Maize Inbreds' Response to Riecito Phosphate Rock and Triple Superphosphate on an Acidic Soil

Abstract

Tropical acidic soils require large inputs of nitrogen (N) and phosphorus (P) fertilizers to sustain crop production. Attempts to use phosphate rock (PR) as a cheaper P source have shown limited success because of low rock solubility. The objective of this study was to evaluate growth and P nutrition of aluminum (Al)‐tolerant maize inbreds fertilized with PR. Twelve Al‐tolerant inbreds from CIMMYT were planted in 2‐kg pots filled with an acidic soil very low in available P and fertilized with 0, 40, or 100 mg kg⁻¹ of Riecito PR or triple superphosphate (SP). Plant shoots were harvested 35 days after planting, and biomass, root length, P uptake, and soil residual P were determined. Inbreds were able to sustain growth when fertilized with PR. There was indication that various mechanisms were involved in the responses to PR fertilization. Cultivars combining high uptake and conversion efficiencies should improve maize utilization of PR.

Keywords:

• Al‐tolerant inbred
• maize
• phosphate rock
• triple superphosphate

Acknowledgments

This research was supported by Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT) and Instituto Nacional de Investigaciones Agrícolas (INIA).