Review: Strategies to increase nitrogen use efficiency of spring barley

Abstract

Anbessa, Y. and Juskiw, P. 2012. Review: Strategies to increase nitrogen use efficiency of spring barley. Can. J. Plant Sci. 92: 617–625. Improvement in nitrogen use efficiency (NUE) is important to reduce input costs and the negative impact of excessive N on the environment. This review found that barley growers in western Canada have over the years adopted a number of improved N management strategies including soil testing and adjusting rate of N fertilization accordingly, switching from fall application to spring application of N fertilizers, and side-dressing placement of N that gives plant roots easier access to N nutrition. However, it is our opinion that use of variable N rates, choice of N fertilizer type that is less susceptible to losses, and improved manure management are some of the areas where further increase in NUE should be sought. As well, barley germplasms show substantial differences in NUE and genetic selection could increase NUE. Genetic improvement of NUE in barley should be possible both by the traditional breeding approach of crossing and pyramiding NUE genes from across different sources as well as through the development of transgenic barley. The integration of improved N management practices and more efficient cultivars may bring about a significant increase in NUE and ultimately grain yield of barley under the target moderate rate of N application.

Effects of Varieties and Nitrogen Fertilizer on Yield and Yield Components of Maize on Farmers Field in Mid Altitude Areas of Western Ethiopia

“…The N accumulation in plants and grains was in agreement with the reports by Zotarelli et al [50]. Grain N yield increased with the rate of N fertilizer and averaged over cultivars, and grain N yield was 94, 126, and 146 kg ha -1 for the low, moderate, and high N regimes [7]. Mean grain N accumulation was ranged from 12 to 17 and 13 to 18 from maize varieties planted with half and full recommended nitrogen fertilizer application.…”

“…Application of half and full recommended nitrogen fertilizer to maize varieties was given higher shoot nitrogen accumulation of 56 and 881% over maize varieties planted without nitrogen fertilizer application. Similarly, Anbessa and Juskiw [7] found that biomass N yield was increased with the rate of N fertilizer. The correlation coefficients between maize productivity and N accumulated in shoots (leaves, corncobs, straws, and stems) were high [48].…”

“…Nonetheless, in cereals, less than half of the applied N is recovered in the grain [6]. The remaining N is incorporated into soil organic matter or lost from farmlands through erosion, surface runoff, leaching, and gaseous (NH 3 , N 2 O, NO, NO 2 , or N 2 ) emissions from 2 International Journal of Agronomy the soil and plants [7]. Freney [8] reported that nitrogen might be lost by ammonia volatilization, during nitrification, by biological denitrification, and by chemodenitrification, leached whenever rainfall exceeds evaporation, and lost by runoff.…”

Nitrogen efficiency of spring barley in long-term experiment

“…The key targets of the NUE research are to increase the proportion of N recovered from the soil (RE N ) and to obtain an enhanced efficiency of utilization of the N taken-up for yield formation (NUtE). Increased N recovery and utilization efficiency may allow growers to maximize yield under a moderate rate of N fertilization instead of the high rate of N fertilization (Anbessa andJuskiw 2012, Bingham et al 2012). If N is applied and not taken up by the crop or immobilized in soil organic N pools, which include both microbial biomass and soil organic matter, is vulnerable to losses from volatilization, denitrification and leaching (Cassman et al 2002).…”

“…If N is applied and not taken up by the crop or immobilized in soil organic N pools, which include both microbial biomass and soil organic matter, is vulnerable to losses from volatilization, denitrification and leaching (Cassman et al 2002). Only 30-50% of applied nitrogen fertilizer is taken up by crops (Dobermann 2005), hence the improvement in NUE is important to reduce input costs and the negative impact of excessive N on the environment (Snyder 2009, Anbessa andJuskiw 2012). Fertilizer N crop recovery efficiency is driven by three main sets of controls: 1. crop N demand; 2.…”