Sulfur partitioning and grain concentration differed from that for nitrogen in malting barley

Abstract

Nutrient uptake per unit grain yield (i.e. the ratio between nutrient uptake and grain yield) is an index of the amount of nutrient available for partitioning to the grain. It can be divided into two components: grain nutrient concentration and nutrient harvest index. The aim of the present study was to analyze and compare the relationships between nutrient uptake per unit grain yield and its components for N and S in malting barley (Hordeum vulgare L.). Fifty field experiments were conducted with treatments that included farmer fertilization rate, +S, +N and + NS. Grain nutrient concentration was positively related to nutrient uptake per unit grain yield for N and S in a curvilinear fashion. However, grain N concentration tended to increase threefold while S concentration doubled as nutrient uptake per unit grain yield increased. Nutrient harvest index showed a constant phase and, after exceeding a certain threshold, a negative association with nutrient uptake per unit grain yield was observed. However, the decrease in S harvest index was far steeper than in N harvest index. Therefore, contrary to what was observed for N, grain S concentration would be hard to modify through sulfur addition, since a high proportion of the absorbed S would be partitioned to the straw.