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Fluid Journal : Fluid Journal 2005-2007
18 Fluid Journal WINTER 2007 applied in the furrow with the seed reduced yield by 21 bu/A compared to the no-starter control. This yield reduction was associated with a 30 percent reduction in plant Yield Rate Placement Sources lbs/A lbs N+P2O5+K2O+S/A 0+0+0+0 None None 392 6+20+0+0 Popup APP 636 6+20+6+4 Popup APP + KTS 690 20+20+6+4 2x0 APP+UAN+KTS 502 20+20+6+4 2x2 APP+UAN+KTS 494 20+20+0+4 2x0 APP+UAN+ATS 512 20+20+0+4 2x2 APP+UAN+ATS 524 20+20+6+0 2x0 UAN + 7-21-7 582 20+20+6+0 2X2 UAN + 7-21-7 526 20+20+10+10 2x0 APP+UAN+KTS+ATS 508 20+20+10+10 2x2 APP+UAN+KTS+ATS 592 20+40+10+10 2x0 APP+UAN+KTS+ATS 534 40+40+10+10 2x0 APP+UAN+KTS+ATS 480 Fluid starter treatments Table 1. Dry matter yield of corn plant as influenced by rate, placement, and source of fluid starter, Waseca, 2005. Table 2. Corn grain yield as influenced by rate, placement, and source of fluid starter, Waseca, 2005. Fluid starter treatments Yield Rate Placement Sources bu/A lbsN+P2O5+K2O+S/A 0+0+0+0 None None 166.5 6+20+0+0 Popup APP 170.4 6+20+6+4 Popup APP + KTS 145.1 20+20+6+4 2x0 APP+UAN+KTS 168.3 20+20+6+4 2x2 APP+UAN+KTS 162.0 20+20+0+4 2x0 APP+UAN+ATS 170.2 20+20+0+4 2x2 APP+UAN+ATS 170.7 20+20+6+0 2x0 UAN + 7-21-7 168.6 20+20+6+0 2x2 UAN + 7-21-7 164.5 20+20+10+10 2x0 APP+UAN+KTS+ATS 171.6 20+20+10+10 2x2 APP+UAN+KTS+ATS 166.3 20+40+10+10 2x0 APP+UAN+KTS+ATS 172.3 40+40+10+10 2x0 APP+UAN+KTS+ATS 159.1 population apparently due to K and S (6 and 4 lbs/A, respectively) placed on the seed. Potassium and S rates and placement position (2x0 and 2x2) did not affect grain yield. These results contrasted with the preceding year's data where the same in-furrow application increased yields 17 bu/A and S application produced an additional 12 bu/A. Grain moisture Grain moisture at harvest was not affected by any of the fluid starter NPKS rates or placement positions. Plant population Initial plant population was reduced 30 percent (to 22,600 plants/A) by the 6+20+6+4 popup treatment placed in the seed furrow on top of the seed. None of the other fluid starter treatments affected plant population, which averaged about 33,500 plants/A, indicating no phytotoxicity for the starter rates or placements. Why did the 6+20+6+4 popup treatment reduce plant stand in 2005 but not in 2004? Comparison of soil temperature (2-inch depth) and precipitation data for the two years at the time of planting and in the following 10 days revealed little difference in precipitation (l.5 inches in 2004 and 1.45 inches in 2005) but a large temperature difference. In 2004, soil temperature at the 2-inch depth was 56oF at planting and averaged 65oF in the next 10-day period. In 2005, soil temperature was 48oF at planting and averaged 59oF in the next 10 days. Moreover, the number of days between planting and emergence was 8 days in 2004 and 15 in 2005. The cool temperatures, which delayed emergence by a week, apparently weakened the germination viability, reducing stand significantly and yield response to starter. Conclusions • In this cool spring, when wet conditions prevailed after planting,
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