1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
Portions of this project were included in Research Project 6435-22000-009-00D that was subjected to an ad-hoc Office of Scientific Quality Review (OSQR) in 2003 as part of National Program 304. Congressionally-mandated expansion of the research in FY 2004 in areas covered by National Program 305 justified the creation of an independent research project. An OSQR review of National Program 305 is scheduled for May-June, 2008. To date, this project has not been scheduled for ad-hoc review under the OSQR process.

In recent years, Louisiana sugarcane producers have faced increased economic pressure. The combined effects of increased input costs, variable sugar prices and the potential implementation of production quotas have compelled growers to find ways to decrease costs and maximize profits and sustainability. In addition, the industry's continued use of burning as a tool to remove extraneous leaf material to increase harvesting efficiency and sugar recovery and to reduce the impact of the plant residue generated at harvest on subsequent crops (ratoons) is in jeopardy due to environmental concerns. New cultural practices must be developed if the industry is to overcome these challenges. Adoption of precision agriculture and reduced tillage techniques offer the greatest promise to achieve these goals.

The overall goal of this research is to develop new and improved sugarcane cultural practices that increase efficiency and sustainability while minimizing the impact of the crop’s culture on the environment. The specific objectives are to:.
1)investigate the utility of precision agricultural techniques, including soil grid sampling, crop yield mapping, and variable lime application;.
2)develop new systems to manage post-harvest residues, which may include mechanical, chemical or biological removal techniques;.
3)characterize sugarcane cultivars and germplasm developed through conventional breeding and genetic transformation for sustainability in integrated systems that contain post-harvest residues; and.
4)develop new or improved cultural practices that maximize the efficiency and productivity of reduced tillage systems and sugarcane planting systems that utilize billets (8 to 10 inch cane pieces generated by chopper harvesters).

The research to be undertaken in this project falls under National Program 305 - Crop Production and addresses Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems as described in the National Program Action Plan. The project also includes elements of components X.A (Cultural and mechanical control of weeds) of National Program 304.

The research and the recommendations developed will lower production costs while insuring yield sustainability. Research on post-harvest residue management and the use of precision agriculture methods will have general applicability to the growers and millers of the Florida and Texas cane sugar industries as well as Louisiana. The research, aimed at making the culture of sugarcane more environmentally friendly, will be useful to the Cooperative Extension Services of the three states, the USDA National Resource Conservation Service, and various National Estuary Programs, as they develop Best Management Practices (BMPs) for sugarcane. This is especially important because sugarcane is grown near some of the largest and most productive estuary systems in the southern U.S. Finally, American consumers will benefit by obtaining a dependable supply of high quality domestic sugar.

2.List the milestones (indicators of progress) from your Project Plan.
Year 1 (FY 2004) Objective 1a. Complete studies to quantify the extent of variability present with respect to soil chemical properties and cane and sugar yields in commercial sugarcane fields. 1b. Continue studies to evaluate the potential profitability and environmental sustainability of variable rate lime application methods versus conventional application methods.

Objective 2a. Initiate studies to quantify the yield loss associated with the retention of post-harvest residues generated during the harvest of green cane with chopper harvesters in light and heavy soils for first-, second- and third-ratoon crops.

Objective 3a. Initiate studies designed to evaluate varietal differences in their abilities to emerge and develop under the adverse conditions associated with post-harvest residue blankets in the late winter. 3b. Continue screening and selection of potential varieties that are self-stripping and hence would be easier to clean with chopper harvesters. 3c. Continue screening and selection of potential varieties that emerge early in the spring under heavy-residue conditions.

Objective 4a. Continue studies to quantify the effect of planting rate and position in the planting furrow on sugarcane yield in billet planting systems. 4b. Initiate studies to quantify the effect of planting depth and pre-emergence herbicide on sugarcane yield in billet planting systems. 4c. In a plant-cane crop, initiate studies designed to compare conventional tillage to minimum tillage systems as influenced by the presence of post-harvest residues generated during the harvesting of green cane with chopper harvesters.

Year 2 (FY 2005) Objective 1a. Complete studies evaluating the potential profitability and environmental sustainability of variable rate lime application methods versus conventional application methods and prepare report. 1b. Initiate studies to determine the utility of sugarcane harvester yield monitors for load monitoring and construction of yield maps to be used in precision applications. 1c. Initiate studies to evaluate variable rate fertilizer and herbicide application versus conventional application methods. 1d. Initiate studies to determine the utility of remote sensing as an indicator of sugarcane yield, health, and quality.

Objective 2a. Continue studies to quantify the yield loss associated with the retention of post-harvest residues generated during the harvest of green cane with chopper harvesters in light and heavy soils for first, second and third ratoon crops. 2b. Initiate cooperative studies to evaluate the utility of collecting and baling post-harvest residues for use as wind and water erosion barriers on vulnerable coastal and offshore beaches. 2c. Report on the physiological reason for the loss associated with residue retention and develop protocols for germplasm screening.

Objective 3a. Utilize plant breeding techniques to develop new varieties that have residue tolerant lines and current near commercial (elite) germplasm as parental material. 3b. Perform similar studies with self-stripping lines and current elite germplasm as parental material.

Objective 4a. Complete studies to quantify the effect of planting rate and position in the planting furrow on sugarcane yield in billet planting systems and prepare report. 4b. Continue studies to quantify the effect of planting depth and pre-emergence herbicide on sugarcane yield in billet planting systems. 4c. Continue studies in the first-ratoon crop comparing conventional tillage to minimum tillage systems as influenced by the presence of post-harvest residues generated during the harvesting of green cane with chopper harvesters.

Year 3 (FY 2006) Objective 1a. Continue studies to determine the utility of sugarcane harvester yield monitors for load monitoring and construction of yield maps in precision agriculture applications. 1b. Continue studies to determine the utility of remote sensing as an indicator of sugarcane yield, health, and quality. 1c. Initiate second year of phosphorus fertility experiments.

Objective 2a. Complete studies to quantify the yield loss associated with the retention of post-harvest residues generated during the harvest of green cane with chopper harvesters in light and heavy soils and prepare report. 2b. Continue cooperative studies to evaluate the utility of collecting and baling post-harvest residues as wind and water erosion barriers on vulnerable coastal and offshore beaches and marshes.

Objective 3a. Continue to evaluate germplasm that can emerge and grow during the late-winter under the cool and wet soil conditions typically found under post-harvest residue blankets. 3b. Continue to evaluate germplasm that characteristically loses its older leaves prior to harvesting.

Objective 4a. Complete studies to quantify the effect of planting depth and pre-emergence herbicide on sugarcane yield in billet planting systems and prepare report. 4b. Report on cane yield and profits under various tillage situations over a complete cane cycle.

Year 4 (FY 2007) Objective 1a. Continue studies to determine the utility of sugarcane harvester yield monitors for load monitoring and construction of yield maps in precision agriculture applications. 1b. Continue and expand studies to determine the utility of remote sensing as an indicator of sugarcane yield, health, and quality. 1c. Complete phosphorus fertility studies and prepare report.

Objective 2a. Initiate studies to determine the response of newly released sugarcane varieties to the presence of post-harvest residues. 2b. Complete studies to investigate the interactive effect of post-harvest residues and sugarcane ripeners. 2c. Continue cooperative studies to evaluate the utility of collecting and baling post-harvest residues as wind and water erosion barriers on vulnerable coastal and offshore beaches and marshes.

Objective 3a. Continue to evaluate germplasm that is tolerant of post-harvest residues. 3b Continue to evaluate germplasm that loses its older leaves prior to harvest.

Objective 4a. Continue research on cane yield and profits under various tillage situations over two complete cane cycles. 4b. Initiate studies to determine the response of newly release varieties to reduced or no-tillage practices and determine the effect of these practices on soil chemical and physical properties.

Year 5 (FY 2008) Objective 1a. Complete studies to determine the utility of sugarcane harvester yield monitors for load monitoring and construction of yield maps in precision agriculture applications and prepare report. 1b. Complete studies to determine the utility of remote sensing as an indicator of sugarcane yield, health, and quality and prepare report.

Objective 2a. Continue studies to determine the response of newly released sugarcane varieties to the presence of post-harvest residues. 2b. Complete studies to investigate the interactive effect of post-harvest residues and sugarcane ripeners. 2c. Complete cooperative studies to evaluate the utility of collecting and baling post-harvest residues as wind and water erosion barriers on vulnerable coastal and offshore beaches and marshes and prepare report.

Objective 3a. Continue to evaluate germplasm that is tolerant of post-harvest residues. 3b. Continue research that will lead to the commercialization of germplasm that lose its older leaves prior to harvest.

Objective 4a. Complete studies to determine the response of newly release varieties to reduced or no-tillage practices and the effects of these practices on soil chemical and physical properties and prepare report.

4a.What was the single most significant accomplishment this past year?
COMPOUNDS IN POST-HARVEST RESIDUES HINDER CANE EMERGENCE. Previous research from the Sugarcane Research Unit has demonstrated that if the post-harvest residues resulting from the chopper harvest of green cane are not removed from the soil surface, yield decreases in the subsequent ratoon crop will occur. An experiment was conducted to determine if the post-harvest residues possess compounds that adversely affect the germination and growth of sugarcane (autotoxicity) or other plants (allelopathy). Sugarcane residue was extracted using distilled water to test for the presence and activity of these compounds on a variety of plants; including sugarcane, oat, rye, and tomato. The extract with the highest concentration significantly reduced the germination of oats, rye, and sugarcane by 31, 33, and 50%, respectively. Sugarcane leaf development was also hindered by the extracts during the initial growth stages. After this two-week duration, extracts did not significantly affect cane growth in terms of height, leaf development, fresh weight, or dry weight. This data suggests that sugarcane post-harvest residue has both autotoxic and allelopathic activity and may partially explain the observed yield depressions. The combined results of this and previous studies have allowed SRU personnel to provide residue removal guidelines to Louisiana sugarcane producers to avoid these negative effects.

4b.List other significant accomplishments, if any.
VARIABLE RATE LIME APPLICATION CAN REDUCE INPUT COSTS WHILE MAINTAINING OR IMPROVING CANE YIELDS. Louisiana sugarcane producers must find ways to decrease costs and maximize profits and sustainability. An experiment was conducted at several locations to determine if soil grid-sampling and variable rate (VR) lime application, could provide growers with a viable system to accomplish this task. In a VR system the lime application rate is continuous varied across the field in response to changes in the grid-sampled soil pH value. In our study, VR application of lime reduced the total amount of lime applied in all experiments, by up to 50%. Results from 2002-2004 show that VR lime application resulted in statistically equivalent cane and sugar yields in plant-cane crops in 2 of 3 studies compared to uniform application. Yields in 1st stubble crops were statistically equivalent or superior and results from 2nd stubble yields showed an advantage to uniform application, with VR application still showing an advantage over no lime application. These combined results are promising, because if similar yields can be obtained with the VR system, while actually applying fewer inputs, then Louisiana sugarcane producers can show an overall increase in profitability while improving sustainability and minimizing adverse environmental impacts.

LEAF REFLECTANCE MEASUREMENTS USED TO DISCRIMINATE BETWEEN SUGARCANE VARIETIES. In a process that may take 12 or more years, Louisiana sugarcane breeders select the best individuals from crosses made between commercial and near commercial varieties and wild canes. A study was initiated to determine if leaf reflectance measurements combined with plant pigment measurements could be used as an aid in the identification and separation of seedlings resulting from true crosses (hybrids) from the unwanted self-fertilized plants (selfs). Seven varieties were selected for reflectance analysis, including five commercial sugarcane varieties, one noble cane, and one wild cane. Differences in reflectance were observed for each variety, with the varieties having a 3-fold difference in reflectance values. When all wavelengths were included in the analysis the varieties were correctly classified in 100% of the cases using plant pigment data and normalized reflectance data. This method should prove useful in separating sugarcane varieties in the field and in identifying seedlings of undesirable selfs from the more desirable hybrids while they are still in the greenhouse. This will improve selection efficiency and aid in the release of superior varieties from sugarcane varietal development programs.

4c.List any significant activities that support special target populations.
None

4d.Progress report.
This project is the parent project for additional research conducted under Reimbursable Agreements between the Agricultural Research Service's, Sugarcane Research Unit and the Barataria Terrebonne National Estuary Program and between SRU and Nicholls State University. Additional details of the research progress can be found in the reports for the subordinate projects 6435-21000-011-00R, "Influence of Chopper-Harvested Green Cane Residue Blankets on Sugarcane Production and Ag Runoff," and 6435-21000-011-02S, "Microbial Decomposition of Post-Harvest Sugarcane Residues as a Replacement for Burning."

5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
Results of experiments in all research objectives addresses National Program 305 - Crop Production, Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems. Research conducted in association with Objective 1 (1a, FY 2004) utilized precision agriculture techniques to document the extent of variability present in commercial sugarcane fields in Louisiana. In these tests, cane and sugar yields were monitored in 9 to 10 acre fields that had been divided into 0.04 acre quadrants. Cane yields were found to vary from 15 to 60 tons per acre within fields. Sugar yields and TRS levels in the same field varied from 3,000 to 13,000 pounds per acre and from 130 to 250 pounds per ton, respectively. When the yield data was analyzed with geostatistical methods the sugar yields were found to be spatially correlated with a range of 278 feet. Soil samples taken from these plots also exhibited spatial correlation with soil pH showing a similar range of 278 feet. Identification of this variability and its correlation with soil properties will allow ARS scientists to conduct further experiments to determine the feasibility of using precision agriculture management techniques, such as the variable rate application of lime to increase grower profitability. These techniques will allow producers to reduce the overall input of soil nutrients while maintaining yields and insuring environmental sustainability.

Further experiments that address Objective 1 (1b, 2004; 1a, 2005) investigated the utility of VR lime application in comparison to a conventional (uniform rate) lime application method. Prior to lime application, soil samples (0-8 in) were taken from each site on a 1-acre grid. A random soil sample was also collected from each field to determine the lime rate, based on current extension recommendations for the conventional treatment. In all experiments the VR treatment reduced the total amount of lime applied to the field in question. Gross cane and sugar yield results from the 2002 plant-cane crop demonstrated an advantage to both VR and conventional lime application methods as compared to the no-lime control. There was no significant difference observed in theoretically recoverable sugar (TRS) in 2002. Results from the conventional application method were also significantly greater than the VR method in both sugar and tonnage yield in the plant-cane crop. A similar trend in both gross cane and sugar yield was observed in the first-ratoon crop in 2003 with the following exceptions. The VR lime treatment yielded a significantly higher TRS than the conventional or no lime treatments and the difference in sugar yields between the conventional and VR treatments decreased significantly to 440 lb sugar/acre. Although, there was a significant difference between the conventional and VR treatments at the 5% significance level, there was not a difference at the 10% level. This would indicate that the VR method is achieving statistically equivalent yields, as compared to the conventional uniform method, while applying less than half of the lime. Results from a plant-cane experiment in 2003 did not show a significant difference in cane or sugar yields between treatments indicating that the amount of lime applied could be reduced, while maintaining yields. Results from 2004 show a significant advantage with VR lime application in 1st stubble yields and a numerical advantage with VR lime in plant cane yields. Results from 2nd stubble yields showed an advantage to uniform application, with VR application still showing an advantage over no lime application. These combined results are promising, because if similar yields can be obtained with the VR system, while actually applying fewer inputs, then an overall increase in profitability will be observed in addition to improving sustainability and minimizing adverse environmental impacts.

The Louisiana Sugarcane industry's continued use of burning as a tool to remove extraneous leaf material to increase harvesting efficiency and sugar recovery and to reduce the impact of the post-harvest residues on the subsequent ratoon crop is in jeopardy due to environmental concerns. In research associated with Objective 2 (2a, FY 2004/5) ARS scientists at the SRU assessed the impact of these residues on yields of ratoon crops of sugarcane during the 2002-2004 growing seasons in field experiments throughout the Louisiana industry. They demonstrated that the presence of the blanket of residue at the start of the subsequent ratoon crop's production year slowed the development of the crop from underground buds and that the slowdown was exacerbated by cold soil temperatures and high rainfall during the winter months. The results of our studies indicate that a 2 to 3 degree (F) decrease in spring soil temperature occurs in those plots where the residue was not removed compared to plots where the residue was removed by burning. The plots with residue also had soil moisture levels that were 3-5% greater than the complete removal treatment. The combined effects of a lower temperature and higher moisture may slow germination of below-ground buds on the sugarcane stubble in the late-winter to a sufficient extent that yield is adversely effected. Recent results have also demonstrated that sugarcane post-harvest residue has both autotoxic and allelopathic activity which may contribute to the observed yield depressions. The results continue to suggest that the residue must be removed at least from the row top as soon after harvest as possible to insure optimum yields the following year in the ratoon crop. Results indicate that the method of removal is of less importance with essentially equal yields obtained with a variety of mechanical removal techniques. However, in poorly drained fields mechanical removal produced lower yields than burning because the residue prevented proper drainage. If the residue is to be removed from a field by burning, this should be done soon after harvest to prevent damage to the re-emerging crop. The combined results of these studies have allowed SRU personnel to provide residue removal guidelines to Louisiana sugarcane producers to avoid these negative effects.

These accomplishments provide knowledge that contributes information towards realizing the goals of National Program 305 - Crop Production, Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems. More specifically, the research results address goal 1, by helping to improve the understanding of the effects of management practices and their interactions on crop productivity and quality, and goal 6, by helping to increase crop productivity and quality in production systems in a sustainable manner.

6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
Significant interaction with customer groups occurred at the following meetings in which ARS researchers were invited to speak: International Society of Sugarcane Technologists 25th Congress in Guatemala City, Guatemala, (attended by over 800 international researchers) (2). American Society of Sugar Cane Technologists Louisiana-Florida Division in Saint Pete Beach, FL, (attended by over 200 growers, researchers, and processors) (2); American Society of Sugar Cane Technologists Louisiana Division Meeting in Baton Rouge, LA (1); American Sugarcane League Contact Committee Meeting (1); Louisiana Cooperative Extension Service-sponsored Research Extension planning meetings (2) and spring (January/February) parish grower meetings (2) and summer (July/August) parish field days (4). Research results were also discussed during meetings of the Louisiana Ag Consultants Association (2), and at raw sugar factory-sponsored pre-harvest grower meetings (3); Louisiana State University South Central Region Advisory Leadership Council’s Sugarcane Residue Management Subcommittee (2); Barataria-Terrebonne National Estuary Program Management Conference Meeting (1). Adoption of this technology is slowed by the fact that the research must consider and address numerous variables (soil type, soil texture, soil fertility, crop age, environments, harvester-mounted yield monitoring technology, etc.) and also by the small number of ARS and University scientists involved in this area of research.

7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
Viator, R.P., Johnson, R.M and Richard Jr., E.P. 2005. Management of the post-harvest residue blanket. Sugar Bulletin. 83:10-11.

Viator, R.P., Johnson, R.M. and Richard Jr., E.P. 2005. Multiple challenges of green-cane harvesting in Louisiana. Sugar Journal. 67(10):6-7. [article printed in English & Spanish].

Johnson, R.M. and Richard Jr., E.P. 2005. Precision Agriculture Research in Louisiana Sugarcane. Sugar Journal 67(11):6-7. [article printed in English & Spanish].

Review Publications
Johnson, R.M., Richard Jr, E.P. 2005. Precision Agriculture Applications in Louisiana Sugarcane Production Systems. International Society of Sugar Cane Technologists Proceedings. 25:351-356.