Potassium and Elemental Sulfur as Factors Determining Nitrogen Management Indices of Soil and Faba Bean (<i>Vicia faba</i> L.)

Abstract

Faba bean plays a significant role in nitrogen (N) cycling as they fix atmospheric N2 through biological symbiosis (SNF). It has been assumed that soil potential to supply plants with potassium (K) and sulfur (S) is crucial for plant and soil N management indices. The experimental factors were as follows: variable soil K availability content and fertilization (K1, K2, K3, and K4); and elemental S application (0, 25, and 50 kg S ha−1). K treatments had a positive impact on N accumulation in crop residues and SNF. The application of S increased the amount of N in grain and SNF. The most beneficial influence of S on these indices was registered on K-poor soil. The total N increase in soil (NgainT) was relatively constant across the years and ranged between 106 and 124 kg N ha−1. This parameter depended however, on the K and S treatments. The highest NgainT increase (52–54 kg N ha−1) was obtained in soil of a medium K content (K2, K3), and simultaneously fertilized with S. The results indicated that balanced fertilization with K and S guarantees not only a high grain yield but also improved soil potential to supply N to successive plants.

Keywords

• broad bean
• crop residues
• leaf dry matter
• N input
• N output
• N uptake efficiency