Reference standards for soils cultivated with Urochloa brizantha and its use in nutritional diagnosis

The Diagnosis and Recommendation Integrated System (DRIS) is a tool to assess the nutritional state of plants. Due to the decrease of soil fertility in pasture areas and little information about fertilization recommendations, the nutritional reference norms for soil and sufficiency range can be useful tools to help future fertilization. Norms DRIS has been proved efficient as a method for nutritional diagnosis in several crops. However, there are a lack of information on the use of DRIS and sufficiency range for Latosols and Acrisols cultivated with Urochloa brizantha. Thus, the objective of the present study was to establish reference nutritional norms using sufficiency ranges and DRIS norms for Latosols and Acrisols cultivated with Urochloa brizantha and their use in nutritional diagnosis. Soils samples from 20 Urochloa brizantha pastures sites of the North of Espírito Santo State were used to establish the reference norms, and a further 85 soils samples were randomly collected for diagnosis analysis, in order to characterize nutritional condition of pastures. DRIS norms and sufficiency ranges were established for Latosols and Acrisols cultivated with U. brizantha pastures. The differences found between soil norms for other Brazilian regions allow us to infer that the norms should be used only in the conditions in which they were developed. Our results suggest that using DRIS norms and sufficiency ranges developed on the basis of soil analysis revealed deficiency of P, B, Cu, and Zn in more than 40% of the pastures cultivated with U. brizantha and 47% of the areas needed liming.