Cultivar improvement and environmental variability in yield removed nitrogen of spring cereals and rapeseed in northern growing conditions according to a long-term dataset

Abstract

The balance between applied and harvested nitrogen (yield removed nitrogen, YRN %) is a recognized indicator of the risk of N leaching. In this study we monitored the genetic improvements and environmental variability as well as differences among crop species (spring cereals and rapeseed) in YRN in order to characterize changes that have occurred and environmental constraints associated with reducing N leaching into the environment. MTT long-term multi-location field experiments for spring cereals (Hordeum vulgare L., Avena sativa L. and Triticum aestivum L.), turnip rape (Brassica rapa L.), and oilseed rape (B. napus L.) were conducted in 1988-2008, covering each crop's main production regions. Yield (kg ha -1 ) was recorded and grain/seed nitrogen content (N grain , g kg -1 ) analyzed. Total yield N (N yield , kg ha -1 ) was determined and YRN (%) was calculated as a ratio between applied and harvested N. A mixed model was used to separate genetic and environmental effects. Year and location had marked effects on YRN and N yield . Average early and/or late season precipitation was often most advantageous for N yield in cereals, while in dry seasons N uptake is likely restricted and in rainy seasons N leaching is often severe. Elevated temperatures during early and/or late growth phases had more consistent, negative impacts on YRN and/or N yield for all crops, except oilseed rape. In addition to substantial variability caused by the environment, it was evident that genetic improvements in YRN have taken place. Hence, YRN can be improved by cultivar selection and through favouring crops with high YRN such as oat in crop rotations.

One century of Nordic barley breeding: nitrogen use efficiency, agronomic traits and genetic diversity

“…One of the main drivers for the recorded yield improvements of cereals over the last century has been the introduction of external N fertilizer and increases in N application rates (Sylvester-Bradley & Kindred 2009; Beatty et al 2010; Lillemo et al 2010), along with the mechanization of agriculture and changes to crop management practices (Lillemo et al 2010; Peltonen-Sainio et al 2015). In addition, breeding for higher-yielding cultivars has been successful (Peltonen-Sainio & Jauhiainen 2010; Bingham et al 2012), with the improved grain yields being associated with many drastic modifications in plant stand structure, such as reduced straw length, increased grain number and higher harvest index (HI) (Austin et al 1980; Ortiz et al 2002; Bertholdsson & Kolodinska-Brantestam 2009; Bingham et al 2012). These genetic improvements in grain yield have often been accompanied with improved NUE (Sylvester-Bradley & Kindred 2009; Bingham et al 2012), but also with decreased grain protein content (Sylvester-Bradley & Kindred 2009; Bingham et al 2012; Peltonen-Sainio et al 2012).…”

Land Use, Yield and Quality Changes of Minor Field Crops: Is There Superseded Potential to Be Reinvented in Northern Europe?

“…This is not, however, likely with the minor crops such as N-fixing grain legumes, crops like potato with reasonably intensive production and rapeseed. Rapeseed has undergone yield decline without being primarily driven by reduced fertilizer use: it has the lowest yield removed N, and thereby, seemingly low N use efficiency [40], which again may be partly attributable to compacted soils impeding the root penetration of rapeseed [41]. On the other hand, turnip rape has faced major challenges during the 2000s caused by insufficient and even reduced availability and use of chemical control agents while plant protection risks have become more severe [29].…”

Risk of Low Productivity is Dependent on Farm Characteristics: How to Turn Poor Performance into an Advantage

“…However, comprehensive data were available only for spring cereals due to their high cultivation areas. Nonetheless, selecting appropriate cultivars is a means to enhance yields, resilience to weather variability and resource use efficiency [48], and thereby reduce the risks of, e.g., nutrient loads on the environment [49]. In Finland, the life cycle of a cultivar is long because a high share of farm-saved seeds are used for sowing [50] in spite of clear yield increases achievable from the use of certified seeds [51] and switching to cultivars with a higher yield potential [50].…”