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Fluid Journal : Fluid Journal 1993-1995
2 Fluid Journal Late Spring 1997 Every Furrow Alternate Furrow Grian Yield - bu/A 150 140 130 120 110 100 1991 1992 Crop Production Year Figure 1. Influence of irrigation water placement on corn grain yields, 1991- 1992. Every Furrow, 30" knife spacing Alternate Furrow, 60" knife spacing Grian Yield - bu/A 150 140 130 120 110 100 1991 1992 Crop Production Year Figure 2. Influence of nitrogen fertilizer placement on corn grain yields, 1991- 1992. spacing) may reduce soil disturbance, tractor pulling power and root pruning. A combination alternate fur-row irrigation/fertilization corn or cotton production system may be possible in some environments. In this system, it is hypothesized that plant roots would acquire adequate water from one side and meet N fertilization needs from the other. A synergistic effect might occur with benefits of better N fertilizer use efficiencies, since irrigation water and N would seldom interact. Turning now our attention to Missouri, we'll zero in on what happened during 199 1/1992 at our research sites located at the University of Missouri Delta Research Center near Portageville, Missouri, taking one crop at a time. Corn No treatment interactions affected corn grain yield during the study, indicating that yield responses at this site were not a function of a combination of experimental treatments, but rather each treatment affected corn yield independently. In 199 1, water placement in alternate furrows caused a 22 bu/A reduction, compared to putting water in every furrow (Figure 1). In 1992 a statistically insignificant trend showed higher yields in plots where each furrow received irrigation. This yield reduction caused by water placement could not be attributed to maturity (grain moisture), plant growth or plant N (higher in alternate furrow irrigation water placement/N fertilizer treatments in 1991). Apparently, alternate furrow irrigated corn experienced an undetected water stress at some point during the growing season. This can be partially explained by the lower decrease in corn yield associated with alternate fur-row irrigation in 1992, which had frequent rainfall and relatively lower temperatures when compared to 1991. This moisture stress must be eliminated before the alternate furrow system can be developed. Every furrow and alternate furrow treatments received equal amounts of water per irrigation. Runoff was higher in alternate furrows. A more appropriate approach would have been to apply more frequent irrigations, but less water per irrigation to the alternate furrow corn. Corn ear leaf N concentrations were slightly higher in alternate furrow irrigation in 1991 but were similar across irrigation treatments in 1992. Thus, potentially improved N-use efficiency caused by irrigating only nonfertilized furrows was not positively determined during the first two years of
Fluid Journal 1996-1998