Nutritional diafnosis for cotton under savannah by using the dris and sufficiency ranges methods

Brazil is the fourth largest cotton exporter and fifth largest producer in the world, however, it is predominantly cultivated under savannah soils, which present natural nutrients limitations. The objective of this study was to diagnose the nutritional factors that most limit high cotton yields, by using leaf analysis interpreted with the aid of the DRIS and sufficiency ranges techniques. So, forty-eight leaf samples were collected in a commercial area of Silvânia, Goiás State, Brazil. Ten cotton leaves were collected to a compound sample, at the full flowering stage (90 day after seeding). For interpreting the leaf analyses results, by using the DRIS technique, indexes for each nutrient from each sample were calculated, according to Alvarez & Leite (1992). For the sufficiency range interpretation, standard values were used. Both methods evaluated N, S, B, and Zn as the most limiting nutrients. The DRIS method showed higher sensibility for diagnosing nutritional deficiencies, especially for the B and Zn micronutrients.

Gossypium sp.; leaf analysis; DRIS index; nutritional status

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