Abstract
Soil waterlogging resulting from extreme precipitation events creates anaerobic conditions that may inhibit plant growth and increase N losses. A three-year (2013–2015) field experiment was conducted in poorly-drained claypan soils to assess the effects of waterlogging [0 or 7-days waterlogging at V3 growth stage of corn (Zea mays L.)] and pre-plant application of different N fertilizer sources and post-waterlogging rescue N application (0 or 84 kg N ha−1 of urea plus urease inhibitor (NCU + UI) at V7) on chlorophyll SPAD meter (CM) readings, stomatal conductance, ear leaf and silage N concentrations, N uptake and apparent N recovery efficiency (ARE) of two corn hybrids with varying amounts of flood tolerance. Pre-plant N fertilizer sources included a non-treated control (CO), urea (NCU), urea plus nitrification inhibitor (NCU + NI) and polymer coated urea (PCU) applied at 168 kg N ha−1. In 7-days waterlogged plots, rescue N applications increased N uptake in PCU treatments 33% and 40% in 2013 and 2014, respectively, as well as in NCU by 48% in 2013. In 7-days waterlogged plots which received rescue N applications, NCU and PCU in 2013 resulted in higher N uptake than CO and NCU + NI by 47 to 77 kg ha−1. PCU had higher N uptake than NCU and NCU + NI by 78 and 72 kg ha−1 in 7-days waterlogged plots that received rescue N applications in 2014. Corn hybrid showed no differences in N uptake and ARE in our study. Our results indicate combining pre-plant N fertilizer source selection and rescue N applications may be a strategy to reduce possible decreases in corn N uptake caused by early season soil waterlogging in average rainfall years.
Highlights
Crop damage in the United States due to excess precipitation and flooding has caused significant historical crop losses and is projected to increase over the 30 years because of increased incidence of extreme weather events leading to increased crop damage and off-farm loss of soil and nutrients from excess water [1,2,3]
Our results indicate combining pre-plant N fertilizer source selection and rescue N applications may be a strategy to reduce possible decreases in corn N uptake caused by early season soil waterlogging in average rainfall years
Over 4.4 million hectares of crops were damaged during the US Midwest floods in 1993 and increased runoff of nutrients, such as nitrate, which contributed to hypoxia in the Gulf of Mexico [1,4]
Summary
Crop damage in the United States due to excess precipitation and flooding has caused significant historical crop losses and is projected to increase over the 30 years because of increased incidence of extreme weather events leading to increased crop damage and off-farm loss of soil and nutrients from excess water [1,2,3]. Over 4.4 million hectares of crops were damaged during the US Midwest floods in 1993 and increased runoff of nutrients, such as nitrate, which contributed to hypoxia in the Gulf of Mexico [1,4]. Excess soil moisture resulting from extreme weather events is a major contributor to crop production losses [6]. A study conducted by Urban et al (2015) over a Agronomy 2018, 8, 102; doi:10.3390/agronomy8070102 www.mdpi.com/journal/agronomy
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