Extraction and export of nutrients by sugarcane under pulsed and continuous irrigation

Abstract

The objective of this work was to determine nutrient extraction and export in sugarcane under pulsed and continuous irrigation at five levels of replacement of crop evapotranspiration. The experiment was conducted from 12/12/2019 to 12/22/2020 under field conditions in the municipality of Carpina, in the state of Pernambuco, Brazil. The used experimental design was randomized complete blocks, in a 2x5 factorial arrangement, with two types of irrigation application (pulsed and continuous irrigation) and five levels of replacement of crop evapotranspiration (40, 60, 80, 100 and 120%), with four replicates, totaling 40 experimental units. For pulsed irrigation, five irrigation pulses were defined, with an interval of 40 min between each of them. For the analyses of nutrient extraction and export, plants were collected in the usable area of each experimental plot, at the time of harvest. The isolated factor type of fertigation application significantly influenced the extraction and export of iron, manganese, and zinc, as well as the export of sulfur. Under pulsed irrigation, the descending order of nutrient extraction and export is: K>N>Ca>S>Mg>P>Fe>Zn>Mn>Cu and N>K>Ca>Mg>S>P>Fe>Zn>Mn>Cu, respectively. Under continuous irrigation, the order of extraction and export is: K>N>S>Ca>Mg>P>Fe>Zn>Mn>Cu and N>K>Mg>Ca>S>P>Fe>Zn>Cu>Mn, respectively.