Testing and validation of methods for the diagnosis and recomendation integrated system for Signal grass

Abstract

The Diagnosis and Recommendation Integrated System (DRIS) allows the interpretation of results of leaf analysis through relationships among nutrients, instead of the absolute and isolated concentration of each one, as it is used by the criterion of sufficiency range. The objective was to evaluate three procedures of calculation of DRIS indices, and to verify the efficiency of DRIS as interpretation method for the results of Brachiaria decumbens (Signal grass). The study was developed with the results of six experiments carried out in a greenhouse at Piracicaba, SP, with nutrient solution. Concentrations of N, P, K, Ca, Mg, S, Cu, Fe, Mn, and Zn were used in the samples of recently expanded leaf laminae of the grass. The validation of the DRIS method used results from an experiment with nitrogen and sulfur rates applied to the same grass from the Mundo Novo farm, Brotas, SP. DRIS indices were calculated according to two criteria to choose the ratio order of nutrients (F value and R value) and three ways to calculate the nutrient functions (methods of Beaufils, Jones, and Elwali & Gascho). Nutritional Balance Index (NBI), calculated according to the generated norms, presented negative and significant correlation coefficients with the productivity in the combinations of methods tested and DRIS methods proposed by Beaufils, Jones and Elwali & Gascho were efficient in detecting concentrations that show nutrients deficiency or excess.

Distribuição espacial de cobre, zinco e níquel em um Latossolo após quinze anos da aplicação de lodo de esgoto

“…Elevados coeficientes de variação para os teores de Cu e Zn em plantas de braquiária podem ser uma característica intrínseca desta cultura, tendo em vista que Silveira et al (2005) observaram coeficientes de variação de 106% a 51%, respectivamente, para Cu e Zn, cultivando as plantas em solução nutritiva. As plantas, todavia, seriam indicadoras adequadas da biodisponibilidade desses elementos no sistema (Chen et al, 2010) e nos mapas obtidos (Figura 5).…”

Diagnosis and Recommendation Integrated System (DRIS) to Assess the Nutritional State of Plants

“…The NBI has been used to prove the effectiveness of the DRIS system in diagnosing the nutritional status of the plant, because the greater the relationship between NBI and yield better the diagnostic system response, to point out the nutritional status of plants (Silveira et al 2005b) (Figure 1). Guindani et al (2009) used the NBI to select the reference population to compose DRIS norms relating to the NBI tracks yield and the yield range that had the highest coefficient of determination (R 2 ) was selected as the reference population.…”

“…Guindani et al (2009) used the NBI to select the reference population to compose DRIS norms relating to the NBI tracks yield and the yield range that had the highest coefficient of determination (R 2 ) was selected as the reference population. (F and R values) in the first growth using the norm of the first growth (a), in the first growth using the general norm (b), in the second growth using the norm of the second growth (c) and in the second growth using the general norm (d) (Silveira et al, 2005b).…”

DRIS formulas for evaluation of nutritional status of cupuaçu trees

“…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). These different conclusions are often related to the type of approach to evaluate the efficiency of the different formulas, e.g, the frequency of the most limiting nutrient and correlation between leaf nutrient levels, without necessarily comparing the diagnostic interpretations with each other.…”