Effects of a new phosphate fertiliser on wheat nutrition and yield

Phosphorus (P) is an essential mineral for plant growth. Given that easily extractable global stocks of P are declining and that P over-fertilisation can be a source of pollution, it would appear necessary to improve the efficiency of phosphate fertilisers in agriculture. Two independent experiments were carried out at Agroscope Changins (Switzerland) and RITTMO-Colmar (France) to compare the efficiency of a fertiliser combining a complexed phosphate with a biostimulant (SSPTIM) to the currently used phosphate fertiliser, the simple superphosphate (SSP). Each experiment was conducted in a greenhouse under controlled conditions. The experiment in Colmar was conducted on an acidic sandy soil, the one in Changins on a neutral clay soil with a high P-fixing capacity. In both cases, five treatments were compared: a control (no P input) and two different doses for each of the two fertilisers (SSP and SSP-TIM) equivalent to 25 and 50 kg of P2O5 per hectare, respectively. On the acidic soil, the SSP-TIM fertiliser at the 25 kg P2O5/ha dose produced a significant increase in total wheat yield 19% higher than that achieved by the SSP fertiliser. On the clay soil, the SSP-TIM also brought a positive of 5% but not significant increase in wheat yield. Results vary according to the stage of development of the plant and the dose of applied fertiliser, among other factors. This study shows that the SSP-TIM fertiliser can be used to good effect in both types of soil, especially when the dose of fertiliser is reduced, which corresponds to numerous agricultural situations in Switzerland.