Characterization of Soil Fertility at Different Relief Points in a Humid Residual Massif in the State of Ceará

Abstract

Introduction: The relief acts as a soil formation factor and interferes, even indirectly, in the physical-chemical composition of soils, so that important variations in fertility can occur along a toposequence. In agricultural crops, variations in fertility have a major impact on productivity and production costs, which makes mapping soil fertility important. The aim of this study was to evaluate the fertility of soils under different agricultural crops and different points of relief in a mountainous area located in the municipality of Aratuba-CE.
 
 Theoretical reference: Various studies that relate soil types to the landscape show that deeper and more developed soils generally occupy flatter, or top, relief positions, where conditions for water percolation are favored. (ARTUR et al., 2014; SOUZA JUNIOR and DEMATTÊ, 2008). Braga et al. (2015) verified the existence of a correlation between soil fertility and distribution of tree species.
 
 Methodology: The design was in a randomized block in a split-plot scheme, with the plots formed by four cultivation areas, namely: banana trees (A1), banana trees and cashew trees (A2); grass (A3); pigeon pea (A4); and a control area (A5), maintained with natural vegetation. The subplots were formed by three relief positions: top, middle and slope. The physical-chemical variables of the soil were analyzed: pH, potassium, magnesium, calcium, phosphorus, aluminum, potential acidity, base sum, base saturation, total CEC, effective CTC, PST and soil density.
 
 Results: It was observed that the top areas have greater amounts of nutrients. Studies of this nature can provide indications about the evolution of pedogeomorphological systems in landscapes and enable the planning of the most appropriate and sustainable agricultural exploration.
 
 Conclusion: The top area presents nutrients in greater quantities, compared to the middle and slope, which may indicate that, although this region is more susceptible to leaching, this still occurs initially, to the point of not affecting soil fertility in the area. local.