Estabelecimento de faixas de suficiência para avaliação nutricional da palma forrageira ‘gigante’

Abstract

It’s been objected to establish the macronutrients and micronutrients normal ranges in the cladodes tissues to evaluate the 'Giant' cactus pear nutritional status. It was used cladodes macro and micronutrients contents and dry matter yield (PMS) of 72 plots of one experiment with four doses of cattle manure (0, 30, 60 and 90 Mg ha-1 year-1 ), three spacings (l.00 x 0.50, 2.00 x 0.25 and 3.00 x 1.00 x 0.25 m) and two production cycles (600 and 930 days after planting), prepared in a 4 x 3 x 2 factorial plan, design in randomized blocks and three repetitions. It was defined sufficiency ranges (FS), average ± standard deviation on macronutrient and micronutrient contents of the plots with PMS ≥ 19.93 mg ha-1 cycle-1 ; mathematical chance (ChM) for plots with PMS ≥ 23.75 Mg ha-1 cycle-1, equivalent to the average plus 0.5 standard deviation; critical level (NCRIz). The FS, NCRIz and ChM are, respectively, for each nutrient in mg kg-1: N,12,7-18,5; 14,7; 15,5-19,7; P, 1,0-1,8; 1,0; 0,4-1,7; K, 31,6-44,1; 33,1; 33,7-39,7; Ca, 23,2-32,8; 26,2; 25,0- 29,6; Mg, 9,5-14,3; 10,5;7,4-14,0; S, 1,1-2,0; 1,2; 1,0-1,8. The ChM are adequate narrower and understood in FS, but the lower limits for P and Mg are underestimated. The FS and the NCRIz are suitable for the evaluation of macronutrient contents in 'Giant' cactus pear, with PMS between 21.8 and 31.2 Mg ha-1 cycle-1. The FS, NCRIz and ChM are, respectively, for each micronutrient, in mg kg-1: B, 22,3-32,7; 24,5; 20,36-27,94; Cu, 2,0- 3,7; 1,8; 1,8-2,8; Fe, 61,1-126,6; 66,1; 35,8-85,3; Mn, 260,0-507,7; 127,7; 54,8-252,2; Zn, 34,5-57,8; 32,6; 19,7-48,5; e, Na, 29,8-56,2; 22,0; 26,6-42,7. For B, Zn and Na, the sufficiency range (FS), mathematical chance (ChM) and critical level (NICRIz) are adequate, while for Cu, Fe and Mn, ChM and NICRIz are more indicated for evaluation of the 'Giant' cactus pear nutritional status, associated with dry substance productivity between 21.8 and 31.2 Mg ha-1 cycle-1 .