Towards optimal use of phosphorus fertiliser

Abstract

Because phosphorus (P) is one of the most limiting nutrients in agricultural systems, P fertilisation is essential to feed the world. However, declining P reserves demand far more effective use of this crucial resource. Here, we use meta-analysis to synthesize yield responses to P fertilisation in grasslands, the most common type of agricultural land, to identify under which conditions P fertilisation is most effective. Yield responses to P fertilisation were 40–100% higher in (a) tropical vs temperate regions; (b) grass/legume mixtures vs grass monocultures; and (c) soil pH of 5–6 vs other pHs. The agronomic efficiency of P fertilisation decreased for greater P application rates. Moreover, soils with low P availability reacted disproportionately strong to fertilisation. Hence, low fertiliser application rates to P-deficient soils result in stronger absolute yield benefits than high rates applied to soils with a higher P status. Overall, our results suggest that optimising P fertiliser use is key to sustainable intensification of agricultural systems.

Understanding the Adaptive Mechanisms of Plants to Enhance Phosphorus Use Efficiency on Podzolic Soils in Boreal Agroecosystems

“…The current global supply of phosphatic fertilizer is 50 MT and is projected to increase to 90 MT by 2050 (FAO, 2019 ; Nedelciu et al, 2020 ). Expansion of fertilizer usage in agriculture will boost food production; however, high consumption of nonrenewable P resources will put more pressure on already depleting global P reserves (Ros et al, 2020 ). Although precision agriculture practices promote the optimum utilization of P resources, only 30% of applied P is used by crops to complete their growth cycle, and 70% of applied P is fixed or released to the environment.…”

“…However, the growing concern on depletion of P reserves and environmental pollution created opportunities to explore the efficient utilization of P in the agriculture industry (Cordell and White, 2013 ). A meta-analysis study documented that overuse of P would not improve crop yield (Ros et al, 2020 ); instead, it causes aquatic pollution. For example, a field experiment on podzolic soil revealed that 22 kg P ha −1 resulted in a higher carrot yield than 110 kg P ha −1 (Sanderson and Sanderson, 2006 ).…”

“…However, because of low P mobility and availability in soils, substantial amounts of autotrophic P (soil P) must be supplied from organic or inorganic fertilizer sources (Grant and Flaten, 2019 ). A major source of inorganic P is fertilizers; therefore, farmlands receive significant quantities of P fertilizers each year because of low soil P status worldwide (Lu and Tian, 2017 ; Ros et al, 2020 ). However, the applied P becomes unavailable because of higher affinities toward cations and soil organic matter (SOM), rendering it the least mobile and phytoavailable nutrient (Hinsinger, 2001 ), particularly, in podzolic soils that are rich in aluminum (Al) and iron (Fe) minerals that fix available P pools (Kedir et al, 2021 ).…”

“…Generally, podzols have a coarse sandy texture, shallow depth, acidic pH, and low fertility, which restricts crop growth and productivity (DeBruyn et al, 2011 ; Ali et al, 2019b ). Higher applications of P fertilizers are, therefore, critical to enhancing crop production, but there are alarming concerns on long-term environmentally sustainable use of nonrenewable P resource (Ros et al, 2020 ). Despite high P applications, PUE is only 15–20% in agricultural croplands, indicating that most of the applied P is not accessible for plant use (Malhotra et al, 2018 ).…”

Phosphorus fertilizer form and application frequency affect soil P availability, chickpea yield, and P use efficiency under drip fertigation

“…2018; Simpson et al, 2011). According to several studies, phosphorus (P) is becoming a limiting factor for crop production in many cropping systems (W. Liu et al, 2018;Maharajan et al, 2021;Ros et al, 2020). P can be found in soil in a variety of forms including P in soil solution, P adsorbed, P in organic compounds, and P in soil minerals (Hinsinger, 2001).…”