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? Why 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 United States Department of Agriculture's National Resource Conservation Service (NRCS), 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 United States. Finally, American consumers will benefit by obtaining a dependable supply of high quality domestic sugar.

2.List by year the currently approved milestones (indicators of research progress)
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 released varieties to reduced or no-tillage practices and the effects of these practices on soil chemical and physical properties and prepare report.

4a.List the single most significant research accomplishment during FY 2006.
RUST INCIDENCE AND SEVERITY RELATED TO EXCESS SOIL NUTRIENTS. Brown rust of sugarcane was not considered to be of major importance in Louisiana until 2000 when an epidemic occurred throughout the sugarcane industry. The outbreak and its continued presence are of concern because the most severely affected variety is LCP 85-384, a variety that occupies the majority of the sugarcane acreage in Louisiana. Five sugarcane fields were sectioned into smaller sections (grids). Soil samples were collected and then rust severity was monitored at weekly intervals for a period of six to seven weeks at each grid point to determine if a relation could be found between soil properties and sugarcane rust levels. The soil properties at each location showed significant variability (9 to 70%) over all locations. In addition, soil properties were spatially correlated in 39 of 40 cases and rust ratings were spatially correlated in 32 of 33 cases. In other words, samples that were spaced at a distance less than the range of spatial correlation were more similar than those at distances greater than this range. The range of spatial correlation for soil properties varied from 39 to 201-meters and from 29 to 241-meters for rust ratings. Rust ratings were correlated with several soil properties, most notably soil phosphorus and soil sulfur. Other soil properties correlated with rust occurrence include: soil acidity (pH), potassium, calcium, magnesium, organic matter, and total negative charge. When all locations were combined the best correlations were obtained with soil sulfur and phosphorus levels and soil pH. Taken together, these relations indicate that rust severity increased with soil fertility levels. This also suggests that sugarcane growers that apply fertilizer in excess of plant requirements will increase the incidence and severity of rust infestations in their fields. Results of these experiments support National Program 305-Crop Production, Component I: Integrated Production Systems, Problem B: Integrated Pest Management and Problem C. Sustainable Cropping Systems. These research results also support National Program 303-Plant Disease, Component IV: Biological and cultural strategies for sustainable disease management, Problem 4A: Biological and cultural control technologies.

4b.List other significant research accomplishment(s), if any.
LEAF REFLECTANCE MEASUREMENTS PREDICT SUGARCANE VARIETY, DISEASE PRESENCE AND SUCROSE LEVEL. Louisiana's sugarcane producers and millers have been under increased economic pressure for the past several years. If the industry is to survive, new technologies that maximize productivity and profitability must be identified and adopted. Several tests were initiated in 2005 to ascertain if leaf reflectance measurements at specific wavelengths could be used to determine disease presence, identify varieties, and predict sucrose levels. Leaf samples were collected at several dates from sugarcane yellow leaf disease (SCYLD) and sugarcane mosaic disease test plots before and after the appearance of visual symptoms. Samples exhibiting either mild or severe mosaic symptoms could be correctly identified with leaf reflectance in 75 and 68% of the cases, respectively. Disease-free controls could be identified in 77% of the cases. Leaf reflectance measurements also identified samples infected with sugarcane yellow leaf virus (SCYLV) in 77% of the cases. The SCYLV-infected leaves also had lower levels of most plant pigments compared to non-infected controls. In a second study, leaf samples were collected from plots in a historical sugarcane nursery containing seven generations of varieties selected for sucrose accumulation over a time period of more than eighty years. Reflectance measurements were effective in correctly identifying 80% of the varieties present in the study. In the final test, which involved the sampling of leaves from the Sugarcane Research Unit's 2005 maturity study, leaf reflectance was effective at predicting theoretically recoverable sugar levels in 77% of the cases in the combined data set. The successful development of remote sensing techniques will help growers identify yield limiting crop disease outbreaks at earlier stages so that corrective actions could be taken in a timely and efficient manner. These techniques could also have a potential benefit to varietal development programs by allowing for increased accuracy and efficiency in varietal selection. Finally, growers and mill personnel could potentially use a simple leaf sample taken in the field to develop ripener treatment and harvest schedules that could aid in maximizing sugar yields. Results of these experiments support National Program 305-Crop Production, Component I: Integrated Production Systems, Problem C. Sustainable Cropping Systems. This research results also support National Program 303-Plant Disease, Component I: Disease diagnosis: detection, identification and characterization of plant pathogens, Problem 1A: New diagnostic methods and tools.

GREEN CANE HARVESTING PROCEDURES OPTIMIZED. Operational settings on sugarcane harvesters are extremely important in green-cane harvesting since one is relying solely on the harvester to remove leafy material instead of the traditional pre-harvest burn method. The objective of this research was to determine the effects of harvester ground speed and cleaning fan speed on sugar yield, cane quality, and field losses. Under the optimal conditions of low leaf and soil moisture (dry harvesting conditions), the high fan speed increased sugar content by 10% but decreased cane yield by 15% compared to the two lower fan speeds resulting in similar sugar yields for all fan settings. Under wet conditions (high leaf and soil moisture), this high fan speed decreased cane yield by 13% without an increase in sugar content, resulting in lower sugar yields than the low or medium fan settings. Harvester ground speed, under both conditions, did not affect cane yield or quality. This study demonstrated the operational settings to optimize harvester efficiency under both ideal and poor harvesting conditions. Results of these experiments support National Program 305-Crop Production, Component I: Integrated Production Systems, Problem C. Sustainable Cropping Systems.

4c.List 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 (SRU) 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 project 6435-21000-011-01R, New and Improved Cultural Practices for Sustainable Sugarcane Production and Environmental Protection, and 6435-21000-011-02S, Microbial Decomposition of Post-Harvest Sugarcane Residues as a Replacement for Burning.

5.Describe the major accomplishments to date and their predicted or actual impact.
Precision agriculture techniques were utilized to document the extent of variability present in commercial sugarcane fields in Louisiana. Cane and sugar yields were monitored in 9 to 10 acre fields that had been divided into 0.04 acre quadrants (grids). Cane yields were found to vary from 15 to 60 tons per acre within fields. Sugar yields and theoretically recoverable sucrose (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 is allowing 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. Results of these experiments address National Program 305 - Crop Production, Component I. Integrated Production Systems, Subsection C. Sustainable Cropping Systems.

The occurrences of within field differences in sugarcane yields were recently documented by ARS scientists at the Sugarcane Research Unit. To explore the possibility that some of these differences may be associated with differences in nutrient availability, experiments were conducted to investigate the utility of variable rate (VR) lime application in comparison to a conventional (uniform rate) lime application and no liming. Prior to lime application, soil samples (0-8 in) were taken from each site on a 1-acre grid. A composite soil sample from each field was used to determine the field liming rate, based on current extension recommendations. In all experiments, both conventional and VR applications of lime increased cane and ultimately sugar yields at the end of each production year of a 3-year crop cycle. Differences in cane and sugar yields were obtained in only one experiment and only in the first production year (plant-cane crop). Results suggest that growers utilizing the VR application of lime method can achieve yields that are similar to the conventional uniform method of lime application. If similar yields can be obtained with the VR system, while actually applying fewer inputs, then growers will realize an overall increase in profitability while minimizing any potentially adverse impacts of the crop's culture on the environment. Results of these experiments support National Program 305-Crop Production, Component I: Integrated Production Systems, Problem C. Sustainable Cropping Systems.

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. ARS scientists at the SRU assessed the impact of these residues on yields of sugarcane in the production years following green cane harvesting in field experiments throughout the Louisiana industry. They demonstrated that the presence of the blanket of residue at the start of the subsequent 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 sugarcane below-ground buds in the late-winter to a sufficient extent that yield is adversely effected. Recent results have also demonstrated that sugarcane post-harvest residues possess compounds that adversely affect the germination and growth of sugarcane (autotoxicity) or other plants (allelopathy). These effects may also 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 these fields. Results indicate that the method of removal from the row top is of less importance with essentially equal yields obtained with a variety of mechanical removal techniques. However, in poorly drained fields mechanical placement of leaf litter from the row top into the wheel furrow 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. Results of these experiments support National Program 305-Crop Production, Component I: Integrated Production Systems, Problem C. Sustainable Cropping Systems.

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 Agronomy Workshop in Khon Kaen, Thailand, (attended by over 300 international researchers) (1); American Society of Sugar Cane Technologists Louisiana Division Meeting in Baton Rouge, LA (attended by over 200 growers, researchers, and processors) (2); American Sugarcane League Contact Committee Meeting (1); Louisiana Cooperative Extension Service-sponsored Research Extension planning meetings (2) and spring (January/February) parish grower meetings (4) and summer (July/August) parish field days (3); Louisiana Ag Consultants Association Annual Meeting (2). 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).
Johnson, R.M., Richard Jr., E.P. 2006. Remote sensing in Louisiana sugarcane. Sugar Bulletin. 84:15-16.

Review Publications
Johnson, R.M., Richard Jr, E.P. 2005. A comparison of conventional and variable rate lime application methods in South Louisiana sugarcane fields. In: Proceedings of the International Conference on Precision Agriculture. 7th International Conference on Precision Agriculture, July 25-28, 2004, Minneapolis, Minnesota. 2005 CDROM.