Efeito do gotejamento contínuo e pulsado e lâminas de irrigação sobre as relações hídricas e características morfofisiológicas da cana-de-açúcar

Abstract

Considering the importance of sugarcane production for Brazil, as well as for the Northeast, the benefits of managing irrigation for this crop and strengthening the management of water resources, as a solution to mitigate adverse climate effects, those produced use additional new irrigation techniques, such as pulse irrigation, to improve cultivation. The objective of this work was to evaluate the influence of pulsed and continuous drip irrigation, in different depths of evapotranspiration retention, on water relations, followed by some morphophysiological aspects of sugarcane. The experiment was carried out at the Carpina Sugarcane Experimental Station (EECAC/UFRPE) with the variety RB041443 (soothing cane) under field conditions. The experimental design used was in randomized blocks, consisting of 10 therapeutic treatments in a 2 x 5 factorial scheme, where the first factor was the type of irrigation application (irrigation by pulses and continuous irrigation) and the second factor was 5 irrigation depths of the crop evapotranspiration (40, 60, 80, 100 and 120% of ETc), considering 4 replications, totaling 40 experimental plots. For the condition of application of pulse irrigation, five irrigation pulses were defined with an interval of 60 minutes of rest between two irrigations. The following variables were followed: leaf area (AF), shoot water content (TAPA), shoot biomass production index (IPBPA) and leaf succulence (SF). The results obtained were subjected to analysis of variance by the F test (p < 0.05) and when significant effects were found, they were subjected to polynomial regression analysis (evapotranspiration replacement slides) and the Tukey test at 5% probability (types of irrigation application). The use of the pulsed drip irrigation method proved to be efficient and essential in the cultivation of sugarcane. Statistical analysis showed that all variables studied (AF, TAPA, IPBPA and SF) showed mean values higher than those obtained with continuous irrigation. The increase in water stress limited the growth of the AF, TAPA, IPBPA and SF variables. The irrigation depths of 90, 77.6, 77.77% of ETc were the ones that provided the highest values for the variables AF, TAPA and IPBPA, respectively. For the SF, the depths of 101 and 120% of the ETc were the ones that provided the best results for the variable in the pulsed and continuous managements, respectively. The application of pulsed irrigation mitigated the deleterious effects of water deficit on the plants, providing higher values of AF, TAPA, IPBPA and SF, in relation to the type of continuous irrigation application.