Location: Sugarcane Research2011 Annual Report
1a. Objectives (from AD-416)
The first objective of the research is to develop new crop and soil management techniques for sugarcane production that overcome limitations in soil and nutrient resources and maximize production efficiency. These techniques will incorporate elements of precision agriculture and remote sensing. The second objective of the research is to identify methods to mitigate the current yield loss associated with post-harvest residue retention and ripener usage in sugarcane production.
1b. Approach (from AD-416)
To address the first objective, a series of experiments will be initiated to investigate the response of sugar and energy-canes to variations in macro- and micronutrients. Results from these experiments will be used to identify critical fertility components and to optimize fertility rates for both sucrose and biomass production. Initial macro-nutrient experiments will focus on nitrogen (N), a critical component of a sugarcane fertility program whose cost has risen dramatically. Initial micronutrient experiments will focus on nickel (Ni) a nutrient that is associated with increases in disease resistance and copper (Cu) which is associated with increases in both cane and sugar yields and may also influence disease resistance. In addition, experiments will be conducted on commercial farms to investigate the utility of electrical conductivity (EC) and soil pH mapping, zone sampling, and variable-rate (VR) application techniques to optimize nutrient availability. All treatments will be arranged in randomized complete block design (RCBD) with six replications. Finally, we will investigate the utility of a newly designed yield monitor and leaf reflectance measurements, from multi-band aerial imagery and from direct hyperspectral measurement as potential indicators of cane biomass levels and sucrose content and to identify crop stresses associated with improper fertility levels of sugarcane dedicated for either sugar or bioenergy. To address the second objective, studies will be initiated to investigate the carry over response of sugar- and energy-cane crops to post-harvest residue and ripener applications made in the previous crop year. The response of energy-canes and newly-released sugarcane varieties to these factors has not been tested. In addition, studies will be implemented to screen basic and commercial germplasm for tolerance to post-harvest residue retention and to screen for self-defoliating clones that may expedite the natural decomposition of leafy residue prior to harvest. Finally, a study will be initiated to investigate in crop N application rate effects under various post harvest residue management schemes to include: partial removal, complete removal by burning, and no removal.
3. Progress Report
Preliminary results suggest that Louisiana sugarcane growers could save money by reducing nitrogen (N) rates in both plant and stubble crops, while maintaining crop yields. Preliminary results with both nickel (Ni) and copper (Cu) suggested positive yield effects in both plant-cane and first-ratoon trials. Yield monitor data was collected on commercial sugarcane farms in the fall of 2010 and results indicated that the system was effective at predicting and mapping cane yields. First-ratoon data indicate that the stresses of glyphosate carryover and full residue retention appear to compound each other as indicated by reductions in cane and sucrose yields. The first-ratoon residue management for energy cane experiment was harvested, and the first year of data indicates that residue management strategies will vary depending on if cane is grown for sugar or biofuels. Residue treatments were applied to basic and commercial germplasm screening studies to identify clones tolerant to the cool, wet conditions caused by the retention of post-harvest residues. In another test that evaluated self-defoliating varieties as an alternative to burning, preliminary data indicates that residue decomposition is not enhanced with early defoliation. Preliminary data using new cultural practices as an alternative to burning indicate that additional nitrogen applied with mechanical removal of residue, produced yields equivalent to where the residue was removed by burning.