1a.Objectives (from AD-416)
The goal of this research is to develop new and improved sugarcane cultural practices which increase efficiency and sustainability and minimize adverse environmental impacts in both the crop and fallowed fields. The specific objectives are to:.
1)investigate the utility of precision agricultural techniques, including soil grid sampling, crop yield mapping, and variable rate application;.
2)to develop new systems to manage post harvest residues, which may include mechanical, chemical or biological removal techniques;.
3)to characterize sugarcane cultivars and germplasm developed through conventional breeding and genetic transformation for sustainability in integrated systems that contain post-harvest residues; and.
4)to develop new or improved cultural practices that maximize the efficiency and productivity of sugarcane billet planting and reduced tillage systems.

1b.Approach (from AD-416)
In an effort to maximize sugarcane efficiency, while minimizing negative environmental impacts, precision agicultural management techniques including GPS based grid soil sampling, crop yield mapping and variable rate application of fertilizers and lime will be investigated in field experiments. Field, laboratory, and greenhouse experiments will also be conducted to determine the effects of chopper harvester-generated trash mulch on: sugarcane development and performance, soil nutrient availability, soil health and water quality. Studies will be conducted to characterize cultivar and germplasm performance under conventional and evolving cultural systems where post harvest residues, reduced cultivation, and billet planting are included. In fallowed fields, the use of short-season, rotational crops and decreased cultivations will be evaluated in an attempt to improve soil fertility, profitability and sustainability.

3.Progress Report
• An experimental yield monitor was evaluated in 2005 on a commercial sugarcane chopper harvester with results compared to yield estimates based on actual field weights. Results were mixed and were influenced by weather and variety. The best correlations were obtained when fields and stalks were dry. Harvesting during wet weather where fields were muddy and foliage wet produced the poorest correlations. Modifications made by the manufacturer for the 2006 harvest season did not improve results.

• Leaf reflectance: (1) correctly identified the presence of mild and severe infestations of the viral disease sorghum mosaic virus in sugarcane leaves in 75 and 68% of the cases, respectively and leaves infested with sugarcane yellow leaf virus in 77% of the cases; (2) predicted sucrose levels in individual varieties in 60 – 90% of the cases; and (3) aerial imagery provided biomass yield estimates in close agreement with estimates obtained by actual plot weights.

• Preliminary results from experiments designed to determine the effects of the post-harvest blanket of leafy residue generated during green-cane harvesting on the growth and yield of three recently released sugarcane varieties (Ho 95-988, HoCP 96-540, L 97-128) in the subsequent production year suggest that the sugarcane variety HoCP 96-540 is extremely sensitive to the blankets of post-harvest residue. This variety will be planted to approximately 40% of the acreage in Louisiana in 2007.

• Preliminary results indicate that Louisiana's more recently released new varieties emerge earlier in the spring, have wider leaves, and canopy sooner than obsolete varieties are more suited for reduced tillage due to increased competition against weeds.

• The project receives fupport from the American Sugarcan League through a Trust Funded Cooperative Agreement; 6435-21000-012-04T, "Improving Sugarcane Production Efficiency," which is part of the parent project 6435-21000-012-00D, Genetic Improvement of Sugarcane by Conventional and Molecular Approaches; and a Cooperative Agreement between the Agricultural Research Service's, Sugarcane Research Unit and Nicholls State University (NSU). Additional details of the research progress can be found in the reports for the subordinate project 6435-21000-011-02S, "Microbial Decomposition of Post-Harvest Sugarcane Residues as a Replacement for Burning."

4.Accomplishments
FACTORS AFFECTING THE IMPACT OF POST-HARVEST RESIDUES IDENTIFIED. The blanket of leafy trash and other material generated during green-cane harvesting can negatively impact the yield of the sugarcane crop the following year. ARS scientists at the SRU showed that the impact of the residue blanket was greatest on crops later in the multiple year production cycle (second and third ratoons.) The effects were also greater on crops planted on poorly-drained clay soils, and in fields where the recommended treatment to harvest interval following glyphosate application (used to accelerate ripening) was exceeded. By minimizing the impact of these various stresses, growers can increase cane and sugar yields in subsequently harvested production years of a crop cycle by 5 to 15%. The results of these studies were relayed to growers during annual spring meetings and summer field days. In addition, results were summarized and included in the Sugarcane Production Handbook which is updated annually by the Louisiana State University Cooperative Extension Service. Results of these experiments address National Program 305 - Crop Production, Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems.

POST-HARVEST RESIDUES DEGRADED BY NATIVE SOIL MICROORGANSISMS. If the leafy residues generated during the harvest of green cane with chopper harvesters, are not removed prior to the re-emergence of the subsequent ratoon crop in the spring of the following year, yields may be reduced from 2 to 6 tons/A. ARS scientists showed that a consortium, of native microbes consisting of two bacteria and two fungi, degraded dry sugarcane leaves significantly greater (22%) than green leaves (14%), and degradation could be increased from 19 to 28% by decreasing the carbon to nitrogen ratio 50:1 to 10:1. Results from a field study showed that populations of these isolates steadily increased after soil inoculation indicating their successful establishment in the field. Although total residue levels were not significantly affected in field studies, soil organic carbon significantly increased where the consortium was applied compared to the control, suggesting that decomposition is being accelerated by the addition of the microbes. Success in this line of research will allow sugarcane growers to utilize the blanket of post-harvest residues generated during the chopper harvesting of green cane to minimize the potential impact of soil, nutrient and pesticide losses from sugarcane fields without significantly impacting crop yields. Results of these experiments address National Program 305 - Crop Production, Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems.

6.Technology Transfer

Number of web sites managed	1
Number of non-peer reviewed presentations and proceedings	20
Number of newspaper articles and other presentations for non-science audiences	2

Review Publications
Johnson, R.M., Grisham, M.P., Richard Jr, E.P. 2007. Relationship between sugarcane rust severity and soil properties in Louisiana. Journal of Phytopathology. 97:748-755.