Soil quality changes in cashew orchard production in Brazilian semiarid areas: a comprehensive field survey across locations, seasons, tree types, and management practices

Abstract

The cashew tree (Anacardium occidentale L.) plays a critical role in tropical agriculture. Although the impact of intensive cashew production on soil quality is recognized, it remains poorly understood. This study investigates how location, management practices, tree type (common and dwarf), and seasons affect soil quality indicators in cashew orchards in Brazilian semiarid. Soil samples (0–40 cm) were collected from four municipalities in Northeast Brazil (Beberibe and Pacajus, Ceará state; Pio IX, Piauí state; and Serra do Mel, Rio Grande do Norte state) during dry and rainy seasons, under managed and unmanaged soil conditions in orchards of dwarf and common cashew trees. Biological indicators, such as microbial biomass carbon, soil basal respiration, metabolic quotients, and enzymatic activities (β-glucosidase, arylsulfatase, acid, and alkaline phosphatases), were assessed. Results revealed significant spatial variability, with location as the main factor influencing soil attributes. Dwarf cashew cultivation reduced nutrient losses by enhancing microbial efficiency, particularly in low-fertility, aluminum-rich soils. All analyzed enzymatic activities were closely linked to total organic carbon, soil fertility, or pH, highlighting their potential as soil health indicators. Seasonal variations influenced microbial activity, especially in iron-rich soils like those in Serra do Mel municipally. Based on these findings, we recommend site-specific management practices, such as maintaining organic residues around dwarf cashew trees and targeting soil acidity correction, to optimize microbial processes and improve soil resilience. Cultivating dwarf cashew trees is encouraged due to their enhanced nutrient use efficiency, which reduces soil nutrient losses and supports microbial activity, particularly in low-fertility soils.