Establishment of Sufficiency Ranges to Determine the Nutritional Status of ‘Gigante’ Forage Cactus Pear—Macronutrients

Abstract

Determining the sufficiency range of essential macronutrients in plants is of utmost importance for successfully diagnosing the crop’s nutrient demands, thereby improving fertilizer recommendations. The aim of this study was to establish the macronutrients ranges in the cladodes for the evaluation of the nutritional status of ‘Gigante’ cactus pear. Macronutrients contents of cladodes and dry matter yield in 72 plots were used. The experiment consisted of four cattle manure rates (0, 30, 60, and 90 Mg ha-1 year-1), three spacings (1.00 × 0.50, 2.00 × 0.25, and 3.00 × 1.00 × 0.25 m) and two production cycles, arranged in a 4 × 3 × 2 factorial in randomized blocks, and three replicates. Sufficiency ranges of plots with dry matter ≥ 19.93 Mg ha-1 cycle-1 were determined as well as the mathematical chance for plots with dry matter ≥ 23.75 Mg ha-1 cycle-1 and the critical level. The sufficiency ranges, critical level and mathematical chance are, respectively, for each nutrient in g kg-1: N, 12.7-18.5; 14.4; 15.5-19.7; P, 1.0-1.8; 1.0; 0.4-1.7; K, 31.6-44.1; 31.9; 33.7-39.7; Ca, 23.2-32.8; 24.6; 25.0-29.6; Mg, 9.5-14.3; 10.2; 7.4-14.0; and S, 1.1-2.0; 1,1; 1.0-1.8. The mathematical chance model was adequate for all macronutrients except for P and Mg which showed low sufficiency range values. Sufficiency range and critical level of nutrients are useful for diagnosing macronutrient contents and improving the nutritional status of ‘Gigante’ forage cactus pear.

Potential nutrient-response curves and sufficiency ranges for ‘Prata-Anã’ banana cultivated under two environmental conditions

“…If leaf nutrient concentrations in a population have a CV higher than 30 %, the sufficiency ranges obtained by MK orig are less precise in detecting nutrient deficiencies. Moreover, Silva (2015) found a wider sufficient Mn range because the author did not use a correction factor (k) that is needed to narrow the range down (Alves et al, 2019) in the event of highly fluctuating tissue nutrient levels, mostly micronutrients with a CV higher than 20 %. The sufficient Zn concentration range obtained by the BLA for CE was 13.5-18.3 mg kg -1 (Table 5), similar to the range determined by MK mod and MK orig , 12.9-18.3 mg kg -1 (Table 6) and 13.1-16.5 mg kg -1 (Table 7), respectively.…”

“…A dataset was from the farm located at Missão Velha, CE, and comprised annual yields and leaf analysis results relative to the years from 2010 to 2017. The initial sample containing 804 recordings, mean ± standard deviation of 35.91 ± 7.8 t ha -1 yr -1 , was subdivided into low-and high-yielding populations; the latter was the reference population, defined as having yields above the average plus 0.5 standard deviation, as used by Alves et al (2019), which corresponded to 39.81 t ha -1 yr -1 (73 % maximum relative yield) (n = 253).…”

Nutrient reference values for ‘BRS Platina’ banana in improved fertility soils

“…The data set was separated into low-yielding population (LYP) and highyielding population (HYP), below and above 38.4 t ha -1 cycle -1 , respectively. As used by Alves et al (2019), the HYP was considered for SR. For MCh, the HYP, mean of 44.91 t ha -1 cycle -1 (n= 49), was subdivided into a reference subpopulation, based on the mean + 0.5 standard deviation, greater than or equal to 47.43 t ha -1 cycle -1 (n=16).…”

“…The SRs were determined by the equation: SR = x± kSx, where x = average content of each nutrient in the leaf; Sx = standard deviation of the mean; and k = correction factor to adjust the sufficiency ranges, avoiding very wide intervals, as used by Alves et al (2019). The values of k considered the coefficient of variation (CV) of each nutrient: k = 1.0 for nutrients with CV below 20%; k = 0.8 for CV between 20.01 and 40%; k = 0.6 for CV between 40.01 and 80%; and k = 0.4 for CV greater than 80%.…”

“…The CLz values of the nutrient contents were determined by the reduced normal distribution method, as used by Alves et al (2019):…”