AIR-FILLED POROSITY AND YIELD OF IRRIGATED COFFEE IN AN OXISOL

Soil air-filled porosity (β) is directly related to the plants development and yield. Thus, the aim of this study was to evaluate how hourly aeration porosity (β) affects the productivity of irrigated coffee cultivated in an Oxisol in the region of Lavras, southeastern Brazil, in order to determine its ideal range. The experiment was conducted with the Rubi MG-1192 cultivar, spaced at 3.5 x 0.8 meters, in randomized blocks with six treatments and three replicates. The treatments consisted of applying percentages of the gross irrigation depth required (Li), being: non-irrigated, 60, 80, 100, 120 and 140% of Li. The soil matric potential (ym) in each treatment was measured with sensors, performing hourly readings at three depths (0.25, 0.50 and 0.75 m). The increase in gross irrigation depths provides a linear reduction of the average air-filled porosity in the soil cultivated with coffee. The T100 treatment showed a significant productivity increase, and from this value the gross irrigation depth showed a tendency to reduce coffee productivity and soil air-filled porosity. The ideal range of β between 0.152 and 0.163 m3 m-3 provided adequate aeration conditions and higher yield for coffee. Keywords: irrigated agriculture, productivity, soil aeration.