Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 1993-1995
2 Fluid Journal Fall 1995 Table 2. Root length density means by position and depth, Millins, et al., Auburn University, 1993. Distance from center of row Subsample Depth Decatur SiL Lucedale SCL inches inches --- - - -cm/cm3- ---- - 0 0-6 2.07 1.52 6-12 1.19 1.03 12-18 1.34 0.74 18-24 1.11 0.51 5 0-6 1.84 1.04 6-12 1.25 0.69 12-18 1.58 0.65 18-24 1.03 0.55 10 0-6 1.65 0.77 6-12 1.16 0.73 12-18 1.64 0.64 18-24 1.11 0.54 20 0-6 1.61 0.69 6-12 1.32 0.78 12-18 1.59 0.80 18-24 1.08 0.61 depths, select combinations of injection depths were made. Just prior to leaf shed, whole plants were harvested from each plot, partitioned into parts, dried, and weighed. Each part was analyzed for rubidium and potassium. Four 1.25-inch diameter root cores were taken per plot at positions relating to 0, 5, 10, and 20 inches from the row center. Sub-samples were made by cutting the cores into 6-inch increments from the surface to 24 inches. Decatur silt loam Yield. There were no significant differences between surface and surface to 21-inch applications in the number of boils produced or total dry matter production (Table 1). K uptake. At this site, K uptake in sterns and leaves and total K uptake was maximized by the combination injection of K from the surface to 21 inches (i.e., surface, 3, 9, 15, 21 inches) as shown in Table 1. This treatment effectively fertilized a greater proportion of the soil profile than did the surface applied K. Uptake by leaves and stems in this treatment was significantly greater than the surface and 3-inch injection treatments. Total K uptake from this combination treatment, however, was not significantly different from the surface K treatment. Band applications of K, single injections at various depths, and foliar treatments did not result in higher uptake as compared to the surface K treatment. Rb uptake. Total Rb uptake was affected by placement for all plant parts. RbCl applied at the 3-inch depth yielded highest Rb uptake with a stair-step decrease in Rb uptake with increasing depth of injection. Root length density. First year root length density measurements by position from the center of the row and depth in the soil profile showed no consistent differences among treatments. Since no significant differences existed among treatments, all treatment means were combined for position and depth (Table 2). Lucedale sandy clay loam Yield. The surface to 3-inch and surface to 15-inch combinations produced higher yields than surface alone (Table 1). However, the yield difference was not sufficient to show statistical significance. K uptake. Total K uptake was affected by the rate of applied K. Highest K uptake was achieved with the combination injection treatments. As shown in Table 1, the surface/3-inch combination was followed by the surface/3/9/l 5-inch combination. Surface banding K and injecting the band to a depth of 3 inches resulted in higher total K uptake when compared to surface broadcast alone, but these differences were not statistically significant. Foliar treatments applied in combination with soil applications of K also resulted in higher K uptake as compared to surface treatments, but, again, these differences were not significant. Rb uptake. Rubidium uptake for all plant parts was affected by placement. Total Rb uptake for single injections to 9 inches provided the highest uptake. Root length density. Root length density measurements by position from the center of the row and depth in the soil profile showed no consistent differences among treatments. Since no significant differences existed among treatments, all treatment means were combined for position and depth (Table 2). Dr. Mullins is associate professor; Burmester is agronomist, and Pate is a graduate research assistant at Auburn University.
Fluid Journal 1996-1998