Use of the diagnosis of the nitrogen nutrition of grasses by plant analysis in agricultural advice

摘要

More than 10 years ago, a method for the diagnosis of the nitrogen nutrition level of a plant cover was defined, that was based on the analysis of the plants'nitrogen content. The present paper shows its possible uses when applied to pastures made up of grasses. It can be used for the management of nitrogen fertilization: 1) for short-term steering (instanced by the paddocks of a rotationally grazed field and the splitting of nitrogen dressings on silage pastures) and 2) for the diagnosis of a setof plots having all the same purpose in order to determine the level of fertilization in the year n+l from the results of year n. Another set of applications regards the creation of regional references through a better utilization of field experiments (5very different examples are given) and also through an improved exploitation of the data supplied by agricultural surveys. Lastly, the limits of the method are shown (application to pastures with a high clover content) and the simplifications consideredpossible.