Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 2002-2004
2 Fluid Journal Fall 2002 Figure 2. Effect of starter on average corn grain yield from 100 on-farm trials in soils testing excessively high in P and K, 1995-1997. be attained with seed-placed applica- tions or whether side placement with higher rates is needed. Results from field studies have been mixed. In one project (Schulte), starter response to side-placed (2 x 2) starters on high- testing soils was maximized via NPK applications of 10-20-20. In another (Wolkowski and Kelling), 2 x 2 starter placement gave a greater no-till corn yield increase than seed-placed treat- ments. However, Howard and Mullen found no difference in no-till corn response to 2 x 2 or seed-placed applications. Similarly, comparing surface band or dribble treatments with seed or side-placed produced mixed results. Surface band or dribble starter treatments were not as effective as seed or side-placed applications in Illinois, while, by contrast, band or surface dribble treatments in Kansas were similar in yield response to 2 x 2 starters. K IN STARTERS Several reports of response to starter or K additions using various placement methods indicate that some reduced-till systems may have higher than antici- pated needs for K. For example, K deficiencies in ridge-till corn at high soil test levels have been reported in Minnesota and these deficiencies were minimized with deep-banded K addi- tions. Studies in Iowa report corn response to deep-banded K at some no- till sites with high soil K levels. In Wisconsin, corn response to starters on high-testing soils was shown to be more likely at soil test K levels below 140 ppm. Another Wisconsin study reports that conventional-till corn yield reduc- tions due to imposed soil compaction could be partially offset by banded K additions, even at relatively high soil K levels. Collectively, these observations suggest that inclusion of some K in 2 x 2 starters or deep-band applications will increase response to these treatments in some environments, and that this response may be more likely in reduced- till systems. EARLYGROWTH/ GRAINMOISTURE Plant growth responses to starters in reduced-till systems are often observed due to colder soils and slow plant growth rates early in the growing season, especially in northern climates. Many studies have reported accelerated plant growth rates where starters were used compared with no-starter controls. While starters accelerate early plant growth under these conditions, yield increases do not always occur. Another study (Bullock et al.) reported that starter on high-testing soils increased plant growth and development rates, but that this increase in early growth often did not result in a yield increase. Similarly, other researchers have concluded that early plant growth response to starters is not a good predictor of yield benefits from the starter treatments. In addition, several studies have reported lower grain moisture contents at harvest where starters were used. Lower grain moisture can translate into reduced grain drying costs and can be a factor contributing to profitability of starter use. NO-TILLEXCELS In a three-year study we conducted (Bundy and Widen), four planting dates were involved, ranging from late April to late May. Tillages were moldboard plow and no-till. Four starter treatments were applied using 2 x 2 placement. The experimental sites were located at Arlington, Wisconsin, on a Plano silt loam soil with P and K soil tests in the high to optimum range. The previous crop was corn. Results showed that starter increased corn yield in 20 of 24 comparisons with positive responses ranging from 0.6 to 27 bu/A. Starter increased yield at all planting dates in moldboard plow tillage. The largest responses to starter were in no-till at the late planting date. Starter treatments usually increased plant height at the late planting date in no-till. Grain moisture at harvest was usually 148 Yield-bu/A No Starter Starter 144 140 135 132 128 124 120 116 44 (1995) Number of farm trials 31 (1996) 25 (1997)
Fluid Journal 1999-2001
Fluid Journal 2005-2007