Influence of the physical, chemical, and hydric attributes of soils and leaf area on degradation levels of cultivated pastures

Abstract

Understanding the predominant factors that explain pasture degradation is crucial for developing reliable and feasible restoration plans. This article describes a multivariate analysis used for detecting correlation patterns between soil physicochemical attributes and leaf area in four different levels of degradation of cultivated pastures (without degradation, with low, medium, and high degradation) in the northwestern region of the state of São Paulo. Principal component analysis, exploratory statistics, and hierarchical cluster analysis dendrograms were produced for soil physicochemical attributes in the 0-0.10 m and 0.10-0.20 m depth layers. Water infiltration rate, phytomass, and leaf area were higher in the non-degraded pasture. The top layer showed more recognizable clusters between eigenvectors and degradation levels than the deeper layer. Chemical attributes (P, K, Ca, Mg, organic matter, sum of bases, and base saturation) were more explicative of the variability of degradation, while physical attributes such as granulometry and soil water parameters were less explicative. More effective actions to restore these pastures may prioritize the most explanatory parameters in the 0 to 0.10 m layer. This approach may be replicated for pasture restoration studies and monitoring plans, to indicate parameter prioritization and cost optimization.