MAPPING SPATIAL AND TEMPORAL POTASSIUM VARIABILITY TO OPTIMIZE THE AGRICULTURAL FERTILIZERS APPLICATION IN THE SW GOIAS – BRAZIL

Rachel Bardy Prado¹, Vinicius Melo Benites¹, Alexey Naumov², Carlos Cesar Evangelista de Menezes³, Carlos Eduardo Gonзalves Ferreira¹

1 - Embrapa Solos

2 - International Potash Institute and Moscow State University

3 - COMIGO

rachel@cnps.embrapa.br

XXIII International Cartography Conference

4-10 August Moscow, 2007

ABSTRACT SUBMISSION FORM

Title: Mapping spatial and temporal potassium variability to optimize the agricultural fertilizers application in the SW Goias – Brazil

Name and surname of 1st author: DSc. Rachel Bardy Prado

E-mail: rachel@cnps.embrapa.br

Organization to which author(s) belong: EMBRAPA SOILS – Rua Jardim Botanico – 1024 - Rio de Janeiro – Brazil, CEP: 22460-000

Conference Theme considered appropriate for the contents of the presentation:

5. Digital Cartography and GIS for Sustainable Development of Territories.

Other authors (name, surname and e-mail): DSc. Vinicius de Melo Benites – vinicius@cnps.embrapa.br (EMBRAPA SOILS – Rio de Janeiro – Brazil); DSc. Alexey Naumov – International Potash Institute and Moscow State University – Russia), DSc. Carlos Cesar Evangelista de Menezes– carlosmenezes@comigo.com.br (COMIGO – Rio Verde – Brazil) and Carlos Eduardo Gonçalves Ferreira- carlosed.gf@hotmail.com (EMBRAPA SOILS Trainee – Rio de Janeiro – RJ).

TEXT OF THE ABSTRACT (NO MORE THAN 400 WORDS).

Brazilian soils are very contrasting in relation to fertility and the main soil classes have low levels of K. Agricultural activities, mainly grains production in Brazilian Cerrado, demand high amounts of K. The most K fertilizers are imported playing important role in crop production costs. Although is common the inadequate use of K fertilizers that may result in environmental contamination. Thus, since 2001 Embrapa and the International Potash Institute (IPI) have kept collaboration to study K behavior to optimize potassium fertilizers application in Brazil. It is necessary to identify regions with different K levels whose variability may occur in spatial and temporal scales. In addiction, a regional agricultural development planning should built and publish a database that integrate environmental and social-economic data. In this way, the purpose this study was to map spatial and temporal K variability by municipality of SW Goias, Brazil, from 2003 to 2005. The soil K availability was obtained from database COMIGO Cooperative composed by approximated 10,000 soil fertility analysis at year. The crops K extraction was calculated from governmental statistics (agricultural productivity) data. First of all, consistence analysis was applied in database to eliminate outliers. After that, descriptive statistic was performed to soil K availability. The ARCGIS 9.1 tools were used to associate values obtained to mapping units (municipality) getting soil K availability and crops K extraction maps. Multicriteria analysis and maps algebra tools were used to overlay these maps to get the K balance map by municipality of SW Goias, Brazil. The results showed that spatial and temporal K variability by municipality occur due to different soil properties, different crops and agricultural economy situation that determine the K amount that should be applied. Once tested and consolidated, this methodology may be applied to mapping other major nutrients of the Brazilian agriculture such as phosphorus, magnesium and calcium. Thus, the intention is to generate and provide information to agricultural institutes and universities, but mainly, to provide technical information applied to sustainable agriculture.