Corn Production Using Alternate Furrow Nitrogen Fertilization and Irrigation

Any overwatering associated with surface furrow irrigation can reduce N fertilizer use efficiency. This 3-yr study was conducted to determine whether an irrigation and fertilizer placement system that puts water and N fertilizer in adjacent furrows could improve corn (Zea mays L.) grain yields by improving N fertilizer use efficiency. The effects of irrigation placement, N fertilizer placement, and N quantities on several plant parameters and yield were investigated at Portageville, MO, on a Tiptonville silt loam (fine-silty, mixed, thermic Typic Arguidoll). Corn grain yields were increased in each year of the study by placing irrigation water in every furrow. Placement of N in alternate furrows produced yields equal to every furrow placement in 1991 and 1992, and an 8.4 bu/acre increase in 1993, despite enhanced early season growth from N placement in every furrow. For corn production under southeast Missouri conditions, it appears necessary to improve the irrigation effectiveness of the alternate furrow system before the benefits of alternate furrow fertilization placement can be fully used. Research QuestionThe difficulty of using surface furrow irrigation and not overwatering often leads to reduced N fertilizer use efficiency. Improving N fertilizer use efficiency will lead to higher crop yields, better crop quality, and reduced risk of fertilizer N entering environmentally sensitive niches. This study investigated whether an alternate irrigation and fertilization placement system, which places water and N fertilizer in adjacent furrows, could improve corn grain yields by improving N fertilizer use efficiency. Literature SummarySeveral studies have investigated the use of alternate furrow irrigation or fertilization as a means of cutting production inputs and improving production efficiency. Alternate furrow irrigation placement has the potential to reduce irrigation water requirements by 20 to 50%, but has shown variable yield responses. Similar studies have not shown yield reductions with alternate furrow N fertilizer placement. Study DescriptionThis study was conducted for 3 yr (1991–1993) at Portageville, MO, on a Tiptonville silt loam. Irrigation placement: Every furrow vs. alternate furrows Fertilizer placement: Every furrow (30-in.) vs. alternate furrows (60-in. spacing) N quantities: 0, 60, 120, 180 lb N/acre as urea ammonium nitrate Applied QuestionsWhat was the effect of alternate furrow irrigation on corn grain yields? Alternate furrow irrigated plants experienced moisture stress during anthesis, which in turn limited grain yield. Alternate furrow irrigation led to a 22 (1991), 6 (1992), and 17 (1993) bu/acre decrease in grain yield. Less yield reduction during the second year can be linked to relatively greater amounts of ambient rainfall and cooler temperatures during anthesis. Corn grain yields were increased by 15 bu/acre over the 3 yr when irrigation water was placed in every furrow (Table 1). What was the effect of alternate furrow N fertilization on corn grain yields? In this study, N fertilizer placement in alternate furrows did not adversely affect grain yields, indicating that corn can be produced with alternate furrow fertilization regardless of irrigation effectiveness. Alternate furrow N placement (60-in.) was statistically equal to every furrow N placement (30-in.) in 1991 and 1992, and increased yields signifiantly by 8.4 bu/acre in 1993. The 3-yr averages for every and alternate N fertilizer placement were virtually equal (Table 1). RecommendationBased on this study, we do not recommend producing corn using alternate furrow irrigation under southeast Missouri environmental conditions. Any potential to reduce inputs or improve N use efficiencies cannot be fully used until improvement in irrigation strategies to reduce moisture stress for the alternate furrow system can be understood and developed. In contrast, we can recommend placement of fertilizer N in alternate furrows for corn production. Table 1Effects of irrigation and N fertilizer placement on average corn grain yields, 1991–1993. Irrigation placementN fertilizer placement----------bu/acre----------Every114.0106.2Alternate98.9106.8