Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2009
Publication Date: 3/15/2010
Citation: Arthur, F.H., Casada, M. 2010. Directional Flow of Summer Aeration to Manage Insect Pests in Stored Wheat. Applied Engineering in Agriculture 26: 115-122.
Interpretive Summary: Using low-volume ambient air to cool stored grain is a common management practice in the southern plains, but little research has been done recently to determine if the direction of airflow makes a difference regarding the cooling patterns. We conducted a study by using suction aeration, pulling air downward through the grain mass, as compared to pressure aeration, the standard strategy of pushing cool air upward through the grain mass. Results of a two-year study show that temperatures on the upper surface of the grain mass were consistently cooler with suction aeration than with pressure aeration. The resulting insect pest populations were also generally lower in the bins with suction versus pressure aeration. Our results demonstrate that using suction aeration would cool the upper surface zone of the grain mass, which is vulnerable to insect infestation, and could reduce the need for additional pesticide inputs through this reduction in pest pressure.
Technical Abstract: Field trials were conducted in metal wheat storage bins to determine whether pressure aeration, pushing ambient air from the bottom, or suction aeration, pulling air down from the top, would be more efficient at cooling the wheat mass and thereby limiting insect population growth. Aeration was accomplished at an approximate airflow rate of 0.22 to 0.31 m3/min/t, and was done by adjusting thermostatic controllers to operate the aeration fans when ambient temperatures fell below specified thresholds. Summer and autumn cooling cycles using suction aeration cooled the warmest part of the bin, the top of the grain mass, first, which resulted in lower overall wheat mass temperatures compared to pressure aeration, where the top of the grain mass always remained warmer than with suction aeration. This cooling effect was most pronounced in the upper surface of the grain mass, and insect pest populations as measured by pitfall traps were consistently lower in bins with suction versus pressure aeration. Results indicate that suction aeration would be more beneficial than pressure aeration for controlling insect pests in wheat stored in the southern plains of the United States.