The Effect of Soil Water Availability on the Interaction of Rotylenchulus reniformis and Cotton in Multiple Soil Types

A trial to determine the effect of water availability on the interaction of Rotylenchulus reniformis and early season cotton growth was conducted in 2011. The trial was a 6x3x2 factorial design with six different soils (clay, silt loam, loam, very fine sandy loam, fine sandy loam, sandy loam), three different soil moisture potentials (-0.33 bar, - 1.00 bar, - 3.00 bar), and R. reniformis present or absent.  At 30 days after planting (DAP), each plot was evaluated for R. reniformis density per gram of root and plant growth parameters.  Water availability affected both R. reniformis populations and plant growth; however, the effects were different dependent on soil type. The density of R. reniformis per gram of root was significantly higher (P < 0.10) at – 3 bar in the fine sandy loam soil compared to – 0.33 bar. Conversely, R. reniformis density per gram of root in the sandy loam soil was significantly lower at – 3 bar compared to the other soil moisture potentials. All other soils supported comparable R. reniformis populations at each of the three moisture potentials. Plant growth exhibited a general increase with increasing water availability, and plants free of R. reniformis were, on average, numerically taller and had higher weights compared to those with R. reniformis. Although there were no significant differences in plant growth between nematode present/absent plots, when compared to the nematode free control, all soils presented a general trend of decreasing plant growth with increasing moisture availability in the presence of R. reniformis.