Transitions to sustainable management of phosphorus in Brazilian agriculture

Paul J A Withers,Paulo S Pavinato,Djalma M G De Sousa,Adilson De Oliveira,Edson L M Coutinho,Rafael De S Nunes,Fernando D Andreote,Teotonio S De Carvalho,Ciro A Rosolem,Marcos Rodrigues,Vinicius De M Benites,Luciano C Gatiboni,Amin Soltangheisi,Luiz R G Guilherme

doi:10.1038/s41598-018-20887-z

Abstract

Brazil’s large land base is important for global food security but its high dependency on inorganic phosphorus (P) fertilizer for crop production (2.2 Tg rising up to 4.6 Tg in 2050) is not a sustainable use of a critical and price-volatile resource. A new strategic analysis of current and future P demand/supply concluded that the nation’s secondary P resources which are produced annually (e.g. livestock manures, sugarcane processing residues) could potentially provide up to 20% of crop P demand by 2050 with further investment in P recovery technologies. However, the much larger legacy stores of secondary P in the soil (30 Tg in 2016 worth over $40 billion and rising to 105 Tg by 2050) could provide a more important buffer against future P scarcity or sudden P price fluctuations, and enable a transition to more sustainable P input strategies that could reduce current annual P surpluses by 65%. In the longer-term, farming systems in Brazil should be redesigned to operate profitably but more sustainably under lower soil P fertility thresholds.

Highlights

Two main strategies exist to meet rising global food and biofuel demand: intensify the existing agricultural land area as much as possible, and/or expand into areas with native vegetation which would be detrimental to global biodiversity
While the P rate applied to soybean is around 25 kg P ha−1 in Paraná state, the average rate is 35 kg P ha−1 in Goiás state, and 50 kg P ha−1 in the Matopiba region, where a higher proportion of the soils are still responding to P fertilizer[25]
This P input strategy may not be sustainable in the long-term if Brazilian cropland continues to expand at its current rate of 2.6% yr−1, and continues to rely on imports of primary fertilizers derived from finite global P reserves

Summary

Introduction

Two main strategies exist to meet rising global food and biofuel demand: intensify the existing agricultural land area as much as possible, and/or expand into areas with native vegetation which would be detrimental to global biodiversity. The considerable importance of agriculture to Brazil’s economy, and the large contribution Brazil’s agriculture makes to global trade as an exporter of soybean (Glycine max) and meat, reinforce the need to merge its future agricultural intensification with sustainable use of natural resources and limited environmental impact. We examine the current and future P demand of Brazilian crop production, and investigate transitional strategies for meeting this demand more sustainably by reducing reliance on costly and finite PR resources. We hypothesized that there is large scope to improve the efficiency and sustainability of P use in Brazil by accounting for the potential stocks of secondary P that could substitute for P imports and increase the resilience of Brazilian agriculture to future P scarcity, or sudden P price fluctuations. We further investigated how radical any change in fertilizer P inputs up to the year 2050 needs to be to reduce Brazil’s P surplus in agriculture to near zero

Methods

Results

Conclusion