Eric Webster, Viator, Sonny | 6/3/2010 8:12:27 PM
A study was initiated at the LSU AgCenter’s Iberia Research Station in 1997 to evaluate the long-term effects of post-harvest residue management on sugarcane. The objective was to measure the benefits and consequences of combine-generated residue retention to subsequent crops in the production cycle.
Residue management treatments included 1) pre-harvest burning; 2) post-harvest raking residue to the middles; and 3) full retention of the residue. Treatments were established in the first stubble crop of production cycle No. 1 in 1998 and maintained in place for the duration of three production cycles. When the study began, many fields were burned prior to combining, a practice that is less frequently used today
While retention of the trash blanket did not diminish yield in all seasons, averaged over all the stubble crops in the three cycles, pre-harvest burning resulted in higher sugar yields than the other residue management approaches. Difference in sugar yield for the other two treatments in the comparison was not significant. It must be acknowledged, however, that differences in measured yield between the burned and nonburned treatments must factor in the direct effects of burning prior to harvesting as well as the effects of the retained residue.
The adverse effects of residue retention appeared to be cumulative within cycles, with the most debilitating effects occurring in the older stubble crops. By the last stubble crop in each of the three cycles, the stalk population for the cane with the retained trash blanket possessed the lowest number of stalks.
The magnitude of the yield advantage of burning over retaining the residue is noteworthy because the cumulative total is tantamount to getting an extra crop (more than 8,000 pounds of sugar per acre when totaled over the three production cycles). The good news about the trash blanket is that the negative effects of retaining it did not carry over through the fallow period to subsequent production cycles – as indicated by the relatively high yields of the plant cane crops at the beginning of each cycle.