Tese
Parâmetros e probabilidades de irrigação para a cultura da soja na região central do Rio Grande do Sul por análise numérica
Fecha
2013-02-22Registro en:
TRENTIN, Roberto. Probability and parameters of irrigation for soybean crop in central region of Rio Grande do Sul by numerical analysis. 2013. 147 f. Tese (Doutorado em Engenharia Agrícola) - Universidade Federal de Santa Maria, Santa Maria, 2013.
Autor
Trentin, Roberto
Institución
Resumen
The objective of this study was to determine the probable duration of the developmental
phases of the cycle for the soybean at different sowing dates, the average values of water
depth and number of irrigations needed and also its relationship with El Niño Oscillation
South (ENSO), considering the capacity of water storage available (CAD) of the main soils of
Central region of Rio Grande do Sul. This study was conducted by means of mathematical
models of development of soybean and data published in the literature meteorological,
climatological station collected in Santa Maria, RS (latitude: 29°43'23 "S, longitude: 53°
43'15" W and altitude: 95 m), from October 1968 to July 2012, totaling 44 years of daily
observations. The simulation of crop development was carried out for different sowing dates
every ten days, considering three maturity groups (GM): 5.9-6.8 6.9-7.3 and 7.8-8.0. To
simulate irrigation, the 13 soils of the region covered in this study into five groups that have
similar characteristics of water storage capacity available (CAD) and infiltration capacity. The
daily water balance determined the variation of water availability and timing of irrigation. The
timing of irrigation was determined when the soil reached a minimum fraction of available
water to be maintained. For this, we used four handlings representing the condition when the
water withdrawn from the soil fraction reached 20%, 30%, 40% and 50% of the CAD. Data
analysis consisted of analysis of variance test for comparison of means and analysis of the
probability distribution for the variables: duration of subperiods and development cycle of
soybeans, water depth, number of irrigation and water depth associated to ENSO. The average
duration of subperiods and soybean development cycle varies according to the date of sowing.
The duration of the development cycle of the soybean crop is higher in the early sowing dates
(October) decreasing until the last sowing dates (December). Early sowing dates require more
water depth than the latest sowing dates. It was found that higher water depth necessary to
soybean is associated with neutral years, while the lowest water depth is related to El Niño
events.