Dimensionamento econômico de profundidades e espaçamentos de drenos para a produção de cana-de-açúcar

Abstract

Com o aumento do preço da terra e da demanda por álcool/açúcar tem-se buscado o aumento da produtividade da cultura da cana e o aproveitamento de novas áreas para a produção, as quais podem necessitar de drenagem. Com isso, tornam-se importantes estudos de dimensionamento de sistemas de drenagem agrícola e sua avaliação econômica. O trabalho teve como objetivo avaliar economicamente, com o auxílio do modelo SISDRENA, a melhor combinação entre profundidade e espaçamento de valas, implantados em três tipos de solo, com condutividades hidráulicas de 1,0, 0,5 e 0,1 m d-1. As profundidades simuladas variaram de 0,20 a 2,00 m, com intervalos de 0,05 m, enquanto os espaçamentos oscilaram de 5 a 100 m, com intervalos de 5 m. Para os três tipos de solo obtiveram-se combinações que revelaram viabilidade econômica para implantação dos sistemas de drenagem. Os resultados indicaram que fatores como o déficit hídrico, a perda de área cultivada pela abertura de valetas e o retorno econômico do empreendimento, são aspectos importantes e devem ser considerados no dimensionamento do sistema de drenagem.

Simulation of Subsurface Drainage in the Sugarcane Crop under Different Spacing and Drain Depths

“…For sugarcane grown in clay soil, Askar et al [45] suggested drain depths of 1.4 to 1.8 m and spaces between drains ranging from 25 to 40 m. In clay-loam soil the drain pipes should be installed at spaces of between 55 and 70 m, with a corresponding drain depth between of 1.4 and 1.8 m. On the other hand" various authors [65,70,72,73] have determined that the best spaces of drains that presented the highest relative yield of sugarcane for clay loam, clay, silt clay loam soils were 60 m, 40 m and 30 m, respectively.…”

“…where Y (decimal) represents the yield loss, estimated using the production function proposed by [90], which is dependent on the evapotranspiration deficit. Finally, the total relative yield (YT, decimal) is determined according to the methodology provided by the authors of [91], considering together the effects of water excess and water deficit, calculated by multiplying YRW (decimal) and YRD (decimal) More information is given in [64][65][66]70,72].…”

“…Therefore, using the methodology proposed by various authors [65,70,72,73] the water balance in the root zone of sugarcane was determined using the available water data in each proposed scenario (Soil 1, Soil 2 and Soil 3, see Section 2.3). The geometric parameters of the drainage system used in the simulations were: spacing between drains ranging from 10 to 100 m, with intervals of 10 m; installation depths of 1.2, 1.4 and 1.6 m; initial depth of the water table at 50% of the installation depth; the depth of the impermeable layer at 5 m; and the effective radius of the drains at 0.05 m. For the simulations, the cultivation of sugarcane, with a one-year cycle, was assumed to be planted in January, with three stages of development.…”

Regional Climate Change and Drainage Systems: Effects on Corn Productivity and Profitability in Campinas, Brazil

“…Within this context, the SISDRENA model simulates the performance of one-dimensional drainage systems (Miranda et al, 1998). Other researchers have used this model for different scientific questions (Silva et al, 2005;Duarte et al, 2002;Mingoti et al, 2006). However, there is a lack of research on using this model to simulate future scenarios of climate change.…”

Does the tolerance of sugarcane to excess water in the soil depend on the stage of development?

“…Empirically adopting drainage systems is often responsible for sugarcane failure. Thus, for the use of artificial drainage, studies are required with values representative of the physical-water and geometric properties of the soil profile, as well as physiological (MINGOTI et al, 2006). Studies of this nature with ratoon crops are still non-existent; the few we have are with cane plant, such as those by (TAVARES et al, 2017a, b;TAVARES et al, 2018a, b).…”