Author
WORTMANN, D - University Of Nebraska | |
Tarkalson, David | |
SHAPIRO, C - University Of Nebraska | |
DOBERMANN, A - International Rice Research Institute | |
FERGUSON, R - University Of Nebraska | |
HERGERT, G - University Of Nebraska | |
WALTERS, D - University Of Nebraska |
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/18/2010 Publication Date: 1/1/2011 Citation: Wortmann, D.D., Tarkalson, D.D., Shapiro, C.A., Dobermann, A., Ferguson, R.B., Hergert, G.W., Walters, D. 2011. Nitrogen Use Efficiency of Irrigated Corn for Three Chopping Systems in Nebraska. Agronomy Journal. 103(1):76-84. Interpretive Summary: Nitrogen use efficiency is of economic and environmental importance. Components of nitrogen use efficiency were evaluated in 32 irrigated corn trials conducted across Nebraska with different nitrogen rates and where the previous crop was either corn, drybean, or soybean. The mean grain yield with adequate nutrient availability was 14.7 Mg per hectare. When no nitrogen was applied, measured soil properties and irrigation water nitrogen accounted for less than 20% of the variation in plant nitrogen uptake. Mean fertilizer nitrogen recovery in above-ground biomass was 74% at the lowest nitrogen rate compared with 40% at the highest nitrogen rate, a mean of 64% at the economically optimal nitrogen rate, and least with corn following drybean. Agronomic efficiency of fertilizer N averaged 29 kg of grain per kg of nitrogen at economically optimal nitrogen rate and was also least with corn following drybean. Partial factor productivity of nitrogen averaged 100 kg of grain per kg of nitrogen at the economically optimal nitrogen rate, and was greater with corn following soybean compared with corn following corn and corn following drybean. After harvest, residual soil nitrate-nitrogen in the 0 to 1.2 m depth ranged from 21 to 121 kg per hectare and increased with nitroten rate. Mean residual soil nitrate-nitrogen was 88, 59, and 59 kg per ha for corn following drybean, corn, and soybean, respectively. High corn yields can be achieved with high nitrogen use efficiency and low residual soil nitrate-nitrogen by management to maximize profitability in consideration of yield potential, and by applying nitrogen at the right amount and time. Technical Abstract: Nitrogen use efficiency (NUE) is of economic and environmental importance. Components of NUE were evaluated in 32 irrigated corn (Zea mays L.) trials conducted across Nebraska with different N rates and where the previous crop was either corn (CC), drybean (Phaseolus vulgaris L.) (CD), or soybean (Glycine max L.) (CS). The mean grain yield with adequate nutrient availability was 14.7 Mg ha–1 . When no N was applied, measured soil properties and irrigation water N accounted for <20% of the variation in plant N uptake (UN). Mean fertilizer N recovery in above-ground biomass was 74% at the lowest N rate compared with 40% at the highest N rate, a mean of 64% at the economically optimal N rate (EONR), and least with CD. Agronomic efficiency of fertilizer N averaged 29 kg grain kg-1 N at EONR and was also least with CD. Partial factor productivity of N averaged 100 kg grain kg-1 N at EONR, and was greater with CS compared with CC and CD. After harvest, residual soil nitrate-N (RSN) in the 0 to 1.2 m depth ranged from 21 to 121 kg ha-1 and increased with N rate. Mean RSN was 88, 59, and 59 kg ha-1 for CD, CC, and CS, respectively. High corn yields can be achieved with high NUE and low RSN by management to maximize profitability in consideration of yield potential, and by applying N at the right amount and time. |