Improving Soil Quality to Increase Yield and Reduce Diseases in Organic Rice Production

Project Overview

Project Type: Research and Education
Funds awarded in 2012: $225,000.00
Projected End Date: 12/31/2015
Region: Southern
State: Texas
Principal Investigator:
Fugen Dou
Texas A&M AgriLife Research

Annual Reports


  • Agronomic: rice


  • Crop Production: nutrient cycling, organic fertilizers
  • Education and Training: demonstration, extension, workshop
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: carbon sequestration, wetlands
  • Pest Management: biological control
  • Production Systems: organic agriculture
  • Soil Management: green manures, organic matter, soil analysis, nutrient mineralization
  • Sustainable Communities: local and regional food systems, sustainability measures


    This research was designed to evaluate cover crop, soil amendment, and nitrogen rate on rice yield, milling quality, and disease severity in integrated studies conducted on organic land in Texas and South Carolina, USA. We have completed the field trials of this project to determine the impact of winter cover crops, soil amendments, and rice varieties on organic rice production at Beaumont, TX and Charleston, SC. In Texas, winter cover crops were established for each of the winters between 2012 and 2014. The amounts of dry biomass were 4,525 and 5,152 kg/ha for clover and ryegrass, respectively. The cover crop aboveground yields were comparable for 2013 and 2014 but lower for 2012. Due to poor rice stands, replanting was made in 2014 but in a field without the effect of winter cover crops. Rice variety had a significant effect on all tested aspects of rice production. Tesanai had higher grain yield and 1,000 grain weight than Presidio and XL753. The averaged grain yields over years for Tesanai, XL753, and Presidio were 9,949, 8,614, and 6,505 kg/ha, respectively. Compared to conventional cultivars, the hybrid XL753 had greater spikelets per panicle and filled grain per panicle than Tesanai and Presidio. Although there was a trend for increasing yield with nitrogen application, it was not statistically significant. However, application of soil amendments reduced the severities of narrow brown leaf spot and brown spot on the susceptible variety Presidio compared to the nonamended fertilizer control. Also, the severity of these diseases varied with rice cultivars with the hybrid having the lowest and Presidio having the highest in. No symptoms of straighthead were observed in plots with any treatments. Thus, as seen in previous years, although fertilizer amendments may have some positive impact on yield and disease control, these are not consistent nor likely economically cost effective. Choice of variety is much more important in optimizing yield and minimizing disease damage. Moreover, an economic analysis based on our field results and farmer-survey indicated that production costs are not as much an issue for organic rice as for conventional rice due to use of fewer costly inputs in organic production systems. Profitability does, however, hinge on obtaining a guaranteed monetary premium. In addition, having good control of irrigation resources for weed control is necessary for achieving profitability in organic rice production. In South Carolina, three-year field studies indicated that variety selection played important role in organic rice production. Winter cover crop selection was site specific. The results of this project have been delivered mainly through the field tours and workshops during the field days, through scientific meetings, on-farm demonstration, and published documents.

    Project objectives:

    1. Quantify the combined effects of cover crop, organic soil amendments, and variety selection on rice yield, milling quality, and disease severity with field trials conducted on organic land in conjunction with an established stakeholder research and outreach advisory board.
    2. Determine ecological services (carbon sequestration, nitrogen retention, and water quality) provided by organic rice farming using the proposed integrated practices.
    3. Demonstrate economic viability of integrated organic rice management through the use of enterprise budgets. Provide information to farmers, researchers, county agents, natural resource managers, and regional public officials on the production potential, financial viability, and ecological impacts of organic rice cropping systems.



    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.