Diagnosis and recommendation integrated system (DRIS) of soybean seed oil content

Alfredo Castamann,Silas Zanella,Pedro Alexandre Varella Escosteguy,Diego Berres

doi:10.1590/s0100-06832012000600016

Abstract

The Diagnosis and Recommendation Integrated System (DRIS) can improve interpretations of leaf analysis to determine the nutrient status. Diagnoses by this method require DRIS norms, which are however not known for oil content of soybean seeds. The aims of this study were to establish and test the DRIS method for oil content of soybean seed (maturity group II cultivars). Soybean leaves (207 samples) in the full flowering stage were analyzed for macro and micro-nutrients, and the DRIS was applied to assess the relationship between nutrient ratios and the seed oil content. Samples from experimental and farm field sites of the southernmost Brazilian state Rio Grande do Sul (28° - 29° southern latitude; 52° -53° western longitude) were assessed in two growing seasons (2007/2008 and 2008/2009). The DRIS norms related to seed oil content differed between the studied years. A unique DRIS norm was established for seed oil content higher than 18.68 % based on data of the 2007/2008 growing season. Higher DRIS indices of B, Ca, Mg and S were associated with a higher oil content, while the opposite was found for K, N and P. The DRIS can be used to evaluate the leaf nutrient status of soybean to improve the seed oil content of the crop.

Highlights

Soybean (Glycine max (L.) Merrill) is the major source of oil and protein in the international market
The most widely used method for the diagnosis of plant nutritional status is based on critical leaf nutrient content
Soybean plants assessed for the development of Diagnosis and Recommendation Integrated System (DRIS) norms were grown in the experimental area of the University of Passo Fundo (UPF), whereas the plants assessed for the validation of these norms were from farm fields of the Planalto Médio Region of the State of Rio Grande do Sul (28° - 29° southern latitude; 52° - 53° western longitude), in the 2007/2008 and 2008/2009 growing seasons

Summary

Introduction

Soybean (Glycine max (L.) Merrill) is the major source of oil and protein in the international market. The most widely used method for the diagnosis of plant nutritional status is based on critical leaf nutrient content. This method does not allow assessing the relationship among nutrients. DRIS can be used to assess the interaction of nutrient leaf analysis (Urano et al, 2007; Farnezi et al, 2009), and most studies with this approach focus on nutrient balance, fertilization practices and crop yield (Urano et al, 2007; Bailey et al, 2009; Farnezi et al, 2009). Few studies have been conducted to assess the effect of nutrient balance on oil content of soybean seeds (Seguin & Zheng, 2006)

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