Phosphorus Application Rates Affected Phosphorus Partitioning and Use Efficiency in Tomato Production

Abstract

Core Ideas The partitioning of P uptake to fruit was maximized at 72 kg ha−1 in 2014. Increasing P rate linearly increased P concentrations in both soil and leachate. Efficiency of converting P fertilizer into yield decreased with increasing P rate. The rate 56 kg ha−1 was considered the sufficient P rate based on tomato yield. Understanding P accumulation and partitioning is essential for improving phosphorus use efficiency (PUE) and minimizing environmental impact. A 2‐yr study was conducted to determine P distribution and PUE in tomato (Solanum lycopersicum L.) production as influenced by P application rates in a calcareous soil. Phosphorus was applied at 0, 29, 49, 78, 98, and 118 kg ha−1 as pre‐plant dry fertilizers. At 95 d after transplanting, total phosphorus uptake (TPU) was not significantly affected by P rates in either year. In 2014, the highest proportion of TPU was accumulated in fruits and the maximum partitioning of TPU to fruits occurred at 72 kg ha−1. A higher or similar percentage of TPU was allocated to leaves comparing with fruits in 2015, which was probably due to the higher rainfall accumulation. Positive soil P budgets occurred with P rates ranging from 29 to 118 kg ha−1 in both years. Phosphorus concentrations in surface soil and subsurface leachate increased linearly with increasing P rate. Tomato marketable yield at the first and second combined harvest was not affected in 2014, whereas the yield increased linearly and attained a plateau at 56 kg ha−1 in 2015. There were no significant differences among treatments in the total season marketable yields in either year, thus, the partial factor productivity decreased with increasing P rate. Consequently, in the calcareous soils with 37 to 51 mg kg−1 of Mehlich‐3 extractable P, 56 kg ha−1 can be the sufficient P rate for tomato production.