to evaluate the growth rates, radiation use efficiency and yield traits in sugarcane cultivated in the understory of Aleurites fordii, in two agroforestry arrangements and monocropping systems. A field experiment was conducted from July 2015 to June 2016 in the city of Frederico Westphalen, Rio Grande do Sul, Brazil. The radiation use efficiency, assimilate partitioning, leaf area index, absolute growth rate, net assimilation rate, number of tillers, plant height, % of intercepted solar radiation, extinction coefficient, and yield in each system was evaluated. In agroforestry systems, the dynamic interactions between multiple plant species change with the time and can result in unique microclimates. The use of agroforestry systems in 12 x 12m arrangements should be prioritized because it enables greater yields and radiation availability in the understory. This study sought to provide new sustainable alternatives for farmers in order to increase the diversification of the rural property and maintain the preservation of existing agroecosystems