Availability of manganese in soils of the oriental region of Paraguay

Abstract

There is little information generated on the situation of micronutrients in Paraguayan soils, including manganese (Mn), an essential micronutrient for plants, so it is important to know its availability and distribution. The aim of the research was to classify the availability of Mn in soils of the Eastern region of Paraguay at the district level. For this, a database was generated with the results of soil analysis from the FCA-UNA, CIHB-IPTA and FUCAI-UCA laboratories. The available Mn content of the soils of 11,331 samples was classified as “high” (>5 mg.kg-1); “medium” level (5 – 1.2 mg.kg-1) and “low” level (<1.2 mg.kg-1), generating a map of Mn availability at the district level. Descriptive statistics were performed from the available Mn values. Of the 234 districts that make up the Eastern region of Paraguay, 195 districts were classified, where 98% presented a “high” level (193 districts) and 2% “medium” level (2 districts) of Mn available, 17% (39 districts) were not classified due to lack of soil analysis results. The department with the highest average of available Mn was Canindeyú with 68.4 mg.kg-1 and the lowest average of available Mn was Amambay with 20.0 mg.kg-1, of which 39% of the samples were classified as level “low” of Mn available. Considering the total number of soil samples analyzed (11,331 samples), 10,670 samples had “high” levels of Mn (94.2%), 516 samples had “medium” levels of Mn (2.6%) and only 145 samples had “low” levels of Mn available (1.3%). The soils of the Eastern region have a predominance of soils with high availability of Mn, so its deficiency is not an impediment for agricultural, livestock and forestry production systems.