Soil fertility, plant nutrition, and grain yield of upland rice affected by surface application of lime, silicate, and phosphogypsum in a tropical no-till system

- Soil acidity limits upland rice plant development in tropical regions.
- Combination of lime, silicate, and phosphogypsum is effective as a subsoil acidity amendment.
- Modification of soil chemical attributes increases upland rice grain yield.

The development of technologies that provide rapid acidity amelioration of the soil profile through the surface application of amendments and phosphogypsum, such as no-till (NT) systems, is extremely important to provide adequate chemical conditions in tropical soils with low natural fertility, which limits the grain yield of upland rice (Oryza sativa L.). Thus, this study aimed to evaluate the effects of surface applications of lime, silicate, and phosphogypsum, applied individually or in mixtures, on the chemical properties of the soil profile in an NT system and to determine their effects on the nutrition, yield components, and grain yield of upland rice. The experiment was designed as a completely randomized block with eight treatments replicated four times. The combination of phosphogypsum with lime and/or silicate improved the surface and subsurface soil chemical properties 12 months following application. The mixtures increased the concentrations of K, Ca, Mg, N-NO3−, and S-SO42 − in the subsurface layers. The sulphur concentration in the flag leaves of upland rice was higher with phosphogypsum application. The number of panicles per m2 and grain yield of upland rice were positively influenced by the surface application of soil acidity amendments and phosphogypsum mixtures.