Effects of the interaction between dicarboxylic acid polymer and CaO on phosphorus use efficiency of cassava grown on the acidic sulfate soil in the Mekong Delta

Introduction Studies have reported that Dicarboxylic acid polymer (DCAP) -coated phosphorus fertilizer (DCAP/P) positively impacts crop growth and yield. However, studies on the effects of interaction between DCAP/P and CaO to improve the PUE of plants on acidic soils are limited. Methods This study aimed to (i) examine the effects of lime and DCAP on improving P uptake and cassava growth on acid sulfate soil and (ii) evaluate the effects of interaction between lime and DCAP/P on cassava PUE. The experiment was conducted in the greenhouse of the School of Agriculture, Can Tho University, from December 2022 to August 2023. The pot experiment was arranged in a completely randomized split-plot design, with factor A comprising two liming doses (0 and 4 t CaO ha -1 ) and factor B comprising three phosphorus (P) fertilization treatments (0P, 60P, and DCAP/60P), each with four replications. The local cassava variety ‘O Ta Bang’ was use inthe experiment. Result Our results showed that the total P uptake (g P 2 O 5 plant -1 ) at 0Pand 60P only reached 72 and 96%, respectively, compared with the total P uptake of DCAP/60P. Among the CaO-treated samples, 60P treatment increased the plant PUE to 28.6%, while DCAP/60P treatment significantly increased the PUE to 48.8%. Discussion The interaction between DCAP/60P and CaO synergistically enhanced PUE more efficiently than between 60P and CaO.