Nitrogen Use Efficiency Analysis from Soil Fertility, Breeding and Physiology Perspectives.

A heightened awareness of nitrate contamination of surface and ground water in the 1970’s prompted Drs. Robert Moll, Eugene Kamprath and William Jackson (MKJ) to form a research team to improve N use efficiency in corn. Their interdisciplinary approach to tackle the problem from breeding, fertility and plant nutritional respective perspectives was unique for that era. Their collaboration was founded on mutual respect and friendship. In 1982 MKJ published a seminal article on component analysis of N use efficiency, with >4900 downloads (Agronomy Journal) and 1225 citations (google scholar). The approach has since been expanded and still used today. There are numerous definitions of N use efficiency, each with its merits. The uniqueness of the MKJ approach is its ability to mathematically divide NUE into component parts that reflect contributions of plant and soil processes. Today, managing N fertilizers for minimizing greenhouse gas emissions is an added research goal for improving cropping system NUE. We will review this approach and its implications for breeding efficient cultivars, evaluating N management practices and making N recommendations, and discerning influential plant physiological NUE processes.