Palma forrageira ‘Gigante’ irrigada com água salina sob densidades de plantio

Abstract

The forage cactus is a relevant crop in the livestock scene, and widely cultivated due to the morphophysiological adaptations of tolerance to the edaphoclimatic conditions of the semiarid region, which allow forage production. The objective of this study was to evaluate the morphometric characteristics, yield and nutrient content of „Gigante‟ forage cactus irrigated with saline water under planting densities.The experimental design was in randomized blocks in a split-split plot scheme, with two irrigation shifts (7 and 14 days) being allocated in the plots, in the subplots four planting densities (20,000; 40,000; 60,000 and 80,000 plants ha-1 ) and in the subplots four blades irrigation (0, 11, 22 and 33% of ETo).Irrigation with high salinity water does not limit the growth and productivity of „Gigante‟ forage cactus, until the second production cycle. The application of the ETo blade 33% promotes an increase in the morphometric characteristics, an increase in the productivity of green matter in the first and second cycle and in the dry matter productivity in the first cycle of the „Gigante‟forage cactus.The maximum yields of green and dry matter, and water use efficiency based on these yields are obtained with planting densities of 61,465 and 67,786 plants ha-1 , and 61,848 and 69,707 plants ha-1 , respectively.The application of increasing irrigation depths reduces the efficiency of water use based on the productivity of green and dry matter.The application of increasing irrigation depths reduces the efficiency of water use based on the productivity of green and dry matter.The application of the 33% ETo blade with high salinity water allows an increase in the levels of N, P, Ca, Mg, B, Cu, Mn and Zn in the tissues of the „Gigante‟ forage cactus cladodes.The maximum levels of K, S and Na in the tissues of the cladodes are obtained with the application of irrigation blades between 16 and 25% of the ETo.