Particle Size Imbalance Index from Compositional Analysis to Evaluate Cereal Sustainability for Arid Soils in Eastern Algeria

For homogeneous fertilization and crop management practices, this work hypothesized that texture could influence cereal yield, particularly in dry regions. Particle size analysis could help improve knowledge of the soil-plant relationship to obtain favorable conditions for better yield. The objective of this work is to develop a single granulometric index for durum wheat (Triticum durum) that is well correlated with yield. For this purpose, 350 independent samples of cereal soils from eastern Algeria were taken and the recorded yields were linked to these samples. The cutoff yield, which separates sub-populations with acceptable yield from those with less acceptable yield, was determined from the inflection point of the cumulative variance ratio functions related to yield by the Richards’ equation. The result obtained is 2.0 Mg.ha⁻¹, with a theoretical critical chi-square value of 4.2, close to 4.6, which is the critical value of r²_granulo as obtained by the Cate-Nelson procedure. The five-granulometric indices were found to be symmetrical around zero as follows: ±0.83 for clay (I_C), ±1.73 for fine silt (I_FL), ±0.31 for coarse silt (I_CL), ±0.44 for fine sand (I_FS), and ±1.30 for coarse sand (I_CS). The two fractions that most influence the textural imbalance are fine silt (I_FL) and coarse sand (I_CS), with a contribution of 41% and 37%, respectively. The critical single imbalance index $r_{granulo}^2$ can be used for determining cereal suitability for soils in the arid region of eastern Algeria. The lower the $r_{granulo}^2$ is, the better the soil for cereal crops.