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Fluid Journal : Fluid Journal 2002-2004
1 Fluid Journal Winter 2002 Summary: Summary: Summary: Summary: Summary: In 1997 at Plains, Georgia, 10-34-0, and 10-34-0 + 32-0-0 starters significantly increased cotton yields over control. The starter that resulted in the greatest yields at Midville in 1997 was 28-0-0-5S, indicating that starters may be an efficient method of S application. The experiments also indi- cate that response to the most appro- priate cotton starter fertilizer may de- pend on soil type and weather condi- tions at planting and stand establish- ment. Net economic returns were higher than in the untreated checks in 23 of 30 comparisons. The only signifi- cant increases that occurred in this study were when the crop was exposed to cool weather for an extended time immediately after planting. Additional research is needed to properly address this question. The response of cotton to starter fertil- izer has been investigated across much of the eastern half of the U.S. Cotton Belt. Most of these studies investigated the effects of ammonium polyphosphate (APP) starter in relation to planting date, tillage practice, fertil- izer placement or application rate. Due to reduced soil P mineralization, P-containing starters are the reasonable source when planting under cool envi- ronmental conditions. Past research, in fact, has reported increased lint yields Drs. C.W. Bednarz, G.H. Harris, and W.D. Shurley Fluid Starters Bump Cotton Yields Net economic returns were also higher than untreated check in 23 of 30 comparisons. from banded P when cool weather pre- vailed for several weeks after planting. Historical weather records from the Coastal Plain Experiment Station, how- ever, indicate that the average soil tem- perature at 4 inches depth at Tifton, Georgia, for the month of April is 64oF. Application of P-containing starters to counter the effects of depressed soil mineralization at this temperature would be unnecessary. In addition, most soils in South Georgia contain medium to high levels of available P. Thus, APP may not be the ideal starter choice. Finally, other research has re- ported that lack of nutrient-holding capacity in many southeastern U.S soils could result in loss of some preplant applied N to leaching. Starter fertilizer may, therefore, be an environmentally and economically attractive method of preplant N fertilization. Objectives in this study were to deter- mine 1) if cotton grown on Coastal Plain soils in South Georgia would re- spond to different starter fertilizer sources, and 2) if the use of starter fertil- izers would result in an economic gain. Yield In these trials, starters resulted in greater yields in two of the six tests. At Midville in 1997, 28-0-0-5S resulted in a greater yield than the untreated and the 9-0-0-11Ca starter (Figure 1). APP re- sulted in a greater yield than the un- treated check, UAN, and calcium nitrate at Plains in 1997. It is interesting to note that the in- creases in lint yield from starter applica- tions occurred when the crop experi- enced a period of cool weather immedi- ately after planting. Prevailing weather conditions were cool for several weeks following planting at Midville and Plains in 1997. The study revealed no statistical dif- ferences in fiber length or fiber strength between fertilizer treatments and the untreated check (data not shown). Dollar return Quality factors available from the study that influence price were fiber Figure 1. Final seed cotton yield from starter fertilizer tests at Midville, Plains, and Tifton, Georgia, 1997.
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