Skip to main content
ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #213833
Title: Integrated Effects of Root-Knot Nematode, Fertility and Landscape Features on Cotton Yield Response

Author
item ORTIZ, B - UGA
item Sullivan, Dana
item PERRY, C - UGA
item Davis, Richard
item VELLIDIS, G - UGA

Submitted to: World Cotton Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2007
Publication Date: 9/10/2007
Citation: Ortiz, B.V., Sullivan, D.G., Perry, C., Davis, R.F., Vellidis, G. 2007. Integrated Effects of Root-Knot Nematode, Fertility and Landscape Features on Cotton Yield Response. In: World Cotton Research Conference Proceedings, Lubbock, TX, September 10-14, 2007.

Interpretive Summary: Site-specific management (SSM) of cotton (Gossypium hirsutum L.) fields may reduce yield losses and pest management costs. Effectively implementing SSM requires identification of the factors contributing to yield variability. Several factors may limit potential yield and can interact to exacerbate yield losses; therefore, it is necessary to determine the combined influence of yield limiting and reducing factors on crop growth and yield. The objectives of this study were to evaluate the integrated effects of fertility, soil properties, terrain and disease (cotton root-knot nematode) on yield loss in two cotton fields in southern Georgia during the 2006 growing season. Results from this study indicated that the percentage of sand, measured indirectly by electrical conductivity, was the most yield limiting factor. However, the presence of high population densities of RKN in coarse textured areas exacerbated yield losses due to the combined effects of low water holding capacity and K for nematode infected plants in sandy areas. The results indicated that the need for RKN management not only depends on nematode population density, but also on soil texture and the interaction between soil texture and the nematode. Maps of the probability of risk for yield losses may provide producers with a basis for utilizing SSM as a means to better allocate on-farm resources and maximize profitability.

Technical Abstract: Site-specific management (SSM) of cotton (Gossypium hirsutum L.) fields may reduce yield losses and pest management costs. Effectively implementing SSM requires identification of the factors contributing to yield variability. Several factors may limit potential yield and can interact to exacerbate yield losses; therefore, it is necessary to determine the combined influence of yield limiting and reducing factors on crop growth and yield. The objectives of this study were to: i) use multiple regression analysis to evaluate the relationship between cotton yield, soil physical and chemical properties, and southern root-knot nematode [Meloidogine incognita (Kofoid & White) Chitwood] pressure (population density); ii) integrate the significant variables from the cotton yield regression model into a logistic regression model to predict the probability of cotton yield losses; and iii) utilize the cotton yield loss response model to develop maps depicting different probability levels of yield loss which could be transformed into management zone (MZ) maps. The effects of soil physical properties (apparent soil electrical conductivity - ECa, slope, soil texture, and elevation), soil chemical properties (P, K, Ca, Mg, and soil pH), and disease [southern root-knot nematode (RKN)] on cotton yield were evaluated in two cotton fields in southern Georgia, USA, in 2006. Multiple linear regression and logistic regression were used to develop a site-specific response model of cotton yield and a probabilistic model depicting the factors associated with the risk for cotton yield losses. The models indicated that the percentage of sand in the soil, measured indirectly by ECd, was the most yield limiting factor. However, the presence of aggregated high population densities of RKN in coarse textured areas exacerbated yield losses due to the conjunction of low uptake of water and K by nematode infected plants and the low availability of these resources in sandy areas. The results indicated that the need for RKN management not only depends on nematode population density, but also on soil texture and the interaction between soil texture and the nematode. Maps of probability of risk for yield losses based on ECd identify low and high risk areas for yield losses, thereby providing the producers with a basis for utilizing SSM as a means to better allocate on-farm resources and maximize profitability.