Algodoeiro fertirrigado por gotejamento sob doses de nitrogênio, lâminas de água e espaçamentos de plantio
Data
2015-12-15
Autores
Sousa, Jackelinne Valéria Rodrigues
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Universidade Federal de Mato Grosso
Resumo
In Brazil, research on irrigation in cotton are still quite scarce. Thus, the
aim of the present study was to evaluate the development and productivity of upland
cotton grown in Cerrado Oxisol due to the nitrogen fertilization, irrigation levels and
crop spacings. The experiment was conducted under field conditions in the
experimental area of the Master's Degree in Agricultural Engineering from the
Federal University of Mato Grosso (UFMT/CUR). The experimental design was
randomized blocks in Box-Behnken design. This planning is based on experiments
with balanced incomplete block containing factors with three levels (low,
intermediate, high). The variables were evaluated statistically with analysis of
response surface, totaling 15 treatments and 4 replications (blocks). The treatments
were: three cultivation spacing (dense – 40 cm, intermediate - 70 cm and
conventional - 100 cm), three doses of nitrogen fertilizer fertigation (low dose - 31 kg
ha-1, intermediate dose - 171 kg ha-1 and High dose - 310 kg ha-1) and three irrigation
levels via drip subsurface (severe - 30% of the demand of ETc, intermediate - 90%
and water surplus - 150%).Growing gaps were defined according to current
recommendations of the productive system for cotton in Mato Grosso, the treatment
of fertigation was based on the recommendation for cotton growing, according to the
soil fertility analysis. The irrigation levels were applied with reference to the irrigation
levels were applied with reference to the crop evapotranspiration (ETc) calculated
from the reference evapotranspiration (ETo) estimated by the Penman-Monteith
method (FAO). crop evapotranspiration (ETc) calculated from the reference
evapotranspiration (ETo) estimated by the Penman-Monteith method (FAO). Daily
surveys were conducted of the growth stage of the plant and Ratings at 45, 75 and
105 days after sowing (DAS) for plant height and SPAD chlorophyll content. After
harvest (141 days) were evaluated: number of bolls per plant, boll weight, dry weight
of cotton, dry mass of reproductive structure, shoot dry mass, lump in productivity
and feather, fiber yield and HVI features (High Volume Instrument). The results were
analyzed in response surface through software "SigmaXL® 7.0". There was no
significant interaction between irrigation levels, nitrogen levels and growing gaps for
plant height and SPAD chlorophyll index at 45 DAS, boll weight, dry weight of boll,
dry mass of reproductive structure, fiber yield and characteristics HVI. Nitrogen
fertilization increases plant height at 75 and 105 DAS, number of bolls, dry weight of
shoot and seed productivity. The SPAD chlorophyll index was positively influenced
by the irrigation depth to 75 DAS and also by nitrogen fertilization to 105 DAS.
Productivity plume was higher when applied blade 150%. Efficiency in water use
showed better results on slide 30%. The maximum yield of cotton seed (2459 kg ha-1)
was obtained in 169.2% nitrogen level. For all variables, we obtained better
responses in dense and intermediate cultivation. The irrigation management, crop
spacing and the nitrogen fertilization provides gains in cotton yield, positively
influencing the development of cotton plants grown in Oxisol in the Cerrado.
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SOUSA, Jackelinne Valéria Rodrigues. Algodoeiro fertirrigado por gotejamento sob doses de nitrogênio, lâminas de água e espaçamentos de plantio. 2015. 79 f. Dissertação (Mestrado em Engenharia Agrícola) - Universidade Federal de Mato Grosso, Instituto de Ciências Agrárias e Tecnológicas, Rondonópolis, 2015.