Soil Type Influences Novel “Milpa” Isolates of <i>Trichoderma virens</i> and <i>Aspergillus tubingensis</i> That Promote Solubilization, Mineralization, and Phytoabsorption of Phosphorus in <i>Capsicum annuum</i> L.

Abstract

The Capsicum genus has significant economic importance since it is cultivated and consumed worldwide for its flavor and pungent properties. In 2021, Mexico produced 3.3 billion tons on 45,000 hectares which yielded USD 2 billion in exports to the USA, Canada, Japan, etc. Soil type has a dramatic effect on phosphorus (P) availability for plants due to its ion retention. In a previous study, novel fungal isolates were shown to solubilize and mineralize P in different kinds of soils with different P retention capacities. The aim of this work was to study the effects of the mineralogy of different kinds of “milpa” soils on the germination, biomass production, and P absorption of chili plants (Capsicum annuum). The germination percentage, the germination speed index, and the mean germination time were significantly increased in the plants treated with dual inoculation. Foliar phosphorus, growth variables, and plant biomass of chili plants grown in a greenhouse were enhanced in different soil types and with different inocula. Correlation studies suggested that the most significant performance in the foliar P concentration and in the growth response of plants was achieved in Vertisol with dual inoculation of 7 × 106 mL−1 spores per chili plant, suggesting this would be an appropriate approach to enhance chili cultivation depending on the soil type. This study stresses the importance of careful analysis of the effect of the soil type in the plant–microbe interactions.

Keywords

• milpa fungal diversity
• phosphorus bioavailability
• plant-growth promotion
• Vertisol
• Andisol
• germination speed