Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2002
Publication Date: 12/1/2002
Citation: RANALLI, R.P., HOWELL, T.A., ARTHUR, F.H., GARDISSER, D.R. CONTROLLED AMBIENT AERATION DURING RICE STORAGE I: TEMPERATURE AND INSECT CONTROL. APPLIED ENGINEERING IN AGRICULTURE, 18(4): 485-490. 2002.
Interpretive Summary: Using aeration, or low-volume ambient air, is a common management practice to control temperature in bulk stored wheat. The use of controllers to regulate aeration has also been shown to be more efficient than traditional manual aeration. Rice is an important stored crop in Arkansas and Louisiana, however, there is limited information regarding aeration management in stored rice. Rice storage bins in Arkansas were equipped with aeration controllers for comparison with bins using manual aeration. Insects were also introduced inside the bins in confined cages and natural populations were sampled. Controlled aeration reduced temperatures much faster and provided more even temperature distribution inside the bins compared to traditional manual aeration. Insect populations were also lower in bins with controlled aeration compared with manual aeration. Results show the potential for expanded use of controlled aeration to manage stored rice in the south-central United States.
Technical Abstract: Rice (cv. Cypress) was harvested in September, 2000 from a farm near Grady, AR, placed in six, 600 t (31,000 bu) bins (each was filled with 430 t, 21,000 bu), and dried gently from 18% to 13% moisture content (MC). Three of the bins were equipped with an aeration control system activated by specific ambient air conditions in three cycles. Three of the bins were aerated by the on-site, storage manager under his normal regimen. Grain temperatures were recorded at four locations within each bin. To monitor insect viability, small cages were filled with approximately 150 g of rice and 20, 1-2 week old mixed sex adults of one insect species. The species that were tested included the lesser grain borer, Rhyzopertha dominica (Fauvel), the rice weevil, Sitophilus oryzae (L.), and the saw toothed grain beetle, Oryzaephilus surinamensis (L.). Cages were removed at 5 wk intervals, and surviving and emerging insects were counted. Grain temperatures were significantly reduced through controlled aeration relative to the traditional, manual aeration. In addition, both live insect counts and total emerged adult insects recovered from the cages were significantly lower (p<0.05) within the bins treated with controlled aeration. The rice weevils were the hardiest of the insects tested, while saw toothed grain beetles survived the least. This work indicates that controlled, ambient aeration can be an effective storage treatment against insects and may be a useful alternative to chemical controls.