Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 2005-2007
FALL 2006 Fluid Journal 15 liquid P fertilizer is surface applied in the fall of the year. To answer this question, we evaluated the positional and temporal availability of P from surface dribble bands following fall application. Our intent was to improve our understanding of soil P dynamics during the months between application and spring planting. 2004 field trials Three weeks after fluid fertilizer (P2O5 at 50 lbs/A) was applied in the fall of 2003, higher concentrations of bioavailable P were measured at a depth of less than one inch to a depth nearly four inches below the soil surface for the 0+50+0 (ortho-P source) and 17+50+17 (APP source) fluid materials, respectively. Concentrations of bioavailable P were uniformly low in the control plots. Measurements made in the spring of 2004 at 20 weeks after application indicated that higher concentrations of bioavailable P still were present up to five inches below the soil surface for both treatments. Final measurements were made 23 weeks after application just prior to planting the 2004 corn crop. Higher levels of bioavailable P still could be measured in treated plots that received fertilizer, but the P was not concentrated in any position relative to the row. Spatial variability probably played a role in what was measured with the exchange membranes. 2005 field trials Following a surface band application of the two P fluid sources in the fall of 2004, higher concentrations of bioavailable P were measured three weeks after application (Figure 1, top row). Highest concentration of bioavailable P was measured at a depth of more Figure 1. Profile distribution of bioavailable P[(x10-8-8) lb. actual P/inch2] 3 and 19 weeks after surface band application of 0+50+0 (middle column) and 17+50+17 (right column) on the soil surface approximately two inches to the side of the previous soybean row in the fall of 2004.
Fluid Journal 2002-2004
Fluid Journal 2008-2009