How phosphorus accumulated in the soil can reach the plant

Balancing the level of phosphorus (P) in crops is one of the challenges to productivity linked to agricultural sustainability. According to professor Paulo Pavinato, from the Soil Science department, at the Luiz de Queiroz College of Agriculture (Esalq/USP), P is one of the most limiting nutrients for plant growth in Brazilian soils. “In general, the problem is not the low concentration of P in the soil, but rather the low availability of this P to plants. A large part (around 70%) of the P applied via fertilizers (mineral or organic) is accumulated in the soil in forms that are little or not accessible to plants. This accumulated or residual P is known as legacy P".

Pavinato led a study, in which it was found that since the 1960s, around 33,4 million tons of P have accumulated in Brazilian agricultural soils. According to the study, this amount represents an accumulation of 1,6 million tons of P per year in the last decade, and if we continue at this pace, more than 100 million tons will be accumulated by 2050.

Driving

For researchers, the adoption of management strategies such as liming, direct planting systems with crop rotation, integrated systems, improved varieties and inoculation of P-solubilizing microorganisms can provide better use of this P accumulated in the soil. “Actions in this sense could generate phosphate fertilizer savings of around US$20 billion in the coming decades. These numbers draw attention, and illustrate the enormous potential we still have to make Brazilian agriculture even more efficient, profitable and sustainable”, adds professor Maurício Cherubin, also from the Soil Science department, one of the authors of the study.

The article, titled Revealing soil legacy phosphorus to promote sustainable agriculture in Brazil, had the collaboration of researchers from University of Bangor – UK and can be accessed on link. The research was supported by the São Paulo State Research Support Foundation.