Potential of Acid Phosphatase Activity and Mycorrhizal Colonization to Reduce Phosphorus Fertilization in Maize Cultivated in Brazil

Abstract

Purpose: It is urgent to mitigate the environmental impacts resulting from agriculture, especially in highly biodiverse and threatened areas, as the Brazilian Cerrado. We aim to investigate whether phosphatase activity and mycorrhizal colonization are alternative plant strategies for nutrient acquisition in maize cultivated under fertilized and unfertilized conditions in Brazil, potentially contributing to reduce the use of phosphate fertilizers needed for production.Methods: Three experiments were performed: the first was conducted in a glasshouse, with 17 experimental pure maize lineages and two phosphorus treatments; the second in the field, with 3 pure maize lineages and two treatments, one without fertilization and another with NPK fertilization; and the third was also carried out in the field, with 13 simple commercial hybrids, grown either under NK or under NPK treatment. Soil and plant variables were measured and tested for the response to fertilization, differences amongst genotypes and response to phosphatase activity and mycorrhizal colonization.Results: We detected a positive effect of mycorrhizal colonization upon growth in pure maize lineages. The activity of acid phosphatase was modulated by the availability of phosphorus and nitrogen in the soil, and promoted grain filling of commercial hybrids in soils with low phosphorus availability. Conclusions: These results demonstrate, for the first time, that it is possible to select genotypes that are more adapted to low soil phosphorus availability aiming at organic production, or to use genotypes that have high phosphatase activity under phosphorus fertilization to reduce the amount of added phosphorus needed for maize production in Brazil.