Physico-chemical and biological characteristics of the soil cultured with maize in conventional, agroecological and mixed systems in the Frailesca, Chiapas
With the aim of characterizing the soil of the maize agroecosystem under conventional, agroecological and mixed production systems, in order to document and identify strategies that consider the environmental, social and economic aspects that lead to alternatives for sustainable production, the physico-chemical and biological properties of 35 samples obtained in 28 communa land areas of Frailesca region, interpreted with the Official Mexican Standard NOM-021-SEMARNAT-2000. The results indicate a generalized acidity for the three systems, with pH of 5.05, 5.25 and 5.24, respectively; the cation exchange capacity is low (13.96, 12.54 and 14.95 cmol (+) kg-1) and organic matter is at average levels (3.5, 2.58 and 3.45%). Likewise, macronutrients are found in high levels, for instance, phosphorous reached 75.36, 74.78, and 45.05 mg kg-1 and potassium was found in low levels (3.86, 3.12, and 2.66 mg kg-1); micronutrients are found in average levels, such as Iron (3.24, 2.03 and 2.62 mg kg-1) and Boron (1.58, 1.06 and 1.37 mg kg‑1). In regard to soil texture, loam-clay-sandy and loam-sandy soils were detected. According to the biological characteristics of the soil, the macro-fauna with the agroecological system reported the greatest biodiversity in terms of the Shannon and Weaver index (H’ = 1.121), where coleopterans, annelids, hymenoptera, isoptera and gastropods were the most outstanding groups. For microorganisms, the greatest biodiversity (H’ = 1.121) was detected in entomopathogens (Beauveria bassiana and Metarhizium anisopliae), nitrogen fixers (Rhizobium, Azotobacter and Azospirillum) and pathogenic fungi such as Rizhoctonia, Fusarium and Alternaria, while the system with smallest diversity was the conventional, with H’ = 0.789. Under these soil conditions, a strategy that allows to increase soil quality and perform sustainable agricultural practices is needed.