Testing and validation of DRIS for apple tree

Abstract

To evaluate three procedures of the calculation of DRIS indices, as well as the efficiency of DRIS as a method for the interpretation of apple tree leaf analyses. This study uses data collected in apple producing areas of the Rio Grande do Sul and Santa Catarina States, Brazil. The concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, boron, copper, iron, manganese, and zinc were determined in the leaf samples. The validation of the DRIS method used results of an experiment of potassium fertilization. The DRIS indices were calculated using two criteria for the choice of the ratio order of nutrients (F value -ratio of variance of the relationships among nutrients between the reference group and the low productivity group, and R value -correlation coefficients between the productivity and the relationship between pairs of nutrients) and three forms of calculation of nutrient functions (methods of Beaufils, Jones and Elwali & Gascho). The Nutritional Balance Index (NBI) presented negative correlation with the productivity in all combinations. The DRIS method described by Elwali & Gascho, using the F value, presented a performance similar to the criterion of sufficiency range, and it can be used for the interpretation of foliar analysis of apple trees, because it presents values of the nutritional balance index that indicates the nutritional status of the plants, and for the efficiency in the nutritional diagnosis of the crop.

DRIS formulas for evaluation of nutritional status of cupuaçu trees

“…Recently, some studies have discussed the efficiency of DRIS functions using the correlation between NBI and yield since the inverse correlation between NBI and yield would define the performance of the methods (Partelli et al, 2006;Silva et al, 2009 Nachtigall & Dechen (2007) evaluated the efficiency of DRIS methods in apple, concluded that the Elwali & Gascho (1984) formula was superior to that of Beaufils (1973) and Jones (1981) because the correlation between the nutritional status of apple trees indicated by NBI and yield was better by the former. Based on the correlation between NBI and yield, Silva et al (2005) reported a contrary result, in that Jones (1981)' formula performed better in evaluating the nutritional status of pastures fertilized with N and S compared to the formulas developed by Beaufils (1973) and Elwali & Gascho (1984).…”

“…Nachtigall & Dechen (2007) concluded that the formula developed by Elwali & Gascho (1984) is more efficient than that of Beaufils (1973) or Jones (1981) for apple orchards. On the other hand, Silveira et al (2005) identified the formula proposed by Jones (1981) as more efficient than that of Beaufils (1973) or Elwali & Gascho (1984) for signal grass (Brachiaria).…”

“…The DRIS evaluation method of the plant nutritional status is considered an effective tool for nutritional diagnosis in Brazil, but less usual than in other countries (Nachtigall & Dechen, 2007), because it is relatively complicated, compared to traditional methods such as critical level and sufficiency range (Prado, 2008). Nevertheless, it is promising for the nutritional diagnosis of perennial crops, for which calibration tests are generally timeconsuming and costly.…”

“…The application of this method to fruit trees of different species e.g., apple, mango and citric fruits, has been promising (Nachtigall & Dechen, 2007;Wadt et al, 2007;Santana et al, 2008). However, for the fruit tree species cupuaçu (Theobroma grandiflorum), widely grown in the Amazon region, there is little information about mineral nutrition and the few studies available address only a limited number of nutrients in fertilizer tests (Alfaia et al, 2004;Ayres & Alfaia, 2007).…”