PHYSICOCHEMICAL AND MICROBIOLOGICAL PROPERTIES OF SOILS WITH SUGARCANE AND MAIZE UNDER IRRIGATED AND RAINFED CONDITIONS

Background: Sugarcane and maize are two main crops in Mexico, and the soil characteristics are important for their proper grow. Soil suitability is assessed through indicators which are chemical, physical and biological.  Objective: We compared physical, chemical and microbiological soil properties in two agroecosystems, one with sugarcane and one with maize, under irrigation and rainfed conditions, so as to detect soil quality changes in each condition. Methodology: Soil samples were evaluated for pH, N, P, K, Ca, Mg, Na, organic matter, cationic exchange and texture, based on the NOM-021-RECNAT-2000. The number of microorganisms was quantified in each agroecosystem, using four culture media. Data was examined with an analysis of variance and Tukey mean test (P ≤ 0.05). Results: Soil quality was low in localities with maize, and there were not statistical differences among them; but it was better in sugarcane under rainy season-based cropping system than under irrigation. More microorganism colonies were found in maize under irrigation and sugarcane under rainy season-based cropping system. Implications: It is important to establish conservation measures that allow buffering and preserving soil and nutrient losses to maintain their productive capacity, especially in soils with more years of production. Conclusions: Soils under rainy season-based cropping system, with both agroecosystems, presented better nutritional contents in comparison with those under irrigation. The largest number of microorganisms in corn under irrigation and sugarcane under rainfed conditions could be because the pH was higher than the other two agroecosystems.